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Gamma oscillations weaken with age in healthy elderly in human EEG

Authors :
Supratim Ray
Mahendra Javali
Naren Prahalada Rao
Keerthana Manikandan
Wupadrasta Santosh Kumar
Ranjini Garani Ramesh
Simran Purokayastha
Dinavahi V. P. S. Murty
Source :
NeuroImage, Vol 215, Iss, Pp 116826-(2020), NeuroImage
Publication Year :
2020
Publisher :
Elsevier, 2020.

Abstract

Gamma rhythms (∼20-70 Hz) have been reported to be abnormal in mental disorders such as autism and schizophrenia in humans, and Alzheimer’s disease (AD) models in rodents. However, the effect of normal aging on these oscillations is not known, especially for elderly subjects (>49 years) for which AD is most prevalent. In a first large-scale (236 subjects; 104 females) electroencephalogram (EEG) study on gamma oscillations on elderly subjects (aged 50-88 years), we presented full-screen Cartesian gratings that induced two distinct gamma oscillations (slow: 20-34 Hz and fast: 36-66 Hz). Power and centre frequency significantly decreased with age for both slow and fast gamma, but not alpha (8-12 Hz). Reduction was more salient for fast gamma than slow. These results were independent of microsaccades and pupillary reactivity to stimulus, as well as variations in power spectral density with age. Steady-state visual evoked potentials (SSVEPs) also reduced with age. These results are crucial first steps towards using gamma/SSVEPs as biomarkers of cognitive decline in elderly.Significance statementNo study in humans has examined visual narrow-band gamma oscillations with healthy aging in elderly subjects. In a first large-scale (236 subjects) EEG study on stimulus-induced narrow band gamma in cognitively normal elderly (>49 years) humans, we show that both power and centre frequency of slow and fast gamma (20-34 Hz and 36-66 Hz respectively) decrease with age, but alpha power does not. Steady-state visual evoked potential (SSVEPs) in gamma range also decrease with age. Any EEG-based biomarker is accessible and affordable to patients of a wide socio-economic spectrum. Our results are important steps for developing such screening/diagnostic tests for aging-related diseases, like Alzheimer’s disease.

Details

Language :
English
ISSN :
10959572
Volume :
215
Database :
OpenAIRE
Journal :
NeuroImage
Accession number :
edsair.doi.dedup.....dedb2e483f4c9a8a08298678ec352941