Abstract
Schizencephalies are abnormal clefts of the cerebral hemispheres that result from abnormal late neuronal migration and cortical organization. In the present study, we report a different type of unusual motor organization in a patient with a schizencephalic cleft in the right hemisphere and polymicrogyria in the opposite hemisphere. Despite similar brain pathology affecting the sensorimotor cortex, motor organization differed from previously known bilateral congenital brain lesions. We conducted a transcranial magnetic stimulation (TMS) and diffusion tensor image (DTI) study to confirm the motor organization. In this case, ipsilateral corticospinal projections to the paretic hands were observed during TMS of the less affected hemisphere, along with polymicrogyria, similar to the previous study. However, a crossed corticospinal tract to the paretic hand from the more severely affected hemisphere was observed in this case-a pattern of motor organization that has yet to be reported in this patient population. Our findings indicate that motor organization after early brain injury may be affected by the interhemispheric competition of the corticospinal system and bilateral brain lesions, thereby resulting in unilateral hemiparesis.
Highlights
Schizencephalies are abnormal clefts of the cerebral hemisphere caused by the enfolding of gray matter, extending from the cerebral wall to the pial surface of the ependyma of the underlying ventricle (Barkovich and Norman, 1988; Hong et al, 1991)
We reported the case of a Korean patient whose paretic hand maintained uncrossed ipsilateral corticospinal projections from the non-schizencephalic hemisphere only (Son et al, 2008)
Brain lesions and clinical manifestations were similar to the previous case, the motor organization differed from that case
Summary
Schizencephalies are abnormal clefts of the cerebral hemisphere caused by the enfolding of gray matter, extending from the cerebral wall to the pial surface of the ependyma of the underlying ventricle (Barkovich and Norman, 1988; Hong et al, 1991). We observed cMEPs on the patient’s paretic hand (latency, 23.7 ± 0.4 ms; amplitude, 153.8 ± 25.7 μV; duration, 25 ms) during right hemisphere stimulation (Figure 2). Any adverse effects of TMS such as syncope, seizure, headache, hearing problems, or changes in emotion were not reported In this case, cMEPs from the more severely affected hemisphere were observed, in the paretic hand. CMEPs from the more severely affected hemisphere were observed, in the paretic hand In this case, MEPs could be elicited in the paretic hand via TMS of the right schizencephalic hemisphere and the opposite dysplastic hemisphere. MEPs with prolonged duration were observed in the left paretic FDI when applying TMS to the schizencephalic right hemisphere. Distorted and deviated white matter bundles were visualized around the schizencephalic cleft (Figure 3)
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