The isodensity maps of normal retina showed that the density decreased with age as the retinal size increased. In contrast to previous studies, we did not find any specific region with increased RGC density, rather the Brn3a+ RGCs were homogeneously distributed over the central retina with decreasing density in the periphery and in the region of the pecten oculli. Injection of 5–10 μg NMDA caused 30–50% loss of Brn3a+ cells and the loss was more severe in the dorsal than in the ventral retina. Pretreatment with brimonidine reduced the loss of Brn3a+ cells both 7 and 14 days post lesion and the protective effect was higher in the dorsal than in the ventral retina. We conclude that α2-adrenergic receptor stimulation reduced the impact of the excitotoxic injury in chicken similarly to what has been shown in mammals. Furthermore, the data show that the RGCs are evenly distributed over in the retina, which challenges previous results that indicate the presence of specific high RGC-density regions of the chicken retina.We have studied the effect of α2-adrenergic receptor stimulation on the total excitotoxically injured chicken retinal ganglion cell population. N-methyl-D-aspartate (NMDA) was intraocularly injected at embryonic day 18 and Brn3a positive retinal ganglion cells (Brn3a+ RGCs) were counted in flat-mounted retinas using automated routines. The number and distribution of the Brn3a+ RGCs were analyzed in series of normal retinas from embryonic day 8 to post-hatch day 11 retinas and in retinas 7 or 14 days post NMDA lesion. The total number of Brn3a+ RGCs in the post-hatch retina was approximately 1.9x10 Excitotoxic injury has been used extensively to study cell death and proliferation in the retina. Treatment of the developing chicken retina with excitotoxins like N-methyl-D-aspartate (NMDA) induces cell type-, developmental stage- and regional-specific injuries –4. The eWe have used an automated method based on flat-mounted whole retina and immunostaining for the RGC-specific transcription factor Brn3a to study the total RGC population. Cells with immunoreactivity (IR) for Brn3a (Brn3a+ RGCs) were counted and isodensity maps were generated to visualize the topographical distribution of Brn3a+ RGCs. This method has successfully been used in mammalian species to analyze the RGC population after injury –25. Brn3The main objective of this work was to study the effects of brimonidine on the survival of injured chicken RGCs. An excitotoxic lesion was inflicted and the total population of RGCs was studied by automated counting of Brn3a+ RGCs in flat-mount retinas. A side-result from the flat-mount analysis showed the topographical distribution of the total RGC population in the chicken retina. We tested the effect of a single bolus intravitreal injection of brimonidine one hour before the lesion at E18 in the late chicken embryo and counted the RGCs 7 or 14 days later. The age was selected because we have previously seen that brimonidine and NMDA give a robust retinal response at that age with activation of Müller cell gliosis. In order to study if the RGC population changes during the experimental period, a series of normal chicken retina from E8 to post-hatch day 11 (P11) was analyzed. The result showed that pretreatment with brimonidine significantly reduced RGC loss as seen both 7 and 14 days post lesion (dpl). The excitotoxic lesion was more severe in the dorsal than in the ventral retina. A similar regional difference was also seen in the effect of brimonidine on RGC survival.ad libitum and kept under standard conditions according to the legislation of the Swedish board of agriculture. Animal experiments were performed according to the guidelines given by the Association for Research in Vision and Ophthalmology and were scrutinized and approved by the local animal ethics committee: Uppsala försöksdjursetisk nämnd.Fertilized White Leghorn eggs from a local breed were obtained from OVA Produktion AB  and incubated at 38°C in a humidified incubator . After hatching, chicks were marked with a numbered plastic ring in the leg and moved to a poultry farm at the National Veterinarian Institute, Uppsala, Sweden. The chicken were fed Animals were divided in the following experimental groups:The normality of Brn3a+ RGCs in control chicken retinas was analyzed in flat-mounts retinas of: E8, E9, E10, E12, E14, E18, E20; and post-natal days (P): P4 and P11 (n = 4/group).To determine the dose of NMDA , a pilot experiment was carried out. A single intraocular injection of 10 μl was made in E18 chick embryos, with three different doses of NMDA, 10, 50 and 100 μg (n = 3/group). Eggs were opened at the blunt end and a small hole was made in the eggshell and chorioallantoic membranes. The head was pulled with a bent glass rod and intraocular injection was done through the amniotic membranes in the right eye with a Hamilton syringe with a 27-gauge needle equipped with a rubber stop to position the tip of the needle in the center of the eye. After the injection, the egg was closed with a porous adhesive tape and kept in the incubator. Retinas were analyzed as cross-sections at time-points: 7 days (10 and 50 μg NMDA) and 14 days post-lesion (dpl) . The number of Brn3a+ RGCs in the GCL of 3 sections per retina were counted (n = 3 retinas per group). The result showed that 10μg NMDA gave a clear lesion and we therefore choose 5 and 10 μg NMDA for the main experiment.Brimonidine intravitreally pretreated  NMDA-injured (5 or 10 μg NMDA in 10 μl) retinas were analyzed as flat-mounts at 7 and 14 dpl (n = 4/group). Pretreatment was one hour before NMDA injection. A saline-only-treatment group with two saline injections, one hour apart, was control for injection effect. All treatment groups were analyzed as flat-mounts at 7 and 14 dpl as well (n = 4 retinas/group).+ and Ca2+ free PBS to facilitate the detachment of the vitreous body from the retina. First, the cornea was removed with scissors. Both limbus and iris were separated with forceps, and the sclera was separated from the choroid by making radial cuts from the anterior to the posterior pole. With the sclera only attached to the pecten oculli, the retina could be cut loose in one piece. The lens was removed and the retina was dissected following the protocol previously described in rats and mice [Both chick embryos and post-natal chickens were decapitated and eyes were enucleated and fixed in 4% paraformaldehyde (PFA) for 1 hour and kept in 0.1 M phosphate buffer saline (PBS) at 4°C. For flat-mount dissection, eyes were covered with cold Mg2and mice , 36. BriFor cross-sectioned retinas, the cornea was removed, the eye cup was incubated in 30% sucrose for 24 hours at 4°C. Eye cups were then embedded in Neg-50TM (Thermo Scientific) and kept at -70°C until cryo-sectioning. Retinal sections parallel to the center of the lens and through the optic nerve head were collected and frozen at -20°C.Brn3a whole-mount immunohistochemistry was carried out following the protocol used for rat and mouse retinas , 25. BriAntibodies:Mouse Anti-Brn3a Rabbit anti-rhodopsin Donkey anti-mouse Alexa Fluor 488 IgG (H+L)  andDonkey anti-rabbit Alexa Fluor 568 IgG (H+L) Brn3a IR fluorescence was captured focusing on the GCL at 10x magnification with a fluorescence microscope  using Alexa Fluor 488 channel and an exposure time of 1000 ms for each frame. The image capture was in tile acquisition mode with an overlap of 5% between frames. The resulting image reconstruction was exporting as .tiff file for further analysis. Because of the big size of our samples, the image reconstruction of each retina was carried out in four parts, following the four quadrants of each retina .s nuclei. Finally, data of each count were displayed and exported to a spreadsheet where they were filed and saved for further analysis. The total number of Brn3a+RGCs was obtained as the sum of the four quadrants of each retina.Every quadrant of the retina was analyzed separately. The automated Brn3a+ cell counting routines for Image-Pro Plus  for rat , 40, 41 The Brn3a staining and automatic counting was validated by manual counting. Evenly distributed sample images  from the GCL were selected from an E18 flat-mount retina. Brn3a+ and DAPI+ nuclei were counted to determine the fraction of Brn3a cells to DAPI+ cells in the GCL and cell density.2, and demonstrated with isodensity maps constructed as previously described [Detailed spatial distribution of Brn3a+ RGCs over the entire retinas was obtained through quadrant analysis with areas of study of 0.0073 mmescribed , 36, 43.Retinal area was measured by manually drawing the retinal contour on each quadrant using IPP software, total area of each retina was obtained as the sum of the four quadrants measurements.® for Windows™ Version 3.11; Systat Software, Inc., Richmond, CA).To compare values from different quadrants of the retina and also to compare retinas from different groups, we used the ANOVA test and Tukey posthoc test . Micrographs from the center and periphery of E10, E14, P4 and P11 flat-mounted retina are shown in The number of Brn3a+ RGC in retinas from E8 to P11 is plotted per quadrant , per halPrevious studies have used high dose of NMDA (>100 μg NMDA) in order to induce total cell loss or to inflict a robust glial injury-response , 19. In in ovo. The study had five groups that were compared to the normal control retina. One control group received two intraocular injections of saline. The experimental groups either received injections of saline followed by injections of 5 or 10 μg NMDA or injections with brimonidine followed by 5 or 10 μg NMDA. The groups were taken 7 or 14 dpl (at P4 and P11) and analyzed by automatic cell counting of flat-mount retina stained for Brn3a. The cell counts were plotted in bar graphs as percent of the number of RGCs in normal control retina, which was denoted 100% , indicating that the double intraocular injections alone did not produce any Brn3a+ RGC loss . We found consistently in total 1.7–2.0x106 Brn3a+ cells in the E12 to P11 retina  using the flat-mount retina and automated counting method. We did not see any increase or decrease in the total number of Brn3a+ cells after E12. Previous RGC number estimations report higher numbers in the embryonic retina than after hatching [3±2.8x103 cells/mm2 compared to 10.1x103±1,2 x103 cells/mm2 when automatically counted. The difference is 9.2% and may indicate that the automated cell counting underestimates the cell number and density. However, the sample areas were not from the peripheral rim of the retina or pecten, which has a lower RGC density. The automatic counting included these regions.Rager and Rager  estimatehatching . A consthatching . The methatching . AssuminThe manual counting showed that 72% of all DAPI-stained nuclei in the GCL of E18 chicken retina were Brn3a positive, indicating that 28% of the cells in the GCL were most likely Brn3a negative RGC or displaced amacrine cells. This fraction is similar to previous data on displaced amacrine cells that accounted for 20–30% of the cells in the GCL , 54.6 Brn3a+ RGCs and a density of 9.3x103 cells/mm2 in the post-hatch chicken retina. Previous studies report 4,5x106 cells with the average density of 10.0x103 cells/mm2. This discrepancy may be explained because Chen and co-workers described regions with increased RGC density [Our data give an average number of 1.8x10 density  while th density . Our datIn conclusion, the automated Brn3a+ RGC counting method, developed for the rodent retina , was useS1 Fig(PDF)Click here for additional data file.S2 Fig(PDF)Click here for additional data file.S1 Table(PDF)Click here for additional data file.


