The literature suggests a strong association between amyloid accumulation and gamma alterations, emerging gamma activity as a biomarker candidate for Alzheimer's pathology. The present study aims to investigate resting-state gamma activity changes in Cerebrospinal fluid (CSF)-proven early-onset Alzheimer's disease (EOAD) patients with a holistic approach that employs structural and functional brain neuroimaging techniques, and neuropsychological aspects.
This cross-sectional study included 24 drug-naive CSF-proven EOAD patients and age-, sex, and education-matched healthy controls. All participants underwent a detailed neuropsychological evaluation, resting-state electroencephalography (EEG) recording, and Magnetic Resonance Imaging (MRI). Gamma power and coherence were measured in total gamma (30-48 Hz), gamma-1 (30-35 Hz), gamma-2 (35-40 Hz), and gamma-3 (40-48 Hz) frequency bands. Gray matter volumes were extracted for 54 regions of interest (ROIs) and compared between groups. Discriminant analysis was performed to determine the classification accuracy of gamma activity for EOAD. Finally, correlations between CSF, neuropsychological tests, EEG, and MRI measures were explored.
Study Type
OBSERVATIONAL
Enrollment
51
Early-onset Alzheimer's disease patients underwent routine laboratory tests to obtain CSF samples. Also, all participants underwent structural MRI examinations and neuropsychological tests.
İzmir University of Economics
Izmir, Turkey (Türkiye)
EEG
The resting state EEG recordings were acquired using Easy-Cap comprising 30 Ag/AgCl electrodes placed according to the international 10-20 system. Coherence and maximum peak power of the total gamma (30-48 Hz) and sub-gamma bands \[gamma-1 (30-35 Hz), gamma-2 (35-40 Hz), and gamma-3 (40-48 Hz)\] were measured for each participant.
Time frame: Day 2
Correlation Analysis
Correlations between CSF, neuropsychological tests (NPT), EEG, and MRI measures were investigated.
Time frame: 3 months
Discriminant Analysis
The discriminative power of gamma measures (power and coherence) was investigated with discriminant analysis (DA).
Time frame: 3 months
MRI
Participants underwent structural magnetic resonance imaging on a Philips Achieva 1.5 Tesla scanner. The gray matter volumes were obtained from the 3D-T1 weighted Turbo field echo (TFE) sequence (TR: 9ms, Time to Echo (TE): 4ms, Field-of-view (FOV): 240mm, matrix: 256, slice thickness: 1mm, numbers of signal averages (NSA): 1). The images were segmented into gray matter, white matter, and CSF with the default parameters of the CAT12 segmentation function. Only the gray matter calculations were compared between groups.
Time frame: Day 1
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