KNOWLEDGE OF VESTIBULAR OCULAR DYSFUNCTION AND UTILIZATION OF VESTIBULAR OCULAR MOTOR SCREENING (VOMS) TOOL COMPONENTS AMONG PROFESSIONAL SPORTS LEAGUE ATHLETIC TRAINERS

Abstract

Background:

The Vestibular Ocular Motor Screen (VOMS) is a relatively new measurement tool intended for the non-vestibular practitioner to identify vestibular ocular dysfunction (VOD) following sport related concussion (SRC). Specific knowledge of VOD and usage of the VOMS among athletic trainers in professional sports leagues is currently unknown.

Hypothesis/Purpose:

The purpose of this study was to examine knowledge of VOD following SRC and utilization of the VOMS tool and other vestibular ocular tests and measures among athletic trainers in professional sports.

Study Design:

Cross Sectional Study

Methods:

A total of 117 athletic trainers from Major League Baseball, the National Basketball Association, the National Football League and Major League Soccer, with a mean of 17 ± 9 years in the athletic training profession were surveyed via Qualtrics™ with a response rate of 33%. The survey contained three primary sub-sections; demographics, knowledge of vestibular ocular deficits following SRC, and VOMS component utilization at baseline, acute and return-to-play phases of management. Total knowledge scores as well as percentage of utilization based on concussion management stages were calculated.

Results:

The average percentage correct on the knowledge items was 56% (range of 30% to 65%). There was no difference in knowledge score among athletic trainers with formal post-professional concussion training (p = 0.29) compared to those with no formal training. There was no relationship found between total years practicing and total knowledge score, r = -.128, (p = 0.17). Smooth pursuit testing was the most commonly utilized (70%) in clinical practice and Visual Motion Sensitivity (VMS) was the least utilized (17%). Balance assessment measures to examine vestibular functioning remained the highest utilized examination technique at all-time points in management of SRC.

Conclusion:

The range of correct responses from 30% to 65% indicates that at the time of survey the participants had decreased knowledge of VOD following SRC. There was low overall utilization of all VOMS components despite recent evidence showing good sensitivity and low false positive rates in SRC. The results of this study identify an opportunity for future training specific to vestibular-ocular impairments and assessment following concussion injury.

Level of Evidence:

2c

INTRODUCTION

Sport related concussion (SRC) is a major public health concern and results in a change in brain function after injury that is often difficult to assess based on the heterogeneity of subjective complaints.¹ Concussion can produce symptoms including blurry vision, dizziness, imbalance, headaches, as well as neurological impairments of cognition.² Vestibular ocular deficits have been shown to be associated with prolonged recovery and can lead to continued post concussive symptomology preventing return to sport or activity.³ The vestibular system is a complex network which includes both peripheral and central components that include the vestibular apparatus and peripheral nerves within the inner ear, as well as connections to the brainstem, cerebellum, cerebral cortex, ocular system and postural musculature.^4,5 The vestibular system functions to maintain upright balance, specifically the vestibular spinal reflex (VSR), and the vestibular ocular reflex (VOR) that serves to maintain clear vision while the head and/or body are in motion. Zhou and Brodsky reported that up to 90% of athletes with sport related concussion presented with a vestibular balance deficit, dizziness, and/or blurry vision.⁶ Previous researchers have reported that athletic trainers (AT) may not be utilizing multi-faceted approaches in their assessment and subsequent referral of post-concussive athletes experiencing prolonged symptomologies.^7,8 With the increased association between vestibular ocular deficits following SRC and increased risk of a prolonged recovery AT's have a crucial role in early identification of these impairments which can guide treatment and potentially decrease time missed from sport or activity. No authors to date have examined AT knowledge of vestibular ocular deficits following concussion and subsequent utilization of the Vestibular Ocular Motor Screening Tool (VOMS) in practice.

In 2014 the Vestibular Ocular Motor Screening Tool (VOMS) was created to be utilized by the non-vestibular specialist for identification of vestibular ocular deficits following injury that may warrant referral to a rehabilitation specialist.⁹ The VOMS consists of five measures of ocular and vestibular function to include; smooth pursuits, saccades, near point of convergence (NPC), vestibular ocular reflex (VOR) and visual motion sensitivity (VMS).⁵ A baseline subjective score of 0 to 10 (0 = no symptoms and 10 = worst symptoms) for headache, dizziness, nausea and fogginess is recorded and then subsequently measured after each of the exam components to identify potential vestibular ocular dysfunction following SRC. All VOMS components have been shown to be positively correlated with the Post-Concussion Symptom Scale (PCSS), which is embedded in the Sport Concussion Assessment Tool Version 5 (SCAT 5).⁵ The VOR and the VMS components are most predictive of concussion and a NPC measure ≥5cm and any VOMS item symptom score ≥2 increases the probability of identifying an individual who has sustained a concussion.⁵ The VOMS has been shown to have a high internal consistency (Cronbach α = .97) and a low false positive rate of 2% in concussed athletes.^10,11

