Bilateral lesions of thalamus and basal ganglia: origin and outcome.

Twenty-seven MRI examinations from 17 children (7 females, 10 males) with bilateral lesions of the basal ganglia and thalamus, presenting over a period of 8 years, were reevaluated, and correlated with the type of cerebral palsy (CP) as well as motor and cognitive impairment. Children were between 1 year 6 months and 17 years old at last examination (mean 5 years 9 months). Brain damage had occurred as a consequence of birth asphyxia in nine patients and of neonatal shock in four patients. No adverse event could be identified in four children. In these, late prenatal compromise is assumed, as extensive screening (including MR spectroscopy in two patients) did not yield an underlying metabolic disorder. Three different degrees of MRI lesion patterns could be defined: a mild pattern (involvement of nucleus lentiformis and ventro-lateral thalamus only; n=7), an intermediate pattern (involvement of nucleus lentiformis, ventro-lateral thalamus, and pericentral region; n=3), and a severe pattern (involvement of nucleus lentiformis, entire thalamus, pericentral region, and hippocampus; n=7). This grading of MRI findings correlated significantly with the severity of both cognitive and motor impairment and type of CP. Normal cognitive development and mild motor delay was only seen with the mild pattern. All children developed CP: purely dyskinetic CP was only seen with the mild pattern, whereas the dyskinetic-spastic or spastic CP types could be seen in all three lesion patterns, with dyskinetic-spastic CP more related to the moderate, and purely spastic CP more related to the severe pattern.