Anosognosia and neglect respond differently to the same treatments.

Different techniques, such as optokinetic stimulation, adaptation to prismatic shift of the visual field to the right, or transcutaneous electrical nerve stimulation (TENS), have been shown to alleviate neglect, at least temporarily. We assessed the effect of these techniques on anosognosia and whether their therapeutic effect, if any, matches that on neglect. The effect of the three types of treatment on anosognosia and neglect was investigated in five patients presenting with both severe anosognosia and neglect. Patient 1 was treatment responsive to anosognosia but not to neglect, whereas patients 4 and 5 showed the reverse pattern, i.e., they were treatment responsive to neglect but not to anosognosia. This "treatment response bias" proved to be a valid means to investigate different effects of treatments in the same patient.