All categories on the VOMS have also shown a high correlation with King Devick test (KD), (r = .325 – .585, p < 0.01).¹² VOMS items have also shown high agreement in total symptom scores between testing trials, with NPC distance demonstrating an Intraclass Correlation Coefficient (ICC) of .95 (95% CI, 0.89-0.98), p < 0.001. An association has also been described in the ability to predict individuals with prolonged recovery between 30-90 days following SRC utilizing acute VMS subcategory scores and cognitive-migraine-fatigue symptoms in the first seven days following injury.¹³ Utilization of the VOMS during acute assessment can lead targeted referrals to a vestibular rehabilitation specialist and decrease the likelihood of increased time missed from sport as well as time experiencing post-concussive symptoms.¹⁴ A recent survey of high school and collegiate AT's shows increased self-efficacy in utilizing symptom checklists, history and clinical evaluation, as well as baseline measures and lowest self-efficacy in utilization of the VOMS and KD tests.¹⁵ Collegiate AT's had higher self-efficacy in utilization of the VOMS as well as KD Test and in management strategies of vestibular ocular deficits as compared to high school AT's.¹⁵ In contrast, ATs from professional sports league data has not been reported to date.

Research is lacking in regards to AT knowledge and assessment of vestibular ocular deficits following concussion injury as well as incidence of utilization of the VOMS. Staying abreast of current literature and available valid and reliable assessment tools is challenging for all professionals involved in the management of SRC despite available resources. Health care providers who care for professional athletes tend to have more available resources to include financial, time, and access to SRC assessment tools as compared to those who work in collegiate or high school programs. The VOMS is a relatively new tool designed for screening of vestibular ocular deficits following concussion and ideal for utilization by the AT profession. Therefore, the purpose of this study was to examine knowledge of vestibular ocular deficits following SRC and utilization of the VOMS tool and other vestibular ocular tests and measures among athletic trainers in professional sports. It was hypothesized that individuals with more practice experience or more recent post-professional concussion education would show higher levels of knowledge and higher utilization of all components of the VOMS, which is required to calculate a total score. Post-professional education was defined as any formal concussion training received after completion of professional degree. The second hypothesis was that ATs may be utilizing individual components of the VOMS, such as NPC, not knowing that a full vestibular ocular screening tool exists.

METHODS

Research Design and Participants

A cross-sectional research design was used for this study. A sample of 358 Professional League ATs were used as potential participants. Recruitment of participants was facilitated by the presidents of the membership associations of four North American professional leagues (National Basketball Athletic Trainers’ Association, Professional Baseball Athletic Trainers’ Society, Professional Football Athletic Trainers’ Society, and the Professional Soccer Athletic Trainers’ Society). Efforts were made to solicit the Professional Hockey Athletic Trainers’ Society membership, but ongoing litigation prevented participation. Participants were included if they were certified ATs and members of the Professional League Associations. There were no exclusion criteria. All participants provided informed consent, which was the first question of the web-based online survey, by clicking “yes” to agreeing to participate in the study. Those who did not agree to participate did not have access to the questions in the survey. The survey response rate was 33% for all professional athletic trainers

Instrument

The questionnaire was a one-time, self-administered online survey delivered via Qualtrics (Qualtrics Inc., Provo, UT). The survey consisted of three primary sections: demographics, vestibular-ocular knowledge questions, and VOMS utilization across phases of concussion management. The first section consisted of demographic questions consisting of age, years practicing, highest earned degree, dual certification, post-professional concussion education (Yes/No Response with follow-up question of year for a Yes response), ImPACT™ Trained Athletic Training (ITAT) certification (Yes/No response), and participation in concussion management in last year (four responses; acute management, treatment, return to play protocol, clearance). ITAT information was collected secondary to the vestibular ocular dysfunction content covered in the training, as well as the VOMS assessment. The second section consisted of 15 knowledge-based questions regarding vestibular ocular dysfunction following concussion to include symptom presentation and current assessment methods in clinical practice. Participants were asked to select true, false, or unsure and a total score for all correct answers was calculated. The final section consisted of utilization of VOMS components in practice. A complete VOMS screening requires all sub-categories to be completed with subjective scores reported. ATs may already be utilizing some of the categories as they are derived from other neurological testing components, and were asked to indicate which components were currently being used in practice. Sub-categories of the VOMS components are smooth pursuits, saccades, near point of convergence, vestibular ocular reflex and visual motion sensitivity. Check boxes for each subcategory as related to concussion management to include: baseline, acute management and return-to-play phase.

