A new set of tests can help predict whether an individual patient will recover the use of their hand and arm after a stroke, report New Zealand researchers.
"This is the first demonstration that there is a combination of techniques that can be used to predict an individual patient's chance of recovery," Byblow tells the Australian Broadcasting Corporation.
"Knowing the difference between who will make some recovery and who will make none is information that the therapists have been asking for a long time."
After a stroke interrupts blood supply to the brain, many people are left unable to use their hand and arm properly, with some limbs being completely paralysed. But, says Byblow, it is very difficult to predict how well an individual will recover with the help of therapy, and who has been damaged beyond the point of no return.
"The very challenging part is you can examine two patients within days of their stroke and they can look exactly the same, but one will make a perfect recovery and one will make no recovery," he says.
"You can imagine the challenge that the therapist who is going to be working with that person is facing because they really don't know what to expect."
Building on research published in 2007, Byblow and colleagues have now developed a set of tests that can be used to predict the potential for recovery of a person who has just suffered a stroke, before they start rehabilitation.
Patients are first scored on how well they are able to perform a number of clinical tasks, such a reaching forward and grasping a glass of water. If their score is high, they are regarded as having a high potential for recovery.
'We think it will make a big difference in terms of people's satisfaction with their outcome because they'll have realistic expectations.' — Winston Byblow
A low score leads to a second test, which involves magnetic stimulation of the motor cortex to see if the nerves in the part of the brain that control the limbs are still working.
"If we see a twitch in the hand or the arm, that shows that those pathways are still functioning," says Byblow. "You would never know that just by looking at them."
A high score on this test means they have good potential for recovery. A low score leads to a third test, which involves using MRI to image the neural pathways and see how badly damaged they are.
The researchers have identified a cut-off point for degradation of the nerves that can determine if a particular individual, who has just suffered a stroke, has any chance of recovery at all.
In a trial of 40 stroke patients, the researchers found the set of tests could accurately predict recovery in the vast majority of patients, with a few doing better than expected. They are now carrying out a three-year trial.
Byblow says the aim is to maximize the extent of recovery for each individual patient, based on their own potential.
For example, if a person has no potential for recovering arm and hand movement, then a therapist could put more effort into rehabilitation of the ability to walk and talk.
"We think it will make a big difference in terms of people's satisfaction with their outcome because they'll have realistic expectations," says Byblow.
"It might also lead to better outcomes in terms of the level of function they achieve simply because they've been working on the right things from the word go."
Rehabilitation researcher Professor Leeanne Carey of the stroke division of the Florey Neuroscience Institutes in Melbourne welcomes the research as an "important contribution".
"Knowledge of an individual's potential for recovery is critical to targeting stroke treatment to the individual and achieving the most optimal outcomes," she says.
"Individuals may require different rehabilitation strategies depending not only on parts of the brain affected by the stroke, but also remaining networks that may be accessed in therapy. Knowledge of viable brain networks helps provide this information for individualised stroke rehabilitation."
Professor Peter Schofield of Neuroscience Research Australia in Sydney also welcomes the research. "Knowing who will best respond to treatment and rehab is important for getting the best outcome for each patient," he says.