Relationship between neurological 'soft signs' and syndromes of schizophrenia

Past research on the importance of 'soft' neurological signs in schizophrenia has often not examined the relationship between specific groups of neurological signs and different dimensions of schizophrenia psychopathology. Gender differences in the reported relationships have never been explored. In this paper we describe a study of 100 DSM-III-R (65 male and 35 female) schizophrenic patients who were rated for neurological 'soft signs' with the Neurological Evaluation Scale (NES) (1), and for schizophrenic symptomatology with the Scale for Assessment of Negative Symptoms (SANS) and the Scale for Assessment of Positive Symptoms (SAPS). Following a factor analysis of NES items, differential relationships were examined between the five derived NES factors and three well-established dimensions of schizophrenic symptomatology, namely psychomotor poverty, disorganization and reality distortion. Our results failed to show any relationship between NES dimensions and either the reality distortion or disorganization dimensions. There was a modest but differentially significant relationship between psychomotor poverty and an extrapyramidal factor on the NES. This relationship was shown only by male subjects, and was influenced by duration of illness but not by age or neuroleptic medication. On the other hand, female subjects showed a significant relationship between psychomotor poverty and an NES factor reflecting attention and initiative, and between reality distortion and coordination/sequencing of motor activity. These relationships in female subjects were, relative to relationships for male subjects, more independent of the effect of medication and duration of illness.