Parkinson’s Disease Treatment

Parkinson's disease is the slow loss of the dopamine-producing cells in a small structure deep in the brain called the substantia nigra. By the time the first changes are noticeable, a large share of those cells has already gone, and the loss carries on quietly for years afterwards.

Medication replaces the missing dopamine and works well at the start. After some years the window of benefit from each dose narrows, and the day splits into stretches when the medicine is working and stretches when it is not. Adding doses shortens the gaps but brings involuntary movement of its own, so the two problems trade against each other.

Surgery does not slow the underlying loss of cells and does not treat the illness. What it does is steady that fluctuating day, by delivering continuous stimulation to the same circuits the drug acts on, so that a lower dose covers more hours.

The diagnosis is clinical. A neurologist makes it by examining you: how you rise from a chair, how you walk and turn, how your handwriting has changed, and how one side compares with the other. A DaTscan can support an uncertain examination, though a normal scan is more useful for ruling the diagnosis out than an abnormal one is for confirming it.

The assessment before an operation asks a different question. It measures how much of what you have left still responds to levodopa, because that response is the best available predictor of the response to stimulation. You are examined formally after a night off medication and again after a dose, and the two scores compared.

An MRI, a cognitive assessment and a psychiatric review complete it. Significant memory impairment or untreated depression changes what an operation is worth, and both are looked for deliberately.

You spend a few days in hospital and go home with the system switched off. The first settings are dialled in a few weeks later, and finding the right combination of settings and medication takes several appointments across three to six months. Nothing about the first month is a fair test of the result.

There is usually a temporary improvement in the days after surgery, from the swelling around the electrodes, and it wears off. Expect that, so you do not read the fade as a failure.

The battery is checked at every visit. A non-rechargeable one is changed under a short anaesthetic every few years; a rechargeable one is topped up at home and lasts far longer.