Cortical Activation during Dorsi-Plantarflexion Tasks and its Association with Sensorimotor Function in Ankle Instability.

Objective: This study aimed to investigate differences in cortical activation between individuals with and without chronic ankle instability (CAI) during a dorsi-plantarflexion task and further explore its association with sensorimotor function.

Methods: In this cross-sectional study, 62 participants were recruited, including 31 adults with CAI and 31 healthy adults. Sensorimotor functions, including joint position sense and force sense, were tested using absolute error associated with joint position reproduction and force reproduction tasks. A block design was used to collect task-state functional magnetic resonance imaging by using a custom-built, MRI-compatible device during a dorsi-plantarflexion task.

Results: Individuals with CAI showed significantly worse joint position sense and force sense in all four movement directions than those without CAI. CAI is significantly associated with lower cortical activation in the sensorimotor network, mainly including the right postcentral gyrus, right supplementary motor area (SMA) and left precentral gyrus. A weaker functional connectivity was found between the right putamen cluster and the left precentral gyrus in CAI. Greater associations between plantarflexion position sense with cortical activation were observed in the left precentral gyrus, bilateral putamen, and right SMA in CAI, but not in healthy controls.

Conclusions: Individuals with CAI had worse sensorimotor function, experienced lower task-related cortical activation in the sensorimotor network, and had a weaker resting-state functional connectivity between the putamen with the left precentral gyrus compared with healthy controls. Plantarflexion position sense was negatively associated with cortical activation in the left precentral gyrus, bilateral putamen and right SMA in individuals with CAI, but not in healthy controls. These findings suggested that impaired sensorimotor function partly corresponded to potential neurophysiological alterations in individuals with CAI.