Differentiation of Normal Cognition and Early Dementia using fNIRS

This study aimed to assess the effectiveness of functional near-infrared spectroscopy in differentiating normal cognition and early dementia. To date, only pen-and-paper tests, which are time consuming, uneconomical in the sense that the services of psychiatrist or psychologist don’t come cheap, and are just behaviour assessments, are used to screen for dementia. The deployment of functional near-infrared spectroscopy not only could study functional connectivity but also could provide the objective confirmation of dementia diagnosis To observe the difference between the brain signal of normal aging individuals and early dementia patients, tasks to activate working memory were designed. A total of 10 subjects (3 healthy controls and 7 early dementia patients) screened using Mini Mental Status Examination and Clinical Dementia Rating underwent three levels of sequencing tasks and three categories of verbal fluency tasks while getting their brain signals measured. The findings showed that the activation level of healthy controls is higher than that of early dementia patients (sequencing tasks – level 1: 0.08 vs 0.04 mM⋅mm, level 2: 0.07 vs 0.06 mM⋅mm, level 3: 0.05 vs 0.04 mM⋅mm; verbal fluency tasks – 0.2 vs 0.1 mM⋅mm). This activation was found to be in the left and right prefrontal cortex. Besides that, more complicated activations were observed during verbal fluency task as it tests not only working memory but also verbal and executive control abilities. As of now, the sample size is not sufficient enough to conclude this study but the data collection is still on-going. Once the data collection is completed and the sample size is large enough, the role of functional near-infrared spectroscopy in dementia diagnosis can be validated and this study can finally be concluded.