Brainwave to let Parkinson's patients sleep through surgery
Melbourne scientists have discovered a unique brain signal that will act as a homing device, making deep brain stimulation surgery for Parkinson’s disease and other conditions more accurate and less confronting for the patient.
Deep brain stimulation has transformed the lives of people with Parkinson’s disease by reducing their tremors and other symptoms. Surgeons insert electrodes to stimulate a tiny part of the brain—the size of a grain of rice. To get the best results the patient has to be awake. And that’s scary for many patients. Now they can sleep through the surgery.
Bionics Institute clinicians and researchers have recorded and studied the brainwaves of 19 patients during surgery—14 with Parkinson’s disease and five with a condition called essential tremor. They discovered that the part that they’re targeting produces a unique brain signal that can be used to guide the surgeon.
This discovery will enable the surgery to be performed without the need for the patient to be awake.
The findings have been published today in the journal Annals of Neurology.
“Deep brain stimulation can dramatically improve the quality of life for people living with Parkinson’s disease as it alleviates its three major debilitating symptoms: tremors, stiffness and slowed movement,” says Hugh McDermott, one of the study’s authors and an expert on medical bionics and implanted devices.
Implanting the electrodes accurately is challenging. Missing the target region by a millimetre can cause side effects and reduce the effectiveness of the treatment.
Wesley Thevathasan, a clinician involved in the study, expects this brain signal will allow surgical teams to improve the accuracy of electrode implantation, and perform the operation more quickly and efficiently.
“I have many patients who could benefit greatly from deep brain stimulation but are dissuaded by the thought of being awake during the operation,” he explains. “The prospect of being able to have the procedure whilst asleep and having a specific homing signal to improve the accuracy of electrode placement is vitally important.”
One of Wesley’s patients, Grant Rowe, who was diagnosed with Parkinson’s disease ten years ago, says he values research that helps people live well with Parkinson’s disease while the search for a cure continues.
“It’s a surreal experience being awake for surgery, cracking jokes with your doctor while he’s digging around in your head. But I can now tell my friends that my own brainwaves are advancing science,” he says.
“It’s made such a difference to my daily life—I’m human again. I can put sugar in my cup of tea without spilling it, and my mum says she can now hug me without it feeling like she’s hugging a statue.”
The researchers believe they will be able to take their discovery further and create a device that will detect changes in the brain signal and adjust the treatment in real time, responding to the patient’s current condition and the severity of their symptoms.
Parkinson’s disease and essential tremor
Parkinson’s disease is a degenerative brain disorder that affects a person’s control of their body movements. The symptoms include tremors or shaking, muscle stiffness or rigidity, slower movement, stooped posture, and balance problems. Parkinson’s disease can also cause pain, depression, and problems with memory and sleep.
An estimated 80,000 Australians are living with Parkinson’s disease. The average age of diagnosis is 65 years, however young people can also develop the condition. 20 per cent of people living with Parkinson’s disease are of working age.
Parkinson’s disease occurs when nerves in the middle of the brain progressively degenerate, leading to a lack of the chemical messenger dopamine, which is involved in controlling muscle movement.
There is currently no cure for Parkinson’s disease, but there is enormous potential to manage and relieve the symptoms so that people can still enjoy a good quality of life. Management and treatment includes a combination of a healthy diet and exercise program, medicines to increase or replace dopamine, and brain surgery to insert a medical device for deep brain stimulation.
Essential tremor is a nerve disorder that causes uncontrollable shaking or tremors. A person’s head, hands and voice are most commonly affected, and tremors are exacerbated by activity or movement. It can develop at any age but is most common in people aged 40 years and older.
Essential tremor is a different condition to Parkinson’s disease. The cause of it is unknown but genetics is a likely factor.
Deep brain stimulation: a pacemaker for the brain
Deep brain stimulation is a treatment for brain disorders that involves the surgical implantation of a medical device that sends electrical impulses to specific places in the brain that control particular functions. Depending on the condition being treated and the area targeted, it can bring about pain relief, lessen tremors, and help with some mental health conditions.
Deep brain stimulation has been used to treat people with advanced Parkinson’s disease and essential tremor for more than 15 years. Surgery to implant the device has typically required patients to be awake and alert for the operation, so that the higher level of brain activity can help guide surgeons to the target region of the brain.
The study was supported by the Colonial Foundation, St Vincent’s Hospital Research Endowment Fund, the National Health and Medical Research Council, and the Victorian Government Operational Infrastructure Support Program. The patients were studied at St Vincent’s Hospital Melbourne and the Austin Hospital.
Reference: “Subthalamic nucleus deep brain stimulation evokes resonant neural activity”, Journal, Annals of Neurology, Volume 83, Issue 4, April 2018, https://doi.org/10.1002/ana.25234.
6 May 2018.