Relation between cognitive function and concentrations of hemoglobin in prefrontal cortex of elderly people by time-resolved near-infrared spectroscopy

Abstract

We evaluated relationship between cognitive function and cerebral blood oxygenation (CBO) of the prefrontal cortex (PFC) at rest in 291 adults (73.0±12.5 years). We employed a two channel time-resolved near infrared spectroscopy (TNIRS), which allows non-invasive measurements of baseline concentrations of oxy-Hb, deoxy-Hb, total-Hb [μM] and SO2 [%] of the bilateral PFC without any tasks. We examined cognitive functions using the Mini-Mental State Examination (MMSE) and the Touch M which evaluates working memory function semi-automatically on a touchscreen. We found a significant positive correlation between MMSE scores and baseline concentrations of oxy-Hb and SO2. In addition, we observed significant positive correlations between Touch M scores and baseline concentrations of oxy-Hb and total-Hb. We used binomial logistic regression analysis. Regression model predicts correct value was 73.2% for the cognitive functions based on TNIRS measurement data, age and sex. TNIRS can be used to predict mild cognitive impairment objectively.