ABSTRACT
Objective
Neurological soft signs (NSS) are minor, non-localizable neurological abnormalities. This study aimed to investigate the factor structure of the Neurological Evaluation Scale.
Material and Methods
A total of 355 subjects (233 patients and 122 general population subjects). NSS were assessed using the NES. Factor analysis with varimax normalized rotation was applied and produced first, second, third, and fourth-order factors.
Results
The first factor analysis returned 13 first-order factors. Subsequent analysis returned 7 second-order factors, 3 third-order factors, and ultimately a single fourth-order factor. These factors could theoretically correspond to functional neural circuits and anatomical structures.
Discussion
The NES captures three core domains that seem to correspond to attentional control, inhibition, and information processing, further subdivided into sensory process and memory, dysfunctional attentional control, process overload, and impaired inhibition with cerebellar involvement. Further research with structural as well as functional imaging methods will be important to elucidate the mechanisms behind the emergence of NSS and identify individuals at risk for the development of psychosis.