Sensorimotor decision-making is believed to involve a process of accumulating sensory evidence over time. While current theories posit a single accumulation process prior to planning an overt motor response, here, we propose an active role of motor processes in decision formation via a secondary leaky motor accumulation stage. The motor leak adapts the “memory” with which this secondary accumulator reintegrates the primary accumulated sensory evidence, thus adjusting the temporal smoothing in the motor evidence and, correspondingly, the lag between the primary and motor accumulators. We compare this framework against different single accumulator variants using formal model comparison, fitting choice, and response times in a task where human observers made categorical decisions about a noisy sequence of images, under different speed–accuracy trade-off instructions. We show that, rather than boundary adjustments (controlling the amount of evidence accumulated for decision commitment), adjustment of the leak in the secondary motor accumulator provides the better description of behavior across conditions. Importantly, we derive neural correlates of these 2 integration processes from electroencephalography data recorded during the same task and show that these neural correlates adhere to the neural response profiles predicted by the model. This framework thus provides a neurobiologically plausible description of sensorimotor decision-making that captures emerging evidence of the active role of motor processes in choice behavior. Sensorimotor decision-making is believed to involve a process of accumulating sensory evidence over time. This study reveals that two concurrent but temporally lagged evidence accumulation signals in human EEG are associated with a double-integration framework in which a secondary motor accumulation process dictates choice behavior while controlling for the urgency in making a decision. The study of sensorimotor decision-making is currently enjoying an ever-increasing amount of attention across different species and levels of neuronal organization –5. CentrMore recent evidence, however, appears to challenge both of these accounts. For instance, several animal and human electrophysiology studies have reported temporal accumulation profiles terminating at different boundaries, scaling proportionally to the amount of available evidence . SimMultiple neurophysiological studies have described activity related to motor preparation beginning before sensory evidence integration completes, effectively lagging the primary process of evidence accumulation –24. ThisHere, we propose an alternative computational framework  that modWe arbitrate between this alternative theoretical account and conventional single-integration models—including a variant with collapsing decision boundaries –34—by leIn doing so, we validate the newly proposed framework and simultaneously demonstrate that the SAT is likely primarily controlled by changes in the proposed leaky motor integration process rather than the long-standing view of boundary adjustments ,35. Our N = 43) indicated their choice via a button press using the index finger of either their right or left hand. The mapping between face/car choices and left/right button presses was counterbalanced across participants. Mean response times were longer in the Accuracy condition (population average of 873 ms) than in the Speed condition (654 ms), while behavioral performance was markedly worse in the Speed condition (population average accuracy of 0.78) compared to the Accuracy condition (0.84)  the evidence accumulated over time and y(t) the resulting motor accumulation. For the analyses in this paper, we will use a simple constant drift diffusion process for the dynamics of x(t) with stimulus-dependent drift speeds vi (i denoting the stimulus condition). The boundaries are not imposed on the accumulating evidence x(t) directly, but on the emergent motor accumulation y(t): We denote the characterizing boundary separation with a, with an upper boundary at x(0) = x0. The leak parameter λ determines the lag between the evidence and motor accumulation, and β is a scaling parameter. When the motor accumulation in y(t) hits a threshold, the physical response ensues, and a choice is made. In terms of choice-RT data alone, the LIT has one redundant parameter: To make the model estimable, we choose β = λ. Solving for y(t) in Mathematically, the dynamics of the deterministic LIT are defined asλ determines the extent of the temporal smoothing and the duration of the corresponding lag. When λ approaches infinity, the LIT has no memory or lag and behaves as a normal threshold on the primary accumulated evidence. Assuming prestimulus evidence accumulation is x(t < 0) = x0 and motor accumulation y(t) has had enough time to adapt, the motor accumulation starting position becomes y(t) = x0.The time smoothing afforded by the motor accumulation effectively increases the signal-to-noise ratio relative to the primary evidence accumulation signal and reduces accidental noise-driven threshold crossings. Unlike traditional instances of the DDM in which the momentary state of the accumulated evidence itself is being evaluated, here, decisions are based on a time-decaying weighted memory of all the evidence accumulator’s past values (hence the term “Leaky Integrating Threshold”). This introduces a lag between the primary evidence accumulation and motor accumulation processes. The leak parameter λ−1 and boundary separation a were significantly smaller in the Speed than in the Accuracy condition looking at their intraindividual differences . In addition, the relative starting position zr and drift speeds vi = 1−4 were indistinguishable .To manipulate the urgency of making a response, participants completed 4 blocks of the face-versus-car categorization task either under a Speed or an Accuracy instruction . To fit Materials and methods below. This approximation is a reparameterized version of a standard diffusion model, in which the original LIT leak parameter translates to a change in the boundary separation, starting position and non-decision time , or collapse rate (c). We emphasize that changes in the inverse leak were reparameterized as equivalent changes in the DDM parameters, such that all of the resulting models have the same number of free parameters, and we can use their fit to the data as a way to arbitrate between the mechanisms (λ−1) is more successful at explaining differences between urgency conditions than both simple boundary separation a  and collapse rate c .Because the dynamics of this model set are described by a simple one-dimensional diffusion process, we can use a grid method as in Voss and Voss  to calcuchanisms . For theNLLLIT = 6.430e4; ∑NLLDDM = 6.448e4) but also survived the penalty for the additional parameter afforded by the Bayesian information criterion (BIC) . Thus, these 2 model fitting approaches suggest similar conclusions: that the leak mechanism of the LIT provides a better computational description of SAT control in the behavioral data.In addition, we fit a standard DDM and the LIT (without reparameterising) using the more common simulation-based approach to estimate the negative log-likelihood of response-time quantiles see . The preTo connect any high-level model of evidence accumulation to EEG data, assumptions have to be made about how exactly the theoretical signal can be expected to manifest at the level of macroscale brain dynamics. In accordance with previous work ,43, we aMoreover, as EEG data could reflect a superposition of different processes, we cannot assume that a clean representation of the evidence accumulation signal can be found at any particular location or for any combination of sensors. Regardless of the unmixing technique used , the eviThis approach has the important advantage that EEG activity that is shared across trials but does not influence final choice-RT outcomes (and hence may be unrelated to the process of interest) is filtered out. More specifically, correlations of momentary signal values with their corresponding final RTs are not affected by an “unspecific” shift in the signal values, as long as it is present in all trials. In other words, adding a constant signal to all trials—although very much altering the resulting mean accumulation signal—would not impact the correlation of momentary accumulation values and RTs. These accumulation “signal-RT” correlations can be calculated in a response-locked fashion, for different points in time leading up to the eventual response.The ensuing signal-RT correlation curves have an amplitude that can be interpreted as the extent to which the eventual trial RTs can be predicted by their preceding accumulation signal at a given point in time. The sign of the signal-RT correlation indicates whether higher accumulation signals lead to slower RTs or the other way around. In trials where the accumulation signals of slow and fast trials are comparable in value, the signal-RT correlation is zero. On the whole, signal-RT correlation curves are driven by how trials with different response times (from slow to fast) evolve compared to each other, and not how their mean value evolves compared to the rest of the brain activity. Signal-RT correlation curves can therefore be seen as a robust metric to compare the internal dynamics of theoretical evidence and motor accumulation signals with what is observed in the EEG signals.t = 0). At all times before the crossing, the low sensory evidence signal is higher than the high sensory evidence signal . The difference between the 2 signals reduces to zero only at t = −∞ and at the threshold crossing (t = 0). The latter is consistent with the idea of a stimulus invariant information threshold, whereby all evidence accumulation signals at t = 0 have the same value. Correspondingly, the evidence signal-RT correlation curve remains positive during this time interval , the signals for the 2 levels of sensory evidence do not coincide, demonstrating a clear deviation from the idea of a stimulus invariant information threshold on the level of the evidence accumulation. This pattern also manifests in the signal-RT correlation  result in an increased lag between motor and evidence accumulation signals. This lag can be quantified by the response-locked time at which the signal-RT correlation curve crosses zero  is executed with only a small