[Rapid Disability Rating Scale-2 in Alzheimer's disease: NORMACODEM project data]

Area of Science:

• Neuroscience
• Gerontology
• Psychometrics

Context:

• Alzheimer's disease (AD) poses significant challenges in accurately measuring functional decline.
• The Rapid Disability Rating Scale-2 (RDRS-2) is a potential instrument for assessing disability in AD patients.

Purpose:

• To evaluate the test-retest reliability, internal consistency, and discriminant validity of the Spanish adaptation of the RDRS-2 in Alzheimer's disease (AD).
• To assess the correlation of the RDRS-2 with other established functional and cognitive measures in individuals with AD, cognitive impairment but no dementia (CIND), and healthy controls.

Summary:

• The study involved 451 participants (254 controls, 86 CIND, 111 AD) assessed using the RDRS-2 and other scales (BDRS, IDDD, ADAS-Cog, MMSE).
• The RDRS-2 demonstrated high internal consistency (Cronbach's alpha=0.91) and test-retest reliability (Intraclass coefficient=0.86).
• RDRS-2 scores were highly correlated with BDRS (r=0.820), IDDD (r=0.882), ADAS-Cog (r=0.762), and MMSE (r=0.742), and were not influenced by sociocultural variables.

Impact:

• The Spanish RDRS-2 is a psychometrically sound instrument for evaluating disability in AD.
• Its high correlation with cognitive and functional measures supports its utility in clinical settings for AD assessment.
• The scale's independence from sociocultural factors enhances its applicability across diverse populations.