Impaired eye tracking is associated with symptom severity but not dynamic postural control in adolescents following concussion

The after-effects of occupational whole-body vibration on human cognitive, visual, and motor function: A systematic review

Whole-body vibration (WBV) is prevalent in labour-related activities and can have adverse effects on the health and performance of the individuals exposed. However, evidence regarding the extent to which human functionality is affected following occupational WBV exposure has not been collated. The current systematic review sought to synthesize existing literature and assess the strength and direction of evidence regarding the acute after-effects of occupational WBV exposure on cognition, visual function, postural stability, and motor control. We conducted a comprehensive search of AMED, CINAHL, MEDLINE, PubMED, Psychology and Behavioural Sciences Collection, SPORTDiscus, APA PsychInfo, Cochrane Library, EMBASE, HMIC, Global Health, ProQuest Central, Scopus, Web of Science, and the US National Technical Information Service on April 26, 2023. Studies that quantified vibration exposure and measured acute changes in cognition, visual function, postural stability, and motor control from baseline to post-vibration were considered without date restriction. Out of the 2663 studies identified, 32 were eligible for inclusion. Based on the Risk of Bias in Non-Randomized Studies of Exposure (ROBINS-E) tool, the studies demonstrated low (66%), moderate (25%) and high risk of bias (9%). The findings indicate that after exposure to WBV, postural stability either deteriorates or remains unchanged. Inconsistent effects of WBV on cognition were reported, while visual function and motor control showed no pronounced changes following WBV. This might be attributed to assessment limitations such as learning effects in neuropsychological and motor tasks, and non-functional measures of vision employed. There was a lack of consistency in the characterization of vibration exposure and the assessment of associated effects on functional performance. Current evidence is therefore insufficient to provide definitive guidance for updating occupational health and safety regulations regarding WBV. However, this review highlights the potential for WBV to jeopardize post-exposure human performance and, consequently, safety. The completion of the review was supported by a UKRI EPSRC training grant. The review has been registered on PROSPERO (ref CRD42023391075).

Acute Eye-Tracking Changes Correlated With Vestibular Symptom Provocation Following Mild Traumatic Brain Injury

OBJECTIVES

To quantify norms and changes in eye-tracking proficiency, and determine vestibular symptom correlations in varsity college athletes following acute mild traumatic brain injury (mTBI). We hypothesized that mTBI impacts central coordination between the vestibular and oculomotor systems with resultant changes in eye-tracking proficiency that are correlated with vestibular symptom provocation.

DESIGN

Retrospective cohort study.

SETTING

Sports medicine care at a single institution.

PATIENTS

One hundred and nineteen college athletes diagnosed with mTBI by a physician between 2013 and 2019.

INTERVENTIONS

N/A.

MAIN OUTCOME MEASURES

Standard deviation of tangential error, standard deviation of radian error, mean phase error, and horizontal gain from virtual reality-based, circular eye-tracking goggles used at baseline and within 72 hours post-mTBI. Headache, dizziness, nausea, and fogginess provocation after the Vestibular Ocular Motor Screening (VOMS) smooth pursuits subtest compared with pretest baseline, assessed within 72 hours post-mTBI.

RESULTS

One hundred and nineteen college athletes (N = 56 women and 63 men) aged 18 to 24 years sustained a total of 177 mTBI. Forty-four percent of athletes displayed abnormal eye-tracking on at least 1 eye-tracking measure following acute mTBI compared with their baseline. From the VOMS, horizontal gain showed medium-sized to large-sized positive correlations with headache ( r = 0.34) and dizziness ( r = 0.54), respectively. Mean phase error showed a medium-sized negative correlation with nausea ( r = -0.32) on the VOMS.

CONCLUSIONS

Eye-tracking proficiency was impaired and correlated with vestibular symptom provocation following acute mTBI in college athletes. Future research should examine eye-tracking proficiency testing in other acute care settings to support mTBI diagnosis.

Effects of recent cannabis consumption on eye-tracking and pupillometry

Introduction

Cannabis consumption is known to immediately affect ocular and oculomotor function, however, cannabis consumption is also known to affect it for a prolonged period of time. The purpose of this study is to identify an eye tracking or pupillometry metric which is affected after recent cannabis consumption but is not confounded by cannabis consumption history or demographic variables.

Methods

Quasi-experimental design. Participants who would consume inhalable cannabis (n = 159, mean age 31.0 years, 54% male) performed baseline neurobehavioral testing and eye-function assessments when they were sober. Eye function assessments included eye-tracking [gaze (point of visual focus), saccades (smooth movement)] and pupillometry. Participants then inhaled cannabis until they self-reported to be high and performed the same assessment again. Controls who were cannabis naïve or infrequent users (n = 30, mean age 32.6 years, 57% male) performed the same assessments without consuming cannabis in between.

Results

Cannabis significantly affected several metrics of pupil dynamics and gaze. Pupil size variability was the most discriminant variable after cannabis consumption. This variable did not change in controls on repeat assessment (i.e., no learning effect), did not correlate with age, gender, race/ethnicity, or self-reported level of euphoria, but did correlate with THC concentration of cannabis inhaled.

Discussion

A novel eye-tracking metric was identified that is affected by recent cannabis consumption and is not different from non-users at baseline. A future study that assesses pupil size variability at multiple intervals over several hours and quantifies cannabis metabolites in biofluids should be performed to identify when this variable normalizes after consumption and if it correlates with blood THC levels.

The Ability of Vestibular and Oculomotor Screenings to Predict Recovery in Patients After Concussion: A Systematic Review of the Literature

OBJECTIVE

The objective of this systematic review was to investigate if a positive vestibular or oculomotor screening is predictive of recovery in patients after concussion.

