title: Severe Impairment Battery Language scale: a language-assessment tool for Alzheimer's disease patients.
abstract: BACKGROUND
  Communication problems are common in Alzheimer's disease (AD) patients, but instruments to assess these symptoms are limited. Our objective was to create a new scale, based on the language subscale of the Severe Impairment Battery (SIB), as a sensitive and reliable measurement of treatment effects on language performance.
  
  
  METHODS
  All 24 items of the SIB language subscale were chosen for analysis. Baseline scores of 1320 moderate-to-severe patients (Mini-Mental State Examination [MMSE] score, <15), from a combined AD database of four Memantine clinical trials (Study Codes: IE-2101, MEM-MD-01, MEM-MD-02, and MRZ-9605), were used for item reduction according to a standard principal components factor analysis. All items with loadings >0.5 on the identified factors were selected for inclusion in the new language scale. Correlations with existing AD scales were examined.
  
  
  RESULTS
  The analysis indicated six factors, with 21 of 24 items showing loadings >0.5. The resulting 21-item SIB Language (SIB-L) scale exhibited high internal consistency (Cronbach's alpha = 0.809). The maximal SIB-L score was 41 points, with a measurement error of 3.7 points. The stratification of baseline SIB-L scores (mean, 31.7; SD, 8.4) by MMSE scores (mean, 9.7; SD, 3.3) showed a high variance in SIB-L scores. This confirms that patients with a low MMSE score can possess preserved language abilities. The SIB-L scale did not exhibit substantial floor-and-ceiling effects.
  
  
  CONCLUSIONS
  The new SIB-L is a fast (<15 minutes) and easily administered scale with favorable psychometric characteristics for assessing language impairment and treatment effects on the language performance of patients with moderate to severe AD.
authors.affiliation: Alzheimer's Disease Center, New York University School of Medicine, New York, NY, USA. steven.ferris@nyumc.org
authors.forename: Steven
authors.initials: S
authors.lastname: Ferris
authors.forename: Ralf
authors.initials: R
authors.lastname: Ihl
authors.forename: Philippe
authors.initials: P
authors.lastname: Robert
authors.forename: Bengt
authors.initials: B
authors.lastname: Winblad
authors.forename: Gudrun
authors.initials: G
authors.lastname: Gatz
authors.forename: Frank
authors.initials: F
authors.lastname: Tennigkeit
authors.forename: Serge
authors.initials: S
authors.lastname: Gauthier
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000145:classification / Q000175:diagnosis* / Q000523:psychology; D003072:Cognition Disorders / Q000145:classification / Q000175:diagnosis* / Q000523:psychology; D004185:Disability Evaluation; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007806:Language Disorders / Q000145:classification / Q000175:diagnosis* / Q000523:psychology; D008297:Male; D008609:Mental Status Schedule / Q000706:statistics & numerical data; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011594:Psychometrics; D012720:Severity of Illness Index