The heterogeneity of thalamic tremor: report of two cases.

BACKGROUND

Thalamic lesions are a well-recognized cause of secondary tremor, most commonly manifesting as a classic Holmes tremor (HT). This phenotype typically combines postural, kinetic, and rest components and may be accompanied by dystonic features, reflecting disruption of thalamo-cortical motor networks.

CASE REPORTS: We report two patients with tremor following unilateral thalamic vascular lesions showing different motor phenotypes. The first patient developed a low-frequency, large-amplitude tremor of the left upper limb after a right lateral thalamic ischemic lesion, consistent with an HT-like presentation. The second patient presented with irregular involuntary movements, dystonic posturing, and marked phenomenological variability over time, as a consequence of a right posterior thalamic hemorrhage involving the pulvinar. Objective assessment of tremor was conducted through kinematic analysis.

DISCUSSION: These cases illustrate the phenotypic variability of tremor due to thalamic injury, ranging from HT-like tremor to more complex phenotypes characterized by dystonic and choreoathetoid features, as well as phenomenological variability over time. Pulvinar-associated networks may contribute to altered sensorimotor integration. Recognition of these patterns is essential for accurate phenotyping and management in secondary thalamic movement disorders.