Differences in Multimodal Electroencephalogram and Clinical Correlations Between Early-Onset Alzheimer's Disease and Frontotemporal Dementia.

Nan Lin,Jing Gao,Chenhui Mao,Qiang Lu,Liying Cui,Heyang Sun

doi:10.3389/fnins.2021.687053

Abstract

BackgroundAlzheimer’s disease (AD) and frontotemporal dementia (FTD) are the two main types of dementia. We investigated the electroencephalogram (EEG) difference and clinical correlation in early-onset Alzheimer’s disease (EOAD), and FTD using multimodal EEG analyses. EOAD had more severe EEG abnormalities than late-onset AD (LOAD). Group comparisons between EOAD and LOAD were also performed.MethodsThirty patients diagnosed with EOAD, nine patients with LOAD, and 14 patients with FTD (≤65 y) were recruited (2008.1–2020.2), along with 24 healthy controls (≤65 y, n = 18; >65 y, n = 6). Clinical data were reviewed. Visual EEG, EEG microstate, and spectral analyses were performed.ResultsCompared to controls, markedly increased mean microstate duration, reduced mean occurrence, and reduced global field power (GFP) peaks per second were observed in EOAD and FTD. We found increased durations of class B in EOAD and class A in FTD. EOAD had reduced occurrences in classes A, B, and C, while only class C occurrence was reduced in FTD. The visual EEG results did not differ between AD and FTD. Microstate B showed correlations with activities of daily living score (r = 0.780, p = 0.008) and cerebrospinal fluid (CSF) Aβ42 (r = −0.833, p = 0.010) in EOAD. Microstate D occurrence was correlated with the CSF Aβ42 level in FTD (r = 0.786, p = 0.021). Spectral analysis revealed a general slowing EEG, which may contribute to microstate dynamic loss. Power in delta was significantly higher in EOAD than in FTD all over the head. In addition, EOAD had a marked increased duration and decreased occurrence than late-onset AD (LOAD), with no group differences in visual EEG results.ConclusionThe current study found that EOAD and FTD had different EEG changes, and microstate had an association with clinical severity and CSF biomarkers. EEG microstate is more sensitive than visual EEG and may be useful for the differentiation between AD and FTD. The observations support that EEG can be a potential biomarker for the diagnosis and assessment of early-onset dementias.

Highlights

Alzheimer’s disease (AD) is the most common form of dementia, accounting for 60–80% of cases (Scheltens et al, 2016)
early-onset AD (EOAD), and frontotemporal dementia (FTD) participants had no significant differences in age and gender
Cerebrospinal fluid biomarker results were available in eight patients with EOAD and eight with FTD at the time of EEG recordings

Summary

Introduction

Alzheimer’s disease (AD) is the most common form of dementia, accounting for 60–80% of cases (Scheltens et al, 2016). A diagnosis of AD below the age of 65 is classed as early-onset AD (EOAD). EOAD accounts for only 5%–10% of all AD cases (Dai et al, 2018). Patients with EOAD display greater cerebrospinal fluid (CSF) anomalies (Dumurgier et al, 2013) and more severe electroencephalogram (EEG) abnormalities (Micanovic and Pal, 2014). Alzheimer’s disease (AD) and frontotemporal dementia (FTD) are the two main types of dementia. We investigated the electroencephalogram (EEG) difference and clinical correlation in early-onset Alzheimer’s disease (EOAD), and FTD using multimodal EEG analyses. EOAD had more severe EEG abnormalities than late-onset AD (LOAD). Group comparisons between EOAD and LOAD were performed

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Results

Discussion

Conclusion