Comparative Analysis of CMAP Amplitudes of Electro-physiologically Evaluated Facial Muscles in Facial Palsy Patients

Background The study describes the retrospective analysis of compound motor action potential (CMAP) amplitudes in 50 cases (25 males & 25 females) of facial nerve palsy seen in our neurophysiology Laboratory during last two years. Methodology Clinically diagnosed cases of facial nerve palsy encountered at neurophysiology laboratory went under facial nerve conduction studies. Patients evaluated for CMAPs of orbicularis occli, Nasalis and Orbicularis oris muscles were analyzed Results Study included 50 male and female (n=25 each) patients of unilateral facial palsy with the mean age of 33.98 ± 14.13 yr. CMAP amplitudes of all the three muscles on affected side were significantly (p value <0.0001) lower compared to that of normal side. CMAP amplitudes in males and females were not significantly different over both affected and normal side muscles. ANOVA of affected and normal side muscles of all the patients showed significantly (p value <0.05) different CMAP amplitudes among both affected side and normal side muscles. Conclusion It was concluded that CMAP amplitudes are significantly reduced on the affected side in facial palsy patients and they do not reflect any gender differences. CMAP amplitudes show an increasing trend from orbicularis occuli, nasalis to orbicularis oris muscle.