and systematic delay relative to the time the motor threshold is reached. However, for the standard DDM, the non-decision time is assumed to include additional time for the choice to be communicated to the motor cortex, after which the button press is planned and executed. If evidence accumulation were to continue during this time with the same drift rate, and the time-course of evidence accumulation was locked to the time of the response, rather than the decision, the signal-RT correlation could become negative so long as there is not substantial variability in the non-decision time across trials. The timing of this zero-crossing is relative to the duration of non-decision time. Under the DDM framework, the signal-RT correlation is dependent on the sensory evidence strength but not on the decision boundary separation, meaning that this model predicts no substantial difference in signal-RT correlations between speed and accuracy conditions.In the next section, we compare these theoretical signal-RT curves with the corresponding curves derived from EEG accumulation signals to offer neurobiological validation for the proposed LIT framework. Specifically, the LIT predicts that the primary evidence accumulation signal-RT correlation will cross zero, and the timing of this zero-crossing will be earlier in the accuracy condition than the speed condition (as it is dependent on the leak). In contrast, the DDM predicts signal-RT correlations that do not substantially differ between the speed and accuracy conditions.To offer neurobiological validation for the LIT, we first aimed to identify candidate accumulator signals from which to derive the required signal-RT curves. Specifically, we used a single-trial multivariate classifier ,46,47 deImportantly, this approach offered an initial opportunity to arbitrate between the predictions of the traditional DDM and the LIT. The traditional DDM assumes a common threshold for the primary evidence accumulator for both low and high evidence trials. This, in turn, should lead to low discrimination performance near the response with systematic improvements in classification accuracy further back in time as the traces associated with the different levels of sensory evidence begin to deviate . In contWe note that the LIT motor accumulation signal  may also contribute to the classification accuracy further away from the response but, because it converges to a common threshold, cannot explain any potential above chance classification near the response itself. We observed 2 local discrimination maxima, one near the response itself and one approximately 400 ms prior the response, on average . This clWe subsequently applied each participant’s spatial weights obtained in the 50-ms time-window centered around the response  on the entire response-locked time window to obtain individual trial-by-trial evidence accumulation signals. This approach can be thought of as projecting the data through the same neural generators responsible for the main discriminating activity and was designed to obtain robust estimates of the full temporal profile of this activity beyond the point of maximum discrimination ,49.An initial qualitative assessment of the resulting temporal profiles is in line with what is predicted by the LIT , wherebyImportantly, these temporally resolved evidence accumulation signals could be examined formally in the framework of signal-RT correlation curves and be directly compared to the theoretical predictions of the LIT. This approach is generally more robust against potentially interfering trends from unspecific neural processes that mix into the EEG signal and are not coupled to RT. In line with the LIT model predictions, both the Speed and Accuracy evidence accumulation signals show trial-by-trial correlations with RT that are negative at response time and become increasingly less negative going back in time until they cross the zero-correlation line while they continue to become increasingly positive . If we assume the inverse leak parameter lleagues  and replλ−1  and the individual motor-lags (obtained purely from the EEG data), such that participants with higher inverse leak λ−1 (relative to boundary separation) also exhibit a longer motor-lag  every 25 ms, with window centers ranging from 150 ms to 50 ms before the response. We expect the build-up of the proposed motor accumulation signals to be most pronounced in this interval due to increases in corticospinal excitability in anticipation of the eventual motor response  In Discussion, the authors state that they "…show computationally that the LIT … offers a better fit to behavior compared to traditional single accumulator diffusion models…". The authors should explain how this claim relates to other publications that contrast quantities like BIC. For example, is it not the case that this approach will not scale with either the number of parameters or the number of models?[B] The analysis pipeline for the EEG data included several choices that a skeptic could query. The manuscript would be improved if the authors demonstrated the robustness of the observations relative to variation of the several steps and parameters used in the analysis.[C] "estimatable" probably should be "estimable"***Reviewer #2: Verdonck et al. have recently proposed a dual integration model of perceptual decisions that are reported with a motor action (the Leaky Integrating Threshold or LIT model). Rather than applying a decision threshold to the integrated sensory evidence, as in the case of a typical single-stage integration-to-threshold model like the drift diffusion model (DDM), the integrated evidence is fed into another (leaky) integrator, which ends up being compared to a decision threshold. The authors propose that the mechanism for implementing the speed-accuracy tradeoff is a change in the time constant of the second integration stage.In this manuscript the authors provide further experimental evidence for the two-stage model based on human behavioral and EEG data from a dynamic face vs. car categorization task.I find the possibility of a dual-integration model interesting and some of the provided evidence, the observation of spatially segregated EEG signals with an appropriate relationship with each other as well as with the timing of individual decisions, quite convincing. At the same time, I have some questions about some of the choices/statements made by the authors, as further detailed below.1) The estimation method for obtaining the model parameters (D*M) is based on RT distributions, but we never get to see any RT distributions, neither those of the data, nor those predicted by the considered models. Could you please show some comparisons?2) One of the characteristic predictions of the LIT model is that a change in the integration time constant of the second stage leads to a change in the timing of the decision that would have to be captured by a change in the nondecision time in the case of a standard DDM. I find it therefore quite surprising that the authors allowed the nondecision time distribution to change with speed/accuracy (urgency condition) in all their model fits, which could potentially undo those kinds of timing changes. Furthermore, as far as I can tell, the resulting estimates of the nondecision time distributions are never reported. Could you please show these ?3) Related to this topic, the authors cite a few studies, which have reported that the nondecision time seemed to change with speed/accuracy when applying a DDM to behavioral data. This, however, is not true for all studies. Palmer et al. (2005) is a good example, where decision times were changed over a wide range based on speed/accuracy instructions, but a DDM was able to capture the behavior quite well with only a change in the decision bound and no systematic change in the nondecision time. It should at least be mentioned that there are studies that did not find a change in the nondecision time with speed/accuracy manipulations.4) In Fig. 3a the authors show accumulated evidence signals from a DDM locked to the decision threshold crossing. It is generally believed that the decision threshold crossing precedes the onset of the motor response and that part of the "nondecision" time that typically is fitted when fitting standard integration-to-threshold models is related to the preparation/execution of the motor response. Model signals that are time-locked to the decision threshold crossing should therefore not directly be compared with neural signals that are time-locked to the onset of the motor response. In fact, models like the DDM do not specify how the accumulated evidence signal should behave after the decision threshold has been crossed, as it is not relevant for the outcome of the decision. It is, however, quite relevant when a comparison between neural activity immediately before the onset of the motor response and model predictions is made. The fact that accumulated evidence reached a fixed level at the time of the threshold crossing, regardless of the strength of the sensory evidence, does not mean that this would still have to be the case at the time of the onset of the motor response. It could, if integration stopped immediately at the time of the threshold crossing without any leak. It would not be expected to be the case, if integration continued after the threshold crossing.  