Reliability and Validity of the Survey

The survey instrument was pilot tested for criterion validity with a group of five athletic trainers with publication history in survey design methodology and one physical therapist well-versed in vestibular therapy. Minor modifications were made based upon their feedback. Further pilot testing was completed to establish reliability with a group of 39 athletic trainers in a variety clinical practice setting to include professional ATs. The knowledge questions and usage items resulted in a high reliability rating (α = .84 and .83 respectively).

Procedure

The professional league membership organizations were contacted and briefed on the project scope and intent with clarification that data would be reported in aggregate and not specific to each league. A convenient time of year for each league was discussed and initial solicitation emails were scheduled for times that are slower for the membership. Solicitation emails were sent from each association's president along with the online survey link. Initial solicitation emails were distributed at the beginning of the week with follow-up solicitation emails mid-week and at one-week.

Statistical Methods

Data was captured anonymously via an online survey platform (Qualtrics, Provo, UT) and transferred to Excel (Microsoft, Redmond, WA) for analysis. Data were analyzed using SPSS Version 24 (IBM Corp. Armonk, NY). Variables were coded when needed and basic descriptive statistics were calculated for each variable. Shaprio-Wilk test revealed non-normally distributed data and therefore non-parametric statistics were utilized to include the following; Mann Whitney U to determine differences between groups with an alpha level set at p = 0.05 and Spearman Rho correlations to examine relationships between variables, utilizing SPSS Version 24 utilizing SPSS Version 24 (IBM Inc. Chicago, IL). This study was approved by Wingate University's Institutional Review Board and informed consent of subjects was obtained prior to the collection of data.

RESULTS

One hundred and seventeen total responses were received for a 33% response rate. The mean age of participants was 40.3 ± 8.7 years and mean experience as an athletic trainer was 17.1 ± 9.1 years. Additional demographics of the sample are presented in Table 1. Table 2 depicts how participants indicated the phases of concussion management they have participated in within the prior year. Phase includes baseline assessment, treatment/rehabilitation, return to play protocol, and medical clearance. Participants answered 56% (range of 30-65%) of our survey questions correctly (Figure 1). The average percentage unsure on the knowledge items was 25% (range of 14% to 30%). There was no difference in knowledge score among athletic trainers with formal post-professional concussion training (p = 0.29) compared to no formal training. There was no relationship found between total years practicing and total knowledge score, r = -.128, (p = 0.17). Balance assessment is the highest utilized in SRC management followed by smooth pursuits (Figure 2). Smooth pursuit testing was the most commonly utilized (70%) in clinical practice and VMS was the least utilized (17%).

Table 1.

Additional demographic variables (N = 117)

Variable	#	%
Bachelor's degree	024	21
Master's degree	075	64
Dual credential (PT/ATC)	018	15
Formal CE on concussion since degree
Yes	085	73
No	032	27

CE = Continuing Education

Table 2.

Participant report of involvement in concussion management within the last year (N = 117).

Management phase	#	%
Acute care	107	91
Rehabilitation	100	93
Return-to-play progression	093	87
Clearance to play	040	34

Figure 1.

Knowledge questions with responses from participants in percentages of correct, incorrect and unsure. VOMS = Vestibular Ocular Motor Screening Tool.

Figure 2.

Percentage of Usage of Balance and Vestibular Ocular Motor Sreening components by time point in post-concussive manaagement. (option to select multiple time points across continuum) VOMS = Vestibular Ocular Motor Screening Tool. Baseline is prior to season of play, Acute is within 24-48 hours, and Return-To-Play is prior to full clearance.

