Research Article| Volume 163, ISSUE 1, P58-60, February 01, 1999

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Idiopathic cortical myoclonus restricted to the lower limbs: correlation between MEPs and 99mTc-ECD single photon emission computed tomography activation study


      We report a 63-year-old woman with cortical reflex myoclonus restricted to the bilateral lower limbs. Somatosensory evoked cortical potentials to posterior tibial nerve stimulation were enlarged with C-responses. Jerk-locked back averaging of the EEG identified a cortical spike related to myoclonic jerks. Motor evoked potentials recorded from the abductor hallucis muscle showed an exaggerated late response. These findings suggest hyperexcitability of the sensorimotor cortex. 99mTc-ECD single photon emission computed tomography (SPECT) after stimulation of the posterior tibial nerve showed increased perfusion in the contralateral peri-Rolandic area which corresponded to the hyperexcitable region. A SPECT activation study as well as MEPs therefore can be employed to determine the hyperexcitable region in cortical myoclonus.


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