ALTERNATING HEMIPLEGIA SYNDROME - ELECTROENCEPHALOGRAM, BRAIN MAPPING, AND BRAIN PERFUSION SPECT SCAN STUDY IN A CHINESE GIRL

A 3-year-old Chinese girl with alternating hemiplegia syndrome failed to respond to anticonvulsants, antimigrainous drugs, and calcium chann el blockers. She made a complete remission with a 4-week course of ste roid, and relapsed after steroid withdrawal. Electroencephalogram and brain mapping during the hemiplegic attack showed unilateral high-volt age sharp slow-wave discharges in the temporo-occipital region contral ateral to the hemiplegic side and diffuse high-voltage slowing during attacks of quadriplegia or other clinical manifestation such as dullne ss, lethargy, or yawning. Brain perfusion single photon emission compu ted tomographic (SPECT) scan study during the attack showed decreased uptake in the temporoparietal region contralateral to the hemiplegic s ide and in the ipsilateral basal ganglia, whereas the perfusion was no rmal between attacks. Electroencephalogram background activity was imp roved while the child was in clinical remission with steroid treatment . Computed tomographic and magnetic resonance imaging scans of the bra in were normal. Carotid angiogram failed to show any structural or dyn amic changes of the carotid arteries. The possible mechanism underlyin g alternating hemiplegia syndrome might be transient and reversible ce rebral ischemia with high-voltage slow-wave discharges shown in the el ectroencephalogram and decreased perfusion in SPECT scan.