The Effect of Contextual Interference on Engagement During Motor Practice in Subacute Rehabilitation for People Post-stroke

Research Objectives: To compare the degree of engagement during motor practice of an upper-extremity skill between practice with high-contextual interference (CI) and practice with low-CI as a mean to explore the role of engagement in the CI-effect.

Design: Controlled trial with counterbalanced group allocation.

Setting: Inpatient rehabilitation center.

Participants: Twenty-six patients undergoing rehabilitation following a stroke (63.65±9.14 years, 6.5±4 weeks post-stroke, Upper Extremity Fugl-Meyer score = 42±12.8), selected using a convenience sample.

Interventions: The intervention consisted of three practice sessions conducted over three consecutive days. Practice sessions focused on three upper-extremity skills, which were practiced 30 times each. The skills were selected individually by the patients, from the items in the Wolf Motor Function Test. Participants were allocated to a high-CI group that practiced items in a random order or a low-CI group that practiced items in a blocked order.

Main Outcome Measures: The participant's cognitive (attentive) engagement was measured using the Cognitive Engagement Index (CEI), derived from prefrontal electroencephalogram signal, which was measured at the start, middle, and end of each practice session. Affective engagement (i.e., arousal) was assessed using the Self-Assessment Manikin tool at the end of each session.

Results: Comparison of CEI between measurements (i.e., start, middle, and end) within the training session (mean of all days) demonstrated that CEI increased from start to middle in the high-CI group (p < 0.001), then decreased (p = 0.01), while in the low-CI group, CEI increased from start to end (p = 0.02). At the middle of practice, CEI was higher in the high-CI group. Arousal was higher in the low-CI group across sessions (p = 0.04).

Conclusions: It is possible that the high cognitive load associated with the high-CI condition exhausted the participants to a degree that interfered with their ability to be engaged during the practice. To optimize engagement during practice sessions, it may be advisable to vary the number of repetitions according to the level of contextual interference within the session.

Author(s) Disclosures: Nothing to disclose.