Masseter reflex latencies and amplitudes are not influenced by supratentorial and cerebellar lesions

The aim of this study was to investigate possible influences of suprasegmen tal lesions on the masseter reflex. The masseter reflex was elicited in 54 patients with supratentorial (37 patients) or cerebellar (17 patients) lesi ons 3-11 days after the acute onset of clinical disease. Patients showing l esions within the pens and midbrain on thin-slice magnetic resonance imagin g were excluded from evaluation. The testing procedure included an addition al facilitating maneuver (opening and closing the jaw before tapping). Mass eter reflex latencies, interside differences, and amplitudes were within th e normal range in all patients. Latencies were not different with and witho ut the facilitating maneuver. Amplitudes were significantly higher with the maneuver, but interside differences of amplitudes were unchanged. Masseter reflex abnormality can be taken as a reliable measure of direct involvemen t of the reflex are. (C) 2000 John Wiley & Sons, Inc.