There is a growing body of evidence that concussion can lead to visio-vestibular deficits post-concussion such as impaired eye movement and pupil response. Over a series of research publications, CIRP’s Minds Matter researchers describe these deficits as potential objective markers seen in the visual system after concussion and their association with prolonged recovery.
One of the primary tools Minds Matter clinicians have to assess these visual deficits is a visio-vestibular exam (VVE) advanced here at CHOP. Researchers have been testing the utility of the VVE to detect deficits after concussion in pediatric and adolescent patients and the use of eye tracking and pupillometry technology to objectively measure these deficits. They have learned that such clinical tools are both effective and feasible and important for diagnosis and recovery.
This line of research has important implications for the management of visual deficits after concussion. Active rehabilitation therapy can be used to treat those with prolonged persisting symptoms, and specific academic accommodations targeting these visio-vestibular deficits can be made for these children when returning to the learning setting.
Areas of Research on Visio-Vestibular Markers for Concussion:
- Vision and Vestibular System Dysfunction Predicts Prolonged Concussion Recovery in Children -- This study looked retrospectively at 432 randomly selected children ages 5-18 years who were seen in a specialty concussion program, of which 88 percent presented with a visio-vestibular deficit on initial clinical examination. Deficits in smooth pursuit and vestibular-ocular reflex function, accommodative amplitude and balance predicted prolonged concussion recovery. Clinical Journal of Sports Medicine. March 2018.
- Near Point of Convergence After Concussion in Children -- In a study of 275 patients age 5-18 with concussion, nearly one-fourth were found to have abnormal near point of convergence (NPC) on physical exam. About half recovered with standard clinical care over a median of 4.5 weeks, 40% recovered a median of 11 weeks post-injury with vestibular therapy and the remainder had persistent abdominal NPC that necessitated referral to a developmental optometrist for vision therapy. Optometry and Vision Science. Jan 2017.
- Vision Diagnoses Are Common After Concussion in Adolescents -- In a single-center cross-sectional study of 100 patients with concussion enrolled at the Minds Matter concussion program at CHOP, 69 percent had at least one vision diagnosis after concussion. Clinician researchers found the Convergence Insuffiency Symptom Survey (CISS) to be a highly cost-effective means for general practitioners to identify patients with concussion-related vision deficits that could require referral to concussion specialist or eye care professional. Clinical Pediatrics. July 2015. Read this blog article for more details.
- Vestibular Deficits Following Youth Concussion -- In a retrospective cohort study of patients ages 5 to 18 referred to a sports medicine clinic, researchers sought to characterize the prevalence and recovery of pediatric patients with concussion who manifest clinical vestibular deficits, as well as describe the correlation of vestibular deficits with neurocognitive function based on computerized neurocognitive testing. Vestibular deficits were highly prevalent, associated with longer recovery and poorer outcomes in neurocognitive testing. The Journal of Pediatrics. March 2015. Read this blog article for more details.
- Oculomotor and Cognitive Test in Youth with Concussion -- This study looked for correlations between different baseline assessments for concussion used for child and adolescent athletes: King-Devick (K-D) is a number-naming test assessing saccadic eye movement, ImPACT assesses working memory, visual motor speed and reaction time, while SCAT3 assesses working memory, concentration, and balance. In addition to these assessment tools, researchers wanted to see if useful information could be also obtained by measuring near point of convergence (NPC), the point at which a single visual object becomes double in near vision. In this study of youth hockey players ages 6-18 years, researchers ultimately determined that use of multiple assessment tools in a clinical evaluation of pediatric concussion is warranted rather than relying on any single tool. Also, the results suggest that the pediatric population may require more frequent than annual baseline testing. Additional research is needed to determine which combination of assessments will be most useful and non-overlapping. Developmental Neuropsychology. February 2015.
Principal Investigator: Daniel J. Corwin, MD, MSCE; Funding: National Institutes of Health
The visio-vestibular exam (VVE) identifies visual and vestibular system deficits which aid in the diagnosis of concussion and can predict prolonged recovery in those who are identified as having such deficits. These systems are responsible for integrating balance, vision and movement. Understanding these deficits early can have a substantial impact on a child’s visual function ability to return to learn and sports after a concussion.
The VVE screening assesses how eyes track a moving object, jump quickly between visual targets and their ability to view an object at near distance without double vision. Taken in the context of a preceding injury, abnormalities on this testing can assist in the diagnosis of concussion, as well as potentially aid in predicting children who will suffer from prolonged symptoms.
- Use of the Vestibular and Oculomotor Examination For Concussion In a Pediatric Emergency Department -- This study analyzed patient charts of 400 children ages 6-18 who presented to the emergency department (ED) with head injury and found that 64 percent of the patients overall were assessed using the VVE. Of those ultimately diagnosed with concussion, 73 percent were assessed using the VVE. Nine percent of patients diagnosed with a concussion had one or fewer symptoms but abnormal exam findings, highlighting that the VVE can assist in more accurately identifying concussed patients. The VVE was least likely to be performed in those children with non-sports related injuries, minimal concussion symptoms, and no prior history of concussion. With training and clinical support tools, pediatricians, emergency medicine clinicians, and advanced practice practitioners are able to conduct the VVE in a high volume acute care setting. American Journal of Emergency Medicine. July 2019.
