Cognitive ocular motor deficits and white matter damage chronically after sports-related concussion

Association of Cognitive Symptoms and Abnormal Oculomotor Signs With Recovery in Adolescents After Sport-Related Concussion

OBJECTIVE

Sport-related concussion (SRC) affects cognitive and oculomotor function. We evaluated recovery from SRC in athletes with cognitive symptoms and/or oculomotor impairments who were prescribed early aerobic exercise treatment.

DESIGN

Secondary exploratory analysis of a randomized controlled trial.

SETTING

Outpatient sports medicine clinics.

PARTICIPANTS

Male and female adolescents (13-18 years) within 10 days of SRC who were prescribed aerobic exercise and who reported either a low (<12 points) or high (≥12 points) burden of cognitive symptom scores on the Post-Concussion Symptom Inventory at initial assessment.

INTERVENTIONS

Early aerobic exercise treatment.

MAIN OUTCOME MEASURES

Recovery time and incidence of persisting postconcussive symptoms beyond 1 month.

RESULTS

Adolescents with a high burden of cognitive symptoms (n = 24, 16.0 ± 1.3 years old, 50% male, 5.3 ± 2.4 days since injury) took longer to recover (34.4 ± 37.1 vs 15.3 ± 7.6 days) than adolescents with a low burden (n = 32, 14.9 ± 1.4 years old, 69% male, 6.1 ± 2.3 days since injury) and had 6-fold higher odds of developing persisting postconcussive symptoms (odds ratio = 6.17 [1.15-33.15]). Abnormal repetitive saccades and vestibular ocular reflex were independently associated with longer recovery after controlling for multiple comparisons ( P < 0.0125), but only abnormal smooth pursuits were a significant effect modifier for the association between cognitive symptoms and recovery (interaction term hazard ratio = 0.133 [0.035-0.504], P = 0.003).

CONCLUSIONS

Individuals with impaired ability to smoothly track a moving target and whose cognitive symptoms are a significant burden are at substantial risk for delayed recovery from SRC. Early initiation of oculomotor rehabilitation may facilitate recovery in these patients.

TRIALS REGISTRATION

Clinicaltrials.gov ID NCT02959216.

Recovery Process for Sports-Related Concussion Assessed with Precise Ocular Motility

Ocular motility has been linked to Sports Concussion Assessment Tool 5 scores. However, the link between ocular motility changes and assessment result changes remains unclear. Hence, we investigated that potential link in patients with sports-related concussions. We retrospectively included participants aged≥18 years who were diagnosed with a sports-related concussion. They underwent smooth pursuit eye movement assessment for allocation to the good improvement (rate of fundamental frequency≥15%) or minor improvement (<15%) groups. Sports Concussion Assessment Tool 5 scores were determined at baseline and two weeks later, and score changes were compared between the groups. Thirteen men (mean±standard deviation age: 20.6±5.0 years) were included: eight (19.0±4.5 years) in the good improvement group and five (20.6±5.7 years) in the minor improvement group. Symptom number (median=2.0 vs. 0.0), symptom severity (median=22.0 vs. 3.0), single-leg stance (median=4.0 vs. 0.5), tandem stance (median=1.0 vs. 0.0), and total errors (median=5.0 vs. 0.5) were worse (all p<0.05) in the minor improvement group. Smooth pursuit eye movement improvements measured using eye-tracking technology was linked to symptom recovery in patients with sports-related concussions. Therefore, ocular motility may be an objective indicator of sports-related concussions. Future studies with more patients are needed to confirm these findings.

Head Trauma and Concussions in Film and Television Stunt Performers: An Exploratory Study

OBJECTIVES

The aims of the study were to assess prevalence and management of head impacts in stunt performers and to evaluate performers' quality of life and ability to work after head injury.

METHODS

Stunt performers completed an online survey about head impacts/head whips history, diagnosed concussions, reasons for not reporting injuries, health care sought after head impacts, attitudes toward on-set concussion management, perceived ability to work as a stunt performer, and health-related quality of life.

RESULTS

One hundred seventy-three performers (80%) indicated at least one head impact/head whip during their stunt career. Of these, 86% exhibited concussion-like symptoms and 38% received one or more concussion diagnoses. Sixty-five percent continued working with concussion-like symptoms. Short Form-12 mental component scores were suggestive of depression in 42%.

CONCLUSIONS

Concussion seems to be a serious occupational health issue in stunt performers. We suggest that concussion management, risk reduction, and education should be addressed in this community.

Sub-acute Changes on MRI Measures of Cerebral Blood Flow and Venous Oxygen Saturation in Concussed Australian Rules Footballers

Background

Sports-related concussion (SRC) is common in collision sport athletes. There is growing evidence that repetitive SRC can have serious neurological consequences, particularly when the repetitive injuries occur when the brain has yet to fully recover from the initial injury. Hence, there is a need to identify biomarkers that are capable of determining SRC recovery so that they can guide clinical decisions pertaining to return-to-play. Cerebral venous oxygen saturation (SvO₂) and cerebral blood flow (CBF) can be measured using magnetic resonance imaging (MRI) and may provide insights into changing energy demands and recovery following SRC.

Results

In this study we therefore investigated SvO₂ and CBF in a cohort of concussed amateur Australian Football athletes (i.e., Australia’s most participated collision sport). Male and female Australian footballers (n = 13) underwent MRI after being cleared to return to play following a mandatory 13-day recovery period and were compared to a group of control Australian footballers (n = 16) with no recent history of SRC (i.e., > 3 months since last SRC). Despite the concussed Australian footballers being cleared to return to play at the time of MRI, we found evidence of significantly increased susceptibility in the global white matter (p = 0.020) and a trend (F_5,21 = 2.404, p = 0.071) for reduced relative CBF (relCBF) compared to the control group. Further, there was evidence of an interaction between sex and injury in straight sinus susceptibility values (F_1,25 = 3.858, p = 0.061) which were decreased in female SRC athletes (p = 0.053). Of note, there were significant negative correlations between straight sinus susceptibility and relCBF suggesting impaired metabolic function after SRC.

Conclusions

These findings support the use of quantitative susceptibility mapping (QSM) and relCBF as sensitive indicators of SRC, and raise further concerns related to SRC guidelines that allow for return-to-play in less than two weeks.

A window into eye movement dysfunction following mTBI: A scoping review of magnetic resonance imaging and eye tracking findings

Mild traumatic brain injury (mTBI), commonly known as concussion, is a complex neurobehavioral phenomenon affecting six in 1000 people globally each year. Symptoms last between days and years as microstructural damage to axons and neurometabolic changes result in brain network disruption. There is no clinically available objective biomarker to diagnose the severity of injury or monitor recovery. However, emerging evidence suggests eye movement dysfunction (e.g., saccades and smooth pursuits) in patients with mTBI. Patients with a higher symptom burden and prolonged recovery time following injury may show higher degrees of eye movement dysfunction. Likewise, recent advances in magnetic resonance imaging (MRI) have revealed both white matter tract damage and functional network alterations in mTBI patients, which involve areas responsible for the ocular motor control. This scoping review is presented in three sections: Section 1 explores the anatomical control of eye movements to aid the reader with interpreting the discussion in subsequent sections. Section 2 examines the relationship between abnormal MRI findings and eye tracking after mTBI based on the available evidence. Finally, Section 3 communicates gaps in our knowledge about MRI and eye tracking, which should be addressed in order to substantiate this emerging field.