title: The Relationship Between Concussion Symptoms and Vestibulo-Ocular and Cervical Spine Function in Combat Sport Athletes
Creators: name: Brown, Daniel A
Publisher: name: Griffith University
Year: 2022
Subjects: subject: concussion
subject: combat sport athletes
subject: cervical spine function
subject: vestibulo-ocular reflex

description: Background: Concussion is a growing concern for athletes who participate in combat sport. Many rule sets allow for intentional and repeated forceful strikes to the head that may result in a concussion. The forceful impacts to the head may lead to impairments in the vestibulo-ocular system and cervical spine complex which can negatively impact athletic performance. Symptoms that are often associated with concussion may be related to deficits in the vestibulo-ocular system or cervical spine complex. Thus, it is important to consider the vestibulo-ocular system and cervical spine complex when assessing and treating an athlete involved in combat sports with a suspected concussion. However, very few studies have explored the prevalence of symptoms associated with concussion or the function of the vestibulo-ocular system and cervical spine complex in athletes involved in combat sports. Objectives: The first aim of this thesis was to investigate the prevalence of concussion-related symptoms in adult athletes who participate in combat sports. The second aim was to compare the function of the vestibulo-ocular system and cervical spine complex between combat sport athletes and active control participants. The third aim was to explore relationships between symptom-based outcome measures and vestibulo-ocular system and cervical spine complex function in combat sport athletes. Methods: Study 1 established the prevalence of concussion-related symptoms using the Post-Concussion Symptom Scale (PCSS) via an online survey of active combat sport athletes (n = 309) and examined relationships between the history of concussion and neck injury with the symptom scores (Chapter 4). Studies 2, 3 and 4 examined differences in the vestibulo-ocular system and cervical spine complex between combat sport athletes (n = 40) and healthy control participants (n = 40). The Vestibular/Ocular Motor Screening (VOMS) assessment (Chapter 5) was used to assess between-group differences in vestibular and oculomotor characteristics. A standardised protocol that assessed: 1) oculomotor function, 2) benign paroxysmal positional vertigo (BPPV), and 3) vestibulo-ocular reflex (VOR) function (Chapter 6) was used to further compare the function of the vestibulo-ocular system between groups. A standardised suite of clinical assessments was conducted to examine the between-group differences in the cervical spine complex (Chapter 7). The PCSS, VOMS, Dizziness Handicap Inventory (DHI) and Neck Disability Index (NDI) were used to explore relationships between symptom-based outcome measures and the function of the vestibulo-ocular system and cervical spine complex. Results: Study 1 found that over half of active combat sport athletes (59.9%) experienced at least two concussion-related symptoms. Athletes with a history of concussion and neck injury also had significantly greater odds of reporting ‘high’ total symptom and severity scores on the PCSS than athletes who did not report a history of injury. In Studies 2 and 3, athletes who participated in combat sports demonstrated differences in vestibulo-ocular function compared with healthy controls. That is, an abnormal VOMS or NPC score was reported by 45% of the combat sport group compared with 22.5% of the control group. A significantly larger proportion of the combat sport group had oculomotor abnormalities than the control group. There were no differences between groups in the presence of BPPV or in the function of the VOR. Overall, the results indicated that athletes who participated in combat sports had a greater number of vestibulo-ocular impairments than control participants. The results of Study 4 indicated that combat sport athletes had a reduced cervical spine range of motion and greater isometric muscle strength and muscle endurance than the control group. No differences were observed between groups for cervical spine proprioception or segmental tenderness on manual spinal examination. Furthermore, the results identified several significant relationships between the vestibulo-ocular system and cervical spine complex with symptom-based outcome measures. Conclusion: Concussion-related symptoms were experienced by most active combat sport athletes, with a history of concussion and neck injury increasing the odds of reporting high symptom scores on the PCSS. This thesis demonstrated functional differences in the vestibulo-ocular system and cervical spine complex in combat sport athletes compared with control participants. In addition, the functions of both the vestibulo-ocular system and cervical spine complex were related to several symptom-based outcome scores. The findings highlight the importance of clinicians who care for combat sport athletes to provide a comprehensive multisystem approach when assessing symptoms often attributed to concussions.