Microstate Dynamics Alterations in Response To 40 Hz Rhythmic Light Intervention in Mild Cognitive Impairment

Area of Science:

• Neuroscience
• Cognitive Science
• Biomedical Engineering

Background:

• Mild cognitive impairment (MCI) is characterized by cognitive deficits that increase dementia risk.
• Brain network dynamics, assessed via electroencephalography (EEG) microstates, are altered in MCI.
• Rhythmic light stimulation is an emerging non-invasive neuromodulation technique.

Purpose of the Study:

• To investigate the effects of 40 Hz rhythmic light (RL) on EEG microstate dynamics in individuals with MCI and healthy controls.
• To assess cognitive performance and subjective sleepiness following RL exposure.
• To explore the potential of 40 Hz RL as a non-invasive intervention for cognitive enhancement.

Main Methods:

• A within-subjects design with 24 MCI patients and 27 healthy controls.
• Exposure to 40 Hz rhythmic light (RL) and a control condition (RLCC).
• EEG recordings, 2-back cognitive task, and Karolinska Sleepiness Scale administered pre- and post-stimulation.

Main Results:

• 40 Hz RL reduced the duration of microstate B and occurrence of microstate C, indicating enhanced neural processing efficiency.
• Microstate configurations (A-D) remained stable, with dynamic shifts between A and B observed, particularly in the MCI group.
• Cognitive performance on the 2-back task showed improvements post-stimulation in both groups.

Conclusions:

• 40 Hz RL may support compensatory neural mechanisms in MCI and enhance sensory/cognitive processing in healthy aging.
• EEG microstate analysis reveals 40 Hz RL's potential to modulate brain networks.
• 40 Hz RL shows promise as a non-invasive intervention to promote cognitive function in aging populations.