MOTOR EVOKED-POTENTIALS (MEPS) ASSESSMENT OF CENTRAL MOTOR CONDUCTIONIN INTRASPINAL TUMORS - A STUDY OF 33 PATIENTS

MEPs to transcutaneous magnetic stimulation have been recorded in 43 p atients with un intraspinal tumor documented by MRI. The tumor was ext ramedullary in 18 patients and intramedullary in 25. MEPs were abnorma l in 62.8% of patients. There, were no significant differences in the rare of MEP abnormalities according to the lesion site or the histolog ical findings, except for meningiomas which showed abnormal MEPs in al l eight patients included in this series. The percentage of patients w ith abnormal MEPs was 9.3% despite the absence af any clinical symptom of central motor pathway dysfunction. Infraclinical MEPs abnormalitie s were observed in 24% of explored limbs. Median and tibial nerves som atosensory evoked potentials (SEPs) were recorded in 41 patients and s howed abnormalities of central conduction or of segmental spinal respo nses in 65.9% of the cases. When combining data from MEP and SEPs, abn ormalities were observed in 70.7% of patients (29/41). Five patients ( 12.2%) had abnormal MEPs, but normal SEPs, and four other patients (9. 8%) had abnormal SEPs, but normal MEPs. This finding suggests that bot h MEPs and SEPs-should be recorded for presurgical evaluation of intra spinal tumor.