title: Glabellar reflex habituation in mentally retarded adults.
abstract: The glabellar tap reflex has been studied in 88 adults with mental retardation and 20 normal controls. None of the 20 controls had abnormal response to glabellar tap. All the subjects with mental retardation had abnormal response to glabellar tap, 80 subjects had 'no habituation' and eight subjects had 'poor habituation' of response to glabellar tap. Thirty-nine subjects, with Down's syndrome, Prader-Willi syndrome and with gross cerebral pathological states with or without motor deficits had 'no habituation' of response to glabellar tap. Of the remaining 49 subjects with unidentified aetiological diagnosis of mental retardation, 41 subjects had 'no habituation' and eight subjects had 'poor habituation' of response to glabellar tap. Age and sex had no significant effect on the response to glabellar tap in the subjects studied. The possible physiological mechanisms responsible for the abnormal response to glabellar tap have been discussed.
mesh_terms: D000328:Adult; D000368:Aged; D001767:Blinking; D001927:Brain Diseases / Q000503:physiopathology; D006185:Habituation, Psychophysiologic; D006801:Humans; D008607:Intellectual Disability / Q000150:complications / Q000503:physiopathology*; D008875:Middle Aged; D012021:Reflex, Abnormal / Q000209:etiology