DEVELOPMENTAL NEUROPSYCHOLOGY, 40(1), 7–11 Copyright © 2015 Taylor & Francis Group, LLC ISSN: 8756-5641 print / 1532-6942 online DOI: 10.1080/87565641.2014.971955
Oculomotor and Neurocognitive Assessment of Youth Ice Hockey Players: Baseline Associations and Observations After Concussion Brian T. Vernau Sports Medicine and Performance Center, Division of Orthopedics, Department of Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
Matthew F. Grady Sports Medicine and Performance Center, Division of Orthopedics, Department of Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, and Division of General Pediatrics, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
Arlene Goodman St. Peter’s Sports Medicine Institute, Somerset, New Jersey
Douglas J. Wiebe and Luke Basta Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
Yong Park Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
Kristy B. Arbogast Center for Injury Research and Prevention, Division of Emergency Medicine, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
Christina L. Master Sports Medicine and Performance Center, Division of Orthopedics, Department of Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
Correspondence should be addressed to Christina L. Master, M.D., CAQSM, Division of Orthopedics, Division of General Pediatrics, The Children’s Hospital of Philadelphia, 3400 Civic Center Boulevard, Philadelphia, PA 19104. E-mail: [email protected]
8
VERNAU ET AL.
Baseline scores on the King-Devick (K-D) Test, Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Sport Concussion Assessment Tool 3 (SCAT3), and convergence were evaluated in youth hockey players. Worse K-D times were associated with worse ImPACT visual motor speed and reaction time. Eleven concussed athletes were retested, and there was a trend toward improved ImPACT and K-D times compared to baseline.
Baseline testing for concussion in youth athletes utilizes tools such as the King-Devick (K-D) test, Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), and the Sport Concussion Assessment Tool 3 (SCAT3). The K-D test is a number-naming test assessing saccadic eye movement. ImPACT evaluates working memory, visual motor speed, and reaction time, while SCAT3 assesses working memory, concentration, and balance. These tests are commonly used to evaluate concussion. Clarifying their interrelationship is important to understand their utility in concussion assessment. Previous studies have shown an association between baseline K-D times and SCAT2 memory scores (Galetta et al., 2013). This link between saccadic function and working memory may be due to co-localization of these functions within the dorsolateral prefrontal cortex (Pierrot-Deseilligny et al., 2003). Moreover, convergence insufficiency has been described following concussion in adults (Borsting et al., 2003; Thiagarajan, Ciuffreda, & Ludlam, 2011). The near point of convergence (NPC), the point at which a single visual object becomes double in near vision, may be receded in such instances. Measuring NPC before and after injury may provide additional information not obtained with other testing. In light of this, we hypothesize that, in children, working memory correlates with visual motor function at baseline, and NPC is receded in concussion. This study sought to identify correlations between K-D times, ImPACT, SCAT3, and NPC at baseline in children and to describe characteristics of these measures post-injury.
METHODS Participants, Measures, and Procedures Following Institutional Review Board approval, 108 youth ice hockey players were enrolled. After parental informed consent and child assent, athletes underwent standardized testing with trained research assistants using the K-D test, ImPACT (≥11 years), and SCAT3 (>12 years) or Child SCAT 3 (≤12 years). NPC was measured using an Astron accommodative rule (Gulden Ophthalmics, Elkins Park, PA) with a single column 20/30 card (Hayes, Cohen, Rouse, & DeLand, 1998; Scheiman et al., 2003). During the season, a subset of athletes sustained a concussion as defined by the Consensus Statement on Concussion in Sport (McCrory et al., 2013) based on any history of forces transmitted to the head with the resulting acute onset of signs or symptoms of a concussion. The diagnosis of concussion was made by a single primary care sports medicine physician. Injured athletes underwent standardized post-injury clinical assessment.
