Concussions are common injuries sustained in the pediatric population. There are nearly 1 million emergency department (ED) visits per year for mild traumatic brain injury, with the highest reported rates in children and adolescents.¹ The incidence of concussion diagnosis is increasing, as reported rates have doubled over the past decade.²

Vestibular and oculomotor deficits have been recognized as a key component of the pathophysiology leading to the morbidity from concussions.^3,4 Recently, studies evaluating the validity and prognostic value of vestibular and oculomotor examination have been completed.^5,6 These studies, however, focus on patients presenting to specialty sports medicine clinics, likely representing a specific cohort of injured patients, though have demonstrated that a portion of this specific population exhibits abnormalities on this testing. Over the past several years, guidelines and position statements have begun recommending the use of a routine a vestibular and oculomotor assessment for the concussed pediatric patient,⁷ with the most recent International Consensus Statement on Concussion recommending vestibular and oculomotor testing by all providers evaluating concussion in the acute setting.⁴ However, there are limited data on non-concussed pediatric subjects assessed with such an examination,⁸ with no data describing the distribution of findings in an non-concussed population. Knowledge of these findings is imperative in order to appropriately interpret the findings on vestibular and oculomotor examination as a diagnostic tool for those presenting to the ED with concussion.

By performing a standardized version of the vestibular and oculomotor examination on a sample of non-concussed subjects with non-neurologic chief complaints presenting to a pediatric ED in a tertiary care children’s hospital, this study aimed to (1) determine the proportion of neurologically-normal, non-concussed children ages 6–18 years old with a failed examination; (2) determine the proportion of failed examinations across both sex and age groups; and (3) determine the youngest age at which the exam can be reasonably completed.

A total of 295 subjects were included in the analysis. A flowchart of patient enrollment is shown in Figure 1. Information on patient demographics is presented in Table 1. Overall, 24% (n = 71) of subjects failed at least one of the nine examination elements (95% confidence interval [CI] 19% to 29%). A breakdown of the failed exam elements is shown in Table 2. The largest proportion of patients showed failures on saccade testing, with 19% (n = 52) of all patients (95% CI 14% to 24%) failing either vertical or horizontal saccades. 87% (n = 33) of those with failed horizontal saccade testing and 72% (n = 28) of those with failed vertical saccade testing only reported symptoms after 15 repetitions; 97% of those who failed either saccade testing reported symptoms after 10 repetitions. Of the 71 subjects with a failed exam, 48% (n = 34) showed an abnormality on only one of nine exam elements. More than 1 failed exam element was noted in 13% (n = 37), and 5% (n = 15) failed more than 2 exam elements. None of the subjects with failed exams reported daily symptoms on secondary questionnaire. By the most common chief complaints, 23% (95% CI 14% to 34%) of patients with upper extremity trauma, 43% (95% CI 27% to 59%) of patients with abdominal pain, 18% (95% CI 9% to 30%) of patients with respiratory distress, 23% (95% CI 12% to 39%) of patients with sore throat, and 21% (95% CI 9% to 38%) of patients with rash had a failure on at least one examination element.

Females exhibited more overall failures than males (29%, n = 43 vs. 19%, n = 28; p=0.043; see Table 3), including saccades (19% [n = 26] vs. 9% [n = 12] for horizontal saccades, p=0.023; 19% [n = 25] vs. 10% [n = 14] for vertical saccades, p=0.071) and near-point of convergence (4.1% [n = 6] vs. 0.7% [ n = 1], p-=0.061). Overall the youngest age group (6–8 years old) showed the fewest overall failed exams for those able to fully complete the examination (15% [n = 12] see Table 4). Those in the youngest age group had more abnormalities on near-point of convergence (6.3% [n = 5] vs. 3.8% [n = 3], 2.5% [n = 2], and 3.6% [n = 2] in the older age groups), however this difference was not significant.

Overall 10% of subjects (n = 28) were unable to complete at least one element of the examination (see Table 5). All subjects unable to complete part of the examination were younger than 10 years old. 24 of those subjects had difficulty completing horizontal saccades, and 23 had difficulty completing vertical saccades. The distribution of subjects unable to complete at least one examination element by age is shown in Table 6.

Finally, each individual exam element had a percent agreement of at least 84%, with a range of 84% to 100%. Due to low prevalence of abnormalities in each individual test among the 29 subjects on whom inter-rater reliability was performed, we were unable to calculate a reliable kappa statistic for these tests.¹⁴

This study evaluated the prevalence of failures on a version of the vestibular and oculomotor examination for concussion in neurologically normal, non-concussed children and adolescents. Previous studies have shown that vestibular and oculomotor deficits are common following concussion, with 70–80% of concussed children exhibiting at least one vestibular or oculomotor deficit.^5,15 Additionally, those with vestibular and oculomotor abnormalities have been shown to be at risk for prolonged recovery from concussion,⁵ and the examination has practical utility in assessing the everyday function of the child and adolescent student. Overall, we found that nearly one quarter of children demonstrated a failure on at least one of the nine elements of the examination. However, nearly half of these subjects only had an abnormality on only one exam element, and a substantial number of those with failed exams only had the failed test result of mild symptom provocation after 10 repetitions of either horizontal or vertical saccades.

