Isolated head tremor: a DAT-SPECT and somatosensory temporal discrimination study

Introduction: To better understand the pathophysiology of isolated head tremor, we investigated somatosensory temporal discrimination threshold (STDT) and dopaminergic neurotransmission with 123I-FP-CIT (DAT-SPECT) in patients with isolated head tremor, as well as potential correlations with their clinical features. Methods: We enrolled 14 patients with isolated head tremor who underwent clinical examination, STDT testing, and DAT-SPECT. Results: We found normal radiotracer uptake in both striata as assessed with DAT-SPECT examination, but higher STDT values in patients as compared to healthy subjects. No significant correlations emerged between STDT values, specific binding ratios of radiotracer uptake, and demographic or clinical features. Conclusion: Our study found normal radiotracer uptake with DAT-SPECT examination, suggesting dopaminergic neurotransmission integrity in patients with isolated head tremor. Patients with isolated head tremor exhibited an abnormally elevated STDT. Both results support the hypothesis that isolated head tremor should be considered a form of dystonia.