Brain health involves how regions communicate, as well as how individual regions function.
Looking across 124 studies
Paitel and colleagues reviewed EEG connectivity research comparing people with mild cognitive impairment or Alzheimer’s disease with cognitively healthy older adults. Connectivity measures describe relationships between electrical signals recorded from different areas.
An overall pattern
The review found an overall tendency toward reduced connectivity, particularly in the alpha band, with the most consistent findings in Alzheimer’s disease. Some studies instead found increased connectivity. Task-related increases in MCI may reflect compensatory activity, but findings depend on the methods and conditions used.
What this means for brain research
The findings strengthen the case for studying communication between brain networks. This review did not test neurofeedback, so it cannot show that training restores connectivity or prevents cognitive decline. Group-level EEG differences also do not mean that a brain map alone can diagnose Alzheimer’s disease in an individual.
Paitel ER, Otteman CBD, Polking MC, Licht HJ, Nielson KA. Functional and effective EEG connectivity patterns in Alzheimer’s disease and mild cognitive impairment: a systematic review. Front Aging Neurosci. 2025;17:1496235. doi:10.3389/fnagi.2025.1496235.
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