Resting State of Dementia of the Alzheimer's Type and Healthy Older Adults Using fNIRS.

Background/objectives: This study explores variations in brain activity between individuals with dementia of the Alzheimer's type (DAT) and healthy older adults during a resting state using functional near-infrared spectroscopy (fNIRS).

Methods: FNIRS measured brain activity in ten AD patients and six healthy individuals. A device with 16 channels was placed on each participant's forehead to measure oxygenation levels while they kept their eyes closed. The data were analyzed using a support vector machine (SVM) model.

Results: The results indicated differences in oxygenated hemoglobin (HbO) levels between the two groups. Specifically, HbO levels were generally higher in the dementia group in the left hemisphere, with a sharp increase after 26 s. Conversely, HbO levels were consistently lower in the right hemisphere of the dementia group. The SVM analysis demonstrated high accuracy in differentiating between the AD and healthy groups based on HbO levels.

Conclusions: The study indicates that differences in brain activity during resting state can potentially distinguish people with DAT from healthy individuals. We found relatively reduced hemoglobin activity in the prefrontal areas of those with DAT. Furthermore, the concentration changes in the HbO in the left lateral prefrontal and right medial brain regions emerged as the most informative in distinguishing individuals with DAT from healthy individuals. The results of the current study show that this method could improve current DAT diagnostic practices due to its efficiency.