Therapeutic Role of Repetitive Transcranial Magnetic Stimulation in Alzheimer’s and Parkinson’s Disease: Electroencephalography Microstate Correlates

Abstract

IntroductionThe microstate analysis is a method to convert the electrical potentials on the multi-channel electrode array to topographical electroencephalography (EEG) data. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method that can modulate brain networks. This study explores the pathophysiological changes through microstate analysis in two different neurodegenerative diseases, Alzheimer’s (AD) and Parkinson’s disease (PD), characterized by motor and cognitive symptoms and analysis the effect of rTMS on the impaired cognitive and motor functions.Materials and MethodsWe included 18 AD, 8 PD patients, and 13 age-matched controls. For both groups, we applied 5 Hz rTMS on the left pre-SMA in PD patients while 20 Hz rTMS on the left lateral parietal region in AD patients. Each patient was re-evaluated 1 week after the end of the sessions, which included a detailed clinical evaluation and measurement of EEG microstates.ResultsAt the baseline, the common findings between our AD and PD patients were altered microstate (MS) B, MS D durations and transition frequencies between MS A–MS B, MS C–MS D while global explained variance (GEV) ratio and the extent and frequency of occurrence of MS A, MS B, and MS D were separately altered in AD patients. Although no specific microstate parameter adequately differentiated between AD and PD patients, we observed significant changes in MS B and MS D parameters in PD patients. Further, we observed that Mini-Mental State Examination (MMSE) performances were associated with the transition frequencies between MS A–MS B and MS C–MS D and GEV ratio. After left parietal rTMS application, we have observed significantly increased visual memory recognition and clock drawing scores after left parietal rTMS application associated with improved microstate conditions prominent, especially in the mean duration of MS C in AD patients. Also, pre-SMA rTMS resulted in significant improvement in motor scores and frequency of transitions from MS D to MS C in PD patients.ConclusionThis study shows that PD and AD can cause different and similar microstate changes that can be modulated through rTMS, suggesting the role of MS parameters and rTMS as a possible combination in monitoring the treatment effect in neurodegenerative diseases.

EEG spectral and microstate analysis originating residual inhibition of tinnitus induced by tailor-made notched music training

“…The rich syntax of the microstate time series provides a range of novel quantifications of the EEG signal with potential neurophysiological relevance. Indeed, many studies have demonstrated that characteristics of the EEG microstate time series vary across behavioral states ( Stevens and Kircher, 1998 ; Lehmann et al, 2010 ), personality types ( Schlegel et al, 2012 ), consciousness ( Bréchet and Michel, 2022 ), sleep ( Peng et al, 2021 ), pain ( May et al, 2021 ) and neuropsychiatric disorders, such as Alzheimer’s disease ( Dierks et al, 1997 ; Hanoglu et al, 2022 ), Parkinson’s disease ( Pal et al, 2021 ; Hanoglu et al, 2022 ), Huntington’s disease ( Faber et al, 2021 ), schizophrenia ( Lehmann et al, 2005 ; Kim et al, 2021 ), panic ( Kikuchi et al, 2011 ), dementia ( Lin et al, 2021 ). Multiple evidence suggest that the microstate time series may provide insights into the neural activity of the brain in the resting state ( Britz et al, 2010 ; Musso et al, 2010 ; Yuan et al, 2012 ).…”

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“…71 Therefore, our identification of the activation of pre-SMA in swallowing may reflect the cognitive demands of the swallowing task. Considering that repetitive transcranial magnetic stimulation (rTMS) targeting pre-SMA significantly improves motor and cognitive function in patients with neurodegenerative diseases, 72 future clinical trials for patients with dysphagia are necessary.…”

The Use of Transcranial Magnetic Stimulation in Attention Optimization Research: A Review from Basic Theory to Findings in Attention-Deficit/Hyperactivity Disorder and Depression

“…The combined application of brain neuroimaging and TMS holds promise for the clinical treatment of ADHD by providing insights into its neural underpinnings and offering targeted interventions [ 97 , 98 ]. Advanced neuroimaging techniques like fMRI can identify specific brain regions and networks associated with ADHD [ 99 , 100 ].…”