Hemifacial spasm in correlation with electrophysiological and radiological findings.

OBJECTIVE To investigate the correlation between the electrophysiological and radiological findings of primary hemifacial spasm patients. SUBJECTS Patients with primary hemifacial spasm who had had no botulinum toxin treatment previously were included in the study. DESIGN In this prospective study patients underwent cerebral magnetic resonance imaging,a magnetic resonance angiography investigation and an electrophysiological examination after informed consent had be given by the patients. The facial nerve distal latency, amplitude and blink reflex responses were recorded as well as clinical and demographic data. RESULTS Twenty five patients completed radiological and electrophysiological investigations. The radiological investigations disclosed neurovascular compromise which can cause hemifacial spasm in twelve patients (48%) while the findings of two patients were not considered as a certain cause of hemifacial spasm. All patients except two had at least one electrophysiological abnormality (92%). The most frequent finding was an increased R1/D ratio which suggested an increased central conduction time. CONCLUSION In this study, an increased R1/D ratio suggests that there is a functional impairment in the brain stem even if it is not possible to disclose structural abnormalities in some hemifacial spasm patients. Combining magnetic stimulation may be a useful tool for further investigations. An inadequate radiological investigation might be the cause of relatively low radiological abnormalities in comparison with the electrophysiological ones.