A combined pattern of movement disorders resulting from posterolateral thalamic lesions of a vascular nature: a syndrome with clinico-radiologic correlation.

We report a series of seven patients in whom a combined pattern of complex movement disorders restricted to one upper extremity emerged as a result of posterolateral thalamic lesions of vascular origin. This disorder was mainly characterized by choreiform and dystonic movements associated with variable, rhythmic, alternating movements of low frequency (myorhythmia). All cases showed, on computed tomography scan and/or magnetic resonance imaging, focal lesions involving the posterolateral quadrant of the thalamus. Review of similar cases reported with identical clinico-radiologic features allows us to conclude that it is possible to establish an accurate anatomoclinical correlation based on the clinical phenomenology, even before imaging studies are performed, in these cases. The opposite is not entirely possible, however, because lesions in the same quadrant of the thalamus are often associated with different patterns of abnormal movements or present without abnormal movements.