When supine is better than upright: evidence from postural effects in extinction patients

There is no clear consensus on the specific effects of gravitational inputs on the manifestations of neglect and extinction. While some studies provided evidence that neglect patients improved their performance in supine position, other studies supported instead the notion that the manipulation of body posture has no effect on neglect and extinction. To investigate the effects of the postural manipulation of the entire body in space on visual extinction, a total of 24 right- and left-brain-damaged patients (with or without signs of visual extinction) and 8 healthy control subjects were tested in a visual detection task in two different gravitational conditions: upright and supine. Two dependent variables were considered: accuracy and speed of response. The results were clear-cut. Changing body posture had only a mild effect on the performance of healthy controls and non-extinction patients, but it clearly modulated the performance of extinction patients. In fact, extinction patients markedly improved their performance on contralesional stimuli in supine position in terms of both accuracy and speed of response. This suggests that the reduction of gravitational inputs obtained by placing patients in supine position results in a significant amelioration of visual extinction.