Personalized Repetitive Transcranial Magnetic Stimulation (rTMS) in Cognitive Fluctuations of Dementia With Lewy Bodies (DLB): Proof of Concept

Overview

The present study is a monocentric, therapeutic clinical trial involving forty patients diagnosed with Dementia with Lewy Bodies (DLB). The aim of this clinical trial is to evaluate the feasibility and relevance of repetitive transcranial magnetic stimulation (rTMS); a non-invasive neuromodulation technique, with a main emphasis on the evaluation of the outcome on cognitive fluctuations. For this purpose, we will compare two distinct rTMS conditions (control and experimental) in a pre-post rTMS setting. The experimental condition will be targeting the insular cortex which has been shown to be affected at prodromal DLB stages, in the form of decreased grey matter concentration and a decreased regional Cerebral Blood Flow (rCBF hypoperfusion) \[Blanc et al., 2015 ; Roquet et al., 2016 ; Roquet et al., 2017\]. Furthermore, these insular alterations are correlated to cognitive fluctuations \[Chabran et al., 2020\]. In DLB, cognitive fluctuations are particularly pervasive and manifest in the form of alertness alterations and modifications of arousal states. Participants will repeatedly undergo a series of clinical and cognitive assessments in addition to several neuroimaging examinations, namely multimodal Magnetic Resonance Imaging (MRI) and electroencephalogram (EEG) recordings, in order to evaluate potential physiological modifications and clinical changes of symptoms, pre-/post-rTMS.

Objectives: * To provide a proof of concept by validating the hypoactivity (hypoperfusion) of the anterior insula ("AI biomarker") as a causal factor of the instability of arousal states in DLB. * To evaluate if improvement of arousal translates clinically into a reduction of cognitive fluctuations and an improvement of other functional parameters (clinical measures of symptoms). * Evaluation of the relevance of the AI biomarker as a predictive tool for clinical response. * Assessment of reproducibility of the AI hypoperfusion (biomarker) at an individual level and thereby its potential as a diagnostic or therapeutic biomarker. * Collection, description and analysis of all adverse events and required information for the implementation of future phase II and III studies Methodological approach: The present study will be conducted at the "non-invasive neurostimulation center of Strasburg" (Centre de Neuromodulation Non-invasive de Strasbourg ; CEMNIS) in collaboration with the Memory Clinic of Strasbourg (Centre Mémoire de Ressources et de Recherches ; CM2R) of the University Hospitals of Strasbourg (HUS) and the ICube laboratory (Team IMIS, UMR 7357, CNRS). We propose a single-centre, two-arm, randomized, crossover, double-blind comparative study. N=40 patients will be prospectively recruited in order to create two experimental groups (arms) (Group A and Group B) in a cross-over study design, following two experimental phases (I and II). The protocol will include two rTMS conditions: (1) verum stimulation (target: insular cortex) and (2) control stimulation (target: occipital cortex). The running order for each participant will be counterbalanced: Group A will start with the verum rTMS in phase I, followed by the control rTMS in phase II. Group B will start with the control rTMS in phase I, followed by the verum rTMS in phase II. One phase of rTMS will consist of a total of ten visits. One visit will include two sessions of rTMS, summing up to a total of twenty sessions of rTMS for each patient. Participants will undergo multiple EEG recordings and multimodal cerebral MRI scans, as well as several different clinical assessments (self-reported, reported by the investigator and the patients' main caregiver) numerous times during the protocol, pre- and post-rTMS sessions. In sum, each patient will undergo five MRI scans and three clinical assessments. The clinical trial schedules a total of N=37 visits for each patient.