Objective: To explore whether EEG microstate evaluation may help in identifying mild cognitive impairment with Lewy bodies (MCI-LB) and to assess whether the changes correlate with the known alpha frequency markers.

Background: Electrophysiological marker of early stage dementia with Lewy bodies (DLB) was already described in spectral domain using dominant peak of alpha frequency and its variability [1]. Promising source of information might be in the sub-second temporal resolution of high density (HD) EEG [2].

Method: We processed resting state HD EEG in 21 consecutive MCI-LB subjects and 21 matched healthy controls (HC). EEG microstates were analyzed in preprocessed 204 channels. Temporal parameters (mean duration, time coverage, segment density) of microstates were then calculated and compared between groups. Thereafter, dominant alpha peak frequency was analyzed in posterior scalp electrodes and correlated with microstate parameters by Pearson correlation.

Results: Four microstate maps describing 76% of global explained variance in the data were revealed (typically referred as Microstate A, B, C and D). We found significant differences (p<0.05 FDR) between MCI-LB and HC group for Microstate B, which showed significantly shorter mean duration and increased time coverage and segment density in MCI-LB compared to HC. Moreover, all four microstates indicated significantly higher (p<0.05 FDR) segment density in MCI-LB group. The subject specific dominant alpha frequency correlated (r = -0.57, p = 0.009) with segment density of Microstate B.

Conclusion: Microstate B (related to visual network) shows specific temporal changes that correlate with dominant alpha frequency in medication-naïve MCI-LB compared to HC group. Longitudinal follow up of our cohort may reveal how EEG microstates reflect brain function deficits and compensatory mechanism in prodromal DLB.

References: [1] Bonanni L, Perfetti B, Bifolchetti S, Taylor J-P, Franciotti R, Parnetti L, et al. Quantitative electroencephalogram utility in predicting conversion of mild cognitive impairment to dementia with Lewy bodies. Neurobiol Aging. 2015;36(1):434–45. [2] Michel CM, Koenig T. EEG microstates as a tool for studying the temporal dynamics of whole-brain neuronal networks: A review. Neuroimage. 2018;180(December 2017):577–93. The work was supported by Ministry of Health of the Czech Republic, grant NU20-04-00294.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/spatiotemporal-dynamics-in-mild-cognitive-impairment-with-lewy-bodies/