Tapping and Task Switching Activation in Individuals With and Without Chronic Ankle Instability: fMRI Pilot Study

Background and Purpose: Chronic ankle instability (CAI) disrupts mechanoreceptors at the talocrural joint, which requires reliance on other forms of sensory information to maintain normal physical function. Understanding central nervous system activation patterns in individuals with CAI may lead to the development of interventions aimed at preventing long-term dysfunction. The primary objective of this study was to explore cortical activation patterns between individuals with CAI and uninjured controls during foot tapping and task switching. Methods: Twenty-six adults (13 CAI) completed a functional MRI protocol. The foot tapping task required participants to tap a response button under their metatarsal heads by plantarflexing their foot in sync with a visual stimulus. The switching task required participants to make a decision about a single stimulus feature (e.g., color or shape) during single and mixed task blocks. Single blocks required attention to either the shape or color of the stimulus, while mixed blocks required participants to switch between features (color and shape). Participants responded to stimuli via a plantarflexion button press. Between and within group voxelwise analyses were then conducted to determine cortical activation patterns. Results: The CAI group demonstrated greater activation in regions of visual processing and sensorimotor integration during foot tapping when compared to the uninjured controls. During task switching, the uninjured group demonstrated more activation in regions of cognitive flexibility, while CAI participants demonstrated more activation in an area of emotional processing. Conclusions: Individuals with CAI and uninjured controls demonstrate different activation patterns during foot tapping and task switching.