Theonella sp. and were long suspected to be produced by symbiotic bacteria. Misakinolide, a structural variant of swinholide, was recently demonstrated to be the product of a symbiotic heterotrophic proteobacterium. Here, we report the production of swinholide A by an axenic strain of the terrestrial cyanobacterium Nostoc sp. strain UHCC 0450. We located the 85-kb trans-AT polyketide synthase (PKS) swinholide biosynthesis gene cluster from a draft genome of Nostoc sp. UHCC 0450. The swinholide and misakinolide biosynthesis gene clusters share an almost identical order of catalytic domains, with 85% nucleotide sequence identity, and they group together in phylogenetic analysis. Our results resolve speculation around the true producer of swinholides and demonstrate that bacteria belonging to two distantly related phyla both produce structural variants of the same natural product. In addition, we described a biosynthesis cluster from Anabaena sp. strain UHCC 0451 for the synthesis of the cytotoxic and antifungal scytophycin. All of these biosynthesis gene clusters were closely related to each other and created a group of cytotoxic macrolide compounds produced by trans-AT PKSs of cyanobacteria and proteobacteria.Swinholides are 42-carbon ring polyketides with a 2-fold axis of symmetry. They are potent cytotoxins that disrupt the actin cytoskeleton. Swinholides were discovered from the marine sponge IMPORTANCE Many of the drugs in use today originate from natural products. New candidate compounds for drug development are needed due to increased drug resistance. An increased knowledge of the biosynthesis of bioactive compounds can be used to aid chemical synthesis to produce novel drugs. Here, we show that a terrestrial axenic culture of Nostoc cyanobacterium produces swinholides, which have been previously found only from marine sponge or samples related to them. Swinholides are polyketides with a 2-fold axis of symmetry, and they are potent cytotoxins that disrupt the actin cytoskeleton. We describe the biosynthesis gene clusters of swinholide from Nostoc cyanobacteria, as well as the related cytotoxic and antifungal scytophycin from Anabaena cyanobacteria, and we study the evolution of their trans-AT polyketide synthases. Interestingly, swinholide is closely related to misakinolide produced by a symbiotic heterotrophic proteobacterium, demonstrating that bacteria belonging to two distantly related phyla and different habitats can produce similar natural products. Each module of the cis-AT PKSs encodes a dedicated AT domain, while the trans-AT PKSs have discrete ATs that are used iteratively in place of the cis-encoded AT domains  and Anabaena sp. strain UHCC 0451 (previously HAN 21/1) in plate diffusion assays (Anabaena sp. UHCC 0451 was identified as 7-OMe-scytophycin-B (Nostoc sp. UHCC 0450 was identified as a swinholide. Ultraperformance liquid chromatography–high-resolution mass spectrometry (UPLC-HRMS) results showed that the methanol extract of Nostoc sp. UHCC 0450 contained a compound whose retention time, protonated mass , and fragmentation were practically identical to those of commercial swinholide A . The other swinholide variants with an identical elemental composition were ruled out by NMR analysis (Table S1). Minor swinholide variants recognized by their similar product ion spectra of the sodiated molecules with swinholide A constituted less than 20% of the total amount of swinholides produced by Nostoc sp. UHCC 0450 . The minor swinholide variants produced by Nostoc sp. UHCC 0450 vary most probably in the methyl/methoxy and hydroxyl/epoxy groups  was located on a single scaffold by BLASTp searches against the recently published misakinolide biosynthesis gene cluster genes due to the close structural resemblance of these molecules , tolytoxin (tto), luminaolide (lum), nosperin (nsp), and phormidolide (phm) clusters , including a standalone AT enzyme (SwiG), which is a hallmark of -AT PKSs . The swiclusters , 25, 26.clusters . The ordclusters . In the H– units  and 5.trans-AT PKS. There are four nonelongating ketosynthases (KS0s) in the swinholide cluster which do not contribute to the lengthening of the polyketide chain. Three of these KS0s are combined with modification enzymes, and the last one is in the terminal part of SwiF. We observed only a minor difference in the organization of catalytic domains in the enzymes encoded by the misakinolide and swinholide biosynthesis gene clusters. There were two acyl carrier proteins (ACPs) in the middle of the SwiC protein, instead of a single ACP as in the corresponding MisC protein  in the SwiF protein were located side by side . The saminholide .The sequence identities of the core genes of the swinholide and misakinolide biosynthesis gene clusters varied from 73 to 85% despite the pronounced structural similarities between the swinholides and misakinolides (Table S3A). In addition, the scytophycin, tolytoxin, and luminaolide biosynthesis cluster genes also shared a high sequence identity to misakinolide and swinholide genes (Table S4). However, SwiC and MisC proteins differ substantially from counterparts of the other mentioned biosynthesis gene clusters, which is explained by their difference in chemical structures  and 5.Anabaena sp. UHCC 0451 in order to identify the scytophycin biosynthesis gene cluster and to increase the amount of trans-AT biosynthesis gene clusters described. The assembled draft genome was 5.74 Mb, with 77 scaffolds. The scytophycin biosynthesis gene cluster could be identified using the newly discovered tolytoxin (tto) gene cluster from Scytonema sp. strain PCC 10023  from Anabaena sp. UHCC 0451 is almost identical to tolytoxin biosynthesis gene cluster (tto) from Scytonema sp. PCC 10023 (scpC to spcF), in addition to an AT-coding gene (scpA). The order of these genes is identical to that of the tolytoxin genes. The scp genes had 76 to 81% similarity (identity) to tolytoxin genes on BLASTp searches (Table S3B). The domains in the tto and scp genes were the same, apart from scpE having an extra acyl carrier protein in the middle of the gene, a tandem-ACP. In addition, the surroundings of the main biosynthesis genes in tto and scp resembled each other. Similar matches, for instance, small additional genes ttoB (methyltransferase) and ttoG (cytochrome P450), were found from the Anabaena sp. UHCC 0451 sequence (scpB and scpG).We obtained a draft genome sequence also from CC 10023  (23). Thtrans-encoded AT proteins showed that all six biosynthesis gene clusters were close together and formed their own well-supported group  event in any of the swinholide modules (Table S5). Given the structural similarity between the swinholide and misakinolide, a codon usage analysis was performed between the “Candidatus Entotheonella” sp. strain TSWA-1 genome and the swinholide cluster. The χ2 test using the raw (P < 2.2E−16) and the normalized (P < 2.2E−16) comparisons indicates that the swinholide gene cluster is also dissimilar from the “Candidatus Entotheonella” sp. TSWA-1 codon usage. Therefore, the results imply that the structural and activity similarities observed from swinholide and misakinolide, if explained by HGT, originate from a third source and not from direct HGT between these two species. Concordantly the codon usage analysis from the misakinolide gene cluster showed differences from the “Candidatus Entotheonella” sp. TSWA-1 using either the raw or normalized comparison. HGTector analysis reported evidence for a HGT event from Oscillatoriales for the misE and misG genes (Table S5). This suggests that this taxon is the best candidate donor group given the similarities between the swinholide and misakinolide. Nevertheless, the HGTector did not provide evidence that Oscillatoriales is the source of any of the modules of swinholide.The χscpC from an Actinomycetales bacterium, scpD from a Thiotrichales bacterium, and scpF from a Burkholderiales bacterium (Table S5). In luminaolide, an HGT event was detected from a Flavobacteriales bacterium for lumJ module (Table S5). An HGT event, from the module ttoD from a Thiotrichales donor, was detected for tolytoxin 1 (Table S5). In contrast, HGT events for tolytoxin 2 were reported from a Burkholderiales donor for the module tto2D and from a Sphingomonadales donor for the module tto2F (Table S5). Overall, the results show evidence of HGT events in several PKS modules and therefore highlight important events in the evolution of these gene clusters.The results from HGTector indicate the occurrence of HGT events that affect the scytophycin genes: Nostoc sp. UHCC 0450. Almost all swinholides found to date have been extracted from marine sponge Theonella sp. samples (Table S1), including the first report of swinholide A from Theonella sp.  culture of the lichen cyanobacterium ella sp. , 12. Howella sp. , 18, 21.swinhoei . Here, wNostoc sp. UHCC 0450 was isolated from lichen. Nostoc cyanobacteria are known from freshwater and soil and are commonly found in lichen symbioses  was isolated from a Finnish lichen sample and purified until an axenic culture was obtained. Anabaena sp. UHCC 0451 (previously named Anabaena sp. HAN21/1) was isolated from a gastropod collected from the Finnish Baltic Sea coast  analyses. Commercial swinholide A, isolated from Theonella swinhoei, was used as a reference compound .Fifty milligrams of freeze-dried cells was extracted with 1 ml of MeOH by homogenizing with FastPrep  at 6.5 ms8 (2) column , which was eluted from 5% isopropanol  to 100% of B in 35 min at 40°C, with a flow rate of 0.15 ml · min−1. Solvent A was 0.1% HCOOH. Mass spectral data were accumulated in the Ultra Scan positive electrospray ionization mode , with a scan range of m/z 50 to 2,200 and by averaging four spectra.Methanol extracts were first analyzed with high-performance liquid chromatography–electrospray ionization–low-resolution ion trap mass spectrometry . A 10-μl sample was injected to Luna C18+ column , which was eluted at 40°C, with a flow rate of 0.3 ml · min−1, from 50% acetonitrile-isopropanol  to 80% of B in 6 min, to 100% of B in 0.01 min, held for 1.99 min, back to 50% of B in 0.5 min, and finally held for 2.5 min before next run. Solvent A was 0.1% HCOOH. QTOF was calibrated with sodium formate, giving a calibrated mass range from m/z 91.000 to 1,921.390. Leucine enkephalin was used as a lock mass reference compound. Mass spectral data were accumulated in positive electrospray ionization resolution mode at a scan range of m/z 50 to 2,000. Product ion spectra were produced with the MSE technique, which is similar to tandem MS (MS/MS) but without precursor selection.High-resolution UPLC-quadrupole time of flight (UPLC-QTOF) analyses were performed with the Acquity I-Class UPLC Synapt G2-Si HDMS  system. A 1-μl sample was injected to Cortecs UPLC Cg for 10 min, and the supernatant was removed with a stream of air. The dry residue was suspended in 10 ml of 70% aqueous acetonitrile with 0.1% HCOOH. The solution was centrifuged at 20,000 × g for 5 min, and the supernatant was injected into a Luna C8 column  in batches of 1 ml. The column was eluted isocratically with 70% aqueous acetonitrile (ACN) with 0.1% HCOOH at speed of 3.5 ml · min−1 at 30°C. The column was washed with 85% aqueous ACN between injections. The pooled fractions were injected into a Zorbax SB-C column  in batches of 100 μl because of insufficient purity of the collected material. The column was eluted with 70% aqueous ACN with 0.1% HCOOH at a speed of 1 ml · min−1 at 30°C. The collected fractions were pooled and dried, and the final yield of swinholide A was 0.9 mg.One gram of freeze-dried cells was extracted with 2 × 45 ml of methanol for 1 min using a SilentCrusher M homogenizer . The sample was centrifuged at 8,000 × 6 (DMSO-d6) and CD3OD for NMR data collection and structural characterization of swinholide A. All NMR spectra were measured using a Varian INOVA 800 MHz NMR spectrometer, equipped with cryogenically cooled 1H, 13C, 15N triple resonance probe head and z-axis pulsed-field gradient unit. All spectra were measured at 25°C. A one-dimensional 1H spectrum as well as two-dimensional 1H, 13C heteronuclear single quantum coherence (HSQC) and 1H, 13C heteronuclear multiple bond correlation (HMBC) spectra were collected for resonance identification and assignment. For data collection in DMSO-d6 (CD3OD), 1H spectrum was accumulated with 8 (16) transients per free induction decay (FID) using 24,038  complex points, corresponding to acquisition time of 2 (2) seconds. 