title: Longitudinal Study of Postconcussion Syndrome: Not Everyone Recovers.
abstract: We examined recovery from postconcussion syndrome (PCS) in a series of 285 patients diagnosed with concussion based on international sport concussion criteria who received a questionnaire regarding recovery. Of 141 respondents, those with postconcussion symptoms lasting less than 3 months, a positive computed tomography (CT) and/or magnetic resonance imaging (MRI), litigants, and known Test of Memory Malingering (TOMM)-positive cases were excluded, leaving 110 eligible respondents. We found that only 27% of our population eventually recovered and 67% of those who recovered did so within the first year. Notably, no eligible respondent recovered from PCS lasting 3 years or longer. Those who did not recover (n = 80) were more likely to be non-compliant with a do-not-return-to-play recommendation (p = 0.006) but did not differ from the recovered group (n = 30) in other demographic variables, including age and sex (p ≥ 0.05). Clustergram analysis revealed that symptoms tended to appear in a predictable order, such that symptoms later in the order were more likely to be present if those earlier in the order were already present. Cox proportional hazards model analysis showed that the more symptoms reported, the longer the time to recovery (p = 7.4 × 10-6), with each additional symptom reducing the recovery rate by approximately 20%. This is the first longitudinal PCS study to focus on PCS defined specifically as a minimum of 3 months of symptoms, negative CT and/or MRI, negative TOMM test, and no litigation. PCS may be permanent if recovery has not occurred by 3 years. Symptoms appear in a predictable order, and each additional PCS symptom reduces recovery rate by 20%. More long-term follow-up studies are needed to examine recovery from PCS.
authors: 1 Division of Neurosurgery, University of Toronto and Toronto Western Hospital , Toronto, Ontario, Canada .|2 Canadian Concussion Center , Toronto Western Hospital, Toronto, Canada .
authors: Carmen
authors: C
authors: Hiploylee
authors: 2 Canadian Concussion Center , Toronto Western Hospital, Toronto, Canada .
authors: Paul A
authors: PA
authors: Dufort
authors: 1 Division of Neurosurgery, University of Toronto and Toronto Western Hospital , Toronto, Ontario, Canada .|2 Canadian Concussion Center , Toronto Western Hospital, Toronto, Canada .
authors: Hannah S
authors: HS
authors: Davis
authors: 2 Canadian Concussion Center , Toronto Western Hospital, Toronto, Canada .|3 Division of Neurology, University of Toronto and Toronto Western Hospital , Toronto, Ontario, Canada .
authors: Richard A
authors: RA
authors: Wennberg
authors: 2 Canadian Concussion Center , Toronto Western Hospital, Toronto, Canada .|3 Division of Neurology, University of Toronto and Toronto Western Hospital , Toronto, Ontario, Canada .
authors: Maria Carmela
authors: MC
authors: Tartaglia
authors: 2 Canadian Concussion Center , Toronto Western Hospital, Toronto, Canada .|4 Division of Neuroradiology, University of Toronto and Toronto Western Hospital , Toronto, Ontario, Canada .
authors: David
authors: D
authors: Mikulis
authors: 2 Canadian Concussion Center , Toronto Western Hospital, Toronto, Canada .|5 Department of Laboratory Medicine and Pathobiology, University of Toronto , Toronto, Ontario, Canada .
authors: Lili-Naz
authors: LN
authors: Hazrati
authors: 1 Division of Neurosurgery, University of Toronto and Toronto Western Hospital , Toronto, Ontario, Canada .|2 Canadian Concussion Center , Toronto Western Hospital, Toronto, Canada .
authors: Charles H
authors: CH
authors: Tator
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D038223:Post-Concussion Syndrome / Q000503:physiopathology* / Q000534:rehabilitation*; D025341:Principal Component Analysis; D013997:Time Factors; D055815:Young Adult
keywords: definitions, eligibility, and exclusions; number of symptoms; postconcussion syndrome; recovery