Injuries that result in concussion happen anywhere and everywhere, from the sports field and schoolyard to the neighborhood playground, and even the home. Head-injured children and teens are initially assessed in a wide range of settings, by an equally wide range of clinicians, coaches, volunteers, and others. Concussion is not always an easy call to make. We've lacked an easily administered test to facilitate early and accurate diagnosis of concussion. A team of researchers at the CHOP Minds Matter Concussion Frontier Program has developed such a test with the goal of improving outcomes for concussed youth. It's known as the visio-vestibular examination (VVE), and Medscape spoke with researcher Daniel J. Corwin, MD, MSCE, about the vast potential of this simple tool.
How would you summarize the VVE? What are you actually testing in an injured patient?
The VVE is a series of physical examination maneuvers testing vision and vestibular function (including balance). It includes testing of:
Smooth pursuits (evaluating symptom provocation while the subject's eyes track a moving object in a single plane);
Saccadic eye movements (assessing symptom provocation while the subject's eyes jump rapidly between two fixed objects);
Gaze stability (the angular vestibulo-ocular reflex, assessing symptom provocation with the subject's eyes fixed and their head moving up and down or side to side);
Near point-of-convergence and monocular accommodation (how close an object can get to the subject's face before becoming double or blurry); and
Balance (using complex tandem gait, walking forward and backward in tandem, with eyes open and closed).
The VVE has evolved over the past decade on the basis of the clinical experience of concussion specialists in treating thousands of concussed youth, and research evaluating the most useful diagnostic and prognostic physiologic markers of injury.
You've made a video to demonstrate the VVE. Tell us what we are going to see here.
|The Visio-Vestibular Examination for Concussion. Video courtesy of Children's Hospital of Philadelphia.|
This is me performing the exam on one of our fabulous nurses. You'll see me explaining step by step how to perform each element, along with a definition of what we consider abnormal. A text description of how to conduct the test can be found here.
Are both parts of the test (eye movements and gait) required? How do you interpret the overall result if one part is negative and the other is positive?
The more information the provider has, the better. Eye movements and gait test two systems (vision and vestibular) that are integrated, but ultimately are unique. It's possible to have some elements of the testing be normal after a concussion. I don't think we'll ever be in a place with concussion where a single test (whether it be a clinical test, an imaging study, or a blood-based biomarker) can give you all the information you need as a clinician for diagnosis, prognosis, and treatment. It's very important to provide a multimodal assessment of a concussed child or adolescent and use that information to provide anticipatory guidance.
How does the VVE help diagnose concussion?
Several features of the VVE make it an incredibly appealing adjunct to classic symptom assessment when evaluating children for concussion across practice settings (the primary care office, urgent care, and the emergency department [ED], where I practice). As with an ankle sprain, whereas a provider might not elicit information about the diagnosis until they assess pain with ambulation, the VVE provides additional information beyond a simple symptom query — there are patients whose symptoms are not provoked until their visio-vestibular system is stressed, particularly right after the injury.
For example, in one study from the ED, we found about 10% of concussion patients had minimal symptoms initially, but abnormal VVE findings facilitated a concussion diagnosis. A standard neurologic exam (cranial nerves, strength, sensation, reflexes, and standard gait test) will almost always be normal in a concussion patient without additional injuries, so the VVE provides the clinician with more concussion-specific information. It goes beyond the subjectivity of simply querying the patient about their symptoms (which can be very nonspecific for concussion; there are lots of reasons to have headache, fatigue, difficulty concentrating, and emotional lability, especially in teenagers!) to provide the clinician with objective data that aid in clinical decision-making.
The VVE has impressive prognostic features, and finally, it is a test of function — we all use the functions being assessed with these exams hundreds of times each day. Children and adolescents, in particular, rely heavily on the ability to perform these tasks effortlessly in the school setting (for example, vertical saccades are used for looking at a board and taking notes, near point of convergence is necessary for reading small print close to one's face, and smooth pursuit helps students track a teacher in person or on a screen). So, an assessment of what is normal (or abnormal) when performing these tasks can help pediatricians tailor their recovery guidance by anticipating areas where children may struggle in resuming their normal lives (individualized care, rather than simply a "one size fits all" approach to concussion management, is extremely important).
What is known about the sensitivity and specificity of the VVE?
This important question gives me chance to talk about the heterogeneity of concussion. We often think of concussion as a single clinical entity, but we're learning that there are many different phenotypes of concussion. Therefore, a comprehensive examination that tests the many systems that may be affected by concussion (vision and vestibular being two key systems) is incredibly important for a pediatrician seeing a child who has had a head injury.
The VVE brings together elements that allow a clinician to maximize sensitivity and specificity. For example, when evaluating balance, our complex tandem gait outperformed a device-based measure of balance (a diagnostic area under the receiver-operating characteristic [AUROC] curve of 0.63 for complex tandem gait vs 0.54 for the balance device); the complex tandem gait has an individual component (having the patient walk backward with eyes closed) with the highest sensitivity (81%) of any of the balance measures evaluated.
