Can Interpreting Nonsignificant Findings Inform the Lessons Learned From an Intervention?

Abstract

Reducing Disability in Alzheimer's Disease (RDAD) is an evidenced-based intervention for individuals with dementia and their caregivers aimed at reducing the psychosocial strain of the caregiver and improving functional ability of the individual with dementia. Overall efficacy, acceptability, and feasibility outcomes have been published regarding RDAD; however, no specific outcome information has been published on the objective physical performance measures (PPM) of gait speed, functional reach, and balance. Data from the Replication of RDAD (n = 508) was utilized to test the hypothesis that each PPM would show change for participants who completed the program. No significant changes were identified in 3 PPM: gait speed (t = .24, P =.81), balance (t = .23, P = .82), and functional reach (t = -.55, P = .58). To strengthen the research about exercise interventions for individuals with dementia, discussion and interpretation of nonfindings is important for improving intervention designs and methodologies. In the case of RDAD, the intervention protocol may require a sufficient dosage of exercise with respect to fundamental exercise science principles, or there may be misalignment between the intervention and outcome measures.