Object. Thalamic neurons firing at frequencies synchronous with tremor are thought to play a critical role in the generation and maintenance of tremor. The authors studied the incidence and locations of neurons with tremor-related activity (TRA) in the thalamus of patients with varied pathological conditions—including Parkinson disease (PD), essential tremor (ET), multiple sclerosis (MS), and cerebellar disorders—to determine whether known differences in the effectiveness of thalamic stereotactic procedures for these tremors could be correlated to differences in the incidence or locations of TRA cells.
Methods. Seventy-five operations were performed in 61 patients during which 686 TRA cells were recorded from 440 microelectrode trajectories in the thalamus. The locations of the TRA cells in relation to electrophysiologically defined thalamic nuclei and the commissural coordinates were compared among patient groups.
The authors found that TRA cells are present in patients with each of these disorders and that these cells populate several nuclei in the ventral lateral tier of the thalamus. There were no large differences in the locations of TRA cells among the different diagnostic classes, although there was a difference in the incidence of TRA cells in patients with PD, who had greater than 3.8 times more cells per thalamic trajectory than patients with ET and approximately five times more cells than patients with MS or cerebellar disorders.
Conclusions. There was an increased incidence of TRA in the thalamus of patients with PD. The location of thalamic TRA cells in patients with basal ganglia and other tremor disorders was similar.
Address reprint requests to: Andres M. Lozano, M.D., Ph.D., Division of Neurosurgery, Toronto Western Hospital, 4–447 West Wing, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8. email: email@example.com.
ZirhAReichSGDoughertyPMet al: Stereotactic thalamotomy in the treatment of essential tremor of the upper extremity: reassessment including a blinded measure of outcome.J Neurol Neurosurg Psychiatry66:772–7751999J Neurol Neurosurg Psychiatry 66: