People with PD responded to a six-week program of self-management rehabilitation with HRQOL benefits beyond best medical therapy. The medium magnitude of the intervention effect was similar to those found in preliminary studies, which suggests a robust positive response to rehabilitation across different samples 7,8,22
This effect translates into clinically relevant improvement rates for rehabilitation that can be anticipated to be 20% to 53% greater than for medication alone (the 95% CI for post ABI). A therapy team can predict that it will have to treat approximately two to six patients with PD before achieving clinically relevant improvement in the HQROL of at least one patient (the 95% CI for post NNT).
Greater improvement rates continued for rehabilitation relative to no rehabilitation at two and six months follow-up, yet the difference between those rates had declined, which likely indicates continued decline into the future. Programs must be designed and tested to determine how best to reinforce self-management gains and sustain HRQOL of patients and family caregivers as the disease progresses.
The differences in outcomes between 18 and 27 hrs were in the expected direction but were not significant, possibly due to limitations in the study design. There may have been insufficient study power, or more than a nine hour difference may be needed between condition intensities. Alternatively, maximum benefits may emerge consistently within 18 hrs of intervention in a clinical setting.
Another explanation is that the social sessions added to the 18 hrs of self-management rehabilitation may not have served the intended control purpose and were active elements of intervention. Descriptive patterns in the PDQ-39 domain scores imply that individuals receiving physical intervention in the home and community sessions (27 hrs) received more benefit in physical areas of function, while those who spent additional hours in talking with one another about their “normal” lives in the social session (18 hrs) received more benefit in psychosocial areas of function. These patterns are consistent with numerous studies that have shown task-specific responses to the content of rehabilitation.7,22,28
When this study was designed there was little evidence for determining how to gradate and powerfully differentiate two PD rehabilitation conditions or for determining a sample size that statistically would discriminate them. The outcomes of this study can guide sample size determination and the development of study designs aimed at documenting the minimal frequency, intensity, and duration of intervention required for achieving HRQOL benefits. In the future, intensity could be conceived as number of targeted HRQOL domains instead of rehabilitation hours.
A limitation of this study was that it did not differentiate the active contributions of rehabilitation methods. For example, it is not known the degree to which the problem-solving training and the physical practice of skills differentially contributed to the outcomes. One of the theoretical premises of the self-management approach is that providing participants with a “toolbox” of daily living strategies and skills to be used as desired and needed would enhance a sense of personal control, activate self-direction, and deepen satisfaction with daily activities.6,14–17
Well-designed measures are needed that would allow an investigation of the differential impact of the tools of PD self-management on 1) feelings of ability to manage specific life domains, 2) the capacity to choose realistic action goals, and 3) the utilization of these tools during daily life.
Furthermore, an examination of baseline participant attributes can help explain responses to rehabilitation and be used to develop more effective interventions. For this reason, the parent investigation measured several participant attributes besides HRQOL. Current studies are examining voice production and consonant articulation measures, apathy, and facial masking.42–44
Recently it was found that self-management rehabilitation more effectively increased walking endurance in our participants whose endurance was lower as opposed to higher at baseline.29
In light of these findings, we conducted follow-up analyses to compare participants who scored below the median on the PDQ-39 at baseline with those who scored above the median (). Rehabilitation more effectively improved mobility outcomes of participants who at baseline had more concerns about their mobility (higher mobility scores) compared to those who had less concerns in this area (F(1,111) = 3.89, p
= .05). This same pattern emerged in activities of daily living (F(1,111) = 12.59, p
= .001), the only targeted domain that had not demonstrated a main effect of rehabilitation intensity. There were similar patterns, yet not significant, for communication (F(1,111) = 0.13, p
= .72) and the summary index (F(1,111) = 2.11, p
= .15). Thus intervention appeared to be most beneficial for participants' self-identified concerns. Continued development of HRQOL measures and rehabilitation programs that are responsive to individuals' concerns are warranted.
HQROL responses of participants with low baseline versus high baseline scores
The strengths of this study include that it is among the largest randomized-controlled trials of physical rehabilitation for community-living PD, provided a rigor that is difficult to achieve in behavioral studies, involved a six-month follow-up period, had high adherence, and had few drop outs, especially given the degree of commitment required for commuting and participation. It sets a standard for the development of future best practice studies designed to provide and test individualized, client-focused intervention.
People with PD typically are referred to rehabilitation when their physical functioning has severely declined or when there is an acute change in status. It is not standard practice for rehabilitation to occur at the earlier to middle stages of this chronic disease when there are gradual declines in HRQOL and daily function. A theory- and evidence-based self-management approach recognizes that individual patient needs, preferences, and action directed toward realistic goals are fundamental to successful rehabilitation outcomes in community-living adults. This study's findings suggest that self-management rehabilitation be considered in the early to middle stages of PD to improve and sustain HRQOL.