I.e., even if a threshold on the accumulated evidence  were to terminate the decision, but the integration continued during a (roughly) fixed time interval between the threshold crossing and the onset of the motor action, a crossing of the accumulated evidence signals like the one shown in Fig. 3b would be possible. I would therefore like to see to what extent a single-stage integration model could still account for (some of) the features of the EEG signal that has been linked to accumulated evidence by the authors and that have been interpreted as evidence for the two-stage model .That said, the change in the zero correlation lag with speed/accuracy could probably not easily be explained that way.5) Hanks et al. (2014) have previously reported invasive recordings from monkey LIP during a perceptual decision task with an urgency manipulation. Are the results that have been reported there  consistent with the LIT model? If so, would activity in LIP correspond to the first or the second integration stage?References:Hanks T, Kiani R, Shadlen MN (2014) A neural mechanism of speed-accuracy tradeoff in macaque area LIP. eLIFE 3:e02260Palmer J, Huk AC, Shadlen MN (2005) The effect of stimulus strength on the speed and accuracy of a perceptual decision. Journal of Vision 5:376-404*** Additional feedback from Reviewer 1 (regarding Reviewer 2 comments):Thoughts on R2 pt 1:The authors have done this in previous publications but it would be good to include here for completeness.Thoughts on R2 pt 2:Very useful point for the authors to address.Thoughts on R2 pt 3:A scholarly and reasonably thorough survey of this issue is merited in this manuscript. If the reviewer knows of other studies complementing Palmer 2005, it would be helpful to share them.Thoughts on R2 pt 4:The duration of the ‘non-decision’ motor delay is an important detail, and the manuscript would be improved by its consideration. We should note that the duration of such an efferent “point of no return” depends on which body part is moving and in what way. The non-decision motor delay for saccades, for example, is about 10 ms, and that’s all because of the brainstem mechanisms generating the ocular rotation. In the present study, participants indicated their choice via a button press using the index finger of either their right or left hand. The relationship between “decision” and “movement” thresholds has been investigated recently by Mathieu Servant, e.g., .Thoughts on R2 pt 5:As noted in my review, the Heitz & Schall (2012) report on neurophysiology of SAT in monkeys reports more happening than the Hanks et al. study. As we are now comparing these studies, we should note that whereas the Heitz study sampled neurons while monkeys alternated between short blocks of Fast and Accurate trials, the Hanks study sampled some neurons when speed was emphasized and other neurons when accuracy was emphasized. In their data, no neuron was sampled in both conditions. This limitation confounds confident interpretations. The authors should also be aware of the Thura & Cisek work on neurophysiology of SAT in a different task  5 May 2023AttachmentResponseToReviewers.docxSubmitted filename: Click here for additional data file. 8 Jun 2023Dear Dr Philiastides,Thank you for your patience while we considered your revised manuscript "Motor accumulation as a final arbiter in sensorimotor decision-making: a tale of double integration" for publication as a Research Article at PLOS Biology. This revised version of your manuscript has been evaluated by the PLOS Biology editors, the Academic Editor and the original reviewers, who are largely satisfied by the changes made.Based on the reviews, we are likely to accept this manuscript for publication. However, before we can accept your manuscript, we encourage you to consider Reviewer 1's remaining remarks, and we suggest you consider incorporating the suggested references and points in your manuscript, as we think this would improve the discussion. **IMPORTANT: Additionally, as you consider reviewer 1's remaining points, please address the following data and other policy-related requests: 1) TITLE: After some discussion, we think that the title should be edited to make it more broadly accessible. We think the ": a tale of double integration" is somewhat confusing to a reader who hasn't read your study, and so suggest that this either be removed, or possibly more clearly incorporated into the title to make it clear exactly what you did and/or found. For example, we might suggest the title be changed to something like (if you agree and if supported): --"Motor accumulation is a final arbiter in sensorimotor decision-making" or--"A double integration, sensory evidence and motor accumulation, framework for understanding sensorimotor decision-making"We will ultimately leave it up to you to refine the title further. 2) ABSTRACT: Similar to the title, we think that the abstract should be edited to make the study more accessible to our broad readership. We have some specific suggestions to increase accessibility, but more broadly we suggest that it may be helpful for you to solicit input from a non-neuroscience colleague. --We think that it would be helpful to explain what a leaky motor accumulator is.--We note you write about 'the behavioral data' and EEG signatures but dont explain this data - From the abstract, this could be a modelling study only- we suggest this be made clearer. -- We think that you should define what urgency manipulations are.--Please note that per journal policy, the model system/species studied should be clearly stated in the abstract of your manuscript.3) ETHICS STATEMENT: Thank you for providing an ethics statement in your methods section. Please update this to note whether the investigation was conducted according to the principles expressed in the Declaration of Helsinki.4) BLURB: In the relevant section of our online system, please provide a blurb which (if accepted) will be included in our weekly and monthly Electronic Table of Contents, sent out to readers of PLOS Biology, and may be used to promote your article in social media. The blurb should be about 30-40 words long and is subject to editorial changes. It should, without exaggeration, entice people to read your manuscript. It should not be redundant with the title and should not contain acronyms or abbreviations. 5) DATA AVAILABILITY: Thank you for providing the behavioral and EEG data related to your study on ownCloud. Is it possible to generate a DOI for this data? If not, we ask that you put this data on a different repository that allows for the generation of a permanent record. 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Read more information on sharing protocols at Please do not hesitate to contact me should you have any questions.Sincerely,LukeLucas Smith, Ph.D.Senior Editor,PLOS Biologylsmith@plos.org------------------------------------------------------------------------Reviewer remarks:Reviewer #1, Jeffrey D Schall (note: reviewer 1 signed this review): The authors have responded to the comments, critiques, and suggestions very well. I have no further comments to make about the revised manuscript, which is improved empirically and conceptually. However, in the spirit of scientific inquiry, let me offer some reactions to the comments of the other referees as they relate to this manuscript and associated work. Let me preface these remarks by stating that I am *not* seeking more citations, just better understanding.R2C4a, the referee wrote: "It is generally believed that the decision threshold crossing precedes the onset of the motor response and that part of the "nondecision" time that typically is fitted when fitting standard integration-to threshold models is related to the preparation/execution of the motor response. Model signals that are time locked to the decision threshold crossing should therefore not directly be compared with neural signals that are time-locked to the onset of the motor response." - This comment is based on some architectural suppositions that recent work has addressed. Principally, the neurons doing the accumulation of evidence in the Gated Accumulator Model of Purcell et al. are the presaccadic movement neurons that can also be described as "motor preparation". In fact, in other work we showed that the neurons in FEF doing evidence accumulation are also doing response preparation and inhibtion: Middlebrooks PG, Zandbelt BB, Logan GD, Palmeri TJ, Schall JD. (2020) Countermanding perceptual decision-making. iScience 2020 23(1):100777. Because this manuscript is advancing the literature in its identification of distinguishable stages of processing, it seems useful to think carefully about the propositions linking particular neurons with particular processes. For what it's worth, I've meditated on this problem in this recent review: Schall JD (2019) Accumulators, neurons, and response time. Trends in Neurosciences. 42(12):848-860.R2C5, in reply the authors wrote, "On the other hand, brain regions may not contain fully homogenous sets of neurons." - The heterogeneity of neurons in every cortical area has been established beyond dispute. We see it in FEF, e.g., Lowe Kaleb A. and Schall JD (2018) Functional categories of visuomotor neurons in macaque frontal eye field eNeuro 5(5): ENEURO.0131-18.2018. doi: 10.1523/ENEURO.0131-18.2018. It is also the case in LIP :2254-67), even though many authors do not incorporate such differences into their theoretical outlooks. Reviewer #2, Jochen Ditterich (note reviewer 2 signed this review): Thank you for your detailed response. All of my comments have been successfully addressed. 13 Jun 2023Attachmentresponse_review2.docxSubmitted filename: Click here for additional data file. 15 Jun 2023Dear Dr Philiastides,Thank you for the submission of your revised Research Article "Secondary motor integration as a final arbiter in sensorimotor decision-making" for publication in PLOS Biology and thank you for addressing our editorial requests in this revision. 