In evaluating saccades and gaze stability, we found that increasing the number of repetitions when administering the test from 10 to 20 to provoke symptoms increases the sensitivity of the test. When looking at the nine elements overall, each additional abnormal element increases the odds of having a concussion by 2.1 times; when we define an "abnormal" test as at least two of the nine elements being abnormal, the patient is 17.2 times more likely to have a concussion when presenting to the ED after a head injury.
Yet in your protocol, you limit saccades testing to 20 repetitions. Why is this important?
Traditionally, saccadic and gaze stability (angular vestibulo-ocular reflex) testing was stopped after 10 repetitions to assess for symptom provocation. We're learning that many concussion tests have a "ceiling effect" — concussed youth may not have symptoms with a task that is too "easy" and may only present symptoms when their vestibular system is adequately stressed with a more difficult and challenging task (which is why walking backward with the eyes closed in the complex tandem gait test is more sensitive for diagnosing a concussion compared with standard gait testing). In one study, we evaluated the diagnostic ability of these tests at 10, 20, and 30 repetitions. Increasing from 10 to 20 repetitions doubled the sensitivity of the four tests (ranging from 19% to 32% for 10 repetitions to 45% to 52% for 20) without affecting specificity. Increasing to 30 repetitions provided additional sensitivity, but at a cost to specificity. The AUC for the three cutoff points showed that 20 repetitions was the optimized number of repetitions with the highest diagnostic utility in balancing sensitivity and specificity.
You compared the performance of concussed youth less than 28 days after their injury, mostly at about 7 days postinjury. But in the real world, wouldn't we want to apply the test as soon as the child presents for evaluation and care? Is this something you are studying?
Yes! We are one of the first groups to evaluate the performance of concussed youth on this testing across practice settings. For our studies that focus on patients enrolled from a specialty concussion program, as a referral practice, often their first encounter and examination is about a week out from injury.
But one of the appealing features of the VVE, particularly for pediatricians, is that we've found it to be easily performed by clinicians other than concussion specialists, including emergency medicine and primary care pediatricians. We currently are conducting a study evaluating how the examination evolves over time; this work was recently presented at the National Neurotrauma Society annual symposium.
We found that the highest likelihood of an abnormal examination peaks several days after injury (not immediately afterward), with various resolution times by age and sex. This emphasizes the importance of the multimodal evaluation for a suspected concussion — the VVE can augment symptom scales to provide the clinician with the most accurate diagnostic information, regardless of whether they are seeing the patient 1 hour or 1 week after the injury.
What is the ideal time, postinjury, to first administer the VVE? Can it be done too early?
It can be done any time. In our current study evaluating how the exam evolves over time, we're finding that the maximum number of abnormalities occur about 1 week after the injury. Some deficits may take some time to develop, so performing the exam immediately after impact may have less sensitivity. This underscores the importance of a multimodal evaluation for a potentially concussed patient, regardless of practice setting; no single test will be perfectly sensitive and specific. But, recognizing the limitations of symptoms (both in terms of their onset as well as their specificity and subjectivity), it is important for the clinician caring for a potentially concussed patient to obtain objective data.
Does the VVE have any prognostic value? Does it help clinicians predict expected duration of recovery or when the patient can return to school or resume other usual activities?
Absolutely. We learned early on in our evaluation of vestibular function after injury that patients with vestibular deficits were more likely to have prolonged recovery times and worse scores on neurocognitive testing. More recently, we found that each individual element of the exam, when abnormal in the first 2 weeks after injury, is independently associated with prolonged recovery, with odds as high as 4.5 for horizontal gaze stability in that study.
Although we're still learning which elements are most prognostic, as a whole, it seems that the more abnormalities a patient has on the VVE, the more likely it is that they will experience a prolonged recovery time. Defining recovery can be a challenge (both in the research and clinical worlds, but using symptoms alone may lead to a premature return to full activity. Monitoring VVE deficits, in combination with symptoms, is particularly useful when determining safety to resume full activity.
Are you suggesting that the VVE be repeated?
Yes, for two big reasons. First, if you are following a concussed patient longitudinally over time, repeat examinations can help track progress and determine when a patient has recovered. Some literature is finding that physiologic markers of injury (of which the VVE is one) often have abnormalities that extend past the timepoint of symptom resolution. Evaluating a VVE along with symptom burden can help the provider most accurately determine when a patient is "recovered" and can resume normal activity.
Just as important is the fact that the VVE is a target for active rehabilitation postinjury. For many children, vision and vestibular deficits resolve spontaneously over the course of days and weeks after the injury. However, for about 30% of concussed youth, these deficits linger and can significantly affect their daily lives. Recognizing lingering deficits can allow the provider to refer a patient to vestibular therapy, which we have shown helps resolve both these deficits on exam, and symptoms associated with these deficits.
What is the age range for administering the tool? What is the youngest age on which you've tested it?
