Glabellar Tap Reflex
Glabellar Tap Reflex
The glabellar tap reflex, also known as Myerson’s sign or the nasopalpebral reflex, is elicited by repeated gentle tapping with a finger on the forehead, preferably with irregular cadence and so that the patient cannot see the finger (to avoid blinking due to the threat or menace reflex), while observing the eyelids blink (i.e., blink reflex). Usually, reflexive blinking in response to tapping habituates quickly, but in extrapyramidal disorders it may not do so. This sign was once thought useful for the diagnosis of idiopathic Parkinson’s disease but in fact it is fairly nonspecific, occurring in many akinetic-rigid disorders.
References
Schott JM, Rossor MN. The grasp and other primitive reflexes. Journal of Neurology, Neurosurgery and Psychiatry 2003; 74: 558-560
Cross References
