Validation and factorial structure of a standardized neurological examination assessing neurological soft signs in schizophrenia

Although neurological soft signs (NSS) have been consistently reported in p atients with schizophrenia, their clinical relevance, the actual impact of treatment or their evolution during the disease are not well clarified, pos sibly because of methodological limitations of the available tools. We have developed a new standardized examination integrating the assessment of 23 NSS selected from the literature and the rating of well-validated scales fo r assessment of extra-pyramidal symptoms. We examined 161 subjects (control s, n=48; patients with schizophrenia, n=95; or recurrent mood disorder, n=1 8). Half of the patients were neuroleptic-free. Schizophrenic patients had significantly higher total score (14.6+/-8) than mood disorder patients (12 .0+/-7) and controls (5.0+/-2). Internal consistency (Cronbach's alpha=0.85 ) and inter-rater reliability were good. Principal component analysis found five consistent factors ('motor coordination', 'motor integrative function ','sensory integration', 'involuntary movements or posture', 'quality of la teralization'). This scale thus confirmed a factorial structure in agreemen t with the conceptual areas of interest explored by NSS and should be a use ful tool for assessment of the different dimensions of neurological dysfunc tion in schizophrenia. (C) 2000 Elsevier Science B.V. All rights reserved.