This research is a randomised controlled study. The study hypothesis is cognitive rehabilitation for attention deficits following mild traumatic brain injury will improve patient's cognitive outcome, measured by neuropsychological and neuroimaging parameters. Participant recruitment is from University Malaya Medical Centre, Malaysia. All mild traumatic brain injury participants have to fulfil the study inclusion criteria and written consented for therapy. Control group receives existing patient-centred cognitive treatment whereas intervention group receives individualised structured cognitive rehabilitation therapy. The intervention begins at three months post injury and ends at six months post injury. Study outcome measurements are applied at pre and post treatment. This study was ethically approved by Medical Research Ethics Committee University Malaya Medical Centre (MREC ID NO: 2016928-4293).

General study objective: to measure the effect of cognitive rehabilitation program for attention deficit applied in mild traumatic brain injury patients.

Specific objectives:

1. To measure the effect of a 12-week cognitive rehabilitation therapy for attention deficits in mild traumatic brain injury patients using neuropsychological and functional assessments.
2. To examine the correlation between neurocognitive deficits and structural brain changes at baseline and at six months post injury.

Study type and location: An interventional study conducted in University Malaya Medical Centre (UMMC), Malaysia.

Participants: Patients diagnosed with mild traumatic brain injury at Accident & Emergency Department in UMMC.

Outcome measures:

1. Neuropsychological Assessment Battery-Screening test
2. Diffusion Tensor Imaging parameters
3. Goal Attainment Scaling

Ethics approval: approved MREC ID NO: 2016928-4293

Consent: informed written consent will be obtained from all participants of research.

Estimated sample size:

Based on medium effect size Cohen's d = 0.35 Investigators used G*Power Version 3.1.9.2 for sample size calculation. Sample size calculated: 60 Estimating drop out rate of 40%=24. Therefore sample size target n= 84 mTBI patients.

Study design:

A two arm randomised controlled trial:

1. Mild traumatic brain injury control group, and
2. Mild traumatic brain injury intervention group.

The study protocol is divided into 3 segments:

1. Neurocognitive evaluation protocol:

   Investigators will perform Neuropsychological Assessment Battery-Screening test on both groups at three months and at six months following brain injury.

2. Imaging protocol:

   Investigators perform Diffusion Tensor Imaging for both groups at three months and at six months following brain injury.

3. Cognitive rehabilitation therapy protocol:

The focus is on attention deficits. Each study arm will receive different treatment approaches.

Mild traumatic brain injury control group will receive a patient-centred cognitive therapy. This is an application of existing cognitive rehabilitation treatment available at UMMC, which include therapy session on symptoms management and coping strategies. This is performed and monitored by a cognitive therapy trained Occupational Therapist. Clinical and treatment review are provided as part of routine outpatient rehabilitation clinic review.

Mild traumatic brain injury intervention group will receive individualised structured cognitive rehabilitation therapy that consist of:

1. Direct attention training:

   A deficit-oriented evidence-based treatment approach. The therapy for attention is computer-based and is divided into focused attention, selective attention, divided attention and sustained attention. Each treatment session is conducted by a trained Occupational Therapist in cognitive therapy and a rehabilitation medicine physician.

2. Strategic approach (metacognitive):

This involves generalisation of tasks to everyday functional skills. This approach is applied after each direct attention training session. This approach include review of individualised goals, review of cognitive related problem(s) encountered in participants daily activities since injury and problem-solving training. This is also performed by similar trained Occupational Therapist and reviewed by a rehabilitation medicine physician.

Randomisation sampling: Investigators apply simple randomisation in selection of mild traumatic brain injury control and intervention group participants.

Inclusion Criteria:

• Mild traumatic brain injury as a result of motor vehicle accidents only.
• No previous history of head trauma.
• Education level of a minimum of 9 years (required for neuropsychological test).
• Normal Computed Tomography (CT) brain scan finding.
• Able to comply with cognitive rehabilitation therapy.
• No pre-existing chronic illness that can cause neurological complications, neurological diseases or psychiatric condition.
• Not on any regular medication that may alter or effect cognitive and psychological status.

Exclusion Criteria:

• Normal neuropsychological assessment test result at 3 months post injury (planned test time) for both study groups.
• Clinical evidence of alcohol influence at time of injury.
• Non Malaysian citizens
• Major polytrauma including long bone fractures, intra-abdominal injuries and chest injuries that require surgical and/or metal insertion.

Participants are randomised on treatment arm. Co-investigators are blinded from knowing which participant receives which treatment arm.

Cognitive outcome assessor is blinded from knowing which participant receives which treatment arm.