Magnetic stimulation in patients with essential blepharospasm

In 31 patients with an essential blepharospasm investigations were undertaken with transcranial cortical and cisternal magnetic stimulation of the facial nerve. Cortical stimulation was performed contralaterally, whereas cisternal stimulation was ipsilateral; the latencies and amplitudes of the potentials were determined. However, the extracranial part of the facial nerve was stimulated in the region of the stylomastoid foramen for neuromyography electrically. In most measurements the response potentials in the orbicularis oculi muscle and the levator labii muscle were determined. Cisternal stimulation yielded normal latencies, whereas cortical stimulation showed an increase of latency in some blepharospasm patients. A difference between the orbicularis oculi muscle and the levator labii muscle as known in patients with hemifacial spasm (20) could not be observed. The mean values of all latencies after cortical stimulation were normal. The method of transcranial magnetic stimulation is an important part of the complete investigation of patients with facial hyperkinesias as shown here in blepharospasm patients.