Table 1

Definitions of postconcussion syndrome used across included studies reporting this outcome

Study ID: author datePCS definition and measurement reported
Babcock 2013Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSMIV): presence of three or more symptoms on the Rivermead Post Concussion Symptoms Questionnaire (RPQ) that were rated as worse (score of >2) than before mTBI at 3 months
Chendrasekar 202036 Author defined: questionnaire assessing presence of any concussion symptoms; measured 4–68 months after mTBI
Corwin 2020International Classification of Diseases (ICD) 10 definition: symptoms that persisted beyond 28 days following mTBI; measured at 28 days and 3 months
Durish 2019ICD 10 definition; presence of one or more symptoms reported to be associated with the concussion that persist for longer than 1 month post-mTBI; measured at 28 days and 3 months
Gravel 2020ICD 10 definition: an increase of at least three symptoms on the child Post-Concussion Symptom Inventory as compared with the child’s baseline behaviour prior to mTBI at 1 week; measured at 1, 4 and 12 weeks
Haase 2015DSMIV definition: presence of three to six symptom categories occurring within 3 months post-mTBI and evidence of neuropsychological dysfunction
Howell 201814 ICD definition: symptoms lasting more than 28 days; measured at 3 months post-mTBI
Jeckell 201937 DSMIV definition: presence of 3 or more symptoms that lead to impairment in functioning and last no less than 3 months post-mTBI
Kelmendi 2021DSMIV definition: the presence of 3 or more symptoms on the RPQ scaler that rated as worse (score of ≥2) than at preinjury, at 3 months post-mTBI
Olsson 2013DSMIV definition: a measure of PCS was derived from parent’s responses on the Child Behaviour Checklist (CBCL), by scoring only the items on CBCL that matched on face validity to one of the Post-Concussion Disorder (PCD) symptoms in criterion C of PCD research criteria in DSMIV
Preiss-Farzanegan 2009DSMIV definition: the presence, nature and extent of postconcussive symptoms on RPQ scale, administered over the telephone 3 months post-mTBI
Riemann 2021ICD 10 definition; at least 3 of the following symptoms: headaches, dizziness, sleep disturbance, fatigue, being irritable/easily angered, forgetfulness/poor memory and poor concentration on RPQ scale (severity rating score ≥2); measured at 3 and 6 months
  • mTBI, mild traumatic brain injury; PCS, postconcussion syndrome.