Affiliations: [a]
Department of Psychological Science, Kennesaw State University, GA, USA
| [b]
Institute of Gerontology, Wayne State University, Detroit, MI, USA
| [c]
University of Primorska, Faculty of Mathematics, Natural Sciences and Information Technologies, Koper, Slovenia
| [d]
University of Primorska, Andrej Marušič Institute, Koper, Slovenia
| [e]
Institute of Mathematics, Physics and Mechanics, Ljubljana, Slovenia
| [f]
Departments of Psychiatry, Neurology, and Psychology and School of Nursing, University of Michigan, Ann Arbor, MI, USA
| [g]
International Institute of Applied Gerontology, Ljubljana, Slovenia
Correspondence:
[*]
Correspondence to: Tim Martin, PhD, Kennesaw State University, MD 2202, 1000 Chastain Rd NE, Kennesaw, GA 30144, USA. E-mail: [email protected].
Abstract: Background:Identification of older individuals with increased risk for cognitive decline can contribute not only to personal benefits (e.g., early treatment, evaluation of treatment), but could also benefit clinical trials (e.g., patient selection). We propose that baseline resting-state electroencephalography (rsEEG) could provide markers for early identification of cognitive decline. Objective:To determine whether rsEEG theta/beta ratio (TBR) differed between mild cognitively impaired (MCI) and healthy older adults. Methods:We analyzed rsEEG from a sample of 99 (ages 60–90) consensus-diagnosed, community-dwelling older African Americans (58 cognitively typical and 41 MCI). Eyes closed rsEEGs were acquired before and after participants engaged in a visual motion direction discrimination task. rsEEG TBR was calculated for four midline locations and assessed for differences as a function of MCI status. Hemispheric asymmetry of TBR was also analyzed at equidistant lateral electrode sites. Results:Results showed that MCI participants had a higher TBR than controls (p = 0.04), and that TBR significantly differed across vertex location (p < 0.001) with the highest TBR at parietal site. MCI and cognitively normal controls also differed in hemispheric asymmetries, such that MCI show higher TBR at frontal sites, with TBR greater over right frontal electrodes in the MCI group (p = 0.003) and no asymmetries found in the cognitively normal group. Lastly, we found a significant task aftereffect (post-task compared to pre-task measures) with higher TBR at posterior locations (Oz p = 0.002, Pz p = 0.057). Conclusion:TBR and TBR asymmetries differ between MCI and cognitively normal older adults and may reflect neurodegenerative processes underlying MCI symptoms.
Keywords: Alzheimer’s disease, hemispheric asymmetry, mild cognitive impairment, older Black Americans, resting-state electroencephalography, theta/beta ratio