1H, 13C HSQC spectra were collected with 180 (512) increments at t1 and 426 (768) complex points at t2, corresponding to acquisition times of 6 (21) ms and 85.2 (128) ms in 13C and 1H dimensions, respectively. For signal accumulation, 64 (32) transients per FID were used. For 1H, 13C HMBC data, 512 (512) t1 increments and 1,700  complex points at t2 were collected, using 72 (256) transients per FID. This translated to acquisition times of 7.1 (7.1) ms and 340 (341.3) ms in 13C and 1H dimensions, respectively. The value for the low-pass filter in the 1H, 13C HMBC experiment was set to 8 Hz.Two samples were prepared and dissolved in dimethyl sulfoxide-dNostoc sp. UHCC 0450 was extracted using bead beating combined with the cetyltrimethylammonium bromide (CTAB) method , and the pellets were divided into Eppendorf tubes. The tubes were kept at −80°C overnight. Two different-size glass beads  and 800 μl of lysis buffer  were added to the tubes. The cells were disrupted mechanically with a FastPrep-24 homogenizer  at 5 m · s−1 for 30 s. The tubes were placed on ice for 5 min and centrifuged for 1 min at 15,000 × g. The supernatant was moved to 10-ml tubes. The mechanical disruption was conducted again for the pellets with 400 μl of lysis buffer. Two hundred twenty-five microliters of 5 M NaCl and 170 μl of 10% CTAB in 0.7 M NaCl were added into each 500 ml of sample, as previously described  method . Approxiescribed . The susarlier 4244.The purity of DNA extracts was checked using a NanoDrop 1000 spectrophotometer (Thermo Scientific) to measure the concentration and an Agilent TapeStation (Agilent Technologies) to assess the quality. High-molecular-weight DNA was subjected to library (Illumina TruSeq PCR-free 350 bp) construction and sequenced by the Illumina HiSeq 2500 platform, with a paired-end 100-cycle run (Macrogen). The raw data were first checked by Spades (version 3.7.1) for error correction and then assembled using Newbler (version 3.0). The results of the assembly were examined in Artemis , and gene clusters were identified using BLASTp searches of the National Center for Biotechnology Information (NCBI) and InterPro scans . Sequencswi) biosynthesis cluster were confirmed by comparing these to corresponding normal domains from swinholide and misakinolide biosynthesis gene clusters with ClustalW multiple alignment in BioEdit (version 7.0.5.3) (0s) were confirmed with the observation of a conserved HGTGT motive which KS0s lack  . For ins.3 . For S0s lack .Sequences were aligned using ClustalW and manually improved and trimmed using BioEdit (version 7.0.5.3) . Phyloge2 test was conducted by using the chisq.test function implemented in R (version 3.3.0) to evaluate the codon usage in the genome and compared with the codon usage observed in the PKS modules separately.To detect the presence of HGT, we used two different approaches previously suggested to be clear-cut and reliable , 49. Firhttps://www.ncbi.nlm.nih.gov/GenBank/) with accession numbers KY767987 and KY767986.The sequences of the swinholide and scytophycin biosynthesis gene clusters are available at NCBI (


This paper presents a variant of multiscale quantum harmonic oscillator algorithm for multimodal optimization named MQHOA-MMO. MQHOA-MMO has only two main iterative processes: quantum harmonic oscillator process and multiscale process. In the two iterations, MQHOA-MMO only does one thing: sampling according to the wave function at different scales. A set of benchmark test functions including some challenging functions are used to test the performance of MQHOA-MMO. Experimental results demonstrate good performance of MQHOA-MMO in solving multimodal function optimization problems. For the 12 test functions, all of the global peaks can be found without being trapped in a local optimum, and MQHOA-MMO converges within 10 iterations. Many real-world optimization problems are multimodal optimization problems, such as classification problems in machine learning  and inveDue to the population-based approach, EAs have natural advantage over classical optimization techniques. EAs maintain a population of candidate solutions, which are processed in every generation. If several distinct solutions can be preserved over all these generations, we will get multiple good solutions, rather than the only best solution. In recent years, there are several attempts to improve EAs so as to deal with multimodal fitness landscapes. Niching methods are widely used in genetic algorithms (GA), differential evolution (DE), and other evolutionary algorithms for multimodal optimization , 3–16.ψ . Calculate the standard deviation σ for all xi.Randomly generate xi, generate xiq  , which are following probability distribution N.For each xibest from all xiq   for each xi.Choose the optimal position xi, xi = xibest. Calculate the standard deviation σk for all new xi.For each σ = |σk − σ|.Calculate Δσ and σs. If Δσ > σs, return to step (3). If Δσ < σs, σs = σs/2.Compare Δσmin and σs. If σs > σmin, return to step (3). If σs < σmin, return xbest′, fbest.Compare The elaborate interpretation of the framework of MQHOA-MMO is as follows:k and m) need to be set. The selection of k is discussed in According to the framework above, only two parameters ). Where i is dimension, j is the number of Gauss sampling areas. For every dimension, MQHOA-MMO calculates the value of σk and Δσ. The QHO process at scale σs will end until Δσ ≤ σs in every dimension.For high dimensional test functions, MQHOA-MMO can use two-dimensional array In this section, we give a brief description of benchmark functions and comparison algorithms. Experimental setup is present at the end of this section.The benchmark functions we choose are widely used in multimodal optimization. Some test functions have various characteristics, such as irregular landscape, symmetric or equal distribution of optima. The goals are thus to evaluate the ability to tackle a complicated problem, to validate its capacity to detect all the global peaks of a function. A brief description of the functions is listed in σ-GSO [σ-group search optimizers;  AL1 (IWO-σ-GSO ): the va  AL2 (scma ): CAM-ES  AL3 (cde ): the or  AL4 (sde ): specia  AL5 (ferpso ): fitnes  AL6 (spso ): specia  AL7 (r2pso ): a lbes  AL8 (r3pso ): a lbes  AL9 (r2psolhc): the same as r2pso , but wit  AL10 (r3psolhc): the same as r3pso , but witTo evaluate the performance of MQHAO-MMO, MQHAO-MMO is compared with the following standard multimodal evolutionary algorithms. MQHOA-MMO is marked as AL0.ε, the peak is considered to be found. The performance of all multimodal algorithms is measured in terms of the following two criteria:Success rate: The percentage of runs in which an algorithm can detect all the global peaks.Average peak number: Peak number found over 30 runs for each function.MQHOA-MMO is coded in Matlab R2014 and the simulations are run on i5 CPU 2.9 GHz with 8 GB memory. Results are averaged over 30 independent runs. If the difference between a computed solution and a known global optimum is less than σs < σmin or the maximum number of function evaluation was exhausted.The experimental studies and analyses are presented in this section. MQHOA-MMO had been run until In this section, we examine the effectiveness and efficiency of MQHOA-MMO by applying it to selected four benchmark functions: Six-Hump Camel Back Function (E1-F4), Himmelblaus's Function (E1-F3), Hansen Function (E1-F8) and 2D Inverted Shubert Function (E1-F18). The numbers of solution individuals are 2, 4, 9, and 18, respectively.k and m. We choose different initial parameter k to test the impact on the ability of finding global optima. We run over 30 times for each k while m = 200. k and the number of global optima which MQHOA-MMO can find. The initial k value begins at 5 and increases by 5 each time. According to Figures k is smaller than the number of global optima, MQHOA-MMO can only find part of global optima. With the increasing of k, we can find most global optima when the initial k is close to the number of global optima. When the number of optimal solutions is small, for example, less than 10, the increased k can find all the optimal solutions. But when the number of global optima is lager (more than 10), with the increase of k, the number of global optima which MQHOA-MMO can find also increases. When k increases to a certain number, the number of global optima which MQHOA-MMO can find is stable. When the domain is large, k should increase in a large scale more than ten times. We can make a conclusion that to find all the global optima the initial value of k should be larger than the number of the global optima. Besides, along with the increase of domain, the number of k should increase correspondingly.In MQHOA-MMO, we generate initial population using two parameters: k optimum function values of test functions. The value of iteration times is the number of QHO processes. For the 12 benchmark test functions, we set parameters as follows: k = 50, m = 200, and σmin = 10e − 6. Results are averaged over 30 independent runs.To be more intuitive, we apply 12 benchmark test functions to demonstrate the convergence and verify the effectiveness of MQHOA-MMO. Figures F1, F2, F3, F5, F6, F9, and F12, can converge to several small areas at the fifth iteration. σs < σmin or the maximum number of function evaluations was exhausted. The results mean that MQHOA-MMO has a fast convergent ability, and for most test functions there is only one QHO process in each M process.From Figures 2k = 35, m = 200, dmin = −10, and dmax = 10. The function is written as follows:In this section, we choose Hansen function (E1-F8) to present the changes of wavefunction in MQHOA-MMO. We set k swarms, which are xi used in QHO's first iteration for each σs. Second notion is incipient wavefunction, which is the wavefunction of xi used in QHO's first iteration for each σs. The last notion is last wavefunction, which is the wavefunction of xi used in QHO's last iteration for each σs. After the last QHO iteration for each σs, σs will be cut half to σs/2.MQHOA-MMO's wavefunction is written as . To desck swarms with different σs. Figures σs. Figures σs. With σs = 20, σs = 2.5, σs = 1.25, σs = 0.3125, σs show the changes of wavefunctions in different QHO iterations. For example, Figures σs = 1.25. As mentioned in σs. Figures of different σs give us the differences of wavefunctions in different M iterations. For example, Figures k swarms and the different σs. From the wavefunctions, we also can find that if there is a large probability of the optimal solution at a certain point, the point will be more attracted in this area, according to Gauss sampling law. It means that the higher probability is that the optimal solution is in the region. With the decrease of σs, the probability distribution of particles is more and more concentrated. This is the principle that MQHOA-MMO uses multiscale to implement the precision of the algorithm.Figures of the same σs < σmin or the maximum number of function evaluations was exhausted. The experimental results of other algorithms are quoted from [k = 50, m = 200, and σmin = 10e − 6. From F3, F5, and F6, MQHOA-MMO can also get 100% success rate while some other algorithms even cannot find the global optima.In this section, we will present a detailed discussion on the performance of various algorithms that were chosen in the comparative study. We use 6 challenging functions of various characteristics to evaluate the MQHOA-MMO's performance. MQHOA-MMO runs until ted from . All perσ-GSO is a new excellent combination algorithm. It can generate acceptable results over the test functions. SCMA can also generate good results over simple and low dimension. Their performance gradually becomes poor when the dimension increases. SDE algorithm shows very poor performance if the number of peaks has high accuracy. Other SDE could not be able to generate satisfactory solution. FERPSO is able to generate relatively satisfactory results in many test functions. For MQHOA-MMO, given suitable parameters, it can get all global optima.In this paper, we proposed a multimodal optimization algorithm named MQHOA-MMO. We used wave function to locate the possibility positions of the optimal solutions. The experimental study undertook 12 distinct test functions with number of global peaks varying from 2 to 25. Through comparison of results which were obtained from optimization of several benchmark functions using MQHOA-MMO and other optimization algorithms with two criteria and results obtained from performance experiments it is revealed that MQHOA-MMO can detect all the global optimum in a fast effective, controllable, and higher accuracy. Furthermore, this algorithm can find the global optimum of multifunction without being trapped in local optimum. The experimental study clearly indicated that, in most of the test cases, performance of MQHOA-MMO remains statistically better than all the other algorithms compared with it. For some complex functions, MQHOA-MMO could not have a good success rate. Future research of MQHOA-MMO will be focused on the optimization of such complex functions and higher-dimensional functions.


