Holmes tremor (HT) is a combination of rest, postural and action tremor. A parallel dysfunction of cerebello-thalamic and nigrostriatal pathways seems necessary to produce this kind of tremor. We present the clinical and neuroimaging study verifying that hypothesis. A total of 10 patients: five male, five female, fulfilling consensus criteria were included. Demographic, clinical and neuroimaging data (MRI = 9; CT = 1, SPECT with the use of 123-I-FP CIT: DaTSCAN in six patients to assess the presynaptic dopaminergic nigrostriatal system involvement, indices of asymmetry for ligand uptake for each striatum were calculated) were analyzed. Hemorrhage was the most frequent etiology and thalamus - the most commonly involved structure. Contrary to the previous reports, the visual assessment did not reveal remarkable interhemispheric differences of DaTSCAN uptake. Quantitative measurements showed only minimal differences. It is open to debate whether nigrostriatal pathway damage is crucial for the phenomenology of HT. Alternative hypothesis is presented that HT represents the heterogeneous spectrum of tremors with similar phenomenology, but different pathophysiology. Copyright © 2010 The Authors. Journal compilation © 2010 Blackwell Munksgaard.
