BLINK REFLEX PATTERNS IN PATIENTS WITH BELL'S PALSY
I.K.Ibrahim; MD, M.A.R. EI-Abd; MD
Faculty of Medicine, University of Alexandria, EGYPT.
Purpose: To identify blink reflex (BR) patterns in patients with Bell's palsy (BP) at different recovery stages and its clinical significance.
Methods: BR patterns of RI and R2 components were studied in 422 patients with unilateral Bell's palsy at different recovery stages, and disease duration within 2 weeks up to 10 years.
Results: Five different patterns were identified and correlated with the type and extent of nerve pathology. Pattern I characterised by absence of R1 and absence of R2 recordings on the paralysed side was encountered in 8.5 % of studied patients. Pattern II (37.8 %) showed absence of R1 but presence of R2 on the paralysed side. Pattern Ill (53.7 %) showed presence of RI as well as R2 on the paralysed side. Pattern IV (11.9 %) showed increasing amplitude of ipsilateral R1 on "healthy" side with improvement of facial paralysis. Pattern V characterised by present R1 and absent R2 on paralysed side was recorded only in one patient. BR changes in patients with Isolated post-Bell's facial dyskinesia could be differentiated from that of post-Bell's hemifacial spasm which suggest a peripheral mechanism (aberrant regeneration) for the first, but central contribution (synaptic and nuclear changes) for the second. Concomitant contralateral facial and ipsilateral trigeminal nerve involvement have been found in 5.6 % and 14 % of studied patients respectively, which may doubt the diagnosis of Bell's palsy.
Conclusion: BR patterns could be correlated well with the type and degree of facial nerve pathology as well as the chronological peripheral and central (synaptic and nuclear) changes.
QUANTITATIVE EVALUATION OF FACIAL HYPOESTHESIA WITH ELECTRICALLY ELICITED BLINK REFLEX
Ryoji Kayamori, Masahiro Mikami, Shiho Toyooka (Teikyo University, Tokyo, Japan)
Purpose: Quantitative evaluation for sensory disturbance makes somatosensory evoked potential useful for the limbs but not for the face yet in the clinical practice.
Method: Electrically elicited blink reflex was serially carried out for 12 stroke patients (male 8, female 4) with facial hypoesthesia. All patients were not involved in facial motor paralysis. Of the12 patients, one had cerebral sensory cortex lesion, 6 thalamic lesions, 5 brainstem lesions.
Result: The latency of R1 failed within normal limits. Stimulation on the affected side of the face elicited low-amplitude or diminished area of R2 in all 12 patients, regardless of pathoanatomical lesions. R2 was delayed in 9. Three patients with thalamic lesions had only attenuation of R2 area without latency delay. In contrast, stimulation on the normal side of the face evoked normal R2 bilaterally in 10 of 12 patients. R2 area was getting bigger and R2 latency was shorter with clinical improvement. A smaller response indicated more complete sensory loss, and stimulation of an anesthetic face due to a thalamic lesion failed to elicit any response at all.
Conclusion: The electrically elicited blink reflex provides a means of quantitating facial sensation.