Dose and timing in neurorehabilitation: prescribing motor therapy after stroke

Abstract

Purpose of review: Prescribing the most appropriate dose of motor therapy for individual patients is a challenge because minimal data are available and a large number of factors are unknown. This review explores the concept of dose and reviews the most recent findings in the field of neurorehabilitation, with a focus on relearning motor skills after stroke.

Recent findings: Appropriate dosing involves the prescription of a specific amount of an active ingredient, at a specific frequency and duration. Dosing parameters, particularly amount, are not well defined or quantified in most studies. Compiling data across studies indicates a positive, moderate dose-response relationship, indicating that more movement practice results in better outcomes. This relationship is confounded by time after stroke, however, wherein longer durations of scheduled therapy may not be beneficial in the first few hours, days, and/or weeks.

Summary: These findings suggest that substantially more movement practice may be necessary to achieve better outcomes for people living with the disabling consequences of stroke. Preclinical investigations are needed to elucidate many of the unknowns and allow for a more biologically driven rehabilitation prescription process. Likewise, clinical investigations are needed to determine the dose-response relationships and examine the potential dose-timing interaction in humans.

Figure

Scatterplot of studies included in meta-regression of the dose-response relationship in stroke rehabilitation (Lohse et al. 2014). Control group data (blue circles) are represented separately from experimental group data (orange circles) for each study. The relative size of the circle represents sample size. Collectively, the data points indicate a moderate relationship between time scheduled for therapy and response, as measured by effect size. Three studies are labeled to aid in interpretation: Wolf et al., 2006; days post stroke 180; outcome = upper limb function; estimated therapy = time in formal therapy + 0.5 * hours constrained.

1. A1: Standard care, prior to crossover

2. A2: Constraint induced movement therapy

Duncan et al., 2011; days post stroke 62; outcome = walking speed

1. B1: Standard care, prior to crossover

2. B2: Home physical therapy, focused on functional strengthening and balance

3. B3: Early locomotor training, body-weight supported treadmill training + over-ground training

Kwakkel et al., 1999; days post stroke 7; outcome = walking speed

1. C1: Standard/conventional therapy

2. C2: Intensive arm-focused training

3. C3: Intensive leg-focused training

[Note to Editors: this figure also exists as an interactive figure, using Tableau visualization software, such that hovering over each data point brings up a pop-up box with study citation and key study parameters. If you are interested, we would be happy to explore with you ways to place this in an online version, or elsewhere on the journal website.]