An on-and-off switch for the brain being pioneered by Australian neuroscientists is giving hope to stroke and Parkinson's disease sufferers with speech problems.

A technique known as transcranial magnetic stimulation, which has previously been used to treat depression, has produced encouraging results in trials conducted by the University of Queensland.

A coil shaped like a figure-eight is held over a patient's head to try to switch on a part of the brain in Parkinson's sufferers and switch off a different part in stroke victims.

"The actual technology was developed back in the mid-80s but it sort of sat around for a while," Professor Bruce Murdoch told AAP ahead of Speech Pathology Australia's national conference in Hobart.


"Now it's starting to come to the fore and people are starting to recognise that the brain is much more plastic... it can heal itself much better than we ever thought it could.

"This seems to be a way of helping the brain to sort of rewire itself."

The trial has produced improvements over 12 months in long-term patients with both conditions who have already been through traditional therapies.

Parkinson's sufferers, 85 per cent of whom experience speech or language difficulties, are improving their articulation and speech intelligibility.

Stroke patients, who suffer a condition called aphasia, are finding they can recall the names of things more quickly and accurately. Aphasia is condition where sufferers can have impaired language ability including difficulty remembering words.

"The main effect's starting to show up after about a week to two months and then it's persisted up to 12 months post-stimulation," Professor Murdoch said.

"That's a bit of a breakthrough. We've never really had that sort of effect with any other treatment before."

The jury is still out on why the technique works, but studies in animals have shown it can increase the branching of some neurones in their brains.


In medical terms the equipment comes cheap at around $50,000 and it is already making a difference to the lives of patients in the trial.

"They're suddenly now seeing improvement after all these years ... it's given them a new life in a way," Professor Murdoch said.