A study into people suffering from a traumatic brain injury aims to find out why Maori and Pacific Islanders are most affected.
A traumatic brain injury can be caused by a car crash, by playing sport or after an assault or fall.
About 24,000 people, mostly Maori and Pacific Islanders, have the injury.
The 12-month survey of 1000 people will be conducted by researchers from the University of Waikato and Auckland University of Technology, beginning next month.
It also plans to look at how to improve services for sufferers.