A Case of Cortical Tremor as a Variant of Cortical Reflex Myoclonus

Postural and action myoclonus in patients with parkinsonian type multiple system atrophy

“…17 It was suggested that small, hyperexcitable zones in the motor cortex could be responsible for generation of the abnormal movements. Similar findings were reported by Toro and coworkers in patients with various disorders, 18 and also by Oguni et al, 19 in a patient with postural tremor. In Japan, cortical tremor has also been described in families with benign essential myoclonus.…”

“…Toro et al 18 found cortical tremor in patients who did not have peripherally induced reflex myoclonus, whereas the patient reported by Oguni et al 19 had repetitive reflex responses to single peripheral stimuli that had the same frequency as the tremor. This suggests that the abnormal bursts of EMG activity were engaged in a circuit triggered by the peripheral stimulus.…”

Two Patients with Tremor Caused by Cortical Lesions

“…In patients with cortical tremor, which is thought as a variant of cortical reflex myoclonus, enhanced excitability may spread more diffusely to the cerebral cortex, and electrophysiological studies reveal giant SEPs with enhanced long loop reflexes and premovement cortical spikes in EEG [9, 10]. In our patients we could not obtain such responses; only the median SEP latencies obtained from the lesioned hemispheres were found slightly prolonged in both of the patients.…”

“…It was reported as a variant of cortical reflex myoclonus in association with EEG abnormalities, seizure, abnormal SEPs and long latency EMG responses [8,9,10]. In the cases of cortical tremor, the neuroimagings of the patients were reported normal, and specific EMG and EEG abnormalities were demonstrated [7,8,9,10]. However, both of our patients had parietal cortical lesions contralateral to the tremor.…”

“…Our patients developed an irregular tremor of the hands secondary to parietal cortical lesions, and these clinical features are similar to the features of cortical tremor originally described by Ikeda et al [7] as a postural and action tremor with a frequency of more than 8 Hz. It was reported as a variant of cortical reflex myoclonus in association with EEG abnormalities, seizure, abnormal SEPs and long latency EMG responses [8,9,10]. In the cases of cortical tremor, the neuroimagings of the patients were reported normal, and specific EMG and EEG abnormalities were demonstrated [7,8,9,10].…”