Proprioception in somatoform disorders.
20 patients with somatoform disorders as defined by DSM-IV and 20 healthy controls were examined for their proprioception. Several psychophysiological theories of somatoform disorders suggest biased proprioceptive abilities. The primary question is, whether we may find an inaccurate myogen perception in somatization as suggested by the approach of Bischoff or a more precise proprioception as may be derived from concepts of a higher awareness of body reactions. Furthermore it is expected, that somatoform patients perceive their muscle tension more intensely than do healthy subjects. Proprioceptive abilities were tested using a visual EMG biofeedback task. Resulting objective data and subjective ratings were analyzed within a psychophysiological regression approach which allows one to estimate the reliability, precision and intensity of proprioception. Results revealed that somatoform subjects demonstrated a more precise but not a more intense perception of muscle tension than did healthy controls.