OCULOMOTOR AND COGNITIVE TESTS IN YOUTH CONCUSSION
9
Statistical Analysis Descriptive statistics were used to summarize the cohort. Measurements of convergence were analyzed both as a continuous and dichotomous variable, with ≥6 cm classified as abnormal (Hayes et al., 1998). All composite ImPACT domains were analyzed with age- and sexstandardized percentile scores, which were each treated as a continuous variable. K-D times were analyzed as continuous. Pairs of continuous variables were compared using scatter plots with least-squares regression lines to allow visual inspection of possible linear relationships, and quantified by Pearson correlation coefficients. Conventional diagnostics were used to identify potentially influential outliers. The relationship between K-D times and SCAT3 were compared via linear regression and the coefficients of determination examined.
RESULTS A total of 108 male participants enrolled in the study (mean age = 12.5 years; range 6–18 years). All baseline assessments were completed by 53 participants. Baseline NPC measurements were obtained in 78 subjects (mean = 4.2 cm, range 1.5–10.5). Abnormal NPC (≥6 cm) was present at baseline in 9 subjects (11.5%). The K-D test was administered to 103 participants (mean = 55.9 seconds; range = 31–103). ImPACT testing was completed by 77 participants. Pearson correlation analysis did not identify any relationship between baseline convergence, ImPACT or K-D times. Worse (higher) K-D times were associated with worse (lower) scores on the ImPACT visual motor speed and reaction time subtests (Table 1). There was no association between K-D score and SCAT3 memory score.
POST-INJURY TESTS Eleven subjects (10%) were diagnosed with concussion during the season (average age = 13.5 years, range 9–17). The average time from baseline testing to post-injury testing was 109 days (range 38–247). NPC measurements were taken in 7 subjects 2–19 days after injury (M = 7, SD = 5.5). One athlete had abnormal post-injury NPC; all injured athletes had normal baseline
TABLE 1 Correlation Between Near Point Convergence, King-Devick Test, and ImPACT Subtest Scores Comparison NPC & Visual Motor Speed NPC & Reaction Time K-D & Visual Motor Speed K-D & Reaction Time NPC & K-D *p < 0.05.
Pearson Correlation
p-Value
–0.1366 –0.0086 –0.4901* –0.4411* 0.0089
0.31 0.95
Oculomotor and Neurocognitive Assessment of Youth Ice Hockey Players: Baseline Associations and Observations After Concussion Brian T. Vernau Sports Medicine and Performance Center, Division of Orthopedics, Department of Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
Matthew F. Grady Sports Medicine and Performance Center, Division of Orthopedics, Department of Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, and Division of General Pediatrics, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
Arlene Goodman St. Peter’s Sports Medicine Institute, Somerset, New Jersey
Douglas J. Wiebe and Luke Basta Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
Yong Park Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
Kristy B. Arbogast Center for Injury Research and Prevention, Division of Emergency Medicine, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
Christina L. Master Sports Medicine and Performance Center, Division of Orthopedics, Department of Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
Correspondence should be addressed to Christina L. Master, M.D., CAQSM, Division of Orthopedics, Division of General Pediatrics, The Children’s Hospital of Philadelphia, 3400 Civic Center Boulevard, Philadelphia, PA 19104. E-mail: [email protected]
8
VERNAU ET AL.
Baseline scores on the King-Devick (K-D) Test, Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Sport Concussion Assessment Tool 3 (SCAT3), and convergence were evaluated in youth hockey players. Worse K-D times were associated with worse ImPACT visual motor speed and reaction time. Eleven concussed athletes were retested, and there was a trend toward improved ImPACT and K-D times compared to baseline.
