Gait and motor imagery of gait in early schizophrenia

Although gait disorders were described in schizophrenia, motor imagery of gait has not yet been studied in this pathology. We compared gait, motor imagery of gait and the difference between these two conditions in patients with schizophrenia and healthy age-matched controls. The mean ± standard deviation (S.D.) of Timed Up and Go (TUG), imagined TUG (iTUG) and delta time (i.e.; difference between TUG and iTUG), was used as outcomes. Covariables include Mini Mental State Examination, the Frontal Assessment Battery (FAB), FAB's subitems, the Positive and Negative Syndrome Scale and the Unified Parkinson's Disease Rating Scale (UPDRS). Seventeen patients with early schizophrenia and 15 healthy age-matched controls were assessed. Schizophrenia patients performed the TUG and the iTUG slower than the controls. Multivariate linear regressions showed that iTUG and delta time were associated with the conflicting instruction of the FAB. The present study provides the first evidence that patients with schizophrenia performed gait and motor imagery of gait slower than healthy controls. These deficits could be in part explained by impaired executive function and specifically by a disturbance in the sensitivity to interference.