Children aged 5 years and younger are at high risk for sustaining concussions due to falls. Post-concussive symptoms (PCS) are common and present in a variety of forms, including physical (e.g., headache), cognitive (e.g., poor concentration), and behavioural (e.g., anxiety) symptoms. Questionnaires exist to measure PCS in school-aged children, adolescents, and adults. In the absence of an age-appropriate tool, these have been used or adapted for young children. Previous studies have thus led to inconsistent findings regarding the presence and nature of PCS after early childhood concussion. The current study sought to assess PCS in 0-5-year-old children with concussion, orthopedic injuries, and healthy community children and to document PCS trajectories over time using a developmentally appropriate, observational measure.

Children with concussion or an orthopedic injury (OI) were recruited in the Emergency Departments of four tertiary, urban pediatric hospitals. Healthy community controls (CC) were recruited in daycares. The Report of Early Childhood Traumatic Injury Observations & Symptoms (REACTIONS) inventory documents 17 symptoms using items representing observable manifestations. This inventory was completed by parents retrospectively (T0: pre-injury), acutely (T1: 24-48h), sub-acutely (T2: 7-14 days) and in the chronic phases (T3: 25-35 days; T4: 75-104 days) post-injury. Separate ordinal regression models were used to investigate the association between group (concussion, OI, CC) and time (Pre, ED, 10D, 1M, 3M) on PCS distribution.

Overall, 310 children were included for analysis (concussion= 184, OI= 62, CC= 64); median age 35.9 months). Children with a concussion showed a significant (p <.001) increase in total PCS from T0 (M= 5.81, SD= 3.93) to T1 (M= 8.47, SD= 4.26), which peaked at T2 (M= 8.66, SD= 4.64) and decreased at T3 (M= 6.98, SD= 4.53) and T4 (M= 5.96, SD= 3.91). No group differences were found retrospectively at T0 (OI: OR = 1.68, 95% CI = 0.98-2.86; CC: OR = 1.51, 95% CI = 0.86-2.66). However, large group differences were found in total PCS at T1 (OI: OR = 4.56, 95% CI = 2.64-7.86; CC: OR = 7.34, 95% CI = 3.84-14.00), T2 (OI: OR = 4.48, 95% CI = 2.24-8.98; CC: OR = 6.85, 95% CI = 3.62-12.96), and T3 (OI: OR = 2.89, 95% CI = 1.67-5.02; CC: OR = 4.29, 95% CI = 2.30-8.01).

Children with early concussion had on average 8 of 17 symptoms acutely and post-acutely following injury, declining to 5-7 symptoms 1- and 3-months post-injury. In comparison to pre-injury and both comparison groups, young children with concussion had more symptoms post-injury. These findings underscore a significant symptom burden after concussion in early childhood, emphasizing the need for further research exploring outcomes and factors promoting recovery in this population.