Patients with scans without evidence of dopaminergic deficit: A long-term follow-up study

Background: We previously reported on a cohort of dystonic tremor and patients with scans without evidence of dopaminergic deficit (SWEDDs). We aim to report the long-term clinical and imaging follow-up of these patients. Patients and Methods: Patients with at least 5-year follow-up were included. These patients had an asymmetric arm tremor, a previous diagnosis of Parkinson's disease (PD), and a subsequent normal DaTscan. The imaging and clinical follow-up was done on the clinical basis. Results: Sixteen patients were included. The mean gap between the first and subsequent scans was 5.4 years. Two patients (12.5%) had reduced nigrostriatal uptake on follow-up DaTscan, whereas 14 continued to have normal dopaminergic imaging. Conclusion: This is the longest follow up of patients with asymmetric rest tremor and normal DaT scans (SWEDDs) reported to date. We show here that only a minority of them show reduced striatonigral uptake over long term follow up.