The head retraction reflex--its specificity in Parkinson's disease.
The head retraction reflex consists of a brief, involuntary extension of the neck on tapping the upper lip. This reflex was found to be present in 17.2% of patients with Parkinson's disease, but in only 4.9% of normal controls and 8% of cases of senile dementia. In addition there was a correlation between the severity of the Parkinson's disease and the presence of the reflex. This suggests that the reflex is specifically related to the Parkinson's disease process rather than to aging or the presence of dementia.
D000368:Aged; D003704:Dementia / Q000503:physiopathology; D005260:Female; D006257:Head / Q000503:physiopathology*; D006801:Humans; D008297:Male; D009422:Nervous System Diseases / Q000503:physiopathology; D010300:Parkinson Disease / Q000503:physiopathology*; D012018:Reflex