[Neurological soft signs: meaning and relevance along the course of psychiatric illness. An objective and rapid screening for psychosis?]

Abstract

Aims: Neurological soft signs (NSS) are minor neurological anomalies indicating non-specific cerebral dysfunction, commonly assessed through the Neurological Evaluation Scale (NES). It is generally accepted that NSS are prevalent in schizophrenic patients respect to healthy subjects, but they have been also found in patients with other neurological and psychiatric disorders. We sought to review studies that have specifically investigated NSS in schizophrenia, bipolar disorder and obsessive-compulsive disorder, and we also focused on their relationship with psychopathological features and antipsychotic treatment.

Methods: In this review we selected published studies investigating NSS in psychiatric patients and their relationship with either psychopathological features and antipsychotic treatment.

Results: Apart from diagnosis, all patients show more NSS than healthy subjects, but schizophrenic patients perform worse respect to other psychiatric diseases. These signs are already present at the onset of the disease. NSS also show a significant correlation with psychopathological measures and they can be predictive of clinical course and response to medications. On the other hand, NSS can be independent of the pharmacological treatment.

Conclusions: These findings argued the hypothesis that NSS could be a trait characteristic in psychosis. NSS are an objective measure for the assessment of serious psychiatric disorder in the prodromal phase, at onset and along the course of the disease.