Clinically, our providers evaluate children as young as 5 years with elements of the examination. In our research, we've evaluated children as young as 6 years to assess whether developmentally they are able to follow the instructions to complete the examination. About half of 6-year-olds were able to complete the exam, and all patients aged 10 or older were able to follow the instructions and complete the testing.
Who can conduct the VVE and how long does it take? You recently evaluated the reliability of the VVE when administered by nonspecialists in ED settings. What did you find?
One of the appealing features of the VVE is its ability to translate across practice settings (not just in the specialty clinical world), where most concussions are diagnosed. Within the CHOP network, the vast majority (over 80%) of concussions are diagnosed by primary care clinicians. It can be performed in 3-5 minutes and is quite easy to learn; all of our research assistants (who are not clinicians) are trained in the exam.
And it can be performed virtually. As a significant proportion of our concussion care moved to telemedicine in the midst of the COVID-19 pandemic, clinicians had to get creative with their evaluation techniques, and our concussion providers perfected the virtual administration of the examination. Athletic trainers and coaches can also be trained on the exam, which becomes important in youth sports where most personnel are volunteers. In terms of reliability, among a wide variety of ED providers (including pediatric emergency medicine physicians, pediatricians, acute care advanced practice providers, and pediatric trainees), we found that the individual exam elements showed fair to moderate agreement between providers and moderate to substantial agreement among the same provider, with substantial interrater and test-retest agreement in the adolescent population.
Are there any conditions or medications that can affect the results of the VVE?
We recently performed a study evaluating the VVE using a large cohort of nonconcussed persons, comparing abnormalities among various patient characteristics (sex; age; concussion history; baseline aerobic activity; motion sickness history; and comorbidities, such as mood disorders, migraine headaches, or attention-deficit/hyperactivity disorder). We found that the exam is relatively robust in all of these groups — a very encouraging result because most providers performing the test will not know the patient's baseline. That being said, about 30% of children (aged 11-18 years) in that study had at least one abnormal element out of nine, though only 3% had more than two abnormalities. So although a single abnormality in the VVE may not be indicative of pathology, the more abnormal elements there are, the more likely the finding is pathologic. One specific group to mention is those with migraine headache history. In this study, we did not find that persons with a history of migraine headaches were more likely to have abnormalities on the exam; however, others have found that those actively experiencing a migraine flare do have VVE abnormalities, and there is an overlap in the pathophysiology of migraine and concussion symptoms.
You've said that the VVE can be done virtually. Can a parent administer the test?
Although a parent could learn how to administer it as a screening tool, we would still recommend that any patient who is suspected of having a concussion and is assessed with the VVE see a clinician experienced in diagnosing and treating concussion for a complete evaluation.
You have suggested that concussion is primarily a clinical diagnosis. How does the VVE improve upon what pediatricians are already doing to reach or rule out concussion?
This is the most important take-home point we'd want pediatricians to learn. For those sitting at home wondering "why spend the extra 3-5 minutes on this test?" — it provides important information for diagnosis, prognosis, and function. As I've mentioned above, some concussed youth will have more subtle presentations, and perhaps they will only have symptoms elicited with VVE testing; therefore, it helps improve diagnostic accuracy.
Prognostically, each individual element of the examination is associated with a prolonged recovery time, in effect sizes that appear to exceed symptom evaluation. And finally, it is an exam of function that can help the provider tailor their anticipatory guidance to the individual patient, an incredibly important component of recovery and school re-integration (as the pandemic taught us, we want to keep kids out of school as minimally as possible).
Where can clinicians find the test and learn how to administer it?
The VVE for Concussion is part of CHOP's Emergency Department Acute Head Trauma Clinical Pathway. A video demonstration of the VVE is also available.
And, while we have a captive audience, a great set of resources for providers (and parents) can be found at the Minds Matter clinical website.
What is next for your research team?
One of the wonderful things about studying concussion is that so much of what we learn is immediately translatable to the clinical setting — we really move quite rapidly from bench to bedside. With regard to improving diagnostic accuracy, the Minds Matter team is currently evaluating several device-based measures of brain physiology to provide objective diagnostic data. Although this work originated in our specialty care settings, we're starting to evaluate these devices in the ED and are eager to see their contribution to diagnostic accuracy in this very acute postinjury state.
For the VVE in particular, we are very excited about its prognostic potential. One of the big challenges for providers evaluating concussed youth shortly after the injury (like most pediatricians in a primary care clinic, urgent care center, or emergency department) is accurate prognosis. Given the predictive power of the VVE elements, we are looking to utilize them to create a risk model to predict shortly after an injury which persons at highest risk of experiencing prolonged recovery times. Because the VVE abnormalities are a therapeutic target, early identification has the potential to facilitate targeted, active rehabilitation strategies in children at high risk for persisting symptoms, with the potential to ameliorate the significant physical, cognitive, and emotional morbidity that we see in children and adolescents who experience prolonged concussion recoveries. A complete overview of what's happening with the research being conducted by the Minds Matter team can found be here.
Cite this: Daniel J. Corwin, Laura A. Stokowski. The New 5-Minute Concussion Test - Medscape - Aug 11, 2021.