Abstract
A long latency EMG (C-response) which was produced by stimulation of the median nerve and recorded from the m. abductor pollicis brevis was studied in order to know if it was of use in diagnosis of cervical myelopathy. Inasmuch as the latency II (peak latency) of the C-response was correlated with the height of a given subject, the ratio of the latency against the height (C/h value) was employed to study the C-response. The C/h value was measured in 19 patients with myelopathy, before and after surgery, as well as in 20 healthy subjects (controls). The patients were classified into 3 types. I, II and III, according to the severity of the clinical manifestations. The CA value was significantly higher in the patients that in the controls, but the value did not change after surgery even in cases in which clinical signs were markedly improved.
These results indicate that the CA value is useful in determining the existence of cervical cord dysfunction, but not in evaluating the effects of surgical treatment.
