title: Auditory brain stem response abnormalities in severely and profoundly retarded adults.
abstract: The auditory brain stem evoked responses (ABRs) of two groups of retarded adults (Down's syndrome and retarded of unknown etiology) were compared with those of a group of non-retarded control subjects as a function of changes in stimulus repetition rate and stimulus intensity. The absence of ABRs at the highest stimulus intensity suggested profound hearing deficits in one or both ears of 4 Down's syndrome and 2 unknown-etiology subjects. Other abnormalities were noted in particular individuals of each group of retarded. In addition, the ABRs of the Down's group as a whole showed a significant pattern of abnormalities. The intervals between peaks I and II and III and IV were shorter than normal white the IV--V interval was prolonged. Wave V also showed abnormally small latency increases at fast click rates. The ABRs of the unknown-etiology group showed a shortened III--IV interval and a prolongation of the IV--V interval, but were otherwise not significantly different from the normal controls. These data suggest a high incidence of hearing loss in both diagnostic categories studies, and abnormal functioning of the auditory brain stem pathway in the Down's syndrome group as a whole.
mesh_terms: D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D001933:Brain Stem / Q000503:physiopathology*; D004314:Down Syndrome / Q000503:physiopathology; D005072:Evoked Potentials, Auditory; D006801:Humans; D008607:Intellectual Disability / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction; D010525:Peripheral Nerves / Q000503:physiopathology; D011930:Reaction Time; D013997:Time Factors