title: The Neurological Impairment Scale: reliability and validity as a predictor of functional outcome in neurorehabilitation.
abstract: OBJECTIVE
  To examine the construct validity and inter-rater reliability of the Neurological Impairment Scale (NIS) and compare ratings by medical and multidisciplinary teams in a mixed neurorehabilitation sample. To assess its concurrent and predictive validity as a predictor of outcome and functional gains during inpatient rehabilitation.
  
  
  METHODS
  The NIS was rated in a consecutive cohort of patients (n = 428) recruited from nine specialist neurorehabilitation units in London. Dimensionality and internal consistency were explored through principal components analysis with Varimax rotation. Inter-rater reliability and the relationship between NIS and functional outcome (UK Functional Assessment Measure (FIM + FAM)) were analysed in a sub-sample (n = 94) from one centre.
  
  
  RESULTS
  Factor analysis identified two principal domains ("Physical" and "Cognitive") together accounting for 35% of the variance: their Cronbach's alpha values were 0.76 and 0.67, respectively. Inter-rater reliability was excellent for overall scores between doctors (ICC = 0.95 (95% CI = 0.91-0.97)) and acceptable between the medical and multidisciplinary team (ICC = 0.92 (95% CI = 0.88-0.95)). Change in NIS-physical score predicted 29% of the variance in functional gain (FIM + FAM change).
  
  
  CONCLUSIONS
  These findings provide the first formal evidence for the validity and reliability of the NIS as a measure of neurological impairment for use in general neuro-rehabilitation settings. Its further application and exploration are now warranted.
  
  
  CONCLUSIONS
  The extent of neurological recovery occurring during rehabilitation can make an important contribution to functional gains. In order to interpret measurement of functional outcome, we need to be able to identify changes at the level of impairment. Many of the available tools to measure severity of impairment are condition specific. The Neurological Impairment Scale (NIS) was developed for use across a broad range of disabling conditions alongside the UK FIM+FAM. This first formal examination of its psychometric properties provides evidence for its scalability, reliability and validity. The NIS has potential to provide useful information for case-mix adjustment and as a predictor of functional gain in general neurorehabilitation settings.
authors.affiliation: School of Medicine, Department of Palliative Care Policy and Rehabilitation, King's College London , London , UK .
authors.forename: Lynne
authors.initials: L
authors.lastname: Turner-Stokes
authors.forename: Aung
authors.initials: A
authors.lastname: Thu
authors.forename: Heather
authors.initials: H
authors.lastname: Williams
authors.forename: Rebecca
authors.initials: R
authors.lastname: Casey
authors.forename: Hilary
authors.initials: H
authors.lastname: Rose
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Siegert
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D004185:Disability Evaluation; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000523:psychology / Q000534:rehabilitation*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011237:Predictive Value of Tests; D011594:Psychometrics / Q000379:methods*; D020127:Recovery of Function / Q000502:physiology; D015203:Reproducibility of Results; D012720:Severity of Illness Index