Clinical and physiological significance of abnormally prolonged central motor conduction time in HAM/TSP.
We measured the central motor conduction time (CMCT), central sensory conduction time (CSCT), F wave and mean F wave/M wave amplitude ratio in patients with HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) and controls. CMCTs in upper (U) and lower (L) limbs were significantly prolonged in HAM/TSP. L-CSCT was significantly prolonged in HAM/TSP, but U-CSCT in HAM/TSP and controls were not significantly different. CMCT and CSCT were significantly correlated in HAM/TSP. U-CMCT, but not L-CMCT, correlated with the clinical severity of HAM/TSP. Although F wave conduction velocity and its occurrence were normal in HAM/TSP, U- and L-mean F wave/M wave amplitude ratio tended to be higher in HAM/TSP, and the L-mean F wave/M wave amplitude ratio was significantly correlated with the L- and thoracic CMCT. These findings demonstrate that the prolongation of CMCT sensitively reflects the extension of the lesions and the disinhibition to the anterior horn cells in HAM/TSP.
Shimizu
H
H
Department of Neurology, Tohoku University School of Medicine, Seiryomachi 1-1, Aoba-ku, Sendai 980-8574, Japan.
Shiga
Y
Y
Fujihara
K
K
Ohnuma
A
A
Itoyama
Y
Y
D000368:Aged; D000870:Anterior Horn Cells / Q000503:physiopathology; D019054:Evoked Potentials, Motor; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction; D015493:Paraparesis, Tropical Spastic / Q000175:diagnosis* / Q000503:physiopathology*