Motor learning characterizes habilitation of children with hemiplegic cerebral palsy

Abstract

Background: This study tested in children with cerebral palsy (CP) whether motor habilitation resembles motor learning.

Methods: Twelve children with hemiplegic CP ages 5 to 12 years with moderate to severe motor impairments underwent a 16-session robot-mediated planar therapy program to improve upper limb reach, with a focus on shoulder and elbow movements. Participants were trained to execute point-to-point movements (with robot assistance) with the affected arm and were evaluated (without robot assistance) in trained (point-to-point) and untrained (circle-drawing) conditions. Outcomes were measured at baseline, midpoint, immediately after the program, and 1 month postcompletion. Outcome measures were the Fugl-Meyer (FM), Quality of Upper Extremity Skills Test (QUEST), and Modified Ashworth Scale (MAS) scores; parent questionnaire; and robot-based kinematic metrics. To assess whether learning best characterizes motor habilitation in CP, the authors quantified (a) improvement on trained tasks at completion of training (acquisition) and 1 month following completion (retention) and (b) quantified generalization of improvement to untrained tasks.

Results: After robotic intervention, the authors found significant gains in the FM, QUEST, and parent questionnaire. Robot-based evaluations demonstrated significant improvement in trained movements and that improvement was sustained at follow-up. Furthermore, children improved their performance in untrained movements indicating generalization.

Conclusions: Motor habilitation in CP exhibits some traits of motor learning. Optimal treatment may not require an extensive repertoire of tasks but rather a select set to promote generalization.

Conflict of interest statement

Declaration of Conflicting Interests

The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article:

Drs H. I. Krebs and N. Hogan are co-inventors of the Massachusetts Institute of Technology (MIT) held patent for the robotic device used in this work and hold equity positions in Interactive Motion Technologies, Inc, Watertown, MA, a company that manufactures this type of technology under license to MIT.

Figures

Figure 1

Configuration of trained and untrained motor tasks

Figure 2

Representative example of children’s performance at baseline and completion of intervention on the trained (point-to-point) reaching task We selected the attempts of the first 4 children enrolled in the study. Similar unassisted reaching attempts can be observed for all the children. Each child is being asked to move to 8 targets equally distributed around the circle. Each target is presented 5 times.

Figure 3

Mean and standard error of kinematic outcome metrics for trained point-to-point and untrained circle-drawing movements Each plot shows whether changes from baseline to discharge and from discharge to follow-up were significant. *Indicates significance (P < .05).