Orbicularis oculi reflex and facial muscle electromyography. Pre- and postoperative evaluation of posterior fossa space-occupying lesions.

The electrically evoked orbicularis oculi reflex was analyzed in 26 patients with proven posterior fossa space-occupying lesions (11 cerebellopontine angle and 15 cerebellar hemispheric masses). In the former group, although only six had clinical evidence of trigeminal or facial involvement, the reflex analysis showed both nerves to be involved in all. Electromyography (EMG) of the orbicularis oculi showed profound denervation of this muscle while only minimal abnormalities of the masseter were seen. The sensory component of the trigeminal nerve was always more involved than its motor component and this was a reliable guide as to the upward and medial extension of the tumor, especially in the absence of clinical localizing signs. In the 15 patients with cerebellar masses, six with masses located posteriorly and entirely within the confines of the cerebellum had normal studies. In eight, the mass was located anteriorly, and fifth nerve involvement could be detected in all by EMG, although only two patients had clinical evidence of such involvement. One patient with dysfunction of the central reflex arc had EMG evidence of an intraventricular dermoid tumor abutting the pons, later confirmed at surgery. Thus, an invaluable body of diagnostic and prognostic data can be obtained by this nontraumatic and simple electrodiagnostic procedure.

Prognostic significance of electrodiagnostic studies in the Guillain-Barré syndrome.

Nerve conduction and needle electromyographic studies were carried out in 50 patients with the Landry-Guillain-Barré syndrome to assess the reliability of this procedure in predicting the prognosis. Two main groups were identified. The first group was characterized by gross abnormalities in nerve conduction and absence of fibrillation potentials during the entire course of the illness. Twenty-five of 31 patients (80.6%) belonging to this group recovered rapidly, and the quality of recovery was good. In 19 patients belonging to the second group, profuse fibrillations were noted within the first four weeks of the illness with or without associated nerve conduction deficits. Recovery in this group was poor (31.5%) and pronounced residual deficits were more common. Electrophysiological studies therefore are of value not only in the diagnosis but also as a reliable prognostic index in this syndrome.

Free sialic acid levels in the cerebrospinal fluid of patients with meningitis.

The free and bound sialic acid content of cerebrospinal fluid from patients with positive evidence (by CSF culture) of pyogenic and tuberculous meningitis was determined. The free sialic acid content was significantly raised only in cases of pyogenic meningitis, but not in tuberculous or other types of the disease.