Changes in self-regulation-related prefrontal activities in eating disorders: a near infrared spectroscopy study.

OBJECTIVE: The aim of this study is to clarify the symptomatology of the eating disorders examining the prefrontal function and activity associated with self-regulation among participants with or without eating disorders. METHODS: Ten patients with anorexia nervosa, fourteen with bulimia nervosa, and fourteen healthy control participants performed two cognitive tasks assessing self-regulatory functions, an auditorily distracted word fluency task and a rock-paper-scissors task under the measurements on prefrontal oxyhemoglobin concentration with near infrared spectroscopy. The psychiatric symptoms of patient groups were assessed with several questionnaires. RESULTS: Patients with bulimia nervosa showed decreased performances and prefrontal hyper activation patterns. Prefrontal activities showed a moderate negative correlation with task performances not in the patient groups but only in the healthy participants. The prefrontal activities of the patient groups showed positive correlations with some symptom scale aspects. CONCLUSIONS: The decreased cognitive abilities and characteristic prefrontal activation patterns associated with self-regulatory functions were shown in patients with bulimia nervosa, which correlated with their symptoms. These findings suggest inefficient prefrontal self-regulatory function of bulimia nervosa that associate with its symptoms

Oxyhemoglobin concentration changes during the rock-paper-scissors intentional loss task in the bilateral prefrontal cortices.

<p>Mean z scores of [oxyHb] during the task and posttask periods each divided into first and last halves are shown. Circles, triangles, and squares represent the healthy control, anorexia nervosa, and bulimia nervosa groups, respectively. Only the bulimia group showed increasing and decreasing activation patterns of [oxyHb]. *<i>p</i><0.05.</p

Task procedures of the word fluency task (WFT) and the rock-paper-scissors intentional loss task (RPST_loss).

<p>(A) Time schedule of one trial of the WFT. (B) Visual instructions presented in the WFT. A set of three different syllables was presented for 20 sec each during a 60-sec task period, to serve as the initial syllables for word generation. During the pretask and posttask periods, participants were instructed to repeat the presented five syllables in turn. (C) Time schedule and instructions of one trial of the RPST_loss. (D) Three hand shape pictures presented in the RPST_loss. The same pictures were used during the pretask, task, and posttask periods.</p

Mean values of accuracy and reaction time of the rock-paper-scissors intentional loss task.

<p>Mean values of accuracy and reaction time of pretask and posttask (instructed to be draw games) and task (instructed to lose intentionally) periods are shown. Circles, triangles, and squares represent the healthy control, anorexia nervosa, and bulimia nervosa groups, respectively. There was no group difference in accuracy. The bulimia group showed a significantly longer reaction time than that of the healthy controls during the task period. BN, bulimia nervosa; HC, healthy control; *<i>p</i><0.05.</p

Correlation coefficients of prefrontal activity with task performances and symptom scales.

<p>Notes: Correlation coefficients were calculated between the symptom scales and mean z scores of [oxyHb] data during the latter half of the task period of the RPST_loss. AN, anorexia nervosa; BN, bulimia nervosa; HADS, Hospital Anxiety and Depression Scale; EDI, the Eating Disorder Inventory; EDE-Q, the Eating Disorder Examination Questionnaire; BITE, the Bulimic Investigatory Test; TAS-20, the 20-item Toronto Alexithymia Scale; BMI, body mass index. <i>r</i>: Pearson’s correlation coefficient, *<i>p</i><0.05.</p

Brain sites observed with near infrared spectroscopy.

<p>The oxyhemoglobin concentrations in the left and right regions (channels 1 and 2, respectively) over the lower dorsolateral prefrontal to orbitofrontal areas were measured. These regions are labelled in the standard brain space <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059324#pone.0059324-Tsuzuki1" target="_blank">[38]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059324#pone.0059324-TzourioMazoyer1" target="_blank">[39]</a>.</p

Oxyhemoglobin concentration changes during the word fluency task in the bilateral prefrontal cortices.

<p>Mean z scores of [oxyHb] during the task and posttask periods each divided into first and last halves are shown. Circular, triangular, and square plots represent the healthy control, anorexia nervosa, and bulimia nervosa groups, respectively. Outlined plots with dashed lines and filled plots with solid lines represent [oxyHb] with white noise and baby crying as an auditory distracter, respectively. There was no significant difference between groups or between auditory distracters. HC, healthy control; AN, anorexia nervosa; BN, bulimia nervosa.</p

Mean numbers of generated words during task periods of the word fluency task (WFT).

<p>Two WFT trials were performed with two types of auditory distracters, respectively: white noise (outlined bars) and baby crying (filled bars). Baby crying significantly affected word generation by the HC and BN groups. The BN group generated a significantly lower number of words than the HC when during hearing the crying baby distracter. Error bars represent the standard error of the mean. HC, healthy control; AN, anorexia nervosa; BN, bulimia nervosa; *<i>p</i><0.05.</p

Demographics of all participants, and scores of symptom scales relevant to the ED group.

<p>Notes: One-way analysis of variances was performed to compare age, height, weight, BMI and HADS subscales between the HC, AN and BN groups. HC, healthy control; ED, eating disorder; AN, anorexia nervosa; BN bulimia nervosa; SD, standard deviation; BMI, body mass index; HADS, Hospital Anxiety and Depression Scale; EDI, the Eating Disorder Inventory; EDE-Q, the Eating Disorder Examination Questionnaire, BITE, the Bulimic Investigatory Test; TAS-20, the 20-item Toronto Alexithymia Scale. Significant differences between each patient group with the HC group were shown with ***<i>p</i><0.001,</p>**<p><i>p</i><0.01 or *<i>p</i><0.05.</p