The orbicularis oculi reflex: diagnostic significance of the reflex amplitude
Stoehr, M.; Petruch, F.
Electromyography and Clinical Neurophysiology 18(3-4): 217-224
1978
ISSN/ISBN: 0301-150X PMID: 699875 Document Number: 129424
Comparative measurements of the amplitude of the orbicularis oculi reflex on both sides were of diagnositc significance in various syndromes. A reduction of the reflex amplitude may be the only sign of an incipient facial or trigeminal nerve lesion in cerebello-pontine angle tumors at an early stage, or in acute facial paresis of peripheral origin. In cases with slight facial paresis of unknown origin this finding allowed differentiation between a peripheral and a central lesion. After total denervation of the mimetic muscles with ensuing reinnervation, measurements of the reflex amplitude helped to assess the degree of reinnervation and the extent of faulty sprouting. Using conventional stimulation technique, only differences of more than 40% could be regarded as pathological, whereas with simultaneous stimulation of both supraorbital nerves differences beyond 20% were abnormal. Investigations of the orbicularis oculi reflex are useful in the evaluation of paresis in the facial and in the trigeminal nerve and of processes in the brain stem (1,2,3,4,5,6). So far, one has mostely focussed on the increase in latency of the early or late reflex response, elicited by stimulation of the supraorbital nerve on the homolateral and on the contralateral side. Furthermore pathological spreading to all of the homolateral mimetic muscles has been observed in postparetic facial spasm and has been used to quantitatively assess the extent of faulty sprouting (7,8). In the present study we mainly focus on the diagnostic significance of the reflex amplitude. The results have been obtained by use of stimulation technique that is described.