It has long been accepted that without hearing aid rehabilitation those with severe or greater hearing losses (thresholds above 70 dB HL) find conversation particularly difficult. That this in turn can lead to feelings of isolation, a reduced quality of life, and in some cases depression  and cognitive decline. Cross-sectional studies provide strong evidence for this link - see Roberts and Allen  for a reMany individuals with MARHL seem to manage without hearing aids. Such a loss for someone whose employment involves demanding auditory tasks will most likely result in recourse to hearing aids. But a MARHL for someone who is retired from work and is happy to avoid any difficult listening environments, is far less likely to visit the audiology clinic. This is sometimes referred to by Audiologists as someone who has “enough hearing for their needs.”But can hearing loss, as Lin  suggestsOne particular focus of these recent investigations has concerned listening effort. Many studies have now shown that high intelligibility can still be achieved with speech degraded as a consequence of MARHL. But only at the cost of effort (and associated fatigue), through increased use of executive function and working memory. Reviews of many of these studies can be found in Hornsby et al. , Peelle What of those who choose to withdraw from noisy situations, choose not to use (or have no access to) hearing aids, and consider themselves to have “enough hearing for their needs?” Recent studies involving the use of hearing aids and more established research findings involving the users of cochlear implants (CI) may help with our understanding. These studies describe the cross-modal cortical re-organization consequences of all types of hearing loss, including MARHL.Neuroimaging studies have shown that peripheral hearing loss can result in both structural and functional changes in the auditory cortex. See Anderson et al.  for a reSharma and Glick  provide To sum up so far. Common causes such as neural and microvascular aging are likely responsible for simultaneous cognitive decline and age-related hearing loss. However, the onset of MARHL seems to trigger its own cascade of conditions including the need for increased cognitive effort when attending to speech in noisy places, and brain plasticity initiating cross-modal auditory cortical re-organization.Our attention needs then to turn toward understanding how and when hearing aids can be used to prevent cognitive decline. To what extent can hearing aids be used to reverse auditory system aging?Initial results from this endeavor are encouraging. Doherty and Desjardins  demonstrWe should not be surprised in the least that hearing aid use is able to reverse central auditory system aging. After all we knew already that the human auditory system has an inherent plasticity, and that this plasticity seems reasonably resistant to healthy aging. It is a plasticity that enables the auditory system to be trained (through experience) to undertake complex signal processing, to be fine-tuned to robustly encode a tonal language or a non-tonal language, and to separate speech from noise. It is a plasticity that enables cochlear implants to have successful outcomes for young and old alike. And last, but not least, a plasticity that will mean that speech recognition will become increasingly reliant upon visual input as the quality of the acoustic input slowly begins to reduce. See both Kraus and White-Schwoch  and LehmWe seem to have reached a conclusion about what should be done at the very onset of age-related hearing loss. It seems that without hearing aid rehabilitation a cascade of conditions will soon begin. And if this turns out to be true then it seems reasonable to hope that hearing aid rehabilitation with modern open-fit digital hearing aids can be used to postpone this cascade for several years at least. We await the results of the many current studies investigating the relationship between Age-Related Hearing Loss and Cognitive Decline. Of particular interest is a more thorough understanding of the triggering of cross-modal cortical re-organization resulting from hearing loss.The author confirms being the sole contributor of this work and approved it for publication.The author works in an NHS England Audiology department. NHS audiologists are employed to assess patients with hearing loss and to fit appropriate hearing aids - this includes the fitting of hearing aids to patients with a mild to moderate age-related hearing loss.


ILDR1-dependent ARNSHL  is a very rare sub-type of hearing disability, with unknown prevalence, caused by function-damaging genetic variants in ILDR1 gene reported in families of Middle-Eastern origin. ILDR1 (Immunoglobulin-Like Domain-containing Receptor 1) is involved in the development of semicircular canal, tricellular tight junction and auditory hair cells. An apparently non-consanguineous family of European ancestry with two affected siblings with profound progressive hearing loss characterized in their infancy and successfully treated with cochlear implants (CI) is presented. Genetic analysis of common ARNSHL genetic causes in the population of origin was negative, thus the next-generation sequencing (NGS) and family segregation analysis to identify underlying causative genetic variant was performed. Unexpectedly and atypical for the population of origin a homozygous non-sense variant ILDR1 c.942C > A (p.Cys314Ter) inherited from both heterozygous parents was identified in both patients. Contrary to the commonly reported phenotype, indices of a progressive hearing loss and potential compensatory mechanism of vestibular function were revealed with the analysis of clinical data. The utilization of NGS was demonstrated as an invaluable tool for the detection of atypical rare variants in diagnostics of unidentified hearing loss disorders.Sensorineural hearing loss (SNHL) is a heterogeneous family of hearing disabilities with congenital (including genetic) as well as acquired etiology. Congenital SNHL of genetic etiology is further sub-divided into autosomal dominant, autosomal recessive and X-linked SNHL. More than 60 genes are involved in the etiology of autosomal recessive non-syndromic hearing loss (ARNSHL) commonly manifesting as heterogeneous pre-lingual profound to severe non-progressive clinical phenotype.  Before cochlear implant surgery (CI) the computed tomography (CT scan) of the temporal bone was performed to evaluate the anatomy of medial and inner ear. Additionally, cochleography and electrically evoked auditory brain responds (EABR) test by reversed electrical 200 μs long stimuli with intensity range from 200 μA to 1 mA, using stimulating golf electrode placed on a round window was performed. This study was carried out in accordance with the recommendations of the Declaration of Helsinki and the Slovenian national medical ethics committee. All subjects or their legal guardians gave written informed consent in accordance with the Declaration of Helsinki. The protocol was approved by the Slovenian national medical ethics committee (#34/4/07).A family case of hereditary hearing loss in two siblings of apparently non-consanguineous parents of European ancestry is presented. The evaluation protocol assessed detailed family history and medical history with focus on potential causes of acquired hearing loss . Additionally, a complete audiological history was recorded to establish the age of the hearing loss onset, the rate of hearing loss progression and to identify other audiological symptoms. Both index patients and their parents underwent a clinical otorhinolaryngological examination, including ear microscopy, with a systematic search for syndromic hearing loss indices. A tympanogram was performed and middle-ear associated causes of hearing loss were excluded. Additionally, they underwent ophthalmological and pedo-neurological examinations. The conditional and partly conditioned classical pure tone audiogram (PTA) was recorded in speech frequencies 0.25, 0.5, 1, 2, and 4 kHz, respectively, followed by the brainstem evoked response audiometry (BERA) analysis with up to 110 dB click stimulation. The function of vestibular organs was tested with caloric stimulation by irrigation of the external ear canal with 50 cmFigure 1A). The computed tomography (CT scan) of the temporal bone revealed normal medial and inner ear. Surprisingly, contrary to the older results the classical bi-thermal caloric stimulation with water at 30 and 44°C at adulthood (age range: 30–35 years) revealed symmetrical, good responses. The cochleography measurements were negative where EABR showed responses at stimulation with 1 mA on the right side. Consequently, the patient received CI on the right side and after the CI surgery, the PTA of implanted side reached between 25 and 35 dB across tested frequencies.First sibling  was admitted for the first time to an audiologist (age range: 0–5 years) due to hearing disorder and fitted with bilateral hearing aids. The caloric stimulation of both vestibular organs was negative, yet the patient did not present with any vestibular problems in recorded medical history. Interestingly, the speech was well developed, enabling education by regular educational program. The hearing above 3 kHz rapidly deteriorated, followed by relatively stable period until the adulthood (age range: 30–35 years) when only some islands of residual hearing were detected at lower frequencies. The level of hearing perception on PTA test performed at the first audiologist examination were 50, 70, 85, 100, and 100 dB for the right side and 40, 55, 70, 90, and 90 dB for left side, respectively. Later the hearing significantly worsened with PTA thresholds reaching 90, 105, 110, 115, and 120 dB at the right side and 85, 100, 110, 115, and 115 dB at the left side for stimulation at 0.25, 0.5, 1, 2, and 4 kHz frequencies, respectively . The BERA potentials were not detected even at stimulation with 110 dB click. On the other hand, the response of vestibular organs to caloric stimulation was well detected and symmetrical. The patient was fitted with bilateral hearing aids at the first year of age. The speech development was not hindered and the second patient completed regular educational program. The hearing further deteriorated to the level where no benefit from conventional hearing aids was detected (age range:25–30 years). The CT scan of temporal bones was normal. The cochleography measurements were negative where the EABR showed responses at stimulation with 300 μA on the right side and at 400 μA on the left side. After CI (age range: 25–30 