Extradural Motor Cortex Stimulation might improve episodic and working memory in patients with Parkinson\u2019s disease

Carla Piano,Antonio Daniele,Daniela Di Giuda,Fabrizio Cocciolillo,Anna Rita Bentivoglio,Francesco Bove,Beatrice Cioni,Paolo Calabresi,Tommaso Tufo,Marco Ciavarro

doi:10.1038/s41531-020-00129-8

Abstract

Electric Extradural Motor Cortex Stimulation (EMCS) is a neurosurgical procedure suggested for treatment of patients with advanced Parkinson’s disease (PD). We report two PD patients treated by EMCS, who experienced worsening of motor symptoms and cognition 5 years after surgery, when EMCS batteries became discharged. One month after EMCS restoration, they experienced a subjective improvement of motor symptoms and cognition. Neuropsychological assessments were carried out before replacement of batteries (off-EMCS condition) and 6 months afterward (on-EMCS condition). As compared to off-EMCS condition, in on-EMCS condition both patients showed an improvement on tasks of verbal episodic memory and backward spatial short-term/working memory task, and a decline on tasks of selective visual attention and forward spatial short-term memory. These findings suggest that in PD patients EMCS may induce slight beneficial effects on motor symptoms and cognitive processes involved in verbal episodic memory and in active manipulation of information stored in working memory.

Highlights

Electric chronic Extradural Motor Cortex Stimulation (EMCS) is a minimally invasive neurosurgical procedure requiring implantation of extradural electrodes
Preliminary observations in Parkinson’s disease (PD) patients treated by EMCS suggest that electrical stimulation of the primary motor cortex (PMC) may modulate neural activity in the basal ganglia (BG), by activating cortico-BG projections[1,3], resulting in slight improvement of Parkinsonian motor symptoms, especially axial motor symptoms[4,5]
Patient 1 is a man with a 11-year history of PD, who started to show at the age of 59 years Parkinsonian motor symptoms and later developed “on–off” fluctuations and peak-dose dyskinesias

Summary

INTRODUCTION

Electric chronic Extradural Motor Cortex Stimulation (EMCS) is a minimally invasive neurosurgical procedure requiring implantation of extradural electrodes. In PD patients treated by bilateral EMCS, comparisons between preoperative and postoperative cognitive performance on neuropsychological tasks did not detect any significant overall cognitive decline at a 6-month[5] and 1-year postoperative follow-up[5,6]. In a case of pure akinesia with gait freezing, a variant of progressive supranuclear palsy (PSP), bilateral EMCS improved motor symptoms (speech and gait), and cognitive performance on language (sublexical and lexical-semantic) tasks[7]. One month after the batteries were replaced, patients experienced a subjective improvement of motor symptoms and cognition. In order to investigate possible changes in cognitive performance, apparently related to battery status, patients underwent an extensive neuropsychological assessment before (off-EMCS) and 6 months after (on-EMCS) replacement of batteries

RESULTS

Piano et al 2

DISCUSSION

METHODS