Brain Dynamics Altered by Photic Stimulation in Patients with Alzheimer’s Disease and Mild Cognitive Impairment

Figures

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  Figure 1. Photic stimulation (PS) session performed during routine clinical EEG examination. Pre- and Post-PS resting-state EEG signals were recorded. PS involved flashing a white light for 10 s at various frequencies with 10-s breaks in between. Subjects kept their eyes closed throughout the EEG recording.

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  Figure 2. Significant between-group differences in EEG power ratios of 36-Hz harmonic responses to 9-Hz PS at (a) electrode O2 and (b) electrode P4 (* Bonferroni-corrected p < 0.05). Distribution plots integrated with box plots are presented; violin plots represent the distributions of the data, black boxes represent interquartile ranges (IQR; 25th to 75th percentiles), white circles in each box indicate medians (50%), and red crosses indicate means.

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  Figure 3. Significant between-group differences in EEG power ratios of 30-Hz harmonic responses to 15-Hz PS at electrodes (a) O1, (b) O2, (c) P3, and (d) P4 (* Bonferroni-corrected p < 0.05). Distribution plots integrated with box plots are presented; violin plots represent the distributions of the data, boxes represent interquartile ranges (IQR; 25th to 75th percentiles), white circles in each box indicate medians (50%), and red crosses indicate means.

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  Figure 4. MSE profiles and between-group differences before PS (Pre-PS), under the effects of 15-Hz PS (During PS), and after PS (Post-PS) at electrodes (a) O1, (b) O2, (c) P3, and (d) P4. In each subfigure, lines in different colors are the mean SE values at each scale factor for each group (* p < 0.05, one-way ANCOVAs).

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  Figure 5. MSE profiles and PS-induced changes (Pre-PS, during 15-Hz PS, and Post-PS) in each group at the representative O1 electrode: (a) Healthy control, (b) Mild cognitive impairment group, (c) Mild AD group, (d) Moderate AD group, and (e) Severe AD group. In each subfigure, each line plots the mean SE values at each scale factor under each condition (Pre-PS, During PS, Post-PS). The shaded error area surrounding each line shows its 95% confidence interval. (* Bonferroni-corrected p < 0.05, † Bonferroni-corrected p < 0.01).

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  Figure 6. Correlations between mean MSE values at large scale factors and EEG power ratios of 30-Hz harmonic responses to 15-Hz PS at electrode O1: (a) SF 9–14 and (b) SF 15–20 (** p < 0.01).