Faculty Bibliography

OBJECTIVE:To determine if native English speakers (NES) perform differently compared to non-native English speakers (NNES) on a sideline-focused rapid number naming task. A secondary aim was to characterize objective differences in eye movement behaviour between cohorts. BACKGROUND:The King-Devick (KD) test is a rapid number-naming task in which numbers are read from left-to-right. This performance measure adds vision-based assessment to sideline concussion testing. Reading strategies differ by language. Concussion may also impact language and attention. Both factors may affect test performance. METHODS:Twenty-seven healthy  NNES and healthy NES performed a computerized KD test under high-resolution video-oculography.  NNES also performed a Bilingual Dominance Scale (BDS) questionnaire to weight linguistic preferences (i.e., reliance on non-English language(s)). RESULTS:Inter-saccadic intervals were significantly longer in  NNES (346.3 ± 78.3 ms vs. 286.1 ± 49.7 ms, p = 0.001), as were KD test times (54.4 ± 15.1 s vs. 43.8 ± 8.6 s, p = 0.002). Higher BDS scores, reflecting higher native language dominance, were associated with longer inter-saccadic intervals in  NNES. CONCLUSION/CONCLUSIONS:These findings have direct implications for the assessment of athlete performance on vision-based and other verbal sideline concussion tests; these results are particularly important given the international scope of sport. Pre-season baseline scores are essential to evaluation in the event of concussion, and performance of sideline tests in the athlete's native language should be considered to optimize both baseline and post-injury test accuracy.

Visual symptoms, such as photophobia and blurred vision, are common in patients with concussion. Such symptoms may be accompanied by abnormalities of specific eye movements, such as saccades and convergence, or accommodation deficits. The high frequency of visual involvement in concussion is not surprising, since more than half of the brain's pathways are dedicated to vision and eye movement control. These areas include many that are most vulnerable to head trauma, including the frontal and temporal lobes. Vision and eye movement testing is important at the bedside and on the sidelines of athletic events, where brief performance measures that require eye movements, such as rapid number naming, are reliable and sensitive measures for concussion detection. Tests of vision and eye movements are also being explored clinically to identify and monitor patients with symptoms of both sport- and nonsport-related concussion. Evaluation of vision and eye movements can assist in making important decisions after concussion, including the prognosis for symptom recovery, and to direct further visual rehabilitation as necessary.

BACKGROUND: Given that post-traumatic headache is one of the most prevalent and long-lasting post-concussion sequelae, causes significant morbidity, and might be associated with slower neurocognitive recovery, we sought to evaluate the use of concussion screening scores in a concussion clinic population to assess for post-traumatic headache. METHODS: This is a retrospective cross-sectional study of 254 concussion patients from the New York University (NYU) Concussion Registry. Data on the headache characteristics, concussion mechanism, concussion screening scores were collected and analyzed. RESULTS: 72% of the patients had post-traumatic headache. About half (56.3%) were women. The mean age was 35 (SD 16.2). 90 (35%) patients suffered from sport-related concussions (SRC). Daily post-traumatic headache patients had higher Sport Concussion Assessment Tool (SCAT)-3 symptom severity scores than the non-daily post-traumatic headache and the headache-free patients (50.2 [SD 28.2] vs. 33.1 [SD 27.5] vs. 21.6 SD23], p < 0.001). Patients with SRC had lower headache intensity (4.47 [SD 2.5] vs. 6.24 [SD 2.28], p < 0.001) and SCAT symptom severity scores (33.9 [SD 27.4] vs. 51.4 [SD 27.7], p < 0.001) than the other patients, but there were no differences in post-traumatic headache prevalence, frequency, and Standardized Assessment of Concussion (SAC) scores. CONCLUSION: The presence and frequency of post-traumatic headache are associated with the SCAT-3 symptom severity score, which is the most important predictor for post-concussion recovery. The SCAT-3 symptom severity score might be a useful tool to help characterize patients' post-traumatic headache.

Background/UNASSIGNED:Sports concussion has an annual incidence of approximately 3.8 million. Over half go unreported and a substantial number may be asymptomatic. A rapid, cost-effective, and reliable tool that facilitates diagnosis of concussion is needed. The King-Devick (K-D) test is a vision-based tool of rapid number naming for assessment of concussion. In this study, we evaluated the utility of the K-D test in real time for identification of symptomatic concussion in youth athletes and to determine if similar impairment (subclinical concussion) exists in youth athletes without an obvious head injury or symptoms. Methods/UNASSIGNED:Youth hockey players underwent K-D testing preseason, postseason, and immediately after suspected concussion. Additional testing was performed in a subgroup of nonconcussed athletes immediately before and after a game to determine effects of fatigue on K-D scores. Results/UNASSIGNED:< 0.05) and 51 nonconcussed players assessed before and after a game revealed no significant time change as a result of fatigue. Conclusions/UNASSIGNED:Rapid number naming using the K-D test accurately identifies real-time, symptomatic concussion in youth athletes. Scores in concussed players may remain abnormal over time. Athletes should undergo preseason and postseason K-D testing, with additional evaluation real time to inform the assessment of suspected concussion. Classification of Evidence/UNASSIGNED:This study provides Class III evidence that the K-D test accurately identifies real-time concussions in youth athletes.

Introduction: The optic nerve and visual pathway are frequent sites for involvement in multiple sclerosis (MS). Optical coherence tomography (OCT) detects retinal nerve fiber layer (RNFL) thinning in eyes of patients with MS or in the case of clinically-or radiologically-isolated syndromes. Current diagnostic criteria do not include the optic nerve as an imaging lesion site despite a high prevalence of acute optic neuritis (ON) among early MS and clinically isolated syndrome (CIS) patients. We sought to determine optimal thresholds for inter-eye difference in RNFL thickness that are most predictive of an optic nerve lesion. Methods: Spectral-domain (SD-)OCT data from an ongoing collaborative study of visual outcomes in MS were analyzed for a single site. Median values for inter-eye difference in RNFL thickness were also calculated from the RENEW trial cohort at the 6-month endpoint. RENEW was a randomized, placebo-controlled trial of opicinumab in subjects with a first episode of acute unilateral ON, and represents the most well-characterized cohort of CIS patients with ON incorporating modern tests of visual structure and function. RENEW utilized SD-OCT with a centralized reading center. Results: Among healthy volunteer control participants in the collaborative investigation (convenience sample, n=31), the 95th percentile value for inter-eye difference (upper boundary of expected for normals) was 6.0 microns. This value, as well as median intereye differences from the RENEW cohort (8.5 microns for placebo, n=41; 13.0 microns for opicinumab, n=41), were applied to convenience sample group of MS patients (n=136) as a validation cohort. Positive predictive value, sensitivity and specificity for identifying MS patients with a history of unilateral ON were greatest for the 6-micron value compared to the RENEW medians in a 2x2 table analysis (p< 0.0001, chi-square). The 6-micron threshold was also predictive of worse binocular low-contrast acuity at 2.5% (p=0.02) and 1.25% (p=0.002, linear regression). ROC curve analysis demonstrated an optimal inter-eye difference threshold of 5 microns for identifying unilateral ON in the MS cohort. Conclusion: Inter-eye differences of 5-6 microns in RNFL thickness are thus far optimal for predicting a unilateral optic nerve lesion in MS. Larger international collaborative investigations involving 20 or more MS validation cohort sites are underway to maximize precision and generalizability for these OCT-based thresholds