Evaluating the Dyadic Benefits of Early-Phase Behavioral Interventions: An Exemplar Using Data From Couples Living With Parkinson's Disease.

Background and objectives: There are a growing number of early-phase (i.e., Stage I, NIH Stage Model) interventions targeted at family care dyads navigating chronic health conditions in older adults. Currently, the benefits of these interventions are often evaluated for older adults and their family care partners separately, even when controlling for interdependence. Without understanding the benefits (and potential harms) for dyads as a whole, understanding of program impact is incomplete. Moreover, few health behavior interventions involving dyads include relational measures to ensure no unintended consequences for the dyad or account for within-dyad pretest risk level.

Research design and methods: We used secondary data from a quasi-experimental trial involving 39 couples in which 1 member of the dyad was living with Parkinson's disease as an exemplar demonstration of 3 proposed approaches: an above-zero approach, a pretest risk status approach, and an expanded pattern analysis matrix approach.

Results: Approaches provided evidence for dyadic benefits of the intervention compared to the wait-list comparison condition, but carried different assumptions that did not always categorize dyads similarly.

Discussion and implications: Implications of using each approach and selecting different benchmarks for defining success are discussed. The descriptive approaches proposed, provide a rationale for more intentional evaluation of small-sample, early-phase dyadic interventions.