There is no single scan that says “concussion.” That is usually delivered to patients as though it meant the injury cannot be established. It means the opposite: the diagnosis rests on a careful history and a targeted examination, so who performs the assessment matters a great deal.
CT: a good test, asked a different question
A head CT in the emergency department is looking for bleeding, skull fracture and mass effect — findings that change what happens that night. In the CENTER-TBI series of over 4,000 admission scans, the most frequent findings were traumatic subarachnoid haemorrhage (45.3%), skull fracture (37.4%), contusion (31.3%) and acute subdural haematoma (28.9%), and all were up to three times more common in moderate-severe injury than in mild.
CT is insensitive to concussion itself, and this is by design. Concussion is a diffuse functional and microstructural disturbance. There is no lesion for the scanner to resolve. A normal CT means you are not in surgical danger — it is the beginning of the evaluation, not the end of it.
Vande Vyvere T, et al. Imaging Findings in Acute Traumatic Brain Injury (CENTER-TBI). J Neurotrauma. 2024;41(19-20):2248–2297. doi:10.1089/neu.2023.0553
MRI: where it earns its place, and where it does not
MRI resolves lesions CT misses, so it reclassifies some patients from uncomplicated to complicated mild TBI. That has genuine prognostic value — but less, and more specifically, than patients expect.
In a prospective cohort of 113 adults imaged 3–17 days after mild TBI and followed for a year, those with intracranial lesions returned to work at a median of 17 days versus 6, and reported more symptoms (RPQ 12.0 vs 6.5). The delay was greatest where multiple lesion types appeared on MRI or where the initial CT was positive — about 31 days. But the authors were explicit that a single intracranial lesion did not predict work disability, and overall return to work at one year was 98%.
So: MRI is worth doing when the clinical picture is not explaining itself, when symptoms are not following the expected course, or when the burden of injury needs documenting. It is not worth doing to confirm a concussion, because a normal MRI is the expected result in an uncomplicated concussion and proves nothing about symptoms.
Huovinen A, et al. Return to work after mild traumatic brain injury: association with positive CT and MRI findings. Acta Neurochir. 2022;164(7):1707–1717. doi:10.1007/s00701-022-05244-4
Blood biomarkers
GFAP and UCH-L1 are validated to exclude a structural lesion visible on CT, within 12 hours of injury, with a negative predictive value around 97%. They are excellent at that job and they are not a blood test for concussion — every validation study used an abnormal CT as the reference standard. Timing and age both change what a result means.
Full detail on what the biomarkers show and when →
Vestibular and oculomotor assessment
The most productive examination in persistent concussion is of the vestibulo-ocular system — how the eyes and the balance apparatus work together. Dysfunction here is common, strongly associated with longer recovery, and invisible to imaging.
Videonystagmography (VNG) records involuntary eye movement with infrared goggles to assess inner-ear and central motor function:
- Ocular testing — tracking eye movement as the patient follows visual targets
- Positional testing — monitoring eye movement as head and body position change
- Caloric testing — stimulating each ear separately, so an asymmetry between sides becomes measurable rather than reported
Among children and adolescents at a multidisciplinary concussion programme, vestibulo-ocular dysfunction was present in 28.6% of acute cases and 62.5% of those already in post-concussion syndrome, and carried roughly four times the odds of developing post-concussion syndrome, with a median symptom duration of 40 days rather than 21.
Ellis MJ, et al. J Neurosurg Pediatr. 2015;16(3):248–255. doi:10.3171/2015.1.PEDS14524
Other tools in current use
- Quantitative EEG (qEEG) and functional MRI — assess brain function rather than structure. They are used to characterise a picture, not to confirm a diagnosis, and are the closest ordinary practice comes to observing the neurometabolic disturbance directly.
- Computerised neuropsychological testing — reaction time, memory and processing speed; most useful where a baseline exists to compare against.
- Impact sensors — instrumented mouthguards and similar wearables that record the force and direction of a hit in real time. Useful in organised sport, irrelevant to the adult injured in a collision, and not a diagnostic test in either case.
- Biomarker assays — an active research area beyond the validated GFAP/UCH-L1 rule-out, including saliva-based work. Promising, not yet standard of care.
We name the last two honestly. Impact sensors and emerging biomarkers are genuinely useful lines of work, but neither replaces a clinical examination today, and any clinic implying otherwise is overselling.
Cognitive assessment: MoCA and Cognivue
The Montreal Cognitive Assessment (MoCA) is a structured screen of attention, memory, executive function, language and orientation. Its weakness is that it is only as good as the person administering it — scoring drifts without training. Dr. Padda is a certified MoCA rater, which means the instrument is scored to standard. Where a return-to-work decision or a claim turns on cognitive findings, that difference is material.
Cognivue is a computerised cognitive assessment. The patient interacts with an adaptive visual test rather than being interviewed, which removes examiner variability entirely and produces a quantified profile across domains including memory, visuospatial processing and reaction time. Because it is self-administered and repeatable, it is well-suited to tracking change across visits rather than yielding a single verdict.
Used together they answer different questions: MoCA gives a clinician-scored screen against a familiar benchmark, Cognivue gives an examiner-independent quantitative profile that can be repeated without practice effects dominating.
Movement and balance: Kinetisense
Balance deficits after concussion are real, and eyeballing them is unreliable. Kinetisense is a markerless motion-capture system — no sensors attached to the patient — that quantifies posture, balance and functional movement from video. It produces numbers where clinical assessment usually produces impressions.
Two reasons that matters here. Clinically, objective balance data tracks recovery and shows when a patient is not ready to return to load. Evidentially, a measured postural deficit is a finding that exists independently of what the patient reports — which is precisely what is missing from most concussion records.
Structured symptom instruments
Concussion symptoms are largely reported rather than observed, which makes them easy to dismiss and easy to dispute. We use the same instruments at intake and follow-up so the trajectory is documented rather than described — RPQ and BC-PSI for post-concussive symptoms, and PCL-5 or CAPS-5 where trauma symptoms are also present. See PTSD and post-concussion syndrome.
What the assessment is for
Two things at once. Clinically, it identifies which systems are affected so treatment can be aimed rather than general. Evidentially, it converts “I still don’t feel right” into a record: objective findings, quantified deficits, and direction of change over time.
Common questions
Can a brain MRI detect a concussion?
Usually not, and a normal MRI is the expected result in an uncomplicated concussion. MRI’s value is finding lesions CT missed in complicated mild TBI, where multiple lesion types predict a longer return to work. It is not a confirmatory test for concussion.
Why was my CT normal if I have a concussion?
Because CT is a test for bleeding, fracture and mass effect — not for concussion. Concussion is a functional injury with no lesion for the scanner to resolve. A normal CT tells you that you are not in surgical danger.
What is the difference between MoCA and Cognivue?
MoCA is administered and scored by a clinician against a familiar benchmark; its reliability depends on rater training, which is why certification matters. Cognivue is computerised and self-administered, removing examiner variability and producing a quantified, repeatable profile. They complement each other rather than substituting.
Do I need all of these tests?
No. The assessment is directed by the history. Someone whose symptoms are dominated by dizziness and visual intolerance needs the vestibular and oculomotor work; someone whose main problem is concentration and memory needs the cognitive side. We do not run a fixed panel.