years) the PTA on implanted side detected the hearing level of 30 dB through the whole frequency range.Due to a family history of hearing loss the second patient  was sent to an audiologist soon after birth (age range: 0–1 year). Comparatively, the PTA test in the childhood (age range: 0–5 years) revealed the hearing thresholds at 50, 70, 90, 100, and 100 dB for the right ear and 50, 65, 80, 90, and 110 dB on the left side at 0.25, 0.5, 1, 2, and 4 kHz frequency range, respectively. The hearing progressively deteriorated in the adulthood (age range: 25–30 years) the PTA thresholds dropped to 85, 100, 110, 115, and 120 dB for the right side and 85, 95, 120, 120, and 120 dB for the left side at 0.25, 0.5, 1, 2, and 4 kHz frequency range, respectively  , to idenFigure 2).The NGS analysis revealed that both siblings were carriers of homozygous ILDR1 non-sense mutation c.942C>A (NM_001199799.1), introducing early stop codon at Cys314. The coverage of identified variant was 189× and 126× in first and second sibling, respectively. Sanger sequencing confirmed the presence of the genetic variant and its zygosity. Additionally, the family segregation analysis was performed by targeted Sanger sequencing of parental DNA samples. Both parents were carriers of a heterozygous ILDR1 c.942C>A variant  homozygous and heterozygous genetic variants (rare hom/het ratio) was calculated as a proxy to further assess the level of consanguinity in the family. The corresponding standard deviation score (SDS) of rare hom/het ratio was derived from comparison of patient’s ratios to a distribution of rare hom/het ratio in the Slovenian population. The population distribution of rare hom/het ratio was calculated from sequencing data of 117 anonymized individuals, generated during a routine genetic diagnostic procedure using identical abovementioned NGS library preparation protocol . The coverage threshold for all variants’ datasets was set to >20×, and only variants passing this threshold were taken into a calculation of SDS of rare hom/het ratio. The SDS of rare hom/het ratio was 2.66 for the first sibling  and 1.42 for the second sibling .GJB2 mutations while other reported genes include SLC26A4, MYO7A, OTOF, CDH23 and TMC1. Interestingly, GJB2 mutations are responsible for approximately 27% and TMPRSS3 mutations are responsible for around 13% of remaining Slovenian ARNSHL population  is a family of heterogeneous conditions spanning acquired as well as congenital causes of the disease. Genetic changes are one of the main contributing factors in the development of congenital SNHL. Non-syndromic hearing loss of genetic etiology has more than 100 genetic loci involved in its etiology . Additiopulation . The advpulation .ILDR1 mutations have been implicated in the development of very rare non-syndromic autosomal recessive deafness type 42 (DFNB42) in humans  recruitment by ILDR1 and failure to form tight junction . The non-sense homozygous mutation in ILDR1 gene inherited from both parents was identified as the cause of their disability. Classified as DFNB42 hearing loss, it is a very rare disorder reported in families of Pakistani, Saudi Arabian, Turkish and Iranian origin (ILDR1 c.942C>A introduces early stop codon p.Cys314Ter and is reported in Human Genome Mutation Database as a disease causing variant (CM163808). It probably renders the ability of ILDR1 to recruit tricellulin and effectively form tight junctions inefficient, consequently affecting the function of auditory hair cells as shown in animal models and cellular cultures  coinciding with previous reports , supporting phenotype diversity of DFNB42 clinical manifestation. Additionally, a recent report on ILDR1-knockout mouse models demonstrated the progressive degradation of outer hair cells and organ of Corti, further supporting the progressive hearing loss disorder phenotype  to approximately 30 dB and drastically improved patients’ quality of life although there is a report where CI in ILDR1-misense-mutation dependent hearing loss was not successful  revealed that the vestibular response recovered. The medical records were carefully reanalyzed and the possibility of a potential analytical error was excluded. Although the existence of potential underlying recovery mechanism is a speculation, there are reports, which indicate that, at least in mice, the recovery of vestibular function could be guided through ILDR1-loss-of-function dependent angulin-1 mediated recovery of tricellulin localization. However, tricellulin/angulin-1 interaction does not recover hearing in mice and consequently the potential positive effect on vestibular function has to be further investigated (Analyzing the PTA data, the characteristic curves with more prominent hearing loss in higher frequency range were revealed ( reports  although reports  indicati reports  both pathenotype . Neverthccessful . Neverthstigated .ILDR1-dependent hearing loss resulting in a homozygous function-damaging variant segregating in affected family members (ILDR1 gene. The haplotype analysis of low-coverage mtDNA revealed that both siblings are carriers of J1c3a2 haplotype. The mitochondrial haplogroup J is widespread in Europe as well as Near East. It is assumed that it was introduced into European population through Neolithic and/or Late Glacial migrations (Consanguinity is a commonly reported underlying characteristic of  members , neverthgrations . ConsequILDR1-dependent hearing loss (This analysis confirmed the underlying variability of clinical phenotype in ing loss , and adding loss , successGK prepared the NGS libraries and performed sequencing. KP performed validation of genetic results, supervised the genetic diagnostic procedures and contributed to the manuscript. SB performed clinical evaluation of the family, performed cochlear implant surgery and contributed to the manuscript. JK analyzed NGS data, performed Sanger sequencing and wrote the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Introduction. Labyrinthine concussion is a term used to describe a rare cause of sensorineural hearing loss with or without vestibular symptoms occurring after head trauma. Isolated damage to the inner ear without involving the vestibular organ would be designated as a cochlear labyrinthine concussion. Hearing loss is not a rare finding in head trauma that involves petrous bone fractures. Nevertheless it generally occurs ipsilateral to the side of the head injury and extraordinarily in the contralateral side and moreover without the presence of a fracture. Case Report. The present case describes a 37-year-old patient with sensorineural hearing loss and tinnitus in his right ear after a blunt head trauma of the left-sided temporal bone . Otoscopy and radiological images showed no fractures or any abnormalities. A severe sensorineural hearing loss was found in his right ear with a normal hearing of the left side. Conclusion. The temporal bone trauma requires a complete diagnostic battery which includes a neurotologic examination and a high resolution computed tomography scan in the first place. Hearing loss after a head injury extraordinarily occurs in the contralateral side of the trauma as what happened in our case. In addition, the absence of fractures makes this phenomenon even more unusual. Labyrinthine concussion is a term used to depict a sensorineural hearing loss (SNHL) with or without vestibular symptoms occurring after head trauma. The temporal bone is at risk for injury in the setting of high-impact craniofacial trauma. Skull fractures due to blunt force trauma occur in 3% to 22% of patients with head trauma. 80% to 90% of cases with temporal bone trauma sustain unilateral injury –3. HeariWe report a case of a 37-year-old male patient who presented to the emergency room with a left side head trauma after being hit with a hammer during an altercation. He complained of contralateral hearing loss and tinnitus denying any right side injury. No vertigo accompanied his deafness. The onset of the symptoms was immediately after the head trauma.The patient had no personal or family history of previous hearing disorders, including hearing loss or anatomical alterations; hence we believe he had a normal hearing prior to trauma since we have no previous audiological records.Otoscopic examination revealed normal bilateral intact tympanic membranes. A positive Rinne test in both ears and a Weber test lateralized to the left side in 256, 512, and 1024 Hz. Severe sensorineural hearing loss in the right ear and normal hearing in his left ear were demonstrated with a pure tone audiometry test . AdditioTreatment with oral corticosteroids (Deflazacort at a 1 mg/kg per day dose beginning with 70 mg and slowly tapering the dose) was administered gaining 15 dB in all frequencies within a week when follow-up was assessed. . The patTemporal bone fractures due to blunt head trauma are not an unusual finding. They are classified according to their anatomical orientation and moreover correlated with their clinical presentation. The three possibilities involve a longitudinal, a transversal, or a mixed type of fracture. These fractures may involve some complications or sequelae such as facial paralysis, conductive hearing loss, cerebrospinal fluid leakage (CSF), SNHL, vertigo, and vascular injury , 3. TempLongitudinal fractures account for the majority of the cases involving usually a conductive hearing loss and in very few cases facial paralysis or vertigo. Some studies have reported the mixed type of hearing loss as the most common. These fractures are usually associated with temporal or parietal bone trauma. Transversal fractures have a major incidence of facial paralysis and if accompanied by hearing loss it usually involves a sensorineural type due to its labyrinth involvement –3. NeverHearing loss is not a rare finding in head trauma that involves petrous bone fractures. It generally occurs ipsilateral to the side of the head injury. Hearing loss extraordinarily occurs in the contralateral side and moreover without the presence of a fracture as what happens in our case .Several theories have been proposed to explain this circumstance such as labyrinthine concussion resulting from a fracture to the bony labyrinthine capsule. However the mechanism involving this phenomenon remains unclear. Labyrinthine concussion is a term used to depict a SNHL with or without vestibular symptoms occurring after head trauma –7. A subDisruption to the organ of Corti has been suggested involving a pattern seen when high-pressure waves of the intracranial CSF caused by intense airborne sounds transmitted to the cochlea. In the animal experiments from which this theory was built, hemorrhage sites and microcirculation disturbances in the cochlea destroying the sensory epithelium due to rupture of vessels in the membranous labyrinth were also seen , 7, 10. One differential diagnosis may include a perilymph fistula but in this case we would expect the hearing loss to be accompanied not only by tinnitus but also by vestibular symptoms. This did not occur in our case , 6, 7. AWe have found only one case described similar to our case except for vestibular symptoms accompanying the SNHL . Three cTemporal bone trauma requires a complete diagnostic battery which includes a neurotologic examination, a high resolution CT scan , an electroneuronography if facial paralysis is present, audiometric tests, and vestibular tests if required .There is no definitive treatment for labyrinthine concussion. Corticosteroids are controversial and most of them are managed expectantly. We administered steroids as described before to our patient and there was 15 dB improvement in all frequencies. Nevertheless, we have no evidence that the hearing improvement was a response to corticotherapy or it just occurred incidentally. Further studies have to be performed to prove the effectiveness of this treatment . The proHearing loss after a head injury extraordinarily occurs in the contralateral side of the trauma as what happened in our case and moreover in the absence of fractures which makes this phenomenon even more unusual.


