THE FUNCTIONAL-ANATOMY OF A HYSTERICAL PARALYSIS

The concept of a conversion disorder (such as hysterical paralysis) ha s always been controversial (Ron, M.A. (1996). Somatization and conver sion disorders. In: B.S. Fogel, R.B. Schiffer & S.M. Rao (Eds.), Neuro psychiatry. Williams and Wilkins, Baltimore, MD). Although the diagnos is is recognised by current psychiatric taxonomies, many physicians st ill regard such disorders either as feigned or as failure to find the responsible organic cause for the patient's symptoms. We report a woma n with left sided paralysis (and without somatosensory loss) in whom n o organic disease or structural lesion could be found. By contrast, ps ychological trauma was associated with the onset and recurrent exacerb ation of her hemiparalysis. We recorded brain activity when the patien t prepared to move and tried to move her paralysed (left) leg and when she prepared to move and did move her good (right) leg. Preparing to move or moving her good leg, and also preparing to move her paralysed leg, activated motor and/or premotor areas previously described with m ovement preparation and execution. The attempt to move the paralysed l eg failed to activate right primary motor cortex. Instead, the right o rbito-frontal and right anterior cingulate cortex were significantly a ctivated. We suggest that these two areas inhibit prefrontal (willed) effects on the right primary motor cortex when the patient tries to mo ve her left leg. (C) 1997 Elsevier Science B.V.