Automated Eye Tracking Assessment
Principal Investigator: Christina L Master, MD, CAQSM; Funding: National Institutes of Health, Centers for Disease Control and Prevention, NCAA, Department of Defense
The automated eye tracking assessment is a rapid, objective, non-invasive aid in the diagnosis of concussion and it does not require an individual patient’s pre-injury baseline as a comparison to identify a concussion. This eye-tracking methodology reflects natural automatic physiologic brain activity and, thus, can be an objective alternative to traditional subjective, symptom-based assessments.
During the assessment, a clinician records a patient’s binocular eye movements with an SR Research Eyelink 1000 eye tracker while they are watching a 220-second video move continuously within a square aperture on the monitor as the patients head is stabilized on a chin rest to minimize head movement. Data collected are automatically processed using Oculogica software to yield metrics relevant to conjugacy, or the ability of the eyes to move well together. In collaboration with other institutions, CIRP researchers evaluated this technology as an objective method for identifying concussions in young patients. In 2019, the Oculogica EyeBox received FDA authorization as one of the few devices cleared for commercial use in objective diagnosis of concussion.
- Objective Eye Tracking Deficits Following Concussion for Youth Seen in a Sports Medicine Setting -- This study evaluated eye tracking measurements among adolescents within 10 days of the injury and healthy controls (n = 79). From among 17 metrics analyzed in this study, one metric measured by the automated eye tracking assessment stood out: The right eye’s ability to track an object predicted overall symptom severity among patients with concussion as compared to healthy controls. Child Neurology. Aug 2018.
- Eye Tracking as a Biomarker for Concussion in Children -- This study evaluated eye tracking measurements among children with concussion seen in a concussion referral setting with a mean of 22 days out from injury and healthy controls (n = 139). For these patients there were 12 metrics from 89 evaluated that were significantly different between concussed and non-concussed children. The assessment’s detection of concussion was independent from the number of symptoms reported by the patient. Clinical Journal of Sport Medicine. Aug 2018.
- Reliability of Objective Eye-Tracking Measures Among Healthy Adolescent Athletes -- This study evaluated healthy young athletes across two different testing sessions to evaluate the reliability of objective eye tracking metrics. No significant differences in outcomes were found in 13 eye movement variables across the two testing times. These results suggest that these automated and quantitative eye movement metrics are relatively stable among a group of healthy youth athletes. Clinical Journal of Sport Medicine. June 2018.
Principal Investigators: Kristy Arbogast, PhD, Christina L. Master, MD, CAQSM, Susan Margulies, PhD; Funding: National Institutes of Health (National Institute of Neurological Diseases and Stroke), Pennsylvania Department of Health
- Prognosis for Persistent Post Concussion Symptoms using a Multifaceted Objective Gait and Balance Assessment Approach -- A prospective cohort study of youth and young adult athletes determined that quantitative dual-task gait measures provide useful information for PPCS prognosis. Single-task gait, stance, and cognitive performance were not associated with PPCS. Researchers recommend that independent validation should be done in larger cohorts to determine utility. Gait & Posture. June 2020.
- Clinical and Device-based Metrics of Gait and Balance in Diagnosing Youth Concussion -- This study of 171 subjects (81 concussed, 90 non-concussed) compared the discriminatory ability of three measures of gait and balance: a device-based measure (a biomechanical force plate device) and two clinical measures (the modified balance error scoring system, or mBESS, of the Sport Concussion Assessment Tool, and the complex tandem gait used in the VVE). Investigators found that each test possessed moderate discriminatory ability, with the two clinical measures performing as well as, if not slightly better than, the device-based measure. In addition, investigators found the complex tandem gait possessed components (having the subject walk backward with his or her eyes closed) with the highest sensitivity for ruling out concussion. Medicine & Science in Sports & Exercise. March 2020. Read this blog article for more details.
Principal Investigator: Christina L Master, MD, CAQSM; Funding: National Institutes of Health (National Institute of Neurological Diseases and Stroke), Pennsylvania Department of Health
- The Utility of Pupillary Light Reflex Metrics as a Physiologic Biomarker for Adolescent Sport Related Concussion --The pupil’s response to light is an autonomic function with metrics easily captured via automated dynamic infrared pupillometry hand-held device. In this study, researchers explored whether PLR could distinguish between concussed and non-concussed adolescents. Researchers were interested in nine specific PLR metrics that objectively assess autonomic function. In a prospective cohort of adolescent athletes between 12 and 18 years old that included both healthy athletes (n = 134) and athletes with a diagnosis of sport-related concussion (SRC; n = 98), they found significant differences between concussed athletes and healthy adolescents for eight of the nine PLR metrics. They also observed differences for females with concussion. JAMA Ophthalmol. Online September 2020. Read this press release for more details.
- Learn more about the vestibular system in this blog
- Learn more about the vision disorders after concussion in this blog
- Read a press release about this line of research
- Read about common signs, symptoms, tests and treatment for concussion
- Read about prolonged symptoms from concussion
- Listen to a JAMA Ophthalmology podcast about the utility of PLR metrics