Baseline testing for concussion in youth athletes utilizes tools such as the King-Devick (K-D) test, Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), and the Sport Concussion Assessment Tool 3 (SCAT3). The K-D test is a number-naming test assessing saccadic eye movement. ImPACT evaluates working memory, visual motor speed, and reaction time, while SCAT3 assesses working memory, concentration, and balance. These tests are commonly used to evaluate concussion. Clarifying their interrelationship is important to understand their utility in concussion assessment. Previous studies have shown an association between baseline K-D times and SCAT2 memory scores (Galetta et al., 2013). This link between saccadic function and working memory may be due to co-localization of these functions within the dorsolateral prefrontal cortex (Pierrot-Deseilligny et al., 2003). Moreover, convergence insufficiency has been described following concussion in adults (Borsting et al., 2003; Thiagarajan, Ciuffreda, & Ludlam, 2011). The near point of convergence (NPC), the point at which a single visual object becomes double in near vision, may be receded in such instances. Measuring NPC before and after injury may provide additional information not obtained with other testing. In light of this, we hypothesize that, in children, working memory correlates with visual motor function at baseline, and NPC is receded in concussion. This study sought to identify correlations between K-D times, ImPACT, SCAT3, and NPC at baseline in children and to describe characteristics of these measures post-injury.
METHODS Participants, Measures, and Procedures Following Institutional Review Board approval, 108 youth ice hockey players were enrolled. After parental informed consent and child assent, athletes underwent standardized testing with trained research assistants using the K-D test, ImPACT (≥11 years), and SCAT3 (>12 years) or Child SCAT 3 (≤12 years). NPC was measured using an Astron accommodative rule (Gulden Ophthalmics, Elkins Park, PA) with a single column 20/30 card (Hayes, Cohen, Rouse, & DeLand, 1998; Scheiman et al., 2003). During the season, a subset of athletes sustained a concussion as defined by the Consensus Statement on Concussion in Sport (McCrory et al., 2013) based on any history of forces transmitted to the head with the resulting acute onset of signs or symptoms of a concussion. The diagnosis of concussion was made by a single primary care sports medicine physician. Injured athletes underwent standardized post-injury clinical assessment.
OCULOMOTOR AND COGNITIVE TESTS IN YOUTH CONCUSSION
9
Statistical Analysis Descriptive statistics were used to summarize the cohort. Measurements of convergence were analyzed both as a continuous and dichotomous variable, with ≥6 cm classified as abnormal (Hayes et al., 1998). All composite ImPACT domains were analyzed with age- and sexstandardized percentile scores, which were each treated as a continuous variable. K-D times were analyzed as continuous. Pairs of continuous variables were compared using scatter plots with least-squares regression lines to allow visual inspection of possible linear relationships, and quantified by Pearson correlation coefficients. Conventional diagnostics were used to identify potentially influential outliers. The relationship between K-D times and SCAT3 were compared via linear regression and the coefficients of determination examined.
RESULTS A total of 108 male participants enrolled in the study (mean age = 12.5 years; range 6–18 years). All baseline assessments were completed by 53 participants. Baseline NPC measurements were obtained in 78 subjects (mean = 4.2 cm, range 1.5–10.5). Abnormal NPC (≥6 cm) was present at baseline in 9 subjects (11.5%). The K-D test was administered to 103 participants (mean = 55.9 seconds; range = 31–103). ImPACT testing was completed by 77 participants. Pearson correlation analysis did not identify any relationship between baseline convergence, ImPACT or K-D times. Worse (higher) K-D times were associated with worse (lower) scores on the ImPACT visual motor speed and reaction time subtests (Table 1). There was no association between K-D score and SCAT3 memory score.
POST-INJURY TESTS Eleven subjects (10%) were diagnosed with concussion during the season (average age = 13.5 years, range 9–17). The average time from baseline testing to post-injury testing was 109 days (range 38–247). NPC measurements were taken in 7 subjects 2–19 days after injury (M = 7, SD = 5.5). One athlete had abnormal post-injury NPC; all injured athletes had normal baseline
TABLE 1 Correlation Between Near Point Convergence, King-Devick Test, and ImPACT Subtest Scores Comparison NPC & Visual Motor Speed NPC & Reaction Time K-D & Visual Motor Speed K-D & Reaction Time NPC & K-D *p < 0.05.
Pearson Correlation
p-Value
–0.1366 –0.0086 –0.4901* –0.4411* 0.0089
0.31 0.95
