EEG alpha reactivity and cholinergic system integrity in Lewy body dementia and Alzheimer’s disease

Schumacher, Julia; Thomas, Alan; Peraza, Luis R.; Firbank, Michael; Cromarty, Ruth; Hamilton, Calum A; Donaghy, Paul C.; O’Brien, John; Taylor, John‐Paul

doi:10.1186/s13195-020-00613-6

Cited by 60 publications

(59 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reactivity of rhythmic background activity to eyes opening was reduced in DLB compared to AD in qualitative and quantitative analyses in one study [ 26 ]. More recently, Schumacher et al [ 63 ] showed that alpha reactivity, quantified by the relative reduction in alpha power over occipital electrodes when opening the eyes, was reduced in DLB and PDD patients compared to AD and healthy controls. The loss of reactivity correlated with loss of NBM volume particularly in PDD patients.…”

Section: Resultsmentioning

confidence: 99%

“…However, due to the heterogeneity of connectivity measures used and the fact that conflicting results had been reported, more studies are needed to explore if the disconnection is, indeed, worse in DLB. Reduced reactivity to eyes opening [63] and intermittent photic stimulation [60] and reduced posterior-to-anterior dPTE suggest the disconnection syndrome affects predominantly posterior regions [48]. Functional connectivity of the basal ganglia, thalamic and cortical networks correlating with longer MS duration in DLB have been implicated as well [55].…”

Section: Discussionmentioning

confidence: 99%

“…In another study, donepezil-treated DLB patients have been reported to have lower delta and theta power and coherence than those not treated with donepezil [32]. Treatment with dopaminergic agents did not have a significant effect on alpha power and reactivity among patients with DLB and PDD in one study [63].…”

Section: Treatment Effect On Eegmentioning

confidence: 89%

“…Based on TF and IAF, the frequency bands for each subject were estimated as follows: delta from TF-4 Hz to TF-2 Hz, theta from TF-2 Hz to TF; low-frequency alpha band (alpha 1 and alpha 2) from TF to IAF; and high-frequency alpha band (or alpha 3) [51]. Mean IAF (equivalent of dominant/peak frequency) and TF were reduced in DLB compared to AD [51,63] even at the mild cognitive impairment (MCI) stage [53]. On spectral analysis, alpha relative power in occipital regions was reduced in AD compared to DLB while delta relative power was higher in DLB than AD [51,53].…”

Section: Spectral Power Analysesmentioning

confidence: 99%

“…Pre-pulse inhibition (auditory sensory filtering) appears moderately reduced in PDD compared to AD, but is less affected when compared to DLB [59]. Both DLB and PDD have reduced reactivity to eyes opening [60,63] and intermittent photic stimulation [60].…”

Section: Dlb Vs Parkinson's Disease Dementia (Pdd)mentioning

confidence: 99%

See 4 more Smart Citations

The Role of EEG in the Diagnosis, Prognosis and Clinical Correlations of Dementia with Lewy Bodies—A Systematic Review

et al. 2020

Self Cite

View full text Add to dashboard Cite

Despite improvements in diagnostic criteria for dementia with Lewy bodies (DLB), the ability to discriminate DLB from Alzheimer’s disease (AD) and other dementias remains suboptimal. Electroencephalography (EEG) is currently a supportive biomarker in the diagnosis of DLB. We performed a systematic review to better clarify the diagnostic and prognostic role of EEG in DLB and define the clinical correlates of various EEG features described in DLB. MEDLINE, EMBASE, and PsycINFO were searched using search strategies for relevant articles up to 6 August 2020. We included 43 studies comparing EEG in DLB with other diagnoses, 42 of them included a comparison of DLB with AD, 10 studies compared DLB with Parkinson’s disease dementia, and 6 studies compared DLB with other dementias. The studies were visual EEG assessment (6), quantitative EEG (35) and event-related potential studies (2). The most consistent observation was the slowing of the dominant EEG rhythm (<8 Hz) assessed visually or through quantitative EEG, which was observed in ~90% of patients with DLB and only ~10% of patients with AD. Other findings based on qualitative rating, spectral power analyses, connectivity, microstate and machine learning algorithms were largely heterogenous due to differences in study design, EEG acquisition, preprocessing and analysis. EEG protocols should be standardized to allow replication and validation of promising EEG features as potential biomarkers in DLB.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Treatment Effect On Eegmentioning

confidence: 89%

Section: Spectral Power Analysesmentioning

confidence: 99%

Section: Dlb Vs Parkinson's Disease Dementia (Pdd)mentioning

confidence: 99%

See 3 more Smart Citations

The Role of EEG in the Diagnosis, Prognosis and Clinical Correlations of Dementia with Lewy Bodies—A Systematic Review

