EEG-BASED PHASE–AMPLITUDE COUPLING ANALYSIS FOR ASSESSING PHOTOPAROXYSMAL RESPONSES IN PATIENTS WITH NEUROCOGNITIVE DISORDERS

Photoparoxysmal response analysis in mild cognitive impairment (MCI) and Alzheimer’s disease (AD) patients is essential for detecting impaired neural adaptability and dysfunction in response to external stimuli, such as photic stimulation (PS), enabling the early identification of neurocognitive disorder progression. This study investigates photoparoxysmal responses by analyzing PS-induced time-domain and frequency-domain linear features, including skewness, kurtosis, power across frontal, parietal, and occipital regions, power asymmetry, organization score, and cognition index, along with nonlinear brain dynamics using phase–amplitude coupling (PAC) analysis in MCI and AD patients. EEG signals were recorded from patients exposed to repetitive PS frequencies ranging from 3[Formula: see text]Hz to 30[Formula: see text]Hz, preprocessed to remove noise artifacts, and analyzed using LASSO regularization to select significant EEG channels. Extracted time-domain and frequency-domain linear features from the power spectrum were used to evaluate oscillatory neural activity and signal variability, while PAC analysis provided insights into nonlinear interhemispheric connectivity and neural adaptability. Results revealed that, with increasing PS frequency, skewness, kurtosis, power asymmetry, and organization scores were lower in MCI than AD, while frontal, parietal, and occipital power, and cognition index were higher in MCI than AD, indicating a transitional shift in brain dynamics associated with disorder progression. Additionally, AD patients exhibited weaker neural responses through low PAC strength, reflecting cortical rigidity and diminished neural flexibility, whereas MCI patients retained more PAC strength, suggesting well interhemispheric connectivity. In AD, delta–alpha and delta–beta coupling strength in the frontal, parietal, and occipital regions was significantly reduced, highlighting progressive dysfunction in PAC modulation. These findings emphasize the importance of linear hand-crafted features with nonlinear PAC representation to effectively assess photoparoxysmal responses in MCI and AD patients, offering a promising approach for the early detection of neurocognitive disorders.