Four acute confusion assessment instruments: reliability and validity for use in long-term care facilities.

Frail older adults in long-term care (LTC) facilities are at high risk for acute confusion. This study evaluated the reliability and validity of four acute confusion instruments for use in LTC: the Clinical Assessment of Confusion-A (CAC-A), the Clinical Assessment of Confusion-B (CAC-B), the NEECHAM Confusion Scale (NEECHAM), and the Visual Analog Scale for Acute Confusion (VASAC). Seventy-four residents from two LTC facilities were evaluated for acute confusion using the four instruments as well as the Mini-Mental Status Examination (MMSE), the Geriatric Depression Scale (GDS), and Diagnostic and Statistical Manual for Mental Disorders (DSM IV) criteria for delirium. Coefficient alphas were .82 for the CAC-A, .86 for the CAC-B, and .80 for the NEECHAM. Interrater reliability on 30 paired evaluations was .90 for the CAC-B, .87 for the NEECHAM, and .80 for the VAS-AC. All instruments were correlated with the MMSE and the DSM IV criteria for delirium at the p < .001 level. Predictive validity was supported for the CAC-B, the NEECHAM, and the VAS-AC. Discriminant validity using the GDS was supported for the VAS-AC. Construct validity using confirmatory factor analysis was supported for the NEECHAM, with a two-factor structure. Based on this study, the VAS-AC is recommended for use as a general screening instrument and when it is positive for acute confusion, the NEECHAM should be used for a more indepth assessment.