The objective of this study is to determine if the nerve pathology in patients with POEMS syndrome is different from CIDP. We hypothesized that nerve biopsies from patients with POEMS syndrome would have more small vessels and axonal degeneration but less inflammation than CIDP.We performed a retrospective analysis of nerve biopsies performed on “classic” CIDP and POEMS cases. Nerve biopsies were blinded and reviewed by two of the authors . Teased fibers, paraffin-embedded sections, semithin sections and immunostains were analyzed. Small endoneurial and epineurial vessels were counted on paraffin sections with smooth muscle actin (SMACTIN) preparation to judge for neovascularization.A total of 61 cases  were included. The POEMS-group had significantly higher axonal degeneration and fewer normal myelinated fibers on teased fiber preparations. The CIDP-group had significantly more endoneurial mononuclear inflammation on paraffin sections and immunostains. Large onion-bulbs were present only in CIDP cases. A significantly higher number of epineurial vessels was present in POEMS biopsies, with a total count of 120 epineurial vessels predicted as best cutoff to differentiate both conditions (77 % specific and 54 % sensitive).In conclusion, nerve biopsy can be helpful in distinguishing POEMS syndrome from CIDP. POEMS syndrome demonstrates more axonal degeneration and epineurial neovascularization whereas CIDP has greater endoneurial inflammation and onion-bulb formation. These findings support the idea that there are differing underlying mechanisms for these disorders, POEMS being related to paraneoplastic vasculopathy associated with angiogenic factors and CIDP related to inflammatory demyelination. The peripheral neuropathy of POEMS Syndrome  has great similarities with that of CIDP (chronic inflammatory demyelinating polyradiculoneuropathy). Both neuropathies cause a motor and sensory, chronic and progressive neuropathy, with polyradicular features , and with demyelinating electrophysiological features. Because of these similarities, distinguishing POEMS syndrome from CIDP can be challenging and many cases of POEMS cases are initially misdiagnosed as CIDP . Most ofAfter Institutional review board approval, we queried “CIDP” and “POEMS syndrome” in the Mayo Clinic-Rochester database from 1979 to 2013. Over 300 patients records were reviewed. “Classic” CIDP cases were included only. Clinical criteria required progressive or fluctuating course over ≥ 8 weeks, preferential impairment of large fibers and proximal and distal involvement of 4 limbs with hypo or areflexia [1). Conduction block or temporal dispersion was present in one motor nerve and in at least one other motor nerve there were 2 or more of the following: prolonged F-waves, prolonged distal latency, slowing of conduction velocity. 2). No conduction block or temporal dispersion was found but in at least 2 motor nerves there were two or more of the demyelinating features described above. Supportive features of diagnosis were the 1) CSF analysis (protein level >60 mg/dL with leukocyte count <10 cells/_L) and 2) response to immunosuppressive therapy. Cases of CIDP included in this study were “definite”  or “probable” . These inclusion criteria were used in a prior CIDP publication .POEMS cases were included if they had polyneuropathy and monoclonal plasma cell disorder, one other major and one minor Dispenzieri criteria .All patients that met criteria for CIDP or POEMS syndrome and had a nerve biopsy taken were included in our study. Only standard distal whole cutaneous sensory nerve biopsies  were included  so as to use the normative data from our laboratory.Nerve biopsies from these patients were retrieved and blinded to the diagnosis by one of the authors (J.E) and reviewed by two other authors (E.A.P. and P.J.B.D.). The biopsies were labeled with age and gender, which was the only information available to both reviewers. Teased fibers were analyzed and re-graded according to previously published criteria . TransveThe pathologic alterations were graded semi-quantitatively: inflammatory cell collections were documented as small collections (10–49 cells), moderate collections (50–99 cells), and large collections (>100 cells). The location of inflammation  was also recorded. Onion-bulbs (OB) were considered present if they were at least moderate (3–4 layers) or large (>5 layers) in size as rudimentary or small onion bulbs can appear in most chronic polyneuropathies. Nerves were graded for myelinated fiber loss  and distribution of fiber loss .Additional slides were immunostained with anti-human smooth muscle actin (SMACTIN). Manual count of small endoneurial and epineurial vessels (neovascularization) was done on one transverse section on one slide per each biopsy. Blood vessels from each section were counted twice for better precision. After all pathologic findings had been documented, biopsies were unblinded (by J.E) and the data was analyzed.P < 0.05 was considered significant for all comparisons. JMP software for MAC (SAS institute) and SPSS software  were used for all statistical analyses.Due to sample size differences and non-normal distribution of the data, nonparametric statistical comparisons were performed. The Mann–Whitney Test (Wilcoxon) was used to examine comparisons of continuous variables between the two groups. Pearson’s chi-squared test was used for comparisons of categorical variables. All statistical tests were two-tailed and A total of 61 cases were included in the study with a median age of 53 years and a range of 14–85. The POEMS group included 35 biopsies  and the CIDP group 26 biopsies . There was a male predominance in the POEMS group  and a slight female predominance in the CIDP group .P < 0.01) rates of axonal degeneration  degree of endoneurial mononuclear inflammation  degree of endoneurial CD-45 positivity in CIDP biopsies. This finding was consistent with the increased endoneurial inflammation seen on paraffin sections. There was no clear difference in endoneurial or epineurial CD-68 (macrophage) staining between the two groups.Immunostains for CD-45 and CD-68 were available in 41/61 cases. There was a significantly higher . In addition, moderate and large OB were only present in six cases of CIDP and in no cases of POEMS (P < 0.01).CIDP showed more frequent and larger OB formation (p = 0.01) than in the CIDP cohort. Moderate and severely decreased fiber densities were present in 17 cases of POEMS and 8 cases of CIDP. The patterns of fiber loss were significantly different between the two groups  in the POEMS group (31/35) than in CIDP (12/26). Multifocal fiber loss was more common (P = 0.048) in CIDP (6/26 cases) than in POEMS (2/31 cases).In semithin epoxy sections, the myelinated fiber density was significantly more reduced in the POEMS cohort , respectively  and not in number of vessels , 17. In Electrophysiologically, a demyelinating polyradiculoneuropathy is characteristic of POEMS as well as CIDP. These similarities on electrophysiology are one of the reasons that POEMS syndrome and CIDP are so frequently confused for each other. Prior electrophysiological studies have shown that POEMS syndrome has more axonal loss as evidenced by reduced amplitudes of motor and sensory potentials and greater degrees of fibrillation potentials than does CIDP , 19, 20.Prior electrophysiology studies have also suggested that the demyelination of POEMS is more uniform than in CIDP affecting all nerve segments including the intermediate ones equally. In contrast, the nerve terminals and proximal nerve segments (nerve roots) are most severely involved pathologically in CIDP , 19, 20.Increased numbers of small epineurial blood vessel formation (neovascularization) from a POEMS nerve biopsy was previously noted in a prior case report . AnotherOur findings of endoneurial inflammation, multifocal myelinated nerve fiber loss and onion bulb formation in our CIDP biopsies are consistent with a chronic inflammatory and demyelinating pathophysiology that have been previously reported in CIDP . EndoneuThe main limitation of our study was the retrospective design. The blinding to the diagnosis by the two reviewers was used in an attempt to reduce bias.Based on our findings, nerve biopsies can be helpful distinguishing POEMS syndrome from CIDP with POEMS syndrome showing a higher degree of axonal degeneration and more epineurial small blood vessel formation whereas CIDP shows more endoneurial inflammation, multifocal fiber loss and onion-bulb formation. These findings strongly suggest that although POEMS neuropathy and CIDP both present as demyelinating polyradiculoneuropathies fundamentally have different pathophysiologies.


