Inserting a "brain pacemaker" deep inside the skull can transform the lives of people with advanced Parkinson's disease and reduce their dependence on powerful drugs.

The once revolutionary surgery has been shown to be more effective than drug treatment alone and should be offered to all those who could benefit from it, the charity Parkinson's UK said yesterday.

Research showed that patients fitted with a neurostimulator – a device similar to a heart pacemaker which stimulates some areas of the brain and blocks abnormal nerve signals – were more likely to improve than those who were given the most appropriate drugs available.

A year after surgery, participants' motor functions had improved, their symptoms had lessened and they needed about a third less medication to control their condition than those who did not have the implant fitted. The trial involving 366 patients, half of whom were offered surgery, is the largest yet conducted, according to a a report in the latest edition of the medical journal The Lancet Neurology.

Kieran Breen, the director of research at Parkinson's UK, said further analysis would assess how the £30,000 cost of the operation and any follow-up treatment compared with the reduced costs of drugs. "The amount you save in medication pays for itself in two to three years," he said. "If somebody is eligible for surgery they should be given surgery. For us that is the bottom line."

The charity said brain surgery was risky and would never become routine. One patient died while having the new implant fitted and 5 per cent suffered severe complications such as infections. But surgery could be an effective treatment for one in 20 Parkinson's sufferers, in particular those whose symptoms are no longer adequately controlled by medication or who have particular, unwanted side-effects.