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

The Cholinergic Brain in Parkinson's Disease

Pasquini

Brooks

Pavese

2021

Movement Disord Clin Pract

View full text Add to dashboard Cite

The central cholinergic system includes the basal forebrain nuclei, mainly projecting to the cortex, the mesopontine tegmental nuclei, mainly projecting to the thalamus and subcortical structures, and other groups of projecting neurons and interneurons. This system regulates many functions of human behavior such as cognition, locomotion, and sleep. In Parkinson's disease (PD), disruption of central cholinergic transmission has been associated with cognitive decline, gait problems, freezing of gait (FOG), falls, REM sleep behavior disorder (RBD), neuropsychiatric manifestations, and olfactory dysfunction. Neuropathological and neuroimaging evidence suggests that basal forebrain pathology occurs simultaneously with nigrostriatal denervation, whereas pathology in the pontine nuclei may occur before the onset of motor symptoms. These studies have also detailed the clinical implications of cholinergic dysfunction in PD. Degeneration of basal forebrain nuclei and consequential cortical cholinergic denervation are associated with and may predict the subsequent development of cognitive decline and neuropsychiatric symptoms. Gait problems, FOG, and falls are associated with a complex dysfunction of both pontine and basal forebrain nuclei. Olfactory impairment is associated with cholinergic denervation of the limbic archicortex, specifically hippocampus and amygdala. Available evidence suggests that cholinergic dysfunction, alongside failure of the dopaminergic and other neurotransmitters systems, contributes to the generation of a specific set of clinical manifestations. Therefore, a “cholinergic phenotype” can be identified in people presenting with cognitive decline, falls, and RBD. In this review, we will summarize the organization of the central cholinergic system and the clinical correlates of cholinergic dysfunction in PD.

show abstract

Alpha tACS Improves Cognition and Modulates Neurotransmission in Dementia with Lewy Bodies

Benussi,

Cantoni,

Rivolta

et al. 2024

Movement Disorders

View full text Add to dashboard Cite

BackgroundDementia with Lewy bodies (DLB) is characterized by a marked shift of electroencephalographic (EEG) power and dominant rhythm, from the α toward the θ frequency range. Transcranial alternate current stimulation (tACS) is a non‐invasive brain stimulation technique that allows entrainment of cerebral oscillations at desired frequencies.ObjectivesOur goal is to evaluate the effects of occipital α‐tACS on cognitive functions and neurophysiological measures in patients with DLB.MethodsWe conducted a double‐blind, randomized, sham‐controlled, cross‐over clinical trial in 14 participants with DLB. Participants were randomized to receive either α‐tACS (60 minutes of 3 mA peak‐to‐peak stimulation at 12 Hz) or sham stimulation applied over the occipital cortex. Clinical evaluations were performed to assess visuospatial and executive functions, as well as verbal episodic memory. Neurophysiological assessments and EEG recordings were conducted at baseline and following both α‐tACS and sham stimulations.ResultsOccipital α‐tACS was safe and well‐tolerated. We observed a significant enhancement in visuospatial abilities and executive functions, but no improvement in verbal episodic memory. We observed an increase in short latency afferent inhibition, a neurophysiological marker indirectly and partially dependent on cholinergic transmission, coinciding with an increase in α power and a decrease in Δ power following α‐tACS stimulation, effects not seen with sham stimulation.ConclusionsThis study demonstrates that occipital α‐tACS is safe and enhances visuospatial and executive functions in patients with DLB. Improvements in indirect markers of cholinergic transmission and EEG changes indicate significant neurophysiological engagement. These findings justify further exploration of α‐tACS as a therapeutic option for DLB patients. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

show abstract

EEG alpha reactivity and cholinergic system integrity in Lewy body dementia and Alzheimer’s disease

Cited by 60 publications

References 46 publications

The Role of EEG in the Diagnosis, Prognosis and Clinical Correlations of Dementia with Lewy Bodies—A Systematic Review

The Role of EEG in the Diagnosis, Prognosis and Clinical Correlations of Dementia with Lewy Bodies—A Systematic Review

The Cholinergic Brain in Parkinson's Disease

Alpha tACS Improves Cognition and Modulates Neurotransmission in Dementia with Lewy Bodies

Contact Info

Product

Resources

About