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Accessory spleen and splenosis are two types of ectopic spleen. An accessory spleen can be found in various sites in the abdomen, but an intrahepatic accessory spleen is very rare though many case reports of intrahepatic splenosis are available.This case report presents the incidental diagnosis of accessory spleen in the liver of a 57-year-old male while undergoing laparoscopic diaphragmatic repair. The patient had a history of splenectomy 27 years ago for hereditary spherocytosis, but his routine haemogram did not show any features of the ectopic splenic function. Intraoperatively, a mass was suspected in the liver and was resected. Histopathology revealed an accessory spleen with well-preserved red and white pulp architecture. Though a history of splenectomy suggested a diagnosis of splenosis, a well-encapsulated and preserved splenic architecture confirmed the diagnosis of accessory spleen.Accessory spleen or splenosis can be diagnosed radiologically using Tc-99m-labeled heat-denatured red blood cells (HRBC) and Tc-99m sulfur colloid scans, but the gold standard is histopathological examination. Ectopic spleen is mostly asymptomatic but usually results in unnecessary surgeries as it is difficult to differentiate from benign or malignant tumors. Thus, a high degree of suspicion and awareness is necessary for early and prompt diagnosis. Ectopic splenic tissue occurs in two different forms - accessory spleen and splenosis. Accessory spleen occurs due to developmental anomalies. Splenosis occurs due to trauma or surgery where some portion of the splenic tissue gets incorporated in the peritoneal cavity and receives local blood supply and becomes functional splenic tissue  An accesThe present case report is a rare case of accessory spleen located in the liver diagnosed incidentally during a diaphragmatic hernia repair in a 57-year-old male with a history of splenectomy for Hereditary Spherocytosis 27 years ago.A 57-year-old male presented to the Emergency Department with a history of abdominal distension and feeling of incomplete evacuation of bowel for ten days. He is a diabetic and hypertensive on regular medications. In 1995, he underwent a laparoscopic cholecystectomy along with an open splenectomy for Hereditary Spherocytosis. He also underwent ureteroscopic lithotripsy in 2018 and developed COVID-19 pneumonia in 2021.A general examination of the patient revealed no pallor, a heart rate of 98 beats /minute, blood pressure of 150/111mmHg, oxygen saturation of 99% in room air, blood sugar of 194mg/dl, and body temperature of 98.6F.5.Systemic examination showed a soft abdomen with sluggish bowel sounds and a surgical scar of the previous left subcostal incision. Hematological investigations showed blood urea levels at 26 mg/dl with borderline creatinine (1.3mg/dl), sodium at 137 mEq/L, potassium at 4.1 mEq/L, C-reactive protein at 12mg/l, and Hb at 13.4 g/dl. The total leucocyte count was elevated with 13600 cells /cu mm, with a normal differential count and a platelet count of 3.66 x10As the patient showed features of partial intestinal obstruction, a plain abdominal CT was done. Intravenous contrast was not given as his renal parameters were borderline. CT showed focal dilated mid-ileal loops with air-fluid level, a left hemi diaphragmatic hernia with herniation of gastric fundus and omental fat, and a small right kidney with a focal area of cortical scarring.The patient was managed conservatively for intestinal obstruction with nil per mouth, intravenous fluids, and other supportive medications. The patient improved with medical management and was discharged. He was reviewed in the outpatient department on day 19 and day 71 after the initial presentation with abdomen fullness and excessive sound from the abdomen.As the patient had a diaphragmatic hernia and mild symptoms of bowel adhesions persisting, elective laparoscopic adhesiolysis with a repair of the hernia was planned. Preoperative investigations were essentially normal except for elevated potassium which was 5.7 meq/l, while renal function tests were within normal limits before surgery and the treadmill test was negative at 10 METS.Surgery was performed under general anesthesia. Intraoperatively, while mobilizing the liver, a mass lesion was suspected in the lateral segment of the left lobe of the liver (segment 2/3) Figure .A review of the previous CT was done and discussed with the radiologist, and a conclusion of a suspicious mass was made (though not contributory as it was a non-contrast film) Figure , 3.Due to the non-availability of a laparoscopic intraoperative ultrasound and after discussing with relatives and obtaining consent, it was decided to convert to laparotomy and proceed. Laparotomy was done through the previous left subcostal incision. Non-anatomic resection of the liver-containing mass was done, along with diaphragmatic hernia repair and adhesiolysis. Reinforcement of the laparotomy was done with a mesh as the scar was very weak. A cut section of the specimen showed an intrahepatic firm oval brown-colored lesion measuring 3x1.2 cm Figure .The patient was extubated at the end of the surgery. Postoperatively, the patient had derangement of renal function tests which normalized with conservative management. The patient was discharged on postoperative day seven. Histological analysis revealed a well-circumscribed and encapsulated lesion with preserved white and red pulp architecture, which was suggestive of accessory spleen. Figure Figure An accessory spleen arises due to the failure of fusion of multiple splenic analges in the dorsal mesogastrium during the fifth week of embryonic development 4]. A me. A me4].An accessory spleen is mostly asymptomatic but can present with infarction, hemorrhage, torsion, and rupture . UsuallyAn intrahepatic spleen does not need any resection if it is asymptomatic. In this case, we proceeded with resection as the possibility of malignancy could not be ruled out. Our patient was admitted for a diaphragmatic hernia repair and adhesiolysis. Despite the open splenectomy for Hereditary Spherocytosis, his laboratory parameters did not show any features of any functional accessory spleen. Though the presence of an accessory spleen is relatively common, its intrahepatic location is very rare. Most of the cases of intrahepatic spleen described in the literature are splenosis rather than an accessory spleen.Izzo et al.  have desHistologically, the spleen can display various developmental anomalies including complete agenesis to polysplenia. Ectopic splenic tissue can be either congenital (accessory spleen or splenunculi ) or acquired (splenosis) . An acceIn our patient, sections studied show a well-circumscribed lesion composed of splenic tissue with preserved white pulp and red pulp. This tissue was separated from the adjacent liver tissue by a well-defined capsule. The presence of a solitary lesion with normal splenic architecture and a capsule separating the splenic tissue from hepatic parenchyma made us consider this as an ectopic hepatic spleen/accessory spleen . The absIntrahepatic spleen, though rare, should be considered in the differential diagnosis of hepatic lesions, especially in patients who have undergone a splenectomy. Awareness and a high degree of suspicion, along with adequate imaging, can prevent unnecessary hepatic resections. In post-splenectomy patients, the presence of Howell-Jolly bodies may be indirect evidence of the absence of ectopic spleen.


Sticks and Stones Or Throw Me a Bone BOGSAT. While not very flattering, BOGSAT  accurately describes traditional decision making across many disciplines, including medicine. In an attempt to validate expert opinion panels using the BOGSAT method, the Evidence-Based Medicine (EBM) movement sprang up from the original writings of Dr. David Sackett and colleagues at McMaster University, Hamilton, Ontario. They defined EBM as the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.


Synechocystis sp. PCC 6803 at 2.6-Å resolution. The structure shows the CpcD domain of ferredoxin: NADP+ oxidoreductase is located at the distal end of CpcL-PBS, responsible for its attachment to PBS. With the evidence of ultrafast transient absorption and fluorescence spectroscopy, the roles of individual bilins in energy transfer are revealed. The bilin 1Iβ822 located near photosystem I has an enhanced planarity and is the red-bilin responsible for the direct energy transfer to photosystem I.Phycobilisomes (PBS) are the major light harvesting complexes of photosynthesis in the cyanobacteria and red algae. CpcL-PBS is a type of small PBS in cyanobacteria that transfers energy directly to photosystem I without the core structure. Here we report the cryo-EM structure of the CpcL-PBS from the cyanobacterium  CpcL-phycobilisome (PBS) is a type of small PBS that transfers energy directly to photosystem I (PSI) without a core structure. Here the authors combine cryo-electron microscopy and ultrafast spectroscopy to explore energy transfer pathway in CpcL-PBS. They are the first organisms that created linear electron transfer with two photosystems, photosystem II (PSII) and photosystem I (PSI), and were responsible for the rise of oxygen content on earth more than 2.4 billion years ago3. The major light harvesting antennae for capturing solar energy in cyanobacteria and red algae are phycobilisomes (PBS)7, which transfer the absorbed light energy to either PSII or PSI to drive electron transfer. PBS consists of phycobiliproteins (PBP), which have covalently attached pigments called bilins, and linker proteins8. Two types of PBS exist in cyanobacteria, the CpcG-PBS and the CpcL-PBS. CpcG-PBS consist of two parts: a core and peripheral rods, which are associated with the core through linker proteins CpcG. Recently determined cryo-EM PBS structures from red algae10 and the cyanobacteria13 revealed how linker proteins and PBP are organized into a highly ordered light harvesting architectures. The CpcL-PBS has a much smaller size and consists of only one rod without allophycocyanin core16. CpcL-PBS, which is attached to thylakoid membranes through the linker protein CpcL , is associated with PSI18 and able to transfer absorbed light energy to PSI19. CpcL-PBS is also involved in the formation of NAD(P)H-dehydrogenase (NDH)-CpcL-PBS-PSI (NDH-PBS-PSI) supercomplex for cyclic electron transfer (CEF)20 and a recent study shows that the attachment of ferredoxin-NADP+ oxidoreductase (FNR) to the CpcL-PBS is required for CEF21. Most cyanobacterial FNR contains three domains: CpcD domain, FAD binding domain, and NADPH binding domain, and the three-domain FNR (FNR3D) is attached to the peripheral rods of the cyanobacterial CpcG-PBS and CpcL-PBS24. However, the attachment of FNR3D to the PBS rods has not been observed in the recently determined cryo-EM structures CpcG-PBS13. To understand the mechanism for direct energy transfer from CpcL-PBS to PSI and its role in NDH-PBS-PSI supercomplex formation, we determine the cryo-EM structures of the CpcL-PBS with an attached FNR from Synechocystis 6803. Combined with picosecond spectroscopic evidence, our study reveals the nature of the terminal emitter-like red-shifted bilin and shed light on how CpcL-PBS could effectively transfer light energy within PBS and to PSI in the absence of a PBS core.The cyanobacteria are one of the earliest groups of organisms to convert solar energy to chemical energySynechocystis 6803 lacking the genes of apcAB24 and the purified CpcL-PBS were analyzed spectroscopically and biochemically for its composition and functional integrity  has not been observed in other PC trimer or rods  in a nearly linear manner with CpcL close to the thylakoid membrane and FNR3D at the distal end , the loop between β1 and β2 , and the helix 9 (α9) of the Pfam01383 domain of CpcC1. These two loops fold towards