Clinical and magnetic resonance imaging manifestations of Holmes tremor.

Holmes tremor is a rare symptomatic slow tremor in the proximal parts of the limbs. It may be present at rest or maintenance of a posture, or during the movement of the affected limb. We describe herein three patients of Holmes tremor with possible etiologies of brainstem infarction and head injury. The intervals between the causal events and the appearance of tremor range from 1 month to 12 months. Magnetic resonance imaging studies reveal hypertrophy of the inferior olivary nucleus in all of the three patients, although only one of them has palatal myoclonus. The surface electromyographic recordings reveal characteristic slow oscillation with frequencies of 3.5 to 4.2 Hz. These features suggest that perturbation of the dentato-rubral-olivary circuitry may play a pivotal role for the generation of Holmes tremor. However, no tight correlation is observed between the presence of inferior olivary nuclear hypertrophy and the appearance of symptomatic palatal myoclonus in the current report.