Neurological soft signs correlate with many different cognitive impairments related to schizophrenia, and these correlations could not be explained by degree of global cognitive deficit, education, or age. Neurological soft signs provide a screening tool for cognitive impairment, according to a study recently published in Schizophrenia Research: Cognition.
This study included 80 participants with schizophrenia (n=76) or schizoaffective disorder (n=4), 14 of whom had subchronic schizophrenia and 66 of whom had chronic schizophrenia. Participants were recruited from a state mental hospital (n=44) and 3 psychiatric long-term units (n=36). The study also included 60 healthy controls who were matched for years of education, sex, and age. The Heidelberg Neurological Soft Signs scale and other neuropsychological tools were used to examine
- cognitive flexibility,
- psychomotor speed,
- theory of mind, and
- autobiographic, logical, working, and short-term memory.
To examine associations between scores and variables, Pearson correlation coefficients were used.
Those in the patient group had significantly higher neurological soft sign scores than healthy controls (P <.001), except for short-term memory. With the exception of semantic autobiographic and short-term memory, neurological soft signs showed a significant relationship with all neuropsychological categories (P <.001 for all). Both groups experienced these correlations regardless of years of education, age, or degree of global cognitive deficit, with the exception of episodic autobiographical memory that showed a significant association only with those in the patient group.
The study researchers concluded that “[neurological soft signs] are associated with a broad range of neurocognitive impairments in patients with chronic schizophrenia as well as healthy controls. With Chan et al. (2015) these findings underline the usability of [neurological soft signs] as a screening instrument for cognitive impairment. From a clinical perspective, these findings facilitate the use of [neurological soft signs] as a marker for severity of the disease and of poor prognosis.”
Herold CJ, Duval CZ, Lässer MM, Schröder J. Neurological soft signs (NSS) and cognitive impairment in chronic schizophrenia. Schizophr Res Cogn. 2018;16:17-24.