The heterogeneity of thalamic tremor: report of two cases

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.

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.

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.