This study explored the psychosocial experiences of adults with hearing loss using the self-regulatory model as a theoretical framework. The primary components of the model, namely cognitive representations, emotional representations, and coping responses, were examined.Individual semi-structured interviews were conducted. The data were analysed using an established thematic analysis procedure.Twenty-five adults with mild-moderate hearing loss from the UK and nine hearing healthcare professionals from the UK, USA, and Canada were recruited via maximum variation sampling.Cognitive representations: Most participants described their hearing loss as having negative connotations and consequences, although they were not particularly concerned about the progression or controllability/curability of the condition. Opinions differed regarding the benefits of understanding the causes of one’s hearing loss in detail. Emotional representations: negative emotions dominated, although some experienced positive emotions or muted emotions. Coping responses: engaged coping  and disengaged coping : both had perceived advantages and disadvantages.This novel application of the self-regulatory model demonstrates that it can be used to capture the key psychosocial experiences  of adults with mild-moderate hearing loss within a single, unifying framework. Hearing loss is a widespread condition, affecting approximately 328 million adults globally . Not onlWhile it is clear that hearing loss can have a considerable psychosocial impact, current understanding of this impact would be greatly enhanced if it were underpinned by an established theoretical framework. This could enable disparate strands of research on the subject to be drawn together to form a cohesive narrative. It could also provide new insights on the psychosocial aspects of hearing loss. Recently, hearing researchers have turned to the discipline of health psychology to identify models that have been successfully applied to other health conditions and that could improve the understanding of the behaviours and experiences of individuals with hearing loss . For exaidentity, or beliefs about the symptoms and labels associated with the condition, (2) causal beliefs, or beliefs about the factors that led to the development of the condition, (3) timeline, or beliefs about the duration of the condition, (4) controllability/curability, or beliefs about the extent to which the condition can be controlled, treated or cured and (5) consequences, or beliefs about the short and long term effects of the condition.The SRM  posits tThe SRM proposes that cognitive and emotional representations influence the selection of coping responses, which in turn influence health outcomes . Coping The SRM was selected for this study as it is an established framework that has been successfully applied to numerous long-term conditions, including diabetes, psoriasis, and epilepsy . Within The aim of this study was to explore the psychosocial experiences of adults with mild-moderate hearing loss using the SRM as a theoretical framework. Specifically, the study explored the cognitive and emotional representations of individuals with hearing loss, as well as their perceptions of their coping responses. The results will be used to inform the development of a questionnaire that measures the psychosocial impact of hearing loss. The study adopted a qualitative approach, as qualitative research is an essential element of questionnaire development . In addiTwo groups of participants were recruited: (1) adults with mild-moderate hearing loss, as defined as having a mean hearing threshold between 20–70 dB HL in the better ear averaged across 0.25–4 kHz or a unilateral hearing loss , and (2)Twenty-five adults with hearing loss (14 men) living in the UK participated in the study . The meahttp://dx.doi.org/10.3109/14992027.2015.1117663. The schedules were flexible due to the semi-structured design of the interviews, though their core content remained the same across each interview. Written informed consent was obtained from each participant prior to their interview. The first author conducted all of the interviews, each of which typically lasted 60 minutes. Thirty interviews were conducted face-to-face in a quiet room in the Nottingham Hearing BRU. Four hearing healthcare professionals who were not located in Nottingham were interviewed via online video call. Each interview was audio-recorded and subsequently transcribed verbatim.The research was approved by the East Midlands NHS Research Ethics Committee and the Nottingham University Hospitals NHS Trust. A pilot study was conducted with two adults with hearing loss and two audiologists. The adults with hearing loss each participated in a pilot interview and hearing assessment. As this did not result in any notable changes to the interview schedule, the data of the two adults with hearing loss were included in the analysis. The audiologists reviewed the interview schedule for the hearing healthcare professionals and suggested revisions. The interview schedules are available as supplementary material in the online version of the journal. Please find this material with the direct link to the article at: For the adults with hearing loss, a hearing assessment was conducted to ensure that they had mild-moderate hearing loss. Otoscopy was performed prior to the measurement of pure-tone air conduction thresholds (0.25–8 kHz) for each ear and pure-tone bone conduction thresholds (0.5–2 kHz) in accordance with the Thematic analysis was performed by the first author in accordance with the procedure outlined by The results are discussed in terms of the primary components of the SRM. An identification code has been assigned to each adult with hearing loss (e.g. AHL1) and each hearing healthcare professional (e.g. HHP1).I want people to see me as me; not me with a hearing aid or me with a [walking] stick…I want them to see me as I was”. Hearing loss was also commonly associated with looking ‘stupid’ or ‘silly’. HHP1 (hearing therapist/academic) said: “There is this fear of appearing stupid, which perhaps doesn’t happen with other disabilities”. Some found that hearing loss was associated with a lack of competence and authority. AHL16 stated: “I have always been…ever so efficient and capable and, you know, running things and organising things but because of my hearing, all that has gone”. Some found that hearing loss was related to being seen as ‘unfriendly’ and ‘difficult’. This is because communication difficulties (e.g. not replying when addressed) and communication tactics (e.g. asking people to speak more clearly) can be confused with rudeness by those who have little awareness of hearing loss. AHL20, who initially concealed her hearing loss, said: I actually made an effort not to talk to people…So when I would be around people I would probably have my head stuck in a book. So I probably came across as quite ignorant and unapproachable”. She added: “after I got my hearing aids somebody did actually say to me that they had been worried because I had been so quiet…and they thought…I was a loner”.“Individuals with hearing loss tended to see hearing loss ‘symptoms’ in terms of activity limitations and participation restrictions, such as difficulties with watching television, using the telephone, and conversing with the others. Many associated hearing loss with various negative labels, one of the most common of which was being seen as ‘old’. While those who saw ageing as a natural process were not especially concerned by this label, others found it upsetting. AHL17 said: “Many people feel that patients should be able to…rattle off their audiogram and many patients don’t particularly care”. Similarly, HHP3 (academic) said: “Audiologists tend to give way too much information…[Patients] want to know if there’s a fix and how can they stop it getting worse. They don’t need to know all of the miniscule details”. Such a lack of interest in a detailed understanding of hearing loss may be beneficial, with HHP4 (audiologist/academic) noting that some patients might become fixated on examining the causes of their hearing loss, rather than accepting the condition and learning to cope with it.When asked about the causes of their condition, individuals with hearing loss most commonly cited ageing and/or noise exposure. However, few had a clear understanding of the causes of their hearing loss and some had little interest in learning more. Indeed, three hearing healthcare professionals suggested that patients often receive more information about hearing loss than they need. HHP2 (audiologist/academic) said: “Reading more about it and trying to understand more about it is my way of coping with it”. HHP5 (hearing therapist) said: “Like with anything in life…if we have an explanation; if we have a foundation, we are able to then get to grips with it”. Ultimately, several of the professionals expressed the view that it is best to tailor the information given to patients based on their individual preferences.Contrasting with this perspective, some individuals with hearing loss and clinicians proposed that understanding the causes and nature of hearing loss could help people to accept the condition and to understand why they need audiological rehabilitation. AHL24 said: “It is a gradual deterioration. So I don’t have any anger, frustration…I passively accept that this is how it will be and just get on with doing what I can”. There were a small number who reported worrying about further decline. While some overcame this worry with time, others continued to feel anxious, particularly if they believed that their hearing loss could become unmanageable in the future. AHL24 began to learn sign language in case her hearing deteriorated: “I will be 68 in twenty years’ time…will I have lost my hearing by then or will it be just a little lower than what it is now?…It is upsetting…because I think, well, how will I communicate with people?”Most individuals with hearing loss were not especially concerned about the progression of their condition. Many had come to accept that their hearing would continue to decline and were determined to carry on regardless. AHL1 said: “I have probably seen people at all points on the spectrum from…people who are very much…“I have got a hearing loss but it doesn’t stop me doing anything”…to people at the other end, who are like, “I just don’t know what I am going to do…my whole life has fallen apart,” and then there is…everything in between”.“individuals with hearing loss can vary greatly in terms of whether or not they feel in control of their hearing loss. HHP1 (hearing therapist/academic) said: It is outside of my control. There is nothing so certain as that. The only way I can control it is by putting hearing aids in and adjusting them…You have got to realise that nothing, nothing is going to replace your hearing…What you can do is find something which will enhance what you have got…if you are not prepared to accept it then I am sorry; you have got a bit of a rotten life”.“Most individuals with hearing loss in this study believed that they could not control or cure their condition, yet this did not appear to hinder their coping. Instead, they had come to accept their hearing loss and were motived to use hearing aids and other coping strategies. AHL23 said: I wish you could give me back my hearing…so I don’t need to wear hearing aids at all, but I just have to accept it really…until you invent something that will help. I expect eventually there will be”. Also, some initially believed that hearing aids would restore normal hearing. HHP5 (hearing therapist) said: “The expectation is that a hearing aid fixes your hearing and I don’t know whether that is the fault of [the] explanation or…whether we, as humans, kind of hope for it to fix things…but [it] often sets people up for a fall”.A small number of individuals with hearing loss hoped that a cure could yet be developed. AHL15 said: “The individuals with hearing loss reported a small number of positive consequences of hearing loss, such as being able to ignore unpleasant sounds and disturbances  and developing a greater awareness of hearing loss and other disabilities. However, for most, any silver lining was outweighed by the negative consequences of hearing loss. These included the negative impact hearing loss can have on identity, with some even feeling stigmatised by the condition. Another consequence is the experience of various negative emotions, discussed in greater detail under the emotional representations theme.I just wanted to be on my own and [with] people that I knew…I was frightened to meet new people because you don’t know how they speak”. Some find formal interactions difficult, such as interactions with doctors, managers and colleagues. In particular, they may feel uncomfortable about disclosing their hearing loss and asking for support in a formal context. HHP1 (hearing therapist/academic) explained: “Something I have had so many times is ‘I couldn’t hear the doctor in the appointment and I didn’t want to say’…So then there is a…worry…with people thinking: ‘Well actually, what did he actually tell me?’”The most substantial consequences of hearing loss reported by the participants were activity limitations and participation restrictions. In particular, individuals with hearing loss struggle to communicate with others, especially in noisy environments, on the telephone or in group conversations. They can also find communicating with strangers demanding and intimidating, as strangers have unfamiliar communication styles and may lack awareness of hearing loss. AHL14, who had sudden-onset hearing loss, said: “I am with the family and they are talking and I feel as though I am not in the same world”. Hearing loss can also place a strain on romantic relationships. Some individuals with hearing loss find that they have fewer joint social activities with their partner, fewer enjoyable conversations with their partner, and greater friction in their relationship. For example, AHL3 described how her boyfriend was irritated by having to repeat himself: “He just gets annoyed at me and doesn’t bother telling me what he has just said…We have lived together for just under two [years] and he still can’t cope with it”. Friendships are also affected, particularly as friends often meet in challenging listening environments, such as pubs and restaurants. AHL5 said: “Where I have difficulty is sitting in a gathering with friends and the conversation is flowing…I am perhaps more taciturn than I might otherwise be”.Hearing loss can also considerably affect the relationships between individuals with hearing loss and their communication partners. Individuals with hearing loss can find it difficult to take part in family gatherings and to converse with family members, particularly grandchildren. AHL9 said: “I am part of the prayer ministry team…a couple of weeks ago I said: “I am really going to have to come off it’…because I can’t do it. I cannot hear what people want prayer for”. She went on to explain the significance of having to sacrifice this activity: “it is…something else that is stripped away…it is not just your hearing that you have lost; it is a lot of other things you have lost as well”. In addition, hearing loss can negatively affect participation in educational activities, especially listening in lectures and contributing to group discussions. It can also affect numerous aspects of work life, including taking part in meetings, participating in training courses, and building relationships with colleagues.Hearing loss can also restrict participation in various social, leisure and community activities. AHL16 said: “ou do go through the stages of grief and anger and disappointment and ‘why me?’