Acquired Acquired APD can be caused by any damage to or dysfunction of the central auditory nervous system and can cause auditory<unk>  problems. For an overview of neurological aspects of APD, see T. D. Griffiths' 2002 article "Central Auditory Pathologies". Genetics Some studies have indicated an increased prevalence of a family history of hearing impairment in these patients. The pattern of results is suggestive that<unk>  may be related to conditions of autosomal dominant inheritance. The ability to listen to and comprehend multiple messages at the same time is a trait that is heavily influenced by our genes, say federal researchers. These "short circuits in the wiring" sometimes run in families or result from a difficult birth, just like any learning disability.<unk>  can be associated with conditions affected by genetic traits, such as various developmental disorders. Inheritance of<unk>  refers to whether the condition is inherited from your parents or "runs" in families. Central<unk>  may be hereditary neurological traits from the mother or the father. Developmental In the majority of cases of developmental APD, the cause is unknown. An exception is acquired epileptic aphasia or Landau-Kleffner syndrome, where a child's development regresses, with language comprehension severely affected. The child is often thought to be deaf, but normal peripheral hearing is found. In other cases, suspected or known causes of APD in children include delay in myelin maturation, ectopic (misplaced) cells in the auditory cortical areas, or genetic predisposition. In a family with autosomal dominant epilepsy, seizures which affected the left temporal lobe seemed to cause problems with auditory<unk> . In another extended family with a high rate of APD, genetic analysis showed a haplotype in chromosome 12 that fully co-segregated with language impairment. Hearing begins in utero, but the central auditory system continues to develop for at least the first decade. There is considerable interest in the idea that disruption to hearing during a sensitive period may have long-term consequences for auditory development. One study showed thalamocortical connectivity in vitro was associated with a time sensitive developmental window and required a specific cell adhesion molecule (lcam5) for proper brain plasticity to occur. This points to connectivity between the thalamus and cortex shortly after being able to hear (in vitro) as at least one critical period for auditory<unk> . Another study showed that rats reared in a single tone environment during critical periods of development had permanently impaired auditory<unk> . ‘Bad’ auditory experiences, such as temporary deafness by cochlear removal in rats leads to neuron shrinkage. In a study looking at attention in APD patients, children with one ear blocked developed a strong right-ear advantage but were not able to modulate that advantage during directed-attention tasks. In the 1980s and 1990s, there was considerable interest in the role of chronic Otitis media (middle ear disease or 'glue ear') in causing APD and related language and literacy problems. Otitis media with effusion is a very common childhood disease that causes a fluctuating conductive hearing loss, and there was concern this may disrupt auditory development if it occurred during a sensitive period. Consistent with this, in a sample of young children with chronic ear infections recruited from a hospital otolargyngology department, increased rates of auditory difficulties were found later in childhood. However, this kind of study will suffer from sampling bias because children with otitis media will be more likely to be referred to hospital departments if they are experiencing developmental difficulties. Compared with hospital studies, epidemiological studies, which assesses a whole population for otitis media and then evaluate outcomes, have found much weaker evidence for long-term impacts of otitis media on language outcomes. Somatic It seems that somatic anxiety (that is, physical symptoms of anxiety such as butterflies in the stomach or cotton mouth) and situations of stress may be determinants of speech-hearing disability.
Auditory processing disorder
Olfactory fatigue
Vibroacoustic disease
Olfactory reference syndrome
Auditory fatigue
Cortical deafness
Speech disorder
Post-lingual deafness