Effects on cognition and quality of life with unilateral magnetic resonance-guided focused ultrasound thalamotomy for essential tremor

Abstract

OBJECTIVE Although neurosurgical procedures are effective treatments for controlling involuntary tremor in patients with essential tremor (ET), they can cause cognitive decline, which can affect quality of life (QOL). The purpose of this study is to assess the changes in the neuropsychological profile and QOL of patients following MR-guided focused ultrasound (MRgFUS) thalamotomy for ET. METHODS The authors prospectively analyzed 20 patients with ET who underwent unilateral MRgFUS thalamotomy at their institute in the period from March 2012 to September 2014. Patients were regularly evaluated with the Clinical Rating Scale for Tremor (CRST), neuroimaging, and cognition and QOL measures. The Seoul Neuropsychological Screening Battery was used to assess cognitive function, and the Quality of Life in Essential Tremor Questionnaire (QUEST) was used to evaluate the postoperative change in QOL. RESULTS The total CRST score improved by 67.3% (from 44.75 ± 9.57 to 14.65 ± 9.19, p < 0.001) at 1 year following MRgFUS thalamotomy. Mean tremor scores improved by 68% in the hand contralateral to the thalamotomy, but there was no significant improvement in the ipsilateral hand. Although minimal cognitive decline was observed without statistical significance, memory function was much improved (p = 0.031). The total QUEST score also showed the same trend of improving (64.16 ± 17.75 vs 27.38 ± 13.96, p < 0.001). CONCLUSIONS The authors report that MRgFUS thalamotomy had beneficial effects in terms of not only tremor control but also safety for cognitive function and QOL. Acceptable postoperative changes in cognition and much-improved QOL positively support the clinical significance of MRgFUS thalamotomy as a new, favorable surgical treatment in patients with ET.

Keywords: CRST = Clinical Rating Scale for Tremor; DBS = deep brain stimulation; ET = essential tremor; MCI = mild cognitive impairment; MRgFUS = MR-guided focused ultrasound; QOL = quality of life; QSI = QUEST summary index; QUEST = Quality of Life in Essential Tremor Questionnaire; RF = radiofrequency; SNSB-II = Seoul Neuropsychological Screening Battery II; Vim = ventral intermediate nucleus; cognition; essential tremor; focused ultrasound; memory; quality of life; thalamotomy.