[EEG-mapping in Alzheimer-type dementias]

Area of Science:

• Neuroscience
• Neurology
• Biomedical Engineering

Background:

• Alzheimer's disease (AD) and senile dementia (SD) are major causes of cognitive decline.
• Understanding EEG changes can help differentiate dementia types and severity.
• Previous research indicates altered brain activity in dementia patients.

Purpose of the Study:

• To investigate the electroencephalogram (EEG) topographic differences between Alzheimer's disease (AD) and senile dementia (SD).
• To correlate EEG patterns with dementia severity, assessed by Mini-Mental State Examination (MMSE) grades.
• To explore the underlying neurophysiological impairments, such as cholinergic deficiency and cortical involvement.

Main Methods:

• EEG data was collected from 18 AD patients, 21 SD patients, and 15 healthy elderly controls.
• Patients were categorized into severity groups based on MMSE scores.
• EEG spectral power (theta-delta, alpha bands) and topographical maps were analyzed.

Main Results:

• Both AD and SD patients exhibited increased theta-delta EEG power and decreased alpha-band power compared to controls.
• These EEG alterations were more pronounced in the left hemisphere for AD patients than for SD patients.
• Distinct EEG topographical changes correlated with the severity of cognitive dysfunction in both dementia groups.

Conclusions:

• EEG topography can differentiate between AD and SD, with specific patterns linked to disease severity.
• The findings suggest significant cholinergic deficiency in AD patients.
• Cortical impairments appear more prominent in AD than in SD, indicating differential neurophysiological deficits.