The palmomental reflex, an involuntary contraction of the mentalis muscle of the chin caused by stimulation of the thenar eminence, can be tested easily and rapidly. Its presence may alert the clinician to the possibility of cerebral pathology.
However, the reflex is often present in normal people and may be absent in disease states. Testing merely for the presence or absence of the reflex therefore lacks both specificity and sensitivity. A strong, sustained, and easily repeatable contraction of the mentalis muscle, which can be elicited by stimulation of areas other than the palm, is more likely to indicate cerebral damage.