…before you can come to anything else”. The individuals with hearing loss often overcame these initial emotions, as they accepted and adjusted to their hearing loss. However, many found that they still experienced negative emotions in daily life because of their hearing loss. In particular, many felt frustrated and irritated, primarily due to communication difficulties and the limitations of hearing aids. HHP1 (hearing therapist/academic) suggested that irritation, though a relatively mild emotion, can take a toll on wellbeing when it becomes an everyday presence. Also, many reported feeling embarrassed by having a hearing loss, by wearing hearing aids, and by having communication difficulties. Some even conceal their hearing loss from others. Another common sensation was loneliness, or isolation, largely due to communication difficulties and participation restrictions. AHL4 said: “If you go to weddings or christenings…all these people around you are having a good time and you are…isolated because you are not fully part of the group”. Also some experienced worry, especially in relation to missing important sounds and information.Most individuals with hearing loss reported negative emotional representations of hearing loss. Initial emotional reactions included disbelief, anger, and fear. HHP6 (audiologist) explained: “Ypleased” to be diagnosed with hearing loss as a teenager: “I always loved the idea of having hearing aids…when you are sixteen-seventeen, you want something special about you…I also liked the idea that there was a reason for why I was having trouble.” However, such a positive emotional response was largely unique to AHL3 and, unfortunately, her emotions become less positive as she realised that hearing aids would not ‘fix’ her hearing loss.There were a small number of reports of positive emotional representations of hearing loss. HHP7 (audiologist) suggested that many patients in clinic are relieved to have an explanation for their hearing difficulties and are grateful for opportunity to receive help. AHL3 was “I don’t know [that] I had many feelings about it…I well understand it is natural and ageing”. HHP8 (audiologist/academic) suggested that some only become emotional when they reflect on how hearing loss has restricted their participation: “The emotional response will start when they think about…participation in the particular situation…Until then, they’re…fine, but when you talk about a particular situation…they get emotionally a bit worked up”.The results indicated that some individuals with gradual-onset hearing loss experience a relatively calm emotional reaction to the condition, possibly because they have time to accept and adjust to hearing loss or because they do not regard it as a serious condition. AHL7 described realising that his hearing was declining: “The individuals with hearing loss displayed two main coping responses. The first, disengaged coping, means avoiding addressing hearing loss, such as by denying or ignoring it or by withdrawing from social situations. The second, engaged coping, means taking action in order to manage hearing loss, such as using hearing aids and communication tactics.withdrawal from situations, refers to avoiding being physically present in challenging situations, such as social gatherings. HHP5 (hearing therapist) said: “People self-isolate quite a lot, I think. As situations become harder and harder to manage, the much easier option is to not do it”. AHL20 said: “I was missing out on life…I was probably isolating myself from social situations…it was just too much effort to try and hear what people were saying”. Rather than entirely withdraw from all social situations, individuals with hearing loss tended to participate in some situations and not others. Some found that they could no longer partake in the social activities they most valued. For example, AHL14 left her ideal job in the police force, though she had permission to stay in the role: “I did give up my police [job] because I knew I couldn’t put myself or a colleague in danger by…having this disability. So my childhood dream had to come to an end”. AHL9, who regarded family as “The most important thing”, was no longer able to babysit her great-grandchildren: “I feel I am too old to babysit for them because I couldn’t hear what they were saying…it is depressing really”.Two primary forms of disengaged coping emerged. The first, withdrawal within situations, refers to being physically present in social situations but being a passive rather than an active presence in those situations. According to HHP1 (hearing therapist/academic) this may be the most prevalent form of withdrawal: “They don’t go or they withdraw within the situation, which is perhaps more common…they say that: ‘I went along but I couldn’t really follow the conversation. So I was just…nodding and smiling.’” Group conversations were the main situation in which individuals with hearing loss reported ‘switching-off’, as it can become too difficult and fatiguing to attempt to contribute to the discussion. AHL16 said: “You are there but you are not there”. She added: “you just sit there like a fool and everything is going on around you”. AHL8 said: “You…say to yourself: ‘Is it important that I need to get involved in this conversation?’…you do sometimes adopt an isolationist attitude and say, ‘Well I am not going to pick up everything that is going on. So why bother?’” Some rely on communication partners to follow the conversation on their behalf. Some use ‘bluffing’ by pretending that they can follow the conversation.The second form of disengaged coping, Disengaged coping can lead individuals with hearing loss to respond inappropriately to questions, to miss important information, to feel isolated in social situations and to become less socially active. Nevertheless, there are those who prefer this approach, as it allows them to avoid the stress and fatigue associated with socialising and the embarrassment of displaying one’s hearing difficulties to others.You either concentrate on the negative side of it…Or you say, ‘Well, that is how it is. Now let’s get on with it’…Which sounds terribly pompous and flag-waving but…you effectively do that”. The majority regularly wore hearing aids and found them to be beneficial. AHL20 said: “They are not just hearing aids any more. They are part of me”. Nevertheless, the participants reported that hearing aids have their limitations. Some felt that hearing aids can be uncomfortable, unattractive, and associated with ageing. Some mentioned that they gain little benefit from hearing aids in noisy environments, such as social gatherings, which means that their participation remains somewhat restricted.Many individuals with hearing loss were determined to continue with their daily lives, despite their hearing loss. AHL5 said: “ou are conscious of the fact [that] if you say anything, you are breaking into the story or you are breaking into the conversation. So you don’t want to do that. So you keep quiet and you don’t hear what they are saying”. Some felt that communication tactics are ineffective when interacting with people who lack awareness of or sympathy towards hearing loss. In addition, some felt that using communication tactics, such as asking people to speak clearly, can result in them being perceived as demanding, annoying, or stupid. Communication tactics also require assertiveness, which does not come naturally to everyone.Many reported successfully using communication tactics, although these tactics were seen as inappropriate in certain circumstances. Specifically, communication tactics, such as asking for repetition, can spoil group conversations, especially when a joke or story is being told. AHL6 said: “YThis study aimed to explore the psychosocial experiences of adults with mild-moderate hearing loss using the self-regulatory model (SRM) as an underpinning theoretical framework. The meaningfulness of the model’s primary components  to the psychosocial experiences of individuals with hearing loss was examined. The findings will be used to inform the development of a new measure of the psychosocial impact of hearing loss.In terms of identity, hearing loss was found to have various negative connotations, including old age, unintelligence, and unfriendliness. This aligns with previous investigations of the stigmatisation of hearing loss and its impact on one’s sense of identity . In termIn terms of timeline, most individuals with hearing loss were not particularly concerned about the progression of their condition. Also, most believed that hearing loss is not controllable or curable. Despite this belief, the majority regularly wore hearing aids. This contrasts with a meta-analysis of SRM studies, which showed that perceived controllability/curability is positively associated with active, problem-focused coping . As mildThis study showed that hearing loss was perceived as having primarily negative consequences. The most substantial of these consequences were activity limitations and participation restrictions, which confirms findings from previous research . In partIndividuals with hearing loss had primarily negative emotional responses to the condition, including frustration, embarrassment and loneliness. The findings suggested that emotional responses can shift over time, reflecting the long-term nature of hearing loss. Emotional representations of hearing loss warrant further attention, as the SRM posits that they can be an important influence on individuals’ management of their health conditions . Also, aThere were two primary coping responses: disengaged coping, or avoiding addressing one’s hearing loss, and engaged coping, or taking action to manage one’s hearing loss. This corresponds to some extent with Despite the disadvantages of disengaged coping, particularly social isolation, it can allow individuals with hearing loss to avoid embarrassment, fatigue, and stress in social situations. Similarly, engaged coping was perceived to have both advantages and disadvantages. Most of the individuals with hearing loss found hearing aids helpful, yet acknowledged that they have various drawbacks, including reduced benefit in noisy environments. Many reported using communication tactics, though they were seen as ineffective in certain situations, such as when they obstruct group conversations or when communication partners are unsympathetic. The finding that both disengaged coping and engaged coping have perceived benefits and drawbacks is supported by previous research. While this study supports the merits of applying the SRM to hearing loss, the model is not without its limitations. The potential limitations of this study must also be addressed. Firstly, the participants with hearing loss were recruited from a database of individuals who were willing to take part in research investigating their hearing difficulties. This means that they may be more likely to be accepting of their hearing loss and to be relatively socially active and thus they may not be representative of all individuals with hearing loss. To counteract this, professionals were also interviewed to provide a broader perspective based on their experiences with a range of patients in clinic. Secondly, the study used a deductive, rather than an inductive, thematic analysis approach, which arguably increases the risk of overlooking important aspects of the psychosocial experiences of individuals with hearing loss where they do not fit within the framework of the SRM. While this risk cannot be denied, it is a concern for all thematic analysis approaches since no researcher is entirely free from preconceptions, including their pre-existing knowledge of the relevant literature and theories .This study used the SRM to explore the psychosocial experiences of adults with mild-moderate hearing loss. While the psychosocial impact of hearing loss has been examined in previous studies, the application of health psychology theory to this subject is still in its infancy. This exploratory, qualitative study could provide a foundation for future applications of the SRM to hearing loss, including quantitative investigations of the components of the model or explorations of the relevance of the model to other populations with hearing loss, such as those with severe to profound hearing loss. The findings support existing research, by confirming that hearing loss is perceived as having primarily negative consequences and primarily negative connotations. Additionally, the study uncovered various novel findings relating to emotional representations, including positive, negative, and muted emotional reactions to hearing loss, and relating to cognitive representations of the timeline, controllability/curability, and causes of hearing loss. The study also showed that both engaged and disengaged coping have perceived benefits and limitations and that disengaged coping can take the form of either physically withdrawing from social situations or mentally withdrawing within social situations. These findings demonstrate the power of the SRM to provide unique and rich insights into the psychosocial experiences of individuals with hearing loss. In particular, the SRM enables key elements of the psychosocial experiences of individuals with hearing loss to be captured within a single, unifying framework.