Objectives: The time required in completing the 26 items of neurological examinations in the standard Neurological Evaluation Scale (NES) may limit its utility in pragmatic clinical situations. We propose the Short Neurological Evaluation Scale (S-NES) for use in busy clinical settings, and in research.
Methods: Using confirmatory factor analyses, we identified 12 items of neurological examination showing significant overlap with previously reported theoretical and empirical categories of neurological soft signs (NSS) in schizophrenia. This provided justification for the development of a shorter version of the NES based on the empirically identified NSS. In the present study, we relied on existing data to present an initial validation of the S-NES against the referent standard 26-item NES. We determined sensitivity, specificity, and likelihood ratios. Posterior-test probability was estimated using a Bayesian nomogram plot.
Results: Using data derived from 84 unmedicated or minimally treated patients with first-episode schizophrenia, 12 empirically determined items of neurological examinations showed high agreement with the 26 items in the standard NES battery (sensitivity=96.3%, specificity=100%, and posterior-test probability=100%).
Conclusions: Within limitations of validity estimates derived from existing data, the present results suggest that the design of the S-NES based on empirically identified 12 items of neurological examination is a logical step. If successful, the S-NES will be useful for rapid screening of NSS in busy clinical settings, and also in research.
Keywords: biological markers; endophenotypes; psychometric analyses; screening tools.