The man with the battery-operated brain
14 December 2020
Early-onset Parkinson’s disease gripped every aspect of Andrew Johnson’s life until implanted electrodes, a neurostimulator and minute conductive wires from Sandvik helped him regain control.
Johnson’s tremors became more noticeable when he tried to feed his infant son. After a year of doctor’s appointments, Johnson was diagnosed with early onset idiopathic Parkinson’s disease. Aging is the greatest risk factor for Parkinson's – the average age at diagnosis is 60.
While typically associated with trembling, Parkinson’s can affect the entire body, including cognitive skills, motor function, vision and muscle behaviour. Once a senior lawyer at one of New Zealand’s “Big Four” banks, the cognitive challenges of Johnson’s condition made his career impossible. “When taking notes, my handwriting would be too small to decipher. I learned this change was micrographia, one of many secondary motor symptoms of Parkinson’s. I was terrified of making any reputation-destroying errors, so I resigned,” said Johnson.
As the disease progressed, Johnson struggled to find a treatment that would allow him to live comfortably. At times, he would be rigid and stuck, unable to move. Other times, he would be flailing wildly, suffering from involuntary movements known as dyskinesia. “What hurt most was being unable to be the kind of husband and father I wanted to be, due to the limitations imposed by this ever-changing disease,” said Johnson. “I struggled for a long time with the loss of my identity.”
Approximately two years after his diagnosis, Johnson’s neurologist raised the possibility of deep brain stimulation (DBS) surgery. Usually offered at least ten years after diagnosis, recent research indicates that having DBS earlier may prolong the longevity and efficacy of treatment in early onset Parkinson’s. Johnson was approved for the surgery in 2012.
During DBS surgery, surgeons precisely place electrodes into the brain site carrying the abnormal signals that produce the patient’s symptoms, using a thin probe called a lead. A wire attached to the lead runs through the body, where it connects to a battery-operated neurostimulator. The system, often called a brain pacemaker, regulates the abnormal signals that the patient’s disease causes.
To achieve the required precision, the wire that connects the electrodes to the neurostimulator is just 0.1 millimetre thick. Sandvik created it as part of the EXERA fine medical wire range.
“A DBS device typically uses multiple wires in a very small space”, explains Gary Davies, Manager at Exera, Sandvik Materials Technology’s business unit for medical wire manufacturing. “The wires usually have a dielectric coating, so they don’t short circuit each other and disrupt the signal that is being sent to the nerve. This has to be done in a precise and reliable way, as we don’t want to introduce stimulation in places or in ways it isn’t required.”
Now a father to two teenagers, Johnson spends much of his time chauffeuring them in between activities and taking on the role of stay-at-home parent. He’s read 86 books so far in 2020 – an important activity for keeping his brain active.
“There are so many things I can do now that would have been impossible before the surgery. I can read without my head or hands shaking so much that everything blurred, and I can participate fully in family life – no longer reduced to being a spectator,” he said.
The EXERA fine medical wire from Sandvik is used across a wide range of medical applications, including modern neurostimulation devices such as those used in deep brain stimulation surgery. To learn more about the wire’s stimulation applications, visit the Sandvik website.
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