Improvement in the Capacity for Activity Versus Improvement in Performance of Activity in Daily Life During Outpatient Rehabilitation

Abstract

We addressed questions about the potential discrepancy between improvements in activity capacity and improvements in activity performance in daily life. We asked whether this discrepancy is:

1. Common in routine, outpatient care, or an artifact of intervention studies?

2. Unique to upper limb (UL) rehabilitation, or is it seen in walking rehabilitation too?

3. Only seen in persons with stroke, or a broader neurorehabilitation problem?

Methods:: A longitudinal, observational cohort of 156 participants with stroke or Parkinson disease (PD) receiving outpatient rehabilitation at 5 clinics was assessed around admission and monthly during their episode of care. Individual, longitudinal capacity (Action Research Arm Test or walking speed) and performance (wearable sensor measurements of use ratio or steps/day) data were modeled to extract predicted change scores. Simulation methods were used to determine whether an individual's change was greater than 1 standard error. Participants were classified into categories based on whether or not they improved in capacity (C+ or C−) and/or performance (P+ or P−).

Results:: A majority (59%) were classified as C+P−. Smaller portions of the sample were classified as C+P+ (20%) and C−P− (21%), with 1 participant (<1%) classified as C−P+. The proportions in the C+P− category were significantly larger in the stroke (χ² = 48.7, P < 0.0001) and PD (χ² = 24.3, P < 0.0001) walking subgroups than in the stroke UL subgroup.

Discussion and Conclusions:: The discrepancy between improvements in capacity and performance is a problem in routine, outpatient neurorehabilitation. If performance information were available, patients and clinicians could act to address it.

Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A396).

Figure 1

Illustration of analytic process to determine whether improvement occurred. (A) Participant in the stroke UL subgroup capacity (top) and performance (bottom) measurements from onset to discharge from outpatient rehabilitation services. Symbols are the measurements and the thick lines are the individual models from those measurements. (B) Individual models were used to simulate distributions of change scores using model coefficients, uncertainties, and covariance estimates. The gray bar = +1 SE in the simulated z distribution. The black bar marks the predicted change z score from the actual model coefficients. (C) Capacity (top) is judged as improved because the z score is larger than 1 SE, while performance (bottom) is judged as unchanged because the z score is smaller than 1 SE. This participant was classified as C+P−. ARAT, Action Research Arm Test; SE, standard error; UL, upper limb.

Figure 2

Flow diagram of participants into the observational cohort. Mercy: Mercy Outpatient Therapy Services, St Louis, Missouri; SRAL: Shirley Ryan Ability Lab, Chicago, Illinois; TRISL: The Rehabilitation Institute of Saint Louis, St Louis, Missouri.

Figure 3

Example participants. Capacity measures are black and scaled by the left y-axis. Performance measures are blue and scaled by the right y-axis. In the left column, symbols are the measurements and the thick, solid lines are the modeled data. In the middle column, SE = 1 standard error from the individual simulated distributions, shown in units of the original scale and change = model predicted change scores, also shown in units of the original scale. (A) Participant from the stroke UL subgroup, classified as C+P+. (B) Participant from the stroke walking subgroup, classified as C+P−. (C) Participant from the Parkinson disease (PD) walking subgroup, classified as C−P−. This figure isavailable in color online (www.jnpt.org).