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Evaluating Postural Control and Lower-extremity Muscle Activation in Individuals with Chronic Ankle Instability
Published on: September 18, 2020
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Potential Corticomotor Plasticity in Those with and without Chronic Ankle Instability
Kyle B Kosik1, Masafumi Terada, Colin P Drinkard
11Department of Rehabilitation Sciences, Division of Athletic Training, University of Kentucky, Lexington, KY; and 2College of Sport and Health Sciences Ritsumeikan University, Kusatsu, Shiga-ken, JAPAN.
Medicine and Science in Sports and Exercise
|August 9, 2016
Summary
Patients with chronic ankle instability (CAI) show reduced corticomotor output maps for the fibularis longus muscle. This suggests altered neural organization in the motor cortex, potentially contributing to recurrent ankle injuries.
Area of Science:
- Neuroscience
- Motor Control
- Sports Medicine
Background:
- Chronic ankle instability (CAI) is associated with neuromuscular control deficits.
- Understanding corticomotor alterations is key to elucidating these deficits.
- Corticomotor output mapping reveals motor cortex organization related to specific muscles.
Purpose of the Study:
- To compare the corticomotor output map of the fibularis longus (FL) muscle between individuals with and without CAI.
- To investigate neurophysiological differences in motor cortex representation in CAI.
- To identify potential neural mechanisms underlying CAI-related deficits.
Main Methods:
- Used transcranial magnetic stimulation (TMS) to map the motor cortex representation of the FL muscle.
- Recruited 18 CAI patients and 16 healthy controls (HC).
- Compared map area, volume, and cortical representation location between groups using independent t-tests.
Main Results:
- CAI patients exhibited significantly smaller corticomotor map volume (P = 0.018) compared to HC.
- CAI patients also showed a significantly smaller corticomotor map area (P = 0.046) compared to HC.
- Specific values: CAI map volume 8.2 ± 3.2 cm mV vs HC 11.3 ± 3.9 cm mV; CAI map area 12.8 ± 6.0 cm vs HC 17.4 ± 6.9 cm.
Conclusions:
- Reduced map area and volume in CAI suggest a more concentrated neuronal representation for the FL muscle.
- This altered organization may lead to less committed motor cortical cells, potentially recruited by adjacent areas.
- This neurophysiological change could explain altered movement strategies and increased risk of ankle reinjury in CAI patients.
