Dieting tendency and eating behavior problems in eating disorder correlate with right frontotemporal and left orbitofrontal cortex: a near-infrared spectroscopy study.

Frontal lobe dysfunctions have been implicated as one of the pathophysiological bases in eating disorder (ED). Neural substrates of ED have been examined in neuroimaging studies employing symptom-related stimuli, such as food and body-image distortion, but with inconsistent results because of differences in study design, task, and stimulus used. In order to elucidate frontal lobe dysfunction correlates of clinical symptoms in ED, we examined the frontal lobe function during a cognitive task, not a symptom-related task, using near-infrared spectroscopy (NIRS), which is suitable for the functional neuroimaging study of ED because of its complete noninvasiveness and natural measurement setting. Regional hemodynamic changes were monitored during a verbal fluency task (letter version) using a 52-channel NIRS apparatus in 27 female ED patients and 27 matched healthy controls, and their correlations with clinical symptoms assessed using the Eating Attitude Scale (EAT-26) were examined. Regional hemodynamic changes were significantly smaller in the ED group than in the control group in the bilateral orbitofrontal and right frontotemporal regions, and negatively correlated with dieting tendency scores in EAT-26 in the right frontotemporal regions and with the eating restriction and binge eating scores in the left orbitofrontal regions. The clinical symptoms of ED are considered to consist of two components: dieting tendency that correlates with the right frontotemporal cortex and eating behavior problems that correlate with left the orbitofrontal cortex.