CpcL and interact from two opposite sides. This tight interface is mediated by a large number of residues of CpcC1 and CpcL, including both polar and hydrophobic sidechains  from the peripheral rod of Synechocystis CpcG-PBS, which is equivalent to the bilin 1Iβ821 of CpcL-PBS, has the three respective angles of 30°, 11°, and 15°, very similar to that of the bilin 1Iβ821 of CpcL-PBS , which is an open chain tetrapyrrole covalently linked to PC at ring A. The conformation of a bilin is defined by the planes of its four pyrrole rings and the three angles between rings. Seven different representative bilins, four from the CpcL-PBS and three from CpcG-PBS, are compiled for conformational comparison Fig. . The maj823 Fig. : the angely Fig. . The ter 32 Fig. . TherefopcL Fig. , it is ePBS Fig. . The bilPBS Fig. . The bil84) and two on β subunits (β82 and β152), similar to the PC αβ monomers of the peripheral rods of CpcG-PBS4. Located in the center of the PC hexamer near the thylakoid membrane, CpcL is close to four bilins and extensively interacts with the three bottom β82 bilins   Fig. . Spectro1Iβ821 bilin from CpcG-PBS rod and CpcL-PBS shows that more interactions could be observed between the bilin 1Iβ821 and CpcL than that between the bilin 1Iβ821G and CpcG   Fig. , 7c. In ues Fig. , 7b. The25   Fig. . In factg D Fig. . In this1IIβ821 ; the bilins 1Iβ823(RS), 1Iβ821, (RL) give rise to the spectra of C651nm/C669nm (401 ps); and the bilin 1Iβ822 (T) give rise to the spectrum of C672nm (1999 ps). The structure and the time-resolved fluorescence emission spectrum of the bilin 1Iβ822 (component T) has special characters of red-PCB like the bilin α84 in ApcD35, clearly demonstrating here that CpcL-PBS has structural features for the formation of a terminal emitter-like red-PCB for direct energy transfer to PSI. Our study also shed light on energy transfer mechanisms in other types of PBS found in red algae and cyanobacteria, including Acaryochloris sp.36.With the determination of the cryo-EM structure of CpcL-PBS and of the components in energy transfer by ultrafast spectroscopy, the energy transfer process from a regular PCB to the “red PCB” within CpcL-PBS is deduced. In femtosecond time-resolved transient absorption spectra, the fastest decay component PSynechocystis sp. PCC 6803 (Synechocystis 6803) and its mutant strain are grown in BG11 medium37 at 25 °C with light intensity of 50 μmol photons m−2 s−1. The medium for the growth of the mutant strain was supplemented with 10 μg ml−1 erythromycin and 10 mM glucose. The cultures were bubbled gently with air plus 1% CO2.The wild-type strain of 38 with some modifications. The upstream and downstream region of apcAB gene and a DNA fragment encoding an erythromycin-resistant gene were amplified by polymerase chain reaction (PCR) using primer pairs of P1/P2, P3/P4, and P5/P6, respectively  (w/v), samples were centrifuged at 20,000 × g. The supernatant was loaded immediately onto a sucrose gradient. The sucrose gradients were made from buffer A , 0.03% β-DDM (w/v), pH 7.0) by adding sucrose to these concentrations: 0.4, 0.55, 0.7, 0.85, 1.0, and 1.5 M. The samples were centrifuged at 370,000 × g for 16 h using a TLA110 rotor on Beckman Optima MAX-XP centrifuge. CpcL-PBS samples were collected at the interface of 0.85 M to 1.0 M sucrose. The sucrose of purified CpcL-PBS samples was removed by ultrafiltration with 30 kD Millipore centrifugal filters. Absorption spectra and fluorescence emission spectra were obtained as described previously11.CpcL-PBS was isolated from the ΔapcAB mutant strain according to Liu et al.−1. Aliquots (3.5 μl) of samples were loaded onto glow-discharged (20 s) holey carbon films copper grids  and waited for 60 s. 3.5 μl aliquot of a buffer ) was then added twice to the grid and mixed immediately with the sample before vitrification . After blotting for 2 s, the grid was plunged into liquid ethane with an FEI Vitrobot Mark IV (18 °C and 100% humidity). Cryo-grids were first screened in a Talos Arctica operated at 200 kV (equipped with an FEI CETA camera). Grids of good quality were transferred to a FEI Titan Krios operated at 300 kV with Gatan BioQuantum GIF/K3 direct electron detector for data collection.Before preparing grids for cryo-EM, CpcL-PBS samples were concentrated to ~0.75 mg ml−/Å2 per second using the EPU 2 software. A GIF Quantum energy filter (Gatan), with a slit width of 20 eV was used at the end of the detector. The defocus range was set from −1.0 to −1.8 μm. The total exposure time was 3.84 s and 32 frames per image were acquired with a total electron exposure of ∼60 e−/Å2. Statistics for data collection are summarized in Supplementary Table Movies were recorded with a BioQuantum GIF/K3 direct electron detector (Gatan) in the super-resolution mode at a nominal magnification of ×81,000, with an exposure rate of 17.9 e39. The Gctf program (v1.06)40 was used to estimate the contrast transfer function (CTF) parameters of each motion-corrected image. All the following data processing was performed with Relion-3.141. 1350 particles were manually picked and subjected to 2D classification to generate templates for automatic particle picking. Then autopicking was done to the images that were manually selected for treatment. The picked particles were subjected to one round of 2D classification, and high-quality particles were further selected for subsequent 3D classifications. Initial model was generated from these particles. After multiple rounds of 3D classification, relatively homogeneous particles were selected for 3D refinement, resulting in a map with a 2.64 Å overall resolution after mask-based post-processing, based on the gold-standard FSC 0.143 criteria. The local resolution map was analyzed using ResMap42 and displayed using UCSF Chimera43. Workflow of data processing was illustrated in the Supplementary Fig. To determine the 3D structure of the CpcL-PBS complex, Two batches of movie stacks were recorded. Raw movie frames were aligned and averaged into motion-corrected summed images with a pixel size of 1.07 Å by MotionCor2Synechocystis 6803 (PDB code 4F0T)44 was used as the initial template for PC hexamer modeling. The atomic models of CpcL, CpcC1, CpcC2, and PetH were adopted from AlphaFold databases45. All structures were firstly docked into the density map using UCSF chimera43 and then manually adjusted in COOT46. The final atomic models were refined in real space using PHENIX47 with secondary structure and geometry restraints applied. The final atomic models were evaluated using Molprobity48 and the statistics of data collection and model validation were included in Supplementary Table Crystal structure of a PC αβ monomer from 49. Briefly, a Ti:sapphire laser  delivered 100 fs (FWHM) pulses at a central wavelength of 800 nm at a repetition rate of 1 kHz. Then the pulses were split into two beams using a beam splitter: one was used to generate a supercontinuum white light which was used as the probe light. The other was used to pump a home-built non-collinear optical parametric amplifier (NOPA) for generating excitation source of tunable wavelength in the visible region. In current experiment, the excitation wavelength was set at 590 nm. The excitation energy was ∼10 nJ per pulse with a spot size of ∼120 μm. The relative polarization of the pump and probe pulses was set at the magic angle. The sample was placed into a 1-mm-thick fused silica flow cell in order to avoid sample damage, the optical density (OD) of the sample was set at 0.26 at its maximum absorption wavelength at 620 nm. The decay kinetics was scanned at a temporal resolution of 0.02 ps per step at early stage while a varied and larger time-delay steps were used at later stage. The time-resolved difference absorption spectral data were averaged over 30 times to obtain a better signal-to-noise ratio.The details of the home-built ultrafast absorption spectroscopy setup has been described elsewhereFor the time-resolved fluorescence measurements, the sample here was placed into a 1-mm-thick fused silica cuvette with an optical density of 0.24 at 620 nm. Femtosecond amplifier  delivered 100 fs pulses at a repetition rate of 5 kHz. The excitation wavelength was set at 565 nm from a commercialized tunable optical parametric amplification system  pumped by the femtosecond amplifier. Pulse energy of 5 nJ per pulse with a spot size of ~200 μm was used to excite the sample. A high-quality 600 nm long-pass band filter was used to block the residual excitation pulse. The emitted fluorescence light was collected and focused into a spectrograph and measured by a streak camera 5200  operating at 1.4 ns or 5 ns scanning ranges with a time resolution of ~30 ps or ~200 ps, respectively. The spectral window recorded by the CCD of streak camera was 260 nm in the measurements, covering the fluorescence wavelength of the sample. The time-resolved fluorescence data were averaged over 10 single measurements.49. DAS (dynamics-associated different spectra) is a kinetic-dependent differential spectrum that can be obtained from global fitting directly. The species-associated emission spectra (SAS) and the corresponding kinetics could be resolved by establishing a model based on the result from DAS as SAS is determined by the analytical model we have chosen. Here we firstly obtained the lifetime of each component from DAS, and then we attribute each process to the corresponding pigments involved in energy transfer model based on the pigment molecules resolved in the cryo-EM structure:Global fitting was used to resolve the individual spectral components from the congested spectrum. The program was implemented based on LabView. We employed the method of singular value decomposition (SVD) according to the previous report50.More details about global fitting could be found in our previous publicationsFurther information on research design is available in the Supplementary InformationPeer Review FileReporting Summary


