Traumatic brain injuries and older adults: The implications of neck strength, muscle activation, and range of motion

Fall-related traumatic brain injuries (TBIs) are a major cause of morbidity and mortality in older adults. Previous research has focused on non-modifiable risk factors, such as age and gender. However, some potential modifiable risk factors to fall-related TBIs in older adults may be related to neck musculature and function. Yet, these risk factors have received less scientific scrutiny in older adults. Thus, the current project quantified isometric neck strength, active and passive range of motion, and neck muscle activation latency in response to postural perturbation in 57 participants. Participants were divided based on age with 20 Young (18 – 30 years old), 23 Young-Old (60 – 74 years old), and 14 Old-Old (75 – 89 years old) adults being included. Participants underwent isometric neck strength testing in four directions using a custom device, active and passive neck ROM were quantified using a standard goniometer, and neck muscle activation latency was quantified using electromyography in response to anterior and posterior translations. The results of the project revealed older adults have reduced isometric neck strength, when compared to young adults, with the Old-Old adults displaying the greatest declines. Furthermore, active and passive neck ROM significantly decreased with advanced age and Old-Old adults displayed the greatest reductions in ROM. Finally, neck muscle activation latency time significantly increased with age in response postural perturbation. The significant age-related differences to neck muscle strength, ROM, and muscle activation latency may be responsible for the elevated prevalence of fall-related TBI in older adults. The findings of this project may be used with future research to identify possible rehabilitation techniques to improve neck muscle strength, ROM, and muscle activation latency in older adults, establish the link between neck musculature and function and head kinematics during a fall, and establish screening and prevention protocols for this significant health problem