Needle EMG of the Masseter Muscle and Blink Reflex Study in the Unilateral Facial Palsy Patient with Brainstem Lesions

J Korean Assoc EMG Electrodiagn Med 2010;12(1):39-43.
Published online June 1, 2010.

Abstract

Objective: To evaluate the trigeminal sensory complex and motor nucleus in the unilateral facial palsy patients with brainstem lesions. Method: In 6 cases with unilateral peripheral facial palsy after brainstem lesion, standard nerve conduction study and needle electromyography (EMG) for the facial nerve were performed. In addition, bilateral blink reflex study and needle EMG of the masseter muscle were performed for the evaluation of trigeminal sensory complex and motor nucleus, respectively. Results: The brainstem lesions were 2 cases of unilateral cerebello-pontine angle (CPA) schwannoma, 3 cases of unilateral brainstem hemorrhage and one unilateral CPA meningioma. The unilateral facial neuropathy and abnormal findings on blink reflex study which implies lesions of trigeminal sensory complex were noted in all cases. Abnormal spontaneous activities and reduced recruitment patterns were noted in needle EMG of masseter muscle in 5 cases. These electrophysiological results imply the lesions of trigeminal motor nucleus combined with the trigeminal sensory nucleus complex. Conclusion: Through this study, we perceive that needle EMG for the masseter muscle and blink reflex study in addition to standard electrophysiologic study for the facial neuropathy would be valuable in facial palsy patients with brainstem lesion to identify the involvement of trigeminal sensory complex or motor nucleus.

Key Words: Facial palsy, Blink reflex study, Needle EMG, Masseter, Trigeminal nerve