Evaluation of Neuromotor Control Measures in Older Adults and People Poststroke

Project Background

Healthy older adults and people post-stroke display similar locomotor impairments that arise from fundamentally different neuro-mechanical mechanisms. Identifying measures of neuromotor control that differentiate between these two populations as well as younger healthy adults are necessary to identify patient subsets, define intervention targets, and evaluate treatment efficacy. We are evaluating three measures of neuromotor function to determine which are able to achieve these goals: muscle synergies, dynamic motor control index for walking, and central drive.

Study 1

In recently published work, we aimed to determine if, compared to the number of muscle synergies, the dynamic motor control index could better quantify age-related differences in neuromuscular control during treadmill walking. We found that the dynamic motor control index, and not the number of muscle synergies, could identify age-related impairments in neuromuscular control. Check out our paper published in Frontiers in Aging for full results.

Study 2

For study 2, our aim was to to test if eight- and five-muscle sets would produce similar dynamic motor control indices as the previously examined eleven-muscle set, and similarly differentiate across age subgroups. Identifying reduced muscle sets would improve clinical translation of the dynamic motor control index. We found that an 8 muscle set, but not a five muscle set could differentiate across age groups but a 5 muscle set could not.

Exploratory Post-Stroke Study

We aimed to extend the previous work in older adults to a small, post-stroke cohort of three individuals. We aimed to 1) evaluate the impact of stroke on neuromuscular complexity as measured by muscle synergies and the dynamic motor control index, 2) explore the relationship between neuromuscular complexity and paretic plantarflexor central drive, and 3) evaluated reduced muscle sets for identifying neuromuscular impairments in individuals post-stroke using the dynamic motor control index. Check our our poster from Neural Control of Movement 2021 and North American Congress of Biomechanics 2022 (coming this summer) for full results.

Muscle Synergy Calculations

Adjusted Burst Superimposition Test and Central Drive Calculations

Dynamic Motor Control Index for Walking Calculations

Publications

Peer Reviewed Journal Articles

Collimore AN, Aiello AJ, Pohlig RT and Awad LN. The Dynamic Motor Control Index as a Marker of Age-Related Neuromuscular Impairment. Frontiers in Aging Neuroscience. 2021. View the paper.

National & International Conference Presentations

Collimore AN, Aiello AJM, Pohlig RT, Awad LN. TMinimum Viable Muscle Set for Identifying Impairments in the Neuromuscular Control of Walking Using the Dynamic Motor Control Index. (POSTER) North American Congress on Biomechanics. Ottowa, Canada. 2021.

Collimore AN, Pohlig RT, Awad LN. Identifying age-related changes in the neuromuscular control of walking using
reduced muscle sets. (PLATFORM) World Congress of Biomechanics. Tapei, Taiwan. Virtual. 2022.

Collimore AN, Aiello AJM, Pohlig RT, Awad LN. The dynamic motor control index is a better marker of age-relatedneuromotor impairments than the number of muscle synergies: Toward early detection of walking deficits. (POSTER)Neural Control of Movement Annual Meeting. Virtual. 2020. View the poster .

Collimore AN, Aiello AJM, Awad LN. Complexity of neuromuscular control is impaired with aging and associatedwith reduced central drive to the paretic plantarflexors after stroke: A preliminary study. (POSTER) NeuroBostonFall 2020 Symposium. Boston, MA. 2020. View the poster.

Related Work

1. Awad LN, Hsiao HY, Binder-Macleod SA. Central Drive to the Paretic Ankle Plantarflexors Affects the Relationship Between Propulsion and Walking Speed After Stroke. J. Neurol. Phys. Ther. 2020;44:42–48.

2. Cheung VCK, Piron L, Agostini M, Silvoni S, Turolla A, Bizzi E. Stability of muscle synergies for voluntary actions after cortical stroke in humans. Proc. Natl. Acad. Sci. 2009;106:19563–19568.

3. Clark DJ, Ting LH, Zajac FE, Neptune RR, Kautz SA. Merging of Healthy Motor Modules Predicts Reduced Locomotor Performance and Muscle Coordination Complexity Post-Stroke. J. Neurophysiol. 2010;103:844–857.

4. Knarr BA, Higginson JS, Binder-Macleod SA. Validation of an Adjustment Equation for the Burst Superimposition Technique in Subjects Post-Stroke. Muscle Nerve. 2012;46:267–269.

5. Steele KM, Rozumalski A, Schwartz MH. Muscle synergies and complexity of neuromuscular control during gait in cerebral palsy. Dev. Med. Child Neurol. 2015;57:1176–1182. Available at: http://doi.wiley.com/10.1111/dmcn.12826. Accessed August 25, 2020.