Multimodal EEG-MRI in the differential diagnosis of Alzheimer's disease and dementia with Lewy bodies

Abstract

Differential diagnosis of Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) remains challenging; currently the best discriminator is striatal dopaminergic imaging. However this modality fails to identify 15–20% of DLB cases and thus other biomarkers may be useful. It is recognised electroencephalography (EEG) slowing and relative medial temporal lobe preservation are supportive features of DLB, although individually they lack diagnostic accuracy. Therefore, we investigated whether combined EEG and MRI indices could assist in the differential diagnosis of AD and DLB.Seventy two participants (21 Controls, 30 AD, 21 DLB) underwent resting EEG and 3 T MR imaging. Six EEG classifiers previously generated using support vector machine algorithms were applied to the present dataset. MRI index was derived from medial temporal atrophy (MTA) ratings. Logistic regression analysis identified EEG predictors of AD and DLB. A combined EEG-MRI model was then generated to examine whether there was an improvement in classification compared to individual modalities.For EEG, two classifiers predicted AD and DLB (model: χ2 = 22.1, df = 2, p < 0.001, Nagelkerke R2 = 0.47, classification = 77% (AD 87%, DLB 62%)). For MRI, MTA also predicted AD and DLB (model: χ2 = 6.5, df = 1, p = 0.01, Nagelkerke R2 = 0.16, classification = 67% (77% AD, 52% DLB). However, a combined EEG-MRI model showed greater prediction in AD and DLB (model: χ2 = 31.1, df = 3, p < 0.001, Nagelkerke R2 = 0.62, classification = 90% (93% AD, 86% DLB)).While suggestive and requiring validation, diagnostic performance could be improved by combining EEG and MRI, and may represent an alternative to dopaminergic imaging.

Systematic Review on Resting-State EEG for Alzheimer’s Disease Diagnosis and Progression Assessment

“…Moreover, disparity in synchronization measures is reported between AD, PDD [ 38 , 42 ], DLB and FTD [ 42 ]. Additionally, a combined model of EEG and MRI improved discrimination between AD and DLB [ 41 ].…”

“…In recent years, quantitative EEG (qEEG, henceforth simply EEG) has been proven to be a reliable clinical tool for the diagnosis and study of illnesses and cortical disorders such as Huntington disease [ 33 ], autism spectrum disorders [ 34 ], epilepsy and seizure [ 35 ], cerebral ischemia [ 36 ], frontotemporal dementia [ 37 ], and Parkinson's disease dementia [ 38 ]. Furthermore, the differential diagnosis between AD and other diseases that lead to dementia as vascular brain injury [ 39 , 40 ] and Lewy body diseases [ 41 , 42 ] was assessed with EEG. In the analysis, EEG signals are commonly divided into 5 major frequency bands, namely, delta ( δ ) 0.1–4 Hz, theta ( θ ) 4–8 Hz, alpha ( α ) 8–12 Hz, beta ( β ) 12–30 Hz, and gamma ( γ ) > 30 Hz.…”

Electroencephalographic derived network differences in Lewy body dementia compared to Alzheimer’s disease patients

“…For instance, Colloby, et al . 13 reported 86% sensitivity and 93% specificity (90% accuracy) classification for DLB versus AD, using a combined EEG-structural MRI approach. Forward projection of the MST-PLI and DF measures presented here, onto independent EEG samples will be required to clarify the robustness of these measures as diagnostic tools for DLB.…”

“… 8 and Babiloni, et al . 9 amongst others 10 – 13 , with the current consensus indicating that there is a slowing of the dominant frequency band (typically in the alpha frequency range) during eye-closed EEG at occipital regions in Lewy body dementia, and that this feature may be useful as a diagnostic biomarker of DLB versus AD 14 . The potential of this EEG feature as a DLB biomarker has been acknowledged as well by the recent consensus criteria for the clinical diagnosis of this dementia 15 , where the slowing of the dominant band in patients has been given the status of supportive biomarker to differentiate DLB from AD 15 .…”

Quantitative electroencephalography as a marker of cognitive fluctuations in dementia with Lewy bodies and an aid to differential diagnosis

“…However, our clinical diagnostic approaches were robust enough to enhance the specificity of our group selections. Evidence for this include DaT scans that were available for 9 of the DLB patients and were all positive, and a multi-modal MRI/EEG analysis on data from all the patients that were recruited in the same cohort as the patients included in this study, where AD and DLB patients were classified with 90% accuracy ( Colloby et al, 2016 ).…”