Task Specific Tremor Subsequently Developing into Parkinson's Disease: Case Series.

BACKGROUND

Parkinson's Disease (PD) can present with dystonia or essential tremor but task specific tremor (TST) preceding PD has been only rarely reported. The relationship between TST and PD is unclear. We report a series of 12 patients with TST who later developed PD.

CASES: Patients with TST and PD were identified from our database. Records and imaging were reviewed and descriptive statistics presented. Twelve patients were identified. All 11 patients who had TST of arm developed rest tremor ipsilateral to the TST arm. DaTscan showed reduced dopaminergic uptake in all 11 patients who were scanned. The TST improved with STN and VIM DBS (3/12) and partially to dopaminergic medications (N = 3) and trihexyphenidyl (N = 2).

CONCLUSION

Rest tremor consistently occurring ipsilateral to TST, positive DaTscan, and partial response to dopaminergic medications but not to ET medications suggests TST is a precursor to PD in this population rather than chance occurrence.