Objective: The neuropsychological effects of thalamotomy and thalamic stimulation in patients with severe drug-resistant tremor due to PD, essential tremor (ET), or MS were compared in a randomized trial.
Methods: Complete neuropsychological evaluations at baseline and 6 months after surgery were obtained in 62 patients who underwent thalamotomy (n = 32: 21 PD, 6 ET, 5 MS) or thalamic stimulation (n = 30: 19 PD, 7 ET, 4 MS).
Results: Six months after thalamotomy, a decline was seen in the scores of the Stroop Color-Word Test, with the exception of the interference score. In the thalamic stimulation group, no significant changes were found on any of the cognitive tests. Age, diagnosis, disease severity, and baseline cognitive status were not correlated to cognitive changes. A difference in score changes between right- and left-sided surgery was found in verbal fluency and Stroop Test scores after both thalamotomy and thalamic stimulation.
Conclusions: Both thalamotomy and thalamic stimulation are associated with a minimal overall risk of cognitive deterioration. Verbal fluency decreased after both left-sided thalamotomy and thalamic stimulation.