VIM deep brain stimulation does not improve pre-existing restless legs syndrome in patients with essential tremor.

The neuroanatomic substrate for restless legs syndrome (RLS) is not known. We implanted deep brain stimulators into the ventralis intermedius nucleus (VIM) of the thalamus in nine subjects for essential tremor (ET) whom all concurrently had RLS. Although the VIM DBS improved tremor, none of the subjects felt there was any meaningful effect on their RLS symptoms. The VIM thalamus, which is involved in ET and Parkinson's disease, does not seem to be primarily involved in RLS.