Mild TBI evidence
Mild traumatic brain injury after a motor accident
“Mild” describes the initial severity classification, not necessarily the effect on the individual. A mild traumatic brain injury may involve brief altered consciousness or memory disturbance followed by headache, dizziness, fatigue or cognitive symptoms. The CTP file must show what happened at the time, what changed afterwards and whether any permanent neurological impairment can be objectively assessed.
Motor accident mechanism
What can happen in a motor accident?
Rear-end crash
Acceleration-deceleration and head restraint forces can cause brief alteration of awareness without visible external injury.
Side-impact crash
Rotational loading or contact with the side structure may affect awareness, memory and balance.
Motorcycle fall
A helmet reduces some risks but does not prevent all mild brain injuries from impact or rotation.
Pedestrian impact
Ground impact after vehicle contact can produce a brief memory gap together with facial, vestibular or neck injury.
Injuries and diagnoses that may follow
- mild TBI with altered mental state
- mild TBI with brief post-traumatic amnesia
- mild TBI with or without loss of consciousness
- associated vestibular, visual or cervical injury
- persistent post-concussion symptoms requiring separate clinical evaluation
Symptoms to record accurately
- slowed processing or difficulty switching between tasks
- short-term memory and concentration difficulty
- headache, dizziness, nausea or imbalance
- sleep disruption, fatigue and reduced cognitive endurance
- irritability, anxiety or low mood that may require separate psychiatric diagnosis
Urgent health warning
New deterioration, seizure, repeated vomiting, focal weakness, marked confusion, severe worsening headache or other red-flag neurological signs require urgent medical assessment.
Clinical evidence
What objective findings and records matter?
The most useful evidence distinguishes an initial mild TBI from later symptom persistence. Hospital observations, post-traumatic amnesia, neurological examination and functional change should be considered together rather than treating the word “mild” as proof of full recovery.
| Record or test | What it can establish | What it cannot establish alone |
|---|---|---|
| Initial severity observations | Glasgow Coma Scale, loss or alteration of consciousness and post-traumatic amnesia help characterise the acute injury. | The initial severity label does not decide long-term impairment. |
| Neurologist or rehabilitation assessment | Tests neurological function, differential diagnoses, prognosis and accident causation. | A diagnosis without analysis of pre-accident function and alternative causes may be incomplete. |
| Neuropsychological assessment | May measure memory, attention, processing speed, language and executive function with validity measures. | One test score does not replace clinical judgment or prove accident causation. |
| OT and work-function evidence | Records pacing, errors, supervision, task tolerance and symptom rebound under real demands. | Temporary difficulty during acute recovery does not necessarily equal permanent WPI. |
Part 5 classification
Is the injury threshold or non-threshold?
A medically established mTBI is a brain injury and may support non-threshold classification. The dispute often concerns whether an mTBI was actually sustained and caused the current symptoms. A cluster of headache, fatigue and poor concentration without a supported neurological diagnosis does not itself decide the classification.
Evidence consistent with a threshold classification
- symptoms better explained by a threshold neck soft tissue injury
- no supported brain injury diagnosis despite normal neurological findings
- psychological symptoms below the recognised-illness test
- pre-existing cognitive symptoms without a documented accident-related change
Evidence that may support a non-threshold injury
- documented acute altered awareness or post-traumatic amnesia with a clinical mTBI diagnosis
- a specialist opinion linking the brain injury and ongoing effects to the crash
- structural intracranial injury or objective neurological deficit
- a separate recognised psychiatric or vestibular injury meeting its own test
Separate questions: threshold injury classification does not set WPI, and receiving statutory benefits does not automatically create a common law damages entitlement.
Part 6 permanent impairment
How is WPI assessed for this injury?
