Touch feel illusion in schizophrenic patients.

BACKGROUND

The rubber hand illusion is a tactile sensation referred to as an alien limb. The illusion has been explained by a spurious reconciliation of visual and tactile inputs reflecting functional connectivity in the brain and was used to explore alterations of functional connectivity in schizophrenia.

METHODS

The rubber hand illusion was achieved when two paintbrushes simultaneously stroke the hand of the subject hidden from vision by a screen, as well as an artificial hand placed in view of the subject. The rubber hand illusion was assessed with a questionnaire affirming or denying the occurrence of the illusion.

RESULTS

Schizophrenic subjects felt the illusion stronger and faster then did normal control subjects. Some rubber hand illusion effects correlated with positive symptoms of schizophrenia but not with negative symptoms.

CONCLUSIONS

Altered functional integration of environmental inputs could constitute the basis for erroneous interpretations of reality, such as delusions and hallucinations.