Knowledge management (KM) emerged as a strategy to promote evidence-informed decision-making. This scoping review aims to map existing KM tools and mechanisms used to promote evidence-informed health decision-making in the WHO European Region and identify knowledge gaps.Following the Joanna Briggs Institute (JBI) guidance for conducting scoping reviews, we searched Medline, PubMed, EMBASE, the Cochrane library, and Open Grey. We conducted a descriptive analysis of the general characteristics of the included papers and conducted narrative analysis of the included studies and categorized studies according to KM type and phase.Out of 9541 citations identified, we included 141 studies. The KM tools mostly assessed are evidence networks, surveillance tools, observatories, data platforms and registries, with most examining KM tools in high-income countries of the WHO European region. Findings suggest that KM tools can identify health problems, inform health planning and resource allocation, increase the use of evidence by policymakers and stimulate policy discussion.Policymakers and funding agencies are called to support capacity-building activities, and future studies to strengthen KM in the WHO European region particularly in Eastern Europe and Central Asia. An updated over-arching strategy to coordinate KM activities in the WHO European region will be useful in these efforts.The online version contains supplementary material available at 10.1186/s12961-023-01058-7. There is increased awareness and need among policymakers on the use of the best available research evidence and data to guide public health and health systems decisions. Barriers to evidence-informed policymaking included the large volume of evidence available and poor access to research , 2. KnowKM is central to achievement of Sustainable Development Goals by bridging the know-do gap and strengthening health systems. Effective KM tools and mechanisms can strengthen national health information systems through reducing data collection burden and proper management and use of big data to complement traditional methods for timely measurement and monitoring of health status and health system performance .The COVID-19 pandemic has proved more than ever the importance of KM. The European Program of Work 2020–2025 emphasized the critical need for countries to strengthen their health data and information systems to ensure that decisions are data driven and facilitate public health monitoring . In timeTo our knowledge, there is no previous work that mapped KM initiatives, tools and mechanisms in the WHO European Region. This scoping review aims to map, identify knowledge gaps and provide an overview of available research evidence on existing KM tools and mechanisms used to promote evidence-informed decision-making in the WHO European Region. It also aims to examine implementation considerations and reported outcomes of the identified KM tools and mechanisms in public health, specifically health systems, in terms of promoting evidence-informed decision-making.https://doi.org/10.17605/OSF.IO/Q2GTU.We registered the protocol for this scoping review in Open Science Framework A scoping review is typically used to present “a broad overview of the evidence pertaining to a topic, irrespective of study quality, to examine areas that are emerging, to clarify key concepts and to identify gaps”. We used the updated Joanna Briggs Institute (JBI) guidance for conducting scoping reviews . We alsoknowledge generation ,knowledge storage ,knowledge processing ,knowledge transfer ,knowledge utilization.We included studies on KM tools and mechanisms based on traditional and digital data sources . KM involves :knowledgWe included studies that assess, examine or describe the role or the impact of the knowledge management tools and mechanisms on health policies and decision-making. We considered public policy that is any statement or position taken by the government or government departments. We excluded studies on knowledge management tools in clinical setting or health business or implemented at organizational level. We included primary studies, narrative reviews, systematic reviews, editorials and commentaries. We restricted our eligibility criteria to articles and reports published after the year 2005. We excluded protocols and abstracts of meetings and conferences. We restricted to studies focusing on the WHO European region  to translate articles to English language. We ran the search from January 2005 till September 2022. We chose to restrict our search to 2005 as this year marks the rise of the “web 2.0” which had major implications on the internet in general and on knowledge management [We searched the following electronic databases: Ovid Medline, PubMed, EMBASE, the Cochrane library, and Open Grey. We used both index terms and free text words for the three following concepts: knowledge management, policy and Europe. The search terms and MeSH terms for each database were developed with the guidance of an information specialist and with input from experts in KM. We also mapped studies and report on KM to identify additional search terms. We did not limit the search to specific languages. For articles in languages different than English, we used DeepL Translator (nagement . Search https://www.covidence.org/) where we conducted the selection process in two stages. Teams of two reviewers used the above eligibility criteria to screen titles and abstracts of identified citations in duplicate and independently for potential eligibility. We retrieved the full text for citations judged as potentially eligible by at least one of the two reviewers. Same teams of reviewers screened the full texts in duplicate and independently and resolved disagreements by discussion or with the help of a third reviewer. We pilot tested screening forms and conducted calibration exercises with a subset of studies to ensure the eligibility criteria are clear and reviewers are on high-level of agreement in the selection process.We imported the results into Covidence , year, language and type of publication, study design, setting (e.g. country(ies) subject of the paper and income level classification according to the World Bank list of economies issued in June 2021), characteristics of the intervention , key results, policy or decision examined , statements on funding and conflict of interest of authors.We conducted descriptive analysis of the general characteristics of the included papers including intervention, study designs, settings and outcome. We also conducted narrative analysis of the included studies and categorized studies according to KM type and phase.We did not conduct risk of bias assessment and methodological assessment of the quality of evidence, which is consistent with the Joanna Briggs Institute guidance manual.n = 324), not intervention of interest (n = 173), not design of interest (n = 104), missing full text (n = 48), not setting of interest (n = 31) and duplicate (n = 4).Figure n = 70; 49.6%) followed by studies examining knowledge management tools at a regional level or across different countries in the WHO European region . Studies were mainly conducted by authors based in high-income European countries . Many of the studies were descriptive case studies or employed observational study design. The KM tools mostly assessed in included studies were evidence networks and collaborations  followed by surveillance tools, observatories, and data platforms , and registries . Most of the studies were reported as funded  and reported no conflict of interest of authors .Table Figure Eight studies assessed the role of indicators in evidence-informed policymaking  guidance for conducting scoping reviews  and we fThis scoping review can inform researchers and funders interested in understanding the role of KM tools and mechanisms in influencing health decision-making mainly in the WHO European region. While we acknowledge the challenges of measuring the effectiveness of knowledge management tools on decision making, researchers are encouraged to conduct better-designed and rigorous research studies to assess this relationship to inform efforts aiming at promoting evidence-informed decision-making in this region mainly in CA and EE countries. Researchers are also called to develop and follow guidelines for designing and reporting studies evaluating the effectiveness or impact of KM tools and mechanisms. Our scoping review can also inform the work researchers aiming at mapping KM initiatives, tools and mechanisms in other WHO regions.As plain language summaries, policy dialogues and evidence networks were shown to increase the use of research evidence by policymakers and stimulate discussion on policy issues, funders are called to support capacity-building activities in this aspect, particularly in the eastern part of the WHO European Region, where research production and KM activities are still at their early stages. Given that most studies on KM systems, tools, and platforms found were from high-income countries in Western Europe, there is a need for further understanding the needs of the CA and EE countries for KM platforms and systems, and accordingly conduct twinning and knowledge exchange activities between high income countries with developed KM systems and platforms with countries who still lag behind. The findings also highlight the need to institutionalize the use of evidence in decision-making and leverage on existing KM tools and mechanism to inform health policies and national strategies.Health systems managers and policymakers are called to ensure data availability, completeness, and standardization of data collection and reporting mechanisms to improve their country’s health information systems and the work of registries, surveillance tools and observatories. These KM tools would allow for better health planning including resource allocation and reimbursement decisions.Additional file 1: Appendix 1: List of Member States of the WHO European Region.Additional file 2: Appendix 2: Search strategies.Additional file 3: Appendix 3. Table of characteristics - Indicators.Additional file 4: Appendix 4. Table of characteristics - Surveys.Additional file 5: Appendix 5. Table of characteristics - Registries.Additional file 6: Appendix 6. Table of characteristics - Surveillance and Observatories.Additional file 7: Appendix 7. Table of characteristics - HIS.Additional file 8: Appendix 8. Table of characteristics - Evidence Synthesis.Additional file 9: Appendix 9. Table of characteristics - Health Reports.Additional file 10: Appendix 10. Table of characteristics - Policy dialogues.Additional file 11: Appendix 11. Table of characteristics - Evidence networks.Additional file 12: Appendix 12. Table of characteristics - Community engagement.Additional file 13: Appendix 13. Table of characteristics - Decision Support Tools.


