What long-term studies show about recovery from post-concussion syndrome
Often it does not. In a Canadian study of 110 patients whose concussion symptoms had lasted at least three months, 27% eventually recovered. Of the 30 who recovered, 20 did so within the first year, and no patient recovered after three years of symptoms.
This page lists the studies behind that answer. For a plain guide to symptoms, a self-check and when to get help, read Post-Concussion Syndrome: Symptoms, Self-Check, When to Get Help.
Medically reviewed by Lynn M. Gaufin, MD, Director of Neurosurgery at Cognitive FX. Last reviewed . The studies on this page did not involve Cognitive FX patients.
What did the Canadian study find?
The authors concluded that post-concussion syndrome may be permanent if recovery has not happened within three years. Patients in the study had tried treatments such as physiotherapy, medication and psychotherapy (Hiploylee et al., Journal of Neurotrauma, 2017. DOI: 10.1089/neu.2016.4677).
The study did not involve Cognitive FX. It measured full recovery, and the Cognitive FX studies on this page measured symptom reduction.
When recovery happened, in 110 patients with symptoms lasting three months or more
80 of the 110 patients had not recovered. Their symptoms had lasted 4.5 years on average when they answered the questionnaire.
Each dot is one patient. Filled dots recovered, and hollow dots had not. 30 patients recovered in all: the 27 shown by year, plus 3 who did not report when. Those who recovered took 11.7 months on average. Data: Hiploylee et al., 2017.
Had these patients already had care?
The Canadian patients were not untreated. They had been seen at a specialty concussion clinic in Toronto, and the study asked them about six common treatments: physiotherapy, occupational therapy, psychotherapy, medication, chiropractic manipulation and vestibular exercises. Patients who recovered and patients who did not rated physiotherapy, occupational therapy, psychotherapy and chiropractic care about the same.
In the large US studies below, standard care often meant an emergency visit and little follow-up. Fewer than half of the patients in that research project saw a doctor or other practitioner in the three months after their injury.
Follow-up care after an emergency visit for a mild traumatic brain injury
Data: Seabury et al., JAMA Network Open, 2018, a US study of 831 patients. PubMed 30646055
Do symptoms fade between three months and a year?
A US study followed 375 patients after a mild traumatic brain injury. About three in four reported post-concussion symptoms at three months, and the share was no lower at six or twelve months.
Patients still reporting post-concussion symptoms, by time since a mild traumatic brain injury
Time after injury. The share did not fall between three and twelve months. Based on 348 patients at 3 months, 250 of 305 patients at 6 months, 163 of 199 patients at 12 months. Data: McMahon et al., 2014, a US study of 375 patients.
Which concussion symptoms last longest?
Headaches, trouble concentrating and fatigue were the most common symptoms in the patients who had not recovered. In the Canadian study, each extra symptom a patient reported slowed recovery by about 20%.
Most common symptoms in the 80 patients who had not recovered
Data: Hiploylee et al., 2017.
Patients reporting symptoms in each area, 12 months after injury
Data: McMahon et al., 2014 (199 patients at 12 months).
What do other studies of lasting concussion symptoms show?
These studies followed people after a concussion or mild traumatic brain injury. None involved Cognitive FX. Each measured something different, so the numbers cannot be set side by side.
- 53%In a US study of 1,154 patients with mild traumatic brain injury seen at 11 level I trauma centers, 53% reported functional limitations 12 months after the injury.Nelson et al., JAMA Neurology 76(9):1049-1059, 2019. PubMed 31157856
- 82%In a US study of 375 patients with mild traumatic brain injury, 82% of those followed up at 12 months (163 of 199) reported at least one post-concussion symptom.McMahon et al., Journal of Neurotrauma 31(1):26-33, 2014. PubMed 23952719
- 47.9%In a New Zealand community study of 341 adults with mild traumatic brain injury, 47.9% reported four or more post-concussion symptoms one year after the injury.Theadom et al., British Journal of General Practice 66(642):e16-23, 2016. PubMed 26719482
- 56%In a US study of patients with a mild head injury and a normal CT scan, 56% of the 659 followed up at six months had not fully recovered.Madhok et al., JAMA Network Open 5(8):e2223245, 2022. PubMed 35976650
- 31.3%A 2023 review that pooled 21 studies estimated that 31.3% of adults had post-concussion symptoms three to six months after a mild traumatic brain injury, or 18.3% under a stricter definition. The authors noted that patients dropping out of studies may push these estimates up.Cancelliere et al., Journal of Neurotrauma 40(11-12):1045-1059, 2023. PubMed 36472218
What research is there on Cognitive FX treatment?
The studies above did not involve Cognitive FX patients. Research on Cognitive FX treatment is on a separate page: Cognitive FX research and results.
In an independent study by Amsterdam UMC and UMC Groningen, 77% of the 52 patients measured six months after treatment had a clinically meaningful reduction in symptoms. Observational, not randomized. Individual results vary.
That study was designed for patients treated at least twelve months after their injury, to limit the effect of natural recovery.