DBS Diary 01: How I reached this point…

Okay, let’s start at the beginning. I have young onset Parkinson’s disease and was diagnosed with same 15 years ago, in late 2006. My symptoms, viewed with the benefit of hindsight, probably started a while earlier and rumbled along unnoticed for a couple of years.

Parkinson’s is notoriously unpredictable with some patients progressing very rapidly, others more slowly. On the whole I have not done too badly (touch wood). My neurologist is generally happy with me. My progression has been relatively slow compared with others I know who have deteriorated much more rapidly.

The drugs have helped, no doubt about that. But there comes a point when, almost unnoticed, they cease to have quite the same effect. It becomes difficult to obtain therapeutic benefit without almost equally disabling side-effects. Indeed some people with Parkinson’s find the dyskinesias worse than the tremor. And as one progresses with the condition, it becomes difficult to achieve a reduction in stiffness and tremor without experiencing dyskinesias. It’s a high price to pay and, eventually one begins to focus on alternatives.

I’ve been fortunate – I have been taking levodopa (the principal culprit when it comes to dyskinesias) for nearly 10 years now and have mostly been free of dyskinesias. This is relatively unusual. Most people experience the onset of dyskinesias after only five years of levodopa, give or take a little bit. Nonetheless, and despite the relative absence of dyskinesias, I do find that the medicines are less effective. Each tablet provides a little less benefit and does not seem to last as long. In essence, the drug wears off too quickly. This part at least is typical.

Recognising this watershed in my management of the condition, I have begun to look at alternative or adjunctive treatments. Many who experience such wearing off episodes resort to apomorphine to fill in