[Physiologic significance of F wave in spastic paralysis in the diseases of the cerebral hemisphere].

In order to evaluate physiological significance of F-wave in the diagnosis of spasticity, 10 patients with intracranial mass lesion who did not show clinically lateralizing evidence especially in DTRs were examined and the data were compared with the results obtained from 10 other normal subjects. F-wave was recorded from thenar muscle with supramaximal stimulation to the median nerve at wrist. Latency and amplitude of F-wave failed to show any significant difference in patients compared with normal subjects both on affected sides, however, frequency of F-wave was found to be significantly higher on affected side except for 2 cases who had a mass lesion in occipital lobe in one case and the other was in the state of diaschisis due to recent hemorrhage in the parietal tumor. The site of lesion was carefully determined with CT scan and it was concluded that the F-wave could be detected quite in early stage of intracerebral mass lesion if the process had affected to internal capsule or cerebral peduncle under indirect mass effect such as cerebral edema. On the contrary, it was interesting to note that the mass with no affection to the premotor cortex likely showed higher frequency of F-wave on the ipsi-lateral side of lesion. As the conclusion, F-wave was found to have advantage in the diagnosis of spasticity in the early stage of illness and more accurate information on spasticity could be obtained compared with T or H-wave.