Neurological soft signs

What are neurological soft signs?

Neurological soft signs (NSS) are neurological abnormalities that can be identified by clinical examination using valid and reliable testing measures. They are referred to as ‘soft’ because they not related to a specific brain area, or part of a defined syndrome. Categories of NSS are commonly grouped into three categories; integrative sensory functioning, motor coordination, and complex motor sequencing. Integrative sensory functioning includes impairments in sensory perception such as audio-visual integration or tactile recognition. Motor coordination involves general coordination, balance and gait. Complex motor sequencing involves complex motor tasks, such as repetitive alternating hand positions.

What is the evidence for NSS?

Moderate to high quality evidence suggests medium to large effects of increased NSS in people with schizophrenia or first-episode psychosis compared to people without a psychiatric disorder (controls). There is a small and less widespread effect when comparing people with a first-degree relative with schizophrenia to controls. Compared to people with bipolar disorder and no psychotic symtoms, moderate to high quality evidence shows a small to medium-sized effect of more NSS in people with schizophrenia on motor coordination tasks only.

There are medium-sized associations between increased NSS scores and increased symptom severity and poorer cognitive performance in people with schizophrenia. Both people with remitting or chronic schizophrenia showed improvements in NSS over time, although remitting symptoms were associated with greatest NSS improvements. Increased severity of NSS in people with schizophrenia was associated with; reduced activation of the basal ganglia and inferior frontal cortex, increased activation of the superior temporal gyrus, reduced grey matter volume in the precentral and inferior frontal gyri and thalamus, and reduced white matter volume in the middle temporal and cerebellum regions.

July 2019

Last updated at: 5:03 am, 13th July 2019
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