Managing and rehabilitating Achilles tendinopathy can be difficult, and the results are often unsatisfactory. Currently, clinicians use ultrasonography to diagnose the condition and predict symptom development. However, relying on subjective qualitative findings using ultrasound images alone, which are heavily influenced by the operator, may make it difficult to identify changes within the tendon. New technologies, such as elastography, offer opportunities to quantitatively investigate the mechanical and material properties of the tendon. This review aims to evaluate and synthesise the current literature on the measurement properties of elastography, which can be used to assess tendon pathologies.A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. CINAHL, PubMed, Cochrane, Scopus, MEDLINE Complete, and Academic Search Ultimate were searched. Studies assessing the measurement properties concerning reliability, measurement error, validity, and responsiveness of the instruments identified in healthy and patients with Achilles tendinopathy were included. Two independent reviewers assessed the methodological quality using the Consensus-based Standards for the Selection of Health Measurement Instruments methodology.Out of the 1644 articles identified, 21 were included for the qualitative analysis investigating four different modalities of elastography: axial strain elastography, shear wave elastography, continuous shear wave elastography, and 3D elastography. Axial strain elastography obtained a moderate level of evidence for both validity and reliability. Although shear wave velocity was graded as moderate to high for validity, reliability obtained a very low to moderate grading. Continuous shear wave elastography was graded as having a low level of evidence for reliability and very low for validity. Insufficient data is available to grade three-dimensional shear wave elastography. Evidence on measurement error was indeterminate so evidence could not be graded.A limited number of studies explored quantitative elastography on Achilles tendinopathy as most evidence was conducted on a healthy population. Based on the identified evidence on the measurement properties of elastography, none of the different types showed superiority for its use in clinical practice. Further high-quality studies with longitudinal design are needed to investigate responsiveness.The online version contains supplementary material available at 10.1186/s13047-023-00623-1. The Achilles tendon is the most commonly injured tendon in the body . AchilleAchilles tendinopathy can be difficult to manage and rehabilitate, taking a prolonged period to obtain positive results in pain reduction and normal functioning , 9. AlthWith improvements in ultrasound technology, elastography has emerged as a potential measurement instrument offering opportunities to quantitatively investigate the mechanical and material properties  within tKnowledge of measurement properties helps to inform the clinician and researchers in the choice of the most appropriate equipment to be used whilst achieving more accurate, reliable, and valid results. Using measurement instruments with poor measurement properties increases the risk of bias in results obtained and may fail to detect a true change when assessing different treatment modalities and monitoring rehabilitation . ConsideThis systematic review was designed and conducted according to guidelines outlined by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) .https://www.cosmin.nl/tools/PubMed-search-filters/). The full search strategy is available in Appendix Electronic databases including EBSCO, CINAHL, PubMed, Cochrane, Scopus, MEDLINE Complete and Academic Search Ultimate were searched by one investigator (TM). A broad search strategy was developed using both free-text terms and MeSH index terms using a combination of keywords as seen in Appendix Two independent reviewers (TM and AG) screened the title and abstract of available articles to identify studies that used elastography to measure the mechanical properties of the Achilles tendon, according to the following inclusion and exclusion criteria as listed in Table Data were extracted by the primary reviewer (TM) for each of the included studies. The secondary reviewer checked the extracted data. Data extracted included: the study design, setting, method of assessment, population characteristics, outcome measures, equipment used and specifications, statistical results, measurement properties focusing on reliability, measurement error, validity, responsiveness, and the limitations of the study. When reliability or measurement errors were investigated, the seven elements that construct the research question were also extracted as per guidelines by the COSMIN Manual 2021 Appendix .The included articles were assessed for methodological quality by the two independent reviewers, using the COSMIN methodology , 26 consSecondly, the statistical results of every study were rated against the criteria for good measurement properties as sufficient ( +), insufficient (-), or indeterminate (?) . ReliabiFinally, the quality of the evidence was graded  using the modified Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. This approach takes into consideration the methodological quality of the studies (COSMIN score), inconsistency of the results per measurement property between the different articles, imprecision, including the total sample size of the available studies and indirectness involving evidence from different populations than the population of interest in this review. Multiple studies were only combined when the same measurement property was evaluated for specific types of elastography. Moreover, when results across reported test conditions were consistent, these results were summarized to determine the overall evidence of the measurement properties. Measurement properties from studies that were rated ‘doubtful or inadequate’ on the COSMIN ROB were not eligible to be combined in evidence synthesis. Any discrepancies between reviewers were discussed and resolved via consensus with a third reviewer (NP).The literature search was conducted on 10th September 2020 and updated on 15th January 2022. It yielded 1644 articles, of which 597 were duplicates and therefore were removed. Of the 1047 article titles and abstracts which were screened, 83 articles were eligible for full-text assessment. Of these 83 articles, 20 articles were found to be appropriate for inclusion, together with another article identified through citation searching. Thus, analysis was conducted on a total of 21 articles. The full PRISMA flow diagram summarizing the screening process and results are provided in Fig. A summary of study characteristics, including participants’ demographics, are provided in Table Results were grouped according to the type and mode of action of elastography for better homogeneity and consistency within the results. Of the 21 articles included, seven articles investigated strain elastography where strain ratio was calculated as a semi-quantitative measure of stiffness , 32–37, The overall quality ratings for each article assessing these measurement properties were predominantly adequate. Articles rated as doubtful are reported at this stage but will not be included in the following phase to combine results for best-quality evidence. These doubtful articles had non-optimal statistical analyses or a lack of proper reporting regarding the blinding of assessors. Refer to Appendix Given the large variety between methodologies and the identified inconsistencies within each type of elastography results were combined cautiously. Appendix Tables Construct validity of strain ratio received positive ratings for correlation to both VISA-A and ultrasonographic imaging when assessing tendinopathic participants. Since only one study investigated this correlation, grading of evidence was not conducted. The strain ratio correlated to isometric contraction obtained a moderate level of evidence, with the ability to significantly detect a decrease in this ratio  with the increase in loading. The intra-rater reliability of the strain ratio was rated as having a moderate level of evidence, for both longitudinal and transverse probe placements. However, the former obtained positive results, with only one article showing low ICC, while the latter obtained only negative ratings within a combined sample size of only 58 participants. Inter-rater reliability was downgraded to moderate for the longitudinal probe placement due to inconsistencies in results.Convergent validity of SWV was correlated to the patient-reported outcome measure, the VISA-A, when tendinopathy was being assessed and was graded as high evidence. For discriminative validity, SWV was able to measure significant differences in foot positions and age, both receiving a high level of evidence, while moderate evidence was found when differentiating between pathological and healthy tendons. The quality of evidence for inter-rater reliability was rated as moderate due to inconsistency in results when using a longitudinal probe position and indirectness when using a transverse position. Intra-rater reliability within the same day was not graded, as only one article was found. However, when intra-rater reliability was assessed in different sessions, mixed results were present, with some articles having an ICC of 0.71 while others reported a lower value of 0.54. This conclusion was based on a total sample size of only 36 participants.No grading of evidence was possible for the criterion validity of SWE as only one article assessed the correlation to MRI, B-mode ultrasound, power Doppler, and ultrasonographic tissue characterisation (UTC). A good correlation between instruments was found for diagnostic accuracy. When convergent validity was assessed, no correlation was found between shear wave modulus and isometric contraction in the two articles. Thus, the grading of evidence was downgraded to low due to the small healthy sample size on which the results are based. Insufficient data is present for all types of reliability assessed when using shear wave modulus and therefore no grading of evidence was conducted. Responsiveness was only investigated in one article and SW modulus showed a significant change when a 6-month follow-up was compared to baseline data. However, only poor monitoring accuracies were found for midportion Achilles tendinopathy so evidence could not be graded.Convergent validity of cSWE to maximum voluntary isometric contraction (MVIC) obtained inconsistent results within a small sample size of healthy people; thus grading of evidence was downgraded to very low. Only one article studied the correlation to shear wave modulus, so evidence was not graded. A low level of evidence is present for intra-rater same-day cSWE reliability due to the indirectness of the study population while inter-rater was not investigated.Evidence was not graded for 3D SWE as only one article was found investigating this method. Moreover, no validity testing in vivo was conducted.This systematic review identified four different modalities of elastography: strain elastography or also known as compression elastography, shear wave elastography, continuous shear wave elastography, and 3D elastography. Each elastography method will first be discussed in light of the inconsistencies (Appendix 5) and quality of evidence collated on the identified measurement properties as presented in Table Strain elastography is considered a semi-quantitative measure, represented as a ratio of tissue stiffness in comparison to its surrounding or external reference material. This strain index can be used as a comparative index and should not be considered an absolute strain measurement. The use of different reference materials led to both high and low ICC values, leading to mixed positive and negative results, especially when Kager’s fat pad was the chosen comparator for patients with Achilles tendinopathy. Material properties of the fat pad can change due to the pathology itself , thus giIn this review, the validity and reliability of strain elastography obtained moderate ratings, supporting its use to measure the Achilles tendon material properties. It was found to be a highly operator-dependent procedure with better reliability in more experienced professionals. Repeated manual compression using the ultrasound transducer causes axial strain in the tissue of interest. These compressions produce a displacement within the tissue, which is less pronounced in harder than softer materials.Shear wave imaging has the advantage of providing quantitative measures within a relatively small region of the tendon, thus tendon pathology which is known to affect discrete areas, can be accurately identified and