PREFRONTAL BRAIN FUNCTION IN PATIENTS WITH EATING DISORDERS: A NEAR-INFRARED SPECTROSCOPY STUDY

Objectives: To investigate prefrontal brain functions during cognitive activation in patients with eating disorders and age-matched control subjects, we measured cerebral blood volume changes using near-infrared spectroscopy (NIRS).

Methods: Eleven female patients with eating disorders (9 anorexia nervosa and 2 bulimia nervosa. Mean age 14.7 years old) and 5 age- and gender-matched healthy control subjects (mean age 13.4 years old) participated in this study after parental consent was obtained from the parents of each child. The cognitive activation consisted of a 15-second period of word fluency task followed by a 15-s posttask baseline. This sequence was repeated five times. In the word fluency task, the subjects were instructed to generate as many words whose initial syllable was /a/,/ka/, /sa/, /ta/, and /na/. The prefrontal total-, oxy-, and deoxy-hemoglobin (Hb) concentrations during the task were measured every 0.1s with NIRS.

Results: The number of words generated during the word fluency task showed no statistically differences between the two subjects (eating disorders: mean 19.7 SD 7.5; control: mean 23.4 SD 5.7). There was a significant positive correlation between the number of words and bilateral prefrontal oxy-Hb concentrations and a significant negative correlation between the number of words and right prefrontal deoxy-Hb concentrations. Significant different oxy-Hb change during the task was seen in the right prefrontal region between the two subjects (eating disorders: mean –0.198 mM.cm SD 3.153 mM.cm; control: mean 7.155 mM.cm SD 4.128 mM.cm p=0.011). There were no significant differences in the total- and deoxy-Hb changes between the two subjects.

Conclusion: Our results demonstrated that regional hemodynamic change during cognitive activation was reduced in patients with eating disorders, suggesting prefrontal dysfunction due to prolonged starvation or bulimia.