Cervical Muscle Activation Due to an Applied Force in Response to Different Types of Acoustic Warnings

Mohammad Homayounpour,Andrew S Merryweather,Nicholas G Gomez,Anita N Vasavada

doi:10.1007/s10439-021-02757-4

Mohammad Homayounpour, Andrew S Merryweather + Show 2 more

Open Access

https://doi.org/10.1007/s10439-021-02757-4

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Abstract

Mild traumatic brain injury (mTBI) and whiplash-associated disorder are the most common head and neck injuries and result from a sudden head or body acceleration. The head and neck injury potential is correlated with the awareness, level of muscle activation, and posture changes at the time of the perturbation. Environmental acoustic stimuli or a warning system can influence muscle activation and posture during a head perturbation. In this study, different acoustic stimuli, including Non-Directional, Directional, and Startle, were provided 1000 ms before a head impact, and the amplitude and timing of cervical muscle electromyographic (EMG) data were characterized based on the type of warning. The startle warning resulted in 49% faster and 80% greater EMG amplitude compared to the Directional and Non-Directional warnings after warning and before the impact. The post-impact peak EMG amplitudes in Unwarned trials were lower by 18 and 21% in the retraction and rebound muscle groups, respectively, compared to any of the warned conditions. When there was no warning before the impact, the retraction and rebound muscle groups also reached their maximum activation 38 and 54 ms sooner, respectively, compared to the warned trials. Based on these results, the intensity and complexity of information that a warning sound carries change the muscle response before and after a head impact and has implications for injury potential.

Highlights

Experimental and simulation studies have investigated the role cervical muscles play in stabilizing the head and neck, as well as how those muscles might become injured.[33,40] The muscles of the head–neck complex have a central role in the abatement of higher head accelerations and are a potential site of injury and pain.[48]
Direct muscle injury may not be responsible for chronic whiplash pain and Mild traumatic brain injuries (mTBI), it has been suggested that muscles likely play an indirect role in how pain presents from injuries to other structures.[48]
In events that may result in whiplash-associated disorders (WAD), such as automobile collisions and impacts to the head during sports, several studies have indicated that there is a neuromechanical delay between cervical muscle activation and head movement.[15,33,40,45]

Summary

Introduction

Experimental and simulation studies have investigated the role cervical muscles play in stabilizing the head and neck, as well as how those muscles might become injured.[33,40] The muscles of the head–neck complex have a central role in the abatement of higher head accelerations and are a potential site of injury and pain.[48]. WAD is often the result of motor-vehicle collisions as well as sports injuries.[19] Clinical evidence of muscular damage resulting from whiplash is potentially debilitating pain.[14] Researchers have speculated that injury occurs due to eccentric loading or forceful lengthening of contracted muscles. In events that may result in WAD, such as automobile collisions and impacts to the head during sports, several studies have indicated that there is a neuromechanical delay between cervical muscle activation and head movement.[15,33,40,45]

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