PERIPHERAL AND CENTRAL MOTOR CONDUCTION IN AMYOTROPHIC-LATERAL-SCLEROSIS

Conventional peripheral motor conduction studies and transcranial magn etic stimulation (TMS) studies, to measure central motor conduction ti me (CMCT), to the first dorsal interosseous muscle (FDI) were performe d on 65 patients with amyotrophic lateral sclerosis (ALS). The hands o f each patient were classified into one of four groups depending on th e presence of physical signs of lower motor neurone (LMN) and/or upper motor neurone (UMN) involvement. Statistical analysis was made of the results from patients compared with previously established normal val ues and with those from a control group of 53 normal subjects. Results between the four groups of patients were compared in order to assess any correlation between neurophysiological findings and physical signs . A reduction in the amplitude of compound muscle action potentials (C MAP), prolongation of distal motor latency (DML) and F wave latency we re found in 36%, 34% and 19% of hands respectively. These abnormalitie s were more common in hands with LMN signs. In nine hands, prolongatio n of DML occurred in the absence of muscle wasting or weakness. CMCT a bnormalities were present in 17% of patients with ALS but did not appe ar to correlate with physical signs. (C) 1998 Elsevier Science BN. All rights reserved.