Decreased activities of prefrontal and temporal lobes in patients with mild cognitive impairment and mild Alzheimer’s disease on a clock drawing task via functional near‐infrared spectroscopy imaging

Background Studies have shown that changes in cerebral blood flow occur the early stage of dementia, including Alzheimer’s disease (AD), and decreased contributes to impairment brain activities, then affects cognitive function. To diagnose AD very stage, such as mild (MCI), it is therefore necessary find a new way detect activities brain, functional near-infrared spectroscopy (fNIRS). Methods The clock drawing task (CLOX) one widely used neurocognitive function scoring test for dementia. In this study, were examined patients with MCI (n = 8) during an unprompted CLOX using concentration oxyhemoglobin (HbO), reflecting indirectly, tested each group via fNIRS. Results Activation right hemisphere was significantly attenuated compared MCI. With development severity from AD, reductions HbO2 concentrations prefrontal temporal lobe observed greater steeper. lower than (false discovery rate corrected, p <0.025). addition, positively associated clinical score MMSE (MCI group, p<0.05; p<0.05). Conclusion This study suggests activity frontal lobes reduced Those results reflects effective tool extracting fNIRS signal features. fNIRS-based analysis has great promise exploring mechanisms sensory-spatial AD.