Professor Winston Byblow, principal investigator of the study published in medical journal Brain this week, said: "Until now it has only been possible to group patients together according to their broad similarity to others who have already gone through upper limb rehabilitation, but this information cannot inform an individual patient's rehabilitation plan.
"We have developed the first clinical algorithm to actually predict the individual patient's potential for recovery based on information gathered before rehabilitation begins."
It began with a bedside test within three days of a stroke, said Dr Cathy Stinear, lead author of the Health Research Council of New Zealand-funded study.
The test took only a few minutes and required no special equipment.
"This is sufficient to provide a prediction for many patients, but for others an additional test is required to measure the integrity of neural pathways from the brain to the arm," Dr Stinear said.
"If this test gives no definitive result, an MRI assessment can be performed to better determine whether the pathways in the stroke-damaged side of the brain remain viable."
The research team have trialled the process in patients and followed their recovery.
"When the tests are combined in our stepwise algorithm they accurately predict each patient's recovery at 12 weeks, which is around the time that therapy normally ends," said Dr Stinear.
Neurologist Professor Alan Barber, a member of the research team and head of the Auckland Hospital Stroke Service, said the findings were very significant.
"This is the first study to predict an individual's potential for motor recovery using measures obtained from that patient in the initial days after stroke. This information can be used to tailor rehabilitation before it begins."
The team is now involved in a three-year trial of the algorithm at the hospital.
The results will show whether the algorithm leads to improved outcomes for patients and increases the efficiency of rehabilitation services.