The term mTBI does not assign a percentage. Any permanent cognitive, behavioural, communication, consciousness or other neurological impairment is assessed under clauses 6.156-6.176. Clauses 6.164-6.169 impose specific evidentiary requirements before the modified mental-status method is used.
| Assessment question | Applicable method | Important limit |
|---|---|---|
| Memory and executive function | Tables 6.9 and 6.10 use a modified Clinical Dementia Rating across memory, orientation, judgment, community affairs, home/hobbies and personal care. | The assessor must rate actual function and explain the chosen percentage; symptoms cannot be converted directly. |
| Language disturbance | Aphasia or dysphasia is considered under AMA4 Chapter 4 Table 1 where medically established. | Word-finding complaints without an established communication disorder do not automatically create a table rating. |
| Other neurological consequences | Seizures, vestibular injury, cranial nerve injury and consciousness disturbance use their specific Chapter 4 or Part 6 methods. | Separate impairments are combined only where permitted and without double counting the same function. |
- Clause 6.164 requires a significant head impact, cerebral insult or high-velocity impact plus a medically verified abnormality such as abnormal initial GCS, post-traumatic amnesia or imaging abnormality for mental-status or emotional/behavioural rating.
- Available psychometric evidence must be considered, but it is not read in isolation.
- The assessor chooses the highest of the four central categories listed in clause 6.160 before considering other separately assessable neurological functions.
- Psychiatric impairment is assessed by a psychiatrist using PIRS and stays separate from physical WPI.
Modified Clinical Dementia Rating for brain injury
Table 6.9 considers memory, orientation, judgment and problem-solving, community affairs, home and hobbies, and personal care. Table 6.10 then maps the supported overall CDR score to a WPI class. Clause 6.164 must be satisfied before this mental-status method is used.
| CDR score | Table 6.10 class | Class range |
|---|---|---|
| 0.5 | Class 1 | 1-14% WPI |
| 1.0 | Class 2 | 15-29% WPI |
| 2.0 | Class 3 | 30-49% WPI |
| 3.0 | Class 4 | 50-70% WPI |
The class is a range, not an automatic percentage. The medical assessor must select and explain the specific percentage from the complete clinical, psychometric and functional evidence.
What does not establish the result by itself?
- the word “mild” or “concussion” without acute records
- brain fog without objective clinical analysis
- a single screening test
- normal imaging used as proof of full recovery
- self-rating memory problems as a WPI percentage
Accident-specific examples
Brief amnesia followed by return to work difficulties
The initial mild classification and later work effect are different issues. The file should connect acute observations, specialist assessment and sustainable work function.
Cognitive symptoms with pre-existing ADHD
The relevant comparison is pre-accident function versus the post-accident change. A pre-existing condition does not automatically defeat causation, but it must be addressed.
Normal MRI with persistent dizziness and concentration problems
The symptoms require differential assessment. They may involve mTBI, vestibular, cervical or psychiatric factors; MRI alone does not resolve that question.
Claim file preparation
Evidence checklist
Assessment source
Mild TBI permanent impairment source
Assessment source: Motor Accident Guidelines v10.1 clauses 6.156-6.176, especially 6.160 and 6.164-6.170; AMA4 Chapter 4 as modified; section 1.6 of the Motor Accident Injuries Act 2017 for threshold injury.
Threshold injury: A supported accident-related brain injury may be non-threshold. Persistent symptoms without a medically established brain injury do not decide the classification.
What the assessor checks
- objective prerequisites in clause 6.164
- modified CDR tables
- psychometric evidence requirement
- separate psychiatric assessment
What does not establish the result by itself
- symptoms
- screening score
- imaging alone
- the mild TBI label
Official sources
Related NSW CTP guides
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Frequently asked questions
- Does “mild” mean the symptoms cannot be disabling?
- No. Mild describes the acute injury classification. Some people have persistent functional difficulty, which must be documented and assessed rather than assumed.
- Is neuropsychological testing always required?
- No. It may be useful where cognitive impairment is alleged, but the appropriate assessment depends on the clinical question and specialist advice.
- Can mTBI be diagnosed with a normal MRI?
- Yes, because mTBI is often a clinical diagnosis. The diagnosis still needs a supported mechanism, acute history and medical assessment.
- How is cognitive WPI calculated?
- It is not calculated from a symptom count. The assessor applies the modified CDR and other applicable Chapter 4 methods after the Part 6 evidence requirements are met.
- Can depression be combined with neurological WPI?
- Not to pass the greater-than-10% test. Psychiatric and physical impairment remain separate for that purpose.