Negative correlation between affective symptoms and prefrontal activation during a verbal fluency task: a near-infrared spectroscopy study.

Only a few studies have examined the relationships between affective symptoms, cognitive function (e.g. verbal fluency), quality of life (QOL), and brain activation in a nonclinical population. The aim of the present study was to assess these relationships and examine the underlying cortical mechanisms in a nonclinical population. Fifty-two healthy male volunteers were assessed for depressive symptoms using the Zung Self-Rating Depression Scale (SDS), for apathy using the Apathy Scale, and QOL using the Medical Outcomes Study short-form 36-item questionnaire (SF36). The volunteers also performed a verbal fluency test (VFT) while hemoglobin concentration changes were assessed on the surface of the frontal cortex using 24-channel near-infrared spectroscopy (NIRS). The SDS and Apathy Scale scores showed significant negative correlations with the scores of most of the SF36 subscales. Frontal activation had a significant negative correlation with the SDS scores and the Apathy Scale. These results suggest that the degree of affective symptoms is associated with a lower QOL in a nonclinical population, and that cortical hypoactivation during a VFT measured by NIRS may objectively identify individuals with a high degree of affective symptoms.