Introduction: Acute neurological rehabilitation aims to reduce the burden of care of patients with traumatic brain injury (TBI) and increase their activity participation. Tracking change throughout the rehabilitation is essential for funders of the service as well as the patient. Valid, reliable and responsive outcome measures are thus needed for accurate measurement of change. This study compared the responsiveness to change of the Functional Independence Measure™+ Functional Assessment Measure (FIM™+FAM) with the Activity Participation Outcomes Measure (APOM). This was administered TBI patients in the acute neurological rehabilitation phase in a private health care facility in South Africa. Method: A quantitative, prospective, longitudinal cohort design was used. A sample of 24 in-patients over 12 months was scored weekly on both outcome measures. The responsiveness between the APOM and FIM™+FAM was tested using the dependent t-test for paired samples and the effect size from admission to discharge was calculated with the standardised response mean. Results: Both measures were responsive to change and tracked improvement in activity participation (APOM) and reduction of burden of care (FIM™+FAM). No significant statistical difference was found between the responsiveness of the two measures however positive changes were reported in each individual patient. Conclusion: Although both measures are responsive to track change in TBI patients, the APOM includes more specific items that occupational therapists address in rehabilitation. The lack of a measure of physical components in the APOM makes it a difficult to be the only one to use in an environment where there is a high physical burden of care in patients. However, the APOM could be used in conjunction with other impairment-based scales that target physical components. It is recommended that more occupational therapists use the APOM with TBI populations.