Key points

  • Concussion is diagnosed from the circumstances of the injury, your symptoms and clinical assessment, not from a scan. A normal CT or MRI does not rule it out.
  • Standard scans are particularly important for identifying structural injuries such as bleeding, rather than confirming or excluding every concussion.
  • When symptoms persist, they rarely have one single cause. Assessment considers headache or migraine, the neck, balance and vision, sleep, mood, cognition and fatigue.
  • For selected people with ongoing dizziness, neck pain or headache, targeted cervical and vestibular rehabilitation may help, depending on the individual assessment.

Why a normal scan does not rule out concussion

Concussion is a form of mild traumatic brain injury that is diagnosed primarily from the circumstances of the injury, symptoms and clinical assessment. A concussion does not require an abnormality to appear on a standard CT or MRI scan. These scans are particularly important when clinicians are concerned about structural injuries, such as bleeding or other complications, rather than being a test that confirms or excludes every concussion.

Why symptoms can vary

Symptoms can also be varied. Headache, dizziness, balance or visual problems, neck pain, fatigue, sleep disturbance and difficulties with concentration can occur after concussion. When symptoms persist, their presence alone does not identify one single underlying cause. Current Australian and Aotearoa New Zealand guidelines recommend assessing the person's most prominent symptoms and considering factors such as headache or migraine, the neck, balance and vision, sleep, mood, cognition and fatigue.

What can help when symptoms persist

For selected people with ongoing dizziness, neck pain or headache, evidence suggests targeted cervical and vestibular rehabilitation may be helpful, although the appropriate approach depends on the individual assessment.

Rapidly worsening symptoms or concern about a more serious brain or neck injury require appropriate medical assessment.

Discuss your symptoms with us

If concussion symptoms are continuing to affect work, study, sport or daily life, an assessment may help identify relevant contributing factors. Book a consultation with our clinic to discuss your symptoms and whether physiotherapy may have a role in your care.

Key evidence

  1. Patricios, J. S., Schneider, K. J., Dvorak, J., Ahmed, O. H., Blauwet, C., Cantu, R. C., et al. (2023). Consensus statement on concussion in sport: The 6th International Conference on Concussion in Sport, Amsterdam, October 2022. British Journal of Sports Medicine, 57, 695–711. DOI: 10.1136/bjsports-2023-106898.
    International consensus supporting the modern clinical definition of concussion, including that standard structural neuroimaging may show no abnormality, and supporting multimodal assessment rather than reliance on imaging alone.
  2. Australian and Aotearoa New Zealand Concussion Guideline Development Group. Australian and Aotearoa New Zealand Clinical Practice Guideline for Assessment and Management of Mild TBI/Concussion. Current guideline accessed 9 September 2026.
    Supports clinical assessment, differential diagnosis and symptom-specific assessment of persistent headache, neck symptoms, dizziness, balance, vision, sleep, cognition, mood and fatigue.
  3. Schneider, K. J., Critchley, M. L., Anderson, V., et al. (2023). Targeted interventions and their effect on recovery in children, adolescents and adults who have sustained a sport-related concussion: A systematic review. British Journal of Sports Medicine, 57, 771–779. DOI: 10.1136/bjsports-2022-106685.
    Systematic review providing evidence that targeted interventions, including cervicovestibular rehabilitation in appropriately selected people with dizziness, neck pain or headache, may assist recovery.
  4. Silverberg, N. D., Iaccarino, M. A., Panenka, W. J., et al. (2020). Management of concussion and mild traumatic brain injury: A synthesis of practice guidelines. Archives of Physical Medicine and Rehabilitation, 101, 382–393. DOI: 10.1016/j.apmr.2019.10.179.
    Synthesis of clinical practice guidelines supporting active, individualised and symptom-directed concussion management rather than reliance on a single test or treatment.

This article is general information and is not a substitute for individual assessment, diagnosis or advice from a qualified health professional. A diagnosis of concussion must be obtained from a medical practitioner. If you are concerned about a medical emergency, call emergency services straight away. To discuss your own situation, get in touch or book a consultation.