CLINICAL PREDICTORS OF SYMPTOM RESOLUTION FOR CHILDREN AND ADOLESCENTS WITH SPORT-RELATED CONCUSSION
Authors: Howell David R. , Potter Morgan N. , Kirkwood Michael W. , Wilson Pamela E. , Provance Aaron , Wilson Julie C. 
Published: March 2019

Background: Early prognosis of expected recovery duration after a sport-related concussion is a challenging task for sports medicine clinicians, as various pre-morbid, injury characteristic, and functional factors have been identified to help predict recovery. The purpose of this investigation was to determine which variables obtained as a part of a routine concussion clinical evaluation were independently associated with symptom resolution time among pediatric patients evaluated after sport-related concussion by a sports medicine physician. Methods: We conducted an analysis of data collected from a prospective clinical registry of children with concussion. Patients included in the current investigation were seen for care at a pediatric sports medicine concussion clinic between January 1, 2015 to August 31, 2017, were less than 19 years of age, evaluated within 10 days of a sport-related concussion, and followed until they no longer reported symptoms. The primary outcome variable was the number of days from injury until symptom resolution. The predictor variables included those assessed during the initial clinical evaluation. They were obtained via a medical history form (pre-injury history of attention-deficit/hyperactivity disorder, learning disability, anxiety, depression, and migraine or headaches), the Health and Behavior Inventory (HBI) symptom frequency questionnaire, headache severity rating (rated on a scale from 0-10), sleep disturbance questionnaire, and performance on a set of balance, vestibular, and oculomotor function tests (Balance Error Scoring System, Romberg, tandem gait, gaze stability, and near point of convergence). Tests were considered abnormal if patients could not maintain balance or demonstrated exaggerated upper body movement (Romberg/tandem gait tests), if they reported symptom provocation after test administration (gaze stability), or if the near point of convergence was greater than 5 cm from the tip of the nose. To identify the independent factors associated with symptom resolution time, we first constructed univariate Cox proportional models with time to symptom resolution as the outcome and each clinical variable as a separate predictor variable. Predictor variables with a univariate significance level of p < 0.05 were then used to construct a multivariate Cox proportional hazards model where total duration of concussion symptoms remained the outcome variable. Results: We examined data from 351 children and adolescents (mean age= 14.6±2.2 years, 33% female, evaluated 5.6±2.6 days after concussion) who required a median of 11.5 [interquartile range= 7-21] days for symptom resolution. One hundred and sixty-three (46%) of patients reported a prior history of concussion, while other pre-injury health conditions were reported less often (Table 1). The most commonly endorsed symptoms by patients at the initial visit were headaches, difficulty paying attention, difficulty concentrating, and getting distracted easily (Table 2). The most common abnormal vestibular or oculomotor test was symptom provocation brought on by gaze stability testing, while 20% of patients had an abnormal Romberg test, 15% demonstrated abnormal tandem gait, and 15% had abnormal near point of convergence (Table 3). Results from univariate Cox proportional hazards models indicated headache severity, headache frequency, confusion, forgetfulness, attentional difficulties, trouble remembering, getting tired often, getting tired easily, dizziness, and an abnormal Romberg test were associated with a longer symptom duration (Tables 2 and 3). The multivariate Cox proportional hazard model indicated that an abnormal Romberg test was independently associated with a longer symptom duration after adjusting for the effect of all other covariates included in the model (Table 4 and Figure 1). Headache frequency and “being tired easily” were not included in the final model due to collinearity with headache severity and “being tired a lot”, respectively. Conclusions: For adolescent and child patients assessed within 10 days of concussion, an abnormal Romberg test was independently associated with longer symptom duration during recovery. This is in line with other recent studies investigating early predictors of symptom resolution, demonstrating that postural instability appears to provide valuable prognostic information for sports medicine clinicians. [Table: see text]