DISCUSSION

This is the first study investigating vestibular ocular knowledge and utilization practices of the VOMS in concussion management among professional sports league AT's. This sample of professional sports league ATs answered 56% (range of 30-65%) of our survey questions correctly (Figure 1). The use of balance assessment measures to examine vestibular functioning remained the highest utilized at all time points in management of SRC. The most utilized component of the VOMS in clinical practice was smooth pursuits with 83 participants (70%) using smooth pursuits as an acute assessment, though it is unknown if symptom provocation was also recorded (Figure 2). The high incidence of smooth pursuit testing may be due to the fact that it is part of the neurological screen on the SCAT 5 and performed routinely following a suspected SRC, though is not a full component of the VOMS unless subjective rating of symptomology is recorded.¹⁶ The least utilized component of the VOMS was visual motion sensitivity (VMS) with 20 participants (17%) using VMS as a baseline assessment. The VMS component of the VOMS assesses a function of the vestibular system, specifically vestibular ocular reflex (VOR) cancellation. VOR cancellation is the ability to keep vision stable and fixed on a moving target while the head and the target are in motion and requires the central vestibular system integration.¹⁷ Impairment of this reflex is associated with intolerance of visual motion, and VMS and NPC performance on the VOMS has been identified as the best subset of independent predictors of prolonged post-concussion symptoms.⁵ Balance assessment at all time-points in SRC management remained the most frequently assessed, which is also a component of the SCAT 5 commonly used in acute concussion management.

No significant relationships were found between post-professional training specific to concussion management and knowledge and utilization of VOMS. Increased funding for continued education or resources, training, as well as time availability, are potential resources professional level AT's have access to. The initial hypothesis of post-professional education specific to SRC and increased knowledge of vestibular ocular dysfunction was found to be invalid among this population. This could suggest knowledge translation specific to VOD is not being included in current educational methods secondary to vestibular rehabilitation is considered a sub-specialty requiring additional training among medical professionals. There was also no relationship between year's practicing and total knowledge of vestibular ocular deficits which could potentially indicate lack of knowledge translation to the clinical environment from recently published research rather than clinical experience.¹⁸

Until recently there was no brief screening tool available for assessment of potential vestibular ocular deficits until the VOMS which shows solid psychometric properties related to validity and reliability as well as measurement of a different construct than other available assessments to include the SCAT 5, Balance Error Scoring System (BESS) test and KD test.^19-21 The VOMS was originally designed for the non-vestibular practitioner to utilize as a screening tool and initiate earlier referral to a vestibular rehabilitation specialist.⁵ Most recently it has been identified as having a very low false positive rate (2%) in identification of athletes with suspected concussion and has the potential to be utilized in the acute management in the future.¹¹ With this new assessment tool available it may serve as a gateway to identification and earlier referral to vestibular rehabilitation. Current evidence supports rehabilitation as an effective strategy in concussion management, specifically vestibular and cervical physical therapy.^14,19 Whether initiated early (10-14 days post-concussion) or in individuals diagnosed with post-concussive syndrome (PCS) vestibular rehabilitation has been shown to be effective in decreasing time missed from sport.^1,19,20

There are several limitations in this study including: response bias of participants, low response rate, though 33% is deemed acceptable in survey-based research, and results are not generalizable to entire AT population at all levels of sports coverage. Another limitation is that this survey was just recently developed, and while reliability seems to be adequate this is not a well-established instrument and could likely use further refinement and study. Furthermore, as is inherent to survey research, those participants that felt confident in their knowledge may have been more likely to respond while those less confident in their knowledge may have chosen to not participate. Future considerations include sampling ATs that provide other levels of care to include collegiate and high-school populations.

CONCLUSIONS

Athletic trainers are part of the first line of defense and experts in the management of SRC. Based on the results of this study, ATs in professional sport leagues had decreased knowledge of vestibular ocular deficits specific to the following areas; NPC, KD Test, pursuit and saccadic eye movements, as well as the VOMS areas of assessment. Balance was most frequently utilized as one assessment of the vestibular system among the sample population, though it only examines one aspect of vestibular functioning, the vestibular spinal reflex, and does not include the vestibular ocular reflex which is needed for clear vision when the head and/or body are in motion. Smooth pursuit testing was the most commonly utilized VOMS component (70%) in clinical practice and VMS was the least utilized (17%).

Vestibular ocular functioning following concussion injury is an important construct and warrants evaluation, which can be easily screened by the VOMS. The results of this study identify a potential area of training and education specific to vestibular ocular deficits following SRC, which have been associated with a prolonged recovery and increased time missed from sport.^3,21-22 Early recognition of these deficits and earlier referral to rehabilitation have the potential to decrease prolonged symptomologies as well as time missed from sport or activity. Focus on knowledge translation from research into clinical practice is key to ensure that the most recent evidence is being applied into SRC management and best practice for translation may warrant further investigation.