Usefulness of motor evoked potentials in compressive myelopathy.
Motor Evoked Potentials elicited by transcranial magnetic stimulation were recorded from 1 degree Dorsal Interosseus for the upper limbs and from Extensor Digitorum Brevis for the lower limbs in 42 subjects with compressive myelopathy (36 in the cervical region and 6 in the dorsal region), radiologically defined by Nuclear Magnetic Resonance (NMR) imaging, with no clinical and radiological signs of radiculopathy. Central motor conduction abnormalities in the cortex-C8 and cortex-L5 tract were compared with clinical signs of motor impairment and with NMR findings. The subjects with medullar hyperintensity of NMR signal at the compression site level, showed a central conduction time (C.C.T.) prolongation in at least one side in the 70% of cases in the cortex-C8 tract and in the 95% of cases in the cortex-L5 tract, while in the cases with no compression site alterations of signal, C.C.T. abnormalities were observed only in 25% in the cortex-C8 tract and in 42% in the cortex-L5 tract. In 12 subjects (10 with cervical compression and 2 with dorsal compression) we compared Motor Evoked Potentials before, two weeks and two months after surgical decompression. The C.C.T. cortex-C8 and cortex-L5 improved at least in one side in 11 out of the 12 subjects, showing a good correlation with clinical recovery. In the examined patients we found a latency reduction statistically significant between the first and second investigation, with a trend to stabilization in the following controls.
De Mattei
M
M
Department of Neurology, Molinette Hospital, Turin.
Paschero
B
B
Sciarretta
A
A
Davini
O
O
Cocito
D
D
D000328:Adult; D000368:Aged; D004576:Electromyography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D013116:Spinal Cord / Q000473:pathology / Q000503:physiopathology; D013117:Spinal Cord Compression / Q000473:pathology / Q000503:physiopathology*