DATA SOURCES

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to search through PubMed, Ovid MEDLINE, SPORTDiscus, and the Cochrane Central Register of Controlled Trials (CENTRAL) and hand searches of included articles.

STUDY SELECTION

Two authors evaluated all articles for inclusion and assessed their quality using the Mixed Methods Assessment Tool.

DATA EXTRACTION

After quality assessment was completed, the authors extracted recovery time, vestibular or ocular assessment results, study population demographics, number of participants, inclusion and exclusion criteria, symptom scores, and any other outcomes of assessments reported in the included studies.

DATA SYNTHESIS

Data were critically analyzed by 2 of the authors and categorized into tables regarding the ability of researchers of each article to answer the research question. Many patients who have vision, vestibular, or oculomotor dysfunction appear to have longer recovery times than patients who do not.

CONCLUSIONS

Researchers routinely reported that vestibular and oculomotor screenings are prognostic of time to recovery. Specifically, a positive Vestibular Ocular Motor Screening test appears to consistently predict longer recovery.

Headers and concussions in elite female and male football: a pilot study

Background

Heading is a risk factor for neurogenerative disease in football. However, the exposure to heading in elite football training is understudied.

Objectives

The primary purpose of this study was to determine the exposure to headers in elite men's and women's football and to describe the effects of the headers on ocular markers.

Methods

Exposure to headers was observed over three days of women's and men's football. The number of headers at each session was determined through video analysis, and the G-force was determined via an impact tracker. Ocular markers were assessed at the start and end of the three days, and the results were compared to determine if there were any changes. Self-reported exposure to heading was recorded after each session and compared to the number of headers observed through video analysis, to assess the validity of players' self-reporting.

Results

Female players made an average of 11 headers per player per session. Ninety percent of the headers were below 10G, and none were above 80G. Male players made an average of three headers per player per session, with 74% of the headers recording a G-force above 10G and 3% above 80G. No meaningful changes were observed post-session in the ocular markers, and no concussions were observed. Neither cohort was able to accurately self-report exposure to headers.

Conclusion

Longitudinal studies should be designed and conducted across different levels of play in both women and men's football as a prerequisite to develop evidence-based measures to prevent or mitigate the potential risks associated with headers and concussions in elite football.

Multi-domain assessment of sports-related and military concussion recovery: A scoping review

OBJECTIVE

This review explores the literature on multi-domain assessments used in concussion recovery, to inform evidence-based and ecologically valid return-to-play. It asks: What simultaneous, dynamic multi-domain paradigms are used to assess recovery of youth and adults following concussion?

METHODS

Five databases were searched (CINAHL, EMBASE, MEDLINE, PsycInfo, SPORTDiscus) until September 30, 2021. Records were limited to those published in peer-reviewed journals, in English, between 2002 and 2021. Included studies were required to describe the assessment of concussion recovery using dynamic paradigms (i.e., requiring sport-like coordination) spanning multiple domains (i.e., physical, cognitive, socio-emotional functioning) simultaneously.

RESULTS

7098 unique articles were identified. 64 were included for analysis, describing 36 unique assessments of 1938 concussed participants. These assessments were deconstructed into their constituent tasks: 13 physical, 17 cognitive, and one socio-emotional. Combinations of these "building blocks" formed the multi-domain assessments. Forty-six studies implemented level walking with a concurrent cognitive task. The most frequently implemented cognitive tasks were 'Q&A' paradigms requiring participants to answer questions aloud during a physical task.

CONCLUSIONS

A preference emerged for dual-task assessments, specifically combinations of level walking and Q&A tasks. Future research should balance ecological validity and clinical feasibility in multi-domain assessments, and work to validate these assessments for practice.

Eye Tracking Metrics Differences among Uninjured Adolescents and Those with Acute or Persistent Post-Concussion Symptoms

SIGNIFICANCE

Eye tracking assessments that include pupil metrics can supplement current clinical assessments of vision and autonomic dysfunction in concussed adolescents.

PURPOSE

This study aimed to explore the utility of a 220-second eye tracking assessment in distinguishing eye position, saccadic movement, and pupillary dynamics among uninjured adolescents, those with acute post-concussion symptoms (≤28 days since concussion), or those with persistent post-concussion symptoms (>28 days since concussion).

METHODS

Two hundred fifty-six eye tracking metrics across a prospective observational cohort of 180 uninjured adolescents recruited from a private suburban high school and 224 concussed adolescents, with acute or persistent symptoms, recruited from a tertiary care subspecialty concussion care program, 13 to 17 years old, from August 2017 to June 2021 were compared. Kruskal-Wallis tests were used, and Bonferroni corrections were applied to account for multiple comparisons and constructed receiver operating characteristic curves. Principal components analysis and regression models were applied to determine whether eye tracking metrics can augment clinical and demographic information in differentiating uninjured controls from concussed adolescents.

RESULTS

Two metrics of eye position were worse in those with concussion than uninjured adolescents, and only one metric was significantly different between acute cases and persistent cases. Concussed adolescents had larger left and right mean, median, minimum, and maximum pupil size than uninjured controls. Concussed adolescents had greater differences in mean, median, and variance of left and right pupil size. Twelve metrics distinguished female concussed participants from uninjured; only four were associated with concussion status in males. A logistic regression model including clinical and demographics data and transformed eye tracking metrics performed better in predicting concussion status than clinical and demographics data alone.

CONCLUSIONS

Objective eye tracking technology is capable of quickly identifying vision and pupillary disturbances after concussion, augmenting traditional clinical concussion assessments. These metrics may add to existing clinical practice for monitoring recovery in a heterogeneous adolescent concussion population.