Digitized analysis of abnormal hand-motor performance in schizophrenic patients

Many studies have shown a high prevalence of discrete neuromotor disturbanc es in schizophrenic patients. It was hypothesized that these disturbances a re lateralized and reflect a neurodevelopmental disorder underlying schizop hrenia. A new method for assessing subtle motor dysfunction and hemispheric asymmetries is the registration of hand movements with a digitizing tablet . Using this method, we studied hand-motor dysfunction and its lateralizati on in schizophrenics, as compared with healthy controls. All subjects (27 schizophrenic patients, 13 of them without neuroleptic med ication, the others under neuroleptics; 31 healthy controls) drew super-imp osed concentric circles. We computed kinematic parameters reflecting veloci ty and automatization to quantify neurological soft signs (NSS). The patients had significant impairments of regularity of repetitive hand m ovements, as compared with the healthy controls (F greater than or equal to 5.35; p less than or equal to 0.024*). Comparing differences of left- and right-hand performance between patients and controls, we found longer strok e duration (F=(15,98); p=0.000***) and decreased automatization (F=18,14; p =0.000***), especially on the left side in schizophrenic patients. Measuring hand movements with a digitizing tablet is a sensitive method for assessing subtle motor dysfunction in schizophrenic patients, not reflecte d in the scores of clinical scales. Our findings show NSS in schizophrenic patients, independently of neuroleptics. Further, the hypothesis of lateral ization of cerebral structures generating NSS towards the right hemisphere in schizophrenia is supported. (C) 2000 Elsevier Science B.V. All rights re served.