measured. It is believed that using shear wave modalities is more reliable than strain elastography as the compressions are automatically induced by using a radiation force of ultrasound beams . However2 where v is SWV and p is tissue density [3 used as a constant tissue density; however, this may not always be true as tendons are found to be heterogeneous [Direct comparison of shear wave imaging results was not possible as some articles based their analysis on estimates of Young’s modulus (E) rather than reporting the underlying shear wave velocity. These two variables are directly related but not the same , 52. Con density , 50. Thiogeneous , anisotrogeneous  and viscogeneous , with vaogeneous . Thus, iAlthough criterion validity against the gold standard method of dynamometry and ultrasonography was not investigated, several studies found shear wave imaging to be a valid tool to differentiate between healthy and diseased tendons, as tendinopathic tendons are significantly less stiff than healthy ones . ResultsOne of the major drawbacks of shear wave imaging is that it can result in saturation of the elastogram in ankle positions around 0° of flexion since the Achilles tendon bears high tensile loads in this position or when dorsiflexed. Given this limitation, authors  of previInconsistencies were also present when calculating the shear wave velocity and modulus. The midportion of the tendon was investigated at different lengths from 1 cm from the insertion up to the myotendinous junction of the soleus muscle and the gastrocnemius myotendinous junction . FurthercSWE overcomes the issue of saturation by using an external actuator to generate shear waves across a specified range of frequencies. However, this recent innovation is still in its infancy stage and insufficient literature is available to grade data. One limitation is that it requires an extra pair of hands due to the added actuator that is placed near the probe.3D SWE has been recently introduced to better acquire a three-dimensional acquisition volume of the tendon’s stiffness. However, its validity remains questionable because of anisotropy when tendon fibres are not perfectly aligned. Advancements in ultrasound transducers allowed for reduced time for the elastogram to stabilise thus reducing the effects of movement artefact when obtaining results. However, any conclusions are premature, inconclusive, and further research is needed to explore the measurement properties of this method.Most of the above gradings of evidence were based on studies investigating healthy subjects. Although this is critical for establishing reliability and validity, uncertainty remains in the presence of tendon injury. Reliability depends on the homogeneity of the study population being assessed, affecting the generalisability of results. Homogeneity reduces the variance between participants, and the ICC values will be a conservative estimate of the reliability to be expected in a cohort more representative of the general population.The importance of having reliable instruments available becomes increasingly essential since the translation of data into clinical practice is safer and more accurately reflects the functional condition of the evaluated person. It was evident that a standardised protocol optimises reliability because repeated measurements are similar and the error of measurement arising from variation in measurement protocols is kept to a minimum. This review reported the methodological inconsistencies found that hinder further analysis of results. Standardised ultrasonographic technical settings and positioning of the patient with monitored muscle activity are imperative for better interpretable results.An important consideration that was missing in some of the assessed reliability articles was the preconditioning of the tendon. Since tendons have elastic  and viscThe overall evidence for measurement error could not be determined because assessing measurement error takes into consideration intra-individual variability between repeated measurements and is often expressed as the coefficient of variation, the smallest detectable change, and the limits of agreement. An instrument with a large error of measurement may fail to detect the true meaningful change in an individual patient.Understanding if a truly meaningful change has occurred, is of added value. This meaningful change has clinical importance in identifying an improvement in physical functioning that is large enough for the person to perceive a difference , 63. If Evidence on responsiveness cannot be determined as very few articles were found to consider this measurement property. Only one article using axial strain elastography and another using SWE having a longitudinal design were found to determine the changes that are occurring over a period of time. This shows that no established measurement instrument is yet identified as a treatment monitoring instrument, which aggravates the detection of early treatment effects or possible complications.This systematic review explored and highlighted the paucity of evidence for the measurement properties of different elastography methods. Our data synthesis focused on the qualitative approach as considerable heterogeneity between studies was present, thus not allowing for a meta-analysis of results. The qualitative approach adopted permitted the best possible synthesis of evidence that accounted for between-study similarities, the quality of each study, and the consistency of measurement properties reported across different studies. There are a limited number of studies exploring quantitative elastography on Achilles tendinopathy as most evidence found in this review was based on a healthy population. Only articles published in the English language were eligible for inclusion. It is, therefore, possible that other potential studies might have been excluded.Based on the identified evidence on the measurement properties of elastography, none of the different elastography methods showed superiority over the others with gradings ranging from very low to moderate. However, strain elastography and shear wave elastography reported as shear wave velocity have the best potential to be used in the identification of tendinopathy. Further high-quality studies with robust longitudinal designs to investigate responsiveness are needed to aid the monitoring of tendon recovery and detect any differences over time that may be attributed to true physiological changes.Additional file 1: Appendix 1. Search strategy keywords.Additional file 2: Appendix 2. Search Strategies.Additional file 3. Appendix 3Additional file 4: Appendix 4. Strain elastography.Additional file 5: Appendix 5. Articles methodology inconsistencies.


COQ5), a C-methyltransferase, modifies coenzyme Q10 (COQ10) during biosynthesis and interacts with polyA-tail regulating zinc-finger protein ZC3H14 in neural development. Here, we present a fifth patient (a third family) worldwide with neurodevelopmental and physiological symptoms including COQ10 deficiency. Our patient harbors one novel c.681+1G>A and one recurrent p.Gly118Ser variant within COQ5. The patient’s mRNA profile reveals multiple COQ5 splice-variants. Subsequently, we comprehensively described patient’s clinical features as compared to phenotype and symptoms of other known congenital coenzyme Q5-linked cases. A core spectrum of COQ5-associated symptoms includes reduced COQ10 levels, intellectual disability, encephalopathy, cerebellar ataxia, cerebellar atrophy speech regression/dysarthria, short stature, and developmental delays. Our patient additionally displays dysmorphia, microcephaly, and regressive social faculties. These results formally establish causal association of biallelic COQ5 mutation with pathology, outline a core COQ5-linked phenotype, and identify mRNA mis-splicing as the molecular mechanism underlying all COQ5 variant-linked pathology to date.Coenzyme Q5 (The online version contains supplementary material available at 10.1007/s13353-023-00773-9. COQ5 is expressed in all human tissues , including COQ5 which directly supports COQ10 biosynthesis. COQ1–9 form a multiprotein complex, the COQ synthome, found on the inner mitochondrial membrane  present with a range of developmental and physiological pathologies with a preponderance of neurodevelopmental manifestations and COQ10 tissue deficiency ; body length: 54 cm (<95 pc); occipital frontal circumference: 31 cm (<3 pc). Apgar scores were 10 points at 1 and 5 min of life.Presented girl displayed normal, uneventful postnatal adaptation and development from birth to 5 months of life.At 22 weeks, directly after third dose-vaccination with DTaP (Infanrix-Hexa), motor and cognitive regression, deterioration of eye contact, and the lack of a smile were noticed. Consequently, further vaccinations were suspended. At the age of 18 months, further developmental regression became apparent. She was intensively rehabilitated, but no progress was observed. In clinical evaluation, she could not stand up or walk independently and she could pronounce a few simple syllables and try to combine them into words. Detailed clinical observations from 1.5 to 10 years of age are described in supplementary data.At the age of 10 years, she had not acquired the ability to walk; cognitive development remains at a low level. Summary of neurological examinations showed global developmental delay, tetraparesis with hypotonia and symmetrical tendon reflexes, limited eye contact, postural defects including a “rounded” back, protruding shoulder blades, and funnel-shaped chest  of the brain at the age of 8 years revealed clear cortico-subcortical atrophy of the cerebellum–enlargement of the 4th ventricle and widening of cerebellar sulci  and corroborated twice at age 9 after 2 months of irregular QuinoMit 32.5 mg/day nasal spray administration, level of COQ10 in leukocytes remained low  revealed one novel variant c.681+1G>A and one recurrent pathogenic variant c.352G>A (p.Gly118Ser) in RNA Supp. showed tCOQ5 mutations compared with our patient 5 is compiled in Table COQ5 disruption.The available genetic and clinical information reported for all known patients with COQ5 variant. Up to date, this is a third pathogenic variant found at the COQ5 locus. The variant was detected in the patient harboring known pathogenic p.Gly118Ser COQ5 variant on the other allele. Biallelic origin of the variants and recessive mode of inheritance was confirmed by Sanger sequencing of parent’s DNA. The patient’s mRNA profile indicated that both inherited COQ5 variants contribute to characteristic mis-spliced mRNA forms, deleting either exon 2, or exons 4 and 5. Further, we comprehensively described clinical features of our patient as compared to phenotype and symptoms of other known congenital coenzyme Q5-linked cases. These allowed us indicating a specific constellation of clinical traits linked to mutations at the COQ5 locus.In this study, we identified a novel splicing c.681+1G>A COQ10 deficiency and pronounced neurodevelopmental traits. Evidently, neither COQ5 variant supports normal COQ5 function or healthy COQ10 levels. If either did, our patient would show healthy neurodevelopment with normal COQ10 levels. Each of these two variants therefore, directly confirms association of the other with pathology. Which symptoms in our patient result from COQ10 deficiency, versus other COQ5-associated enzymatic, regulatory, or structurally associated dysfunctions, such as binding interactions with CZ3H14, or COQ8, or the COQ-synthome itself, are elusive.Our patient has COQ5 patients  of these traits occurring together represents a core phenotype linked to COQ5 disruption. While not diagnostically definitive, a clinical perspective pointing strongly to a specific COQ-locus, in this case COQ5, should accelerate the diagnostic procedure and enable crucial interventions earlier in patient development. Eventually, gene-trait associations should allow mapping of specific traits to protein domains, specific functions, and particular alleles, informing etiologic gene test panels. These could facilitate rapid differential clinical diagnoses for specific traits, syndromes, or compound conditions, early on in developmental stages, potentially even in utero. For example, rapid in utero distinction of primary versus secondary COQ10 deficiencies in biallelic patients, eliminating the “trial and error” factor currently inherent in both diagnosis and COQ10 supplementation therapy, could be life-changing.Compilation of the phenotypes for all five biallelic ts Table , exposests Table . This suCOQ-locus clinical pathologies and COQ10-related metabolism, with concomitant progress in clinical handling.In conclusion, our data clarifies the intricate molecular biology underlying ESM 1(DOCX 644 kb)