Neurological soft signs (NSS) and cognitive impairment in chronic schizophrenia

Abstract

Recent studies indicate that neurological soft signs (NSS) in schizophrenia are associated with generalized cognitive impairments rather than changes in specific neuropsychological domains. However, the majority of studies solely included first-episode patients or patients with a remitting course and did not consider age, course, education or severity of global cognitive deficits as potential confounding variables. Therefore, we examined NSS with respect to cognitive deficits in chronic schizophrenia, i.e. patients who are particularly vulnerable to both, NSS and cognitive impairments.Eighty patients with chronic schizophrenia (43.36 ± 15a) and 60 healthy controls (47.52 ± 14.8a) matched for age, sex and years of education were examined on the Heidelberg NSS scale and a broad neuropsychological battery including short term, working, logical and autobiographic memory (AM), theory of mind (ToM), psychomotor speed and cognitive flexibility.When contrasted with the controls, patients showed significantly higher NSS scores and impairments in all neuropsychological domains but short-term memory. NSS were significantly associated with all neuropsychological domains considered but short-term memory and semantic AM. Except for episodic AM (which was significantly correlated with NSS in patients only) these correlations applied to both groups and were confirmed when age, years of education and severity of global cognitive deficits (Mini Mental State Examination) were controlled for.Results demonstrate that NSS reflect a rather wide range of cognitive impairments in schizophrenia, which also involves episodic AM and ToM. These associations were not accounted for by age, education or severity of global cognitive deficits and facilitate the clinical usage of NSS as a screening instrument.

Editorial: Neurological Soft Signs in Neuropsychiatric Conditions

“…While the respective studies—among them probably the first fMRI study in schizophrenia (6) and a single longitudinal trail (8)—solely included patients with schizophrenia, results suggest that NSS refer to disseminated changes in the whole motor system in particular a cerebello-thalamo-prefrontal network (9) rather than to deficits in discrete cerebral sites. Similarly, NSS are associated with a wealth of cognitive deficits ranging from attention/psychomotor speed and executive dysfunctions to complex neuropsychological abilities, such as logical memory, autobiographic episodic memory, and theory of mind (10).…”

Neurological soft signs (NSS) and brain morphology in patients with chronic schizophrenia and healthy controls

“…Interestingly, it has been shown that learning motor sequences requires the involvement of bilateral superior and anterior prefrontal cortex, right superior temporal cortex and left cerebellum [68]. Along with this, we recently described that NSS reflect a rather wide range of cognitive deficits in schizophrenia [69], a finding that may additionally explain the involvement of frontal and temporal sites.…”

From a Lived Event to Its Autobiographical Memory: An Ecological Study Using Wearable Camera in Schizophrenia

“…Indeed, initial perceptual deficits, working memory impairments, or encoding disorder have been thought to explain patients’ memory impairments. A more recent study also pointed out that neurological soft signs might be correlated with autobiographical memory performance (58). Future studies using wearable cameras or virtual reality could provide new insights on the role of those factors, as they enable to control and manipulate the to-be-encoded event.…”