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

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 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.

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.

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.