Deficits in haptic perception and right parietal theta power changes in patients with anorexia nervosa before and after weight gain

Objective: Our goal was to investigate whether patients with anorexia nervo sa (AN) show deficits in haptic exploration tasks before and after weight g ain. Method: The haptic exploration tasks consisted of palpating the struct ure of six sunken reliefs in sequence with both hands, eyes closed. After e ach exploration, the structure was reproduced on a piece of paper. A 19-cha nnel digital electroencephalogram (EEG; linked ears) was continuously re co rded during rest and haptic tasks for 10 AN patients (females, mean age: 15 .90) and 10 healthy controls (CO; females, mean age: 16.14). Mean spectral power density was calculated as the mean amplitude of the spectral lines of the theta band (4-8 Hz). The AN patients were examined again after weight gain (T-0 and T-1). Results: The reproductions submitted by the AN patients were of notably poorer quality than those of the CO. Reproduction quality was unchanged after weight gain and independent of body mass index and inte lligence. Mean exploration time was similiar in AN patients and CO. The ana lysis of spectral EEG power of both groups showed significant decrease in p ower data in the theta frequency band during haptic exploration compared wi th the rest intervals. The comparison of the theta power between CO and AN patients during haptic exploration showed major differences between the gro ups in both T-0 and T-1. Theta power was lower in AN patients than in the C O over the right hemisphere and right parietal regions. Discussion: The qua lity of reproduction of the haptic stimuli and the theta-power changes indi cate a cortical dysfunction and deficits in somatosensory integration proce ssing of the right parietal cortex in AN patients even after weight gain. ( C) 2001 by John Wiley & Sons, Inc.