Social insecurity in relation to orbitofrontal activity in patients with eating disorders: a near-infrared spectroscopy study
1 Department of Psychiatry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi-ken 466-8550, Japan
2 Department of Psychiatry, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi-ken 466-8550, Japan
3 Division of Clinical Science and Neuropsychopharmacology, Graduate School of Pharmacy, Meijo University, 150 Yagotoyama, Tenpaku-ku, Nagoya, Aichi-ken 468-8503, Japan
4 The Academic Frontier Project for Private Universities, Comparative Cognitive Science Institutes, Meijo University, 1-501 Shiogamaguchi, Tenpaku-ku, Nagoya, Aichi-ken 468-8502, Japan
5 Center for Advanced Medicine and Clinical Research, Nagoya University Hospital, Nagoya, Aichi-ken 466-8550, Japan
BMC Psychiatry 2014, 14:173 doi:10.1186/1471-244X-14-173Published: 12 June 2014
Functional neuroimaging techniques are widely used to elucidate changes in brain activity, and various questionnaires are used to investigate psychopathological features in patients with eating disorders (ED). It is well known that social skills and interpersonal difficulties are strongly associated with the psychopathology of patients with ED. However, few studies have examined the association between brain activity and social relationships in patients with ED, particularly in patients with extremely low body weight.
In this study, 22-channel near-infrared spectroscopy was used to quantify regional hemodynamic changes during a letter fluency task (LFT) in 20 female patients with ED with a mean body mass index of 14.0 kg/m2and 31 female controls (CTLs). Symptoms were assessed using the Eating Disorder Inventory-2 and Beck Depression Inventory. We hypothesized that frontal activity in patients with ED would be lower than in CTLs and would show different correlations with psychopathological features compared with CTLs.
The LFT performance and score on the social insecurity subscale of the Eating Disorder Inventory-2 were significantly higher in the ED group than in the CTL group. The mean change in oxygenated hemoglobin (oxy-Hb) in bilateral frontal regions during the LFT was significantly smaller in the ED group than in the CTL group. Social insecurity score was positively correlated with the concentration of oxy-Hb in the bilateral orbitofrontal cortex in the ED group but not in the CTL group.
These results suggest that activity of the orbitofrontal cortex is associated with social insecurity and disturbed in patients with ED. Therefore, disturbed orbitofrontal cortex activity may underlie the lack of insight and social isolation that is characteristic of patients with ED.