The limited data on the performance of non-concussed children on a version of the vestibular and oculomotor examination for concussion exists only in the setting of validating the examination in comparison to concussed youth. As part of their validation study of the Vestibular/Ocular Motor Screening (VOMS) Assessment, Mucha and colleagues used a population of 78 subjects age 10–17, all of whom were athletes.⁶ The VOMS includes assessments of smooth pursuits, horizontal and vertical saccades, gaze stability, and near-point of convergence; it additionally includes a test for visual motion sensitivity, but unlike our version, does not include dysmetria, nystagmus, or gait/balance testing. They found 9% reported symptom provocation with gaze stability, horizontal saccades, or smooth pursuits. Yorke and colleagues evaluated the performance of 105 healthy high school students, and assessed for symptom provocation change prior to and following administration of the elements of the VOMS.⁸ They found a median change of 0 (range 0–5), though they do not quantify the overall percentage that reported symptom change with each exam element. They do, however, report abnormal near-point of convergence in 25% of subjects. McDevitt and colleagues evaluated a sample of 60 college-aged athletes, and found that 5.4% of controls reported symptom provocation on vestibular and oculomotor assessments. Finally, Vernau and colleagues performed near-point of convergence in 108 male hockey players age 6–18, and found 11.5% of subjects had abnormal near-point of convergence. ¹⁷ It should be noted that convergence insufficiency (a diagnosis consisting of abnormal near-point of convergence plus other accommodative defects) has been more broadly studied in the pediatric population in the optometry literature, where data has shown between 5% and 17% of children have abnormal exams;^18–20 no such data, however exists for measurements of symptom provocation with saccades or vestibulo-ocular reflex testing. No children exhibited failures on our dysmetria and nystagmus testing, most likely due to the fact that these tests observed purely objective findings rather than some element of symptom provocation.

Several differences exist between the populations in these prior studies and our assessed population. The prior studies all included either only athletes or teenagers and young adults. Our study, by enrolling in the ED setting and including a larger sample and age range of children (including non-athletes), likely more accurately reflects the general population. There is a potential that high functioning athletes at baseline might have more robust oculomotor and balance systems than the average child, and symptom provocation on saccade and gaze stability testing would occur more easily in non-athletes with less exposure to repetitive motion associated with exercise. While similar to the VOMS (which was the exam performed in two of the four above studies), the examination performed in this study has several key differences, specifically including a component of balance testing, which may have increased our overall percentage of exam abnormalities (and in fact, 8% of our population had an abnormality on their tandem gait).

Additional findings from our study were the significantly higher proportion of females with failed exams as compared with males, specifically in symptom provocation during horizontal and vertical saccades. Among the various age groups, the lowest proportion of failures occurred in the lowest age range (6–8 years old) and the highest among those aged 9–11 years-old. These data reflect the findings of recent studies attempting to describe the distribution of concussion-like symptoms in non-concussed children. Iverson and colleagues, among a sample of over 31,000 non-concussed teenagers, found that a significantly higher proportion of non-concussed females reported symptoms on a 22-question post-concussion scale when compared with non-concussed males.²¹ Hunt and colleagues conducted a similar study among a wider age range, and found the youngest non-concussed children reported concussion-like symptoms less frequently than older teenagers.²² This may partially explain the lower proportion of young children with failed fast saccades.

This study is unique in examining this specific testing among children as young as 6 years of age. Our results show that developmentally, the exam can be reliably completed in those 10 years of age and older, and can be attempted in children as young as 6 years old, with over 50% of 6-year-olds being able to complete all exam elements. When analyzing the particular exam elements, the youngest children struggled with horizontal and vertical saccades compared to the other exam elements.

There are several limitations to this study. First, this study was conducted exclusively in the emergency department setting among subjects with non-neurologic chief complaints, a sample chosen do to the fact we believe represent the population of children who will present to acute care with concern for concussion. The same pediatric emergency medicine physician trained in the performance of the examination conducted all 295 exams. While a second pediatric emergency medicine physician repeated the examination for 10% of the sample, with high percent agreement scores (all greater than 84%), we were unable to calculate a kappa statistic due to the relatively low overall percentage of abnormalities among each exam element in the random sample.¹³ Finally, while the VOMS examination has been validated in comparison with concussion symptom scores, and shown high internal consistency and sensitivity,⁶ we acknowledge that there do exist key differences between that examination and the examination performed in this study, specifically in the area of balance testing. Future studies include assessing this examination for both internal validity and inter-rater reliability amongst a sample of concussed children.

These results have implications for the diagnosis of pediatric concussion. When using this examination to aid in the diagnosis of a child with concussion, the provider should be aware that a proportion of non-concussed children may demonstrate failures on a single exam element, specifically on the tests of horizontal and vertical saccades. The vast majority of these subjects reported symptoms after at least 10 repetitions of saccades, therefore symptom provocation with fewer repetitions is more likely to be pathologic in the setting of a head injury. The proportion of non-concussed children exhibiting a failure on more than one of the nine elements of the examination is significantly lower (13%), and it is quite rare for a non-concussed child to show greater than two abnormalities (only 5% of our population). This suggests that, while one or two failed exam elements, in the absence of other symptoms, may not be sufficient for a concussion diagnosis, the practitioner can use this examination in conjunction with a careful history and subsequent acute onset of concussion symptomatology to make the diagnosis of pediatric concussion. The examination should be used as a tool in the acute care provider’s toolkit when taking a multimodal approach to evaluating pediatric concussion.