Exploratory Study on Screening Dementia Based on Frontal Polar Cognitive Activation Using Portable Wireless Functional Near-Infrared Spectroscopy

Objectives The aims of this study were to examine whether a portable wireless functional near-infrared spectroscopy device ([fNIRS] Hb-13-2, Astem Co., Ltd., Kanagawa, Japan) could potentially be used as a simple and minimally burdensome tool for screening cognitive function in older adults, particularly for identifying dementia-related changes, and to explore the feasibility of establishing a methodological framework for such assessment. Methods Subjects with dementia (n=10) and cognitively intact subjects (n=10) over 60 years of age were asked to perform a simple arithmetic task (Uchida-Kraepelin psychodiagnostic [UKP] test: 30 s × 5 trials) while undergoing frontal polar hemodynamic monitoring. Results Significantly increased changes in oxygenated hemoglobin (oxyHb) in Fp1 and Fp2 on the frontal polar cortex (FPC) during the task were more pronounced in the dementia subjects than in the cognitively intact subjects. In addition, the peak increase in oxyHb in cognitively intact subjects occurred in the first half of the task period, whereas it occurred in the second half of the task period in subjects with dementia. In all subjects, the relationship between increase/decrease of oxyHb in Fp1 and Fp2 and the UKP test results showed a positive correlation (R=0.307 and R=0.386, respectively). Conclusion The pattern and timing of hemodynamic responses in the FPC measured by portable fNIRS during the UKP test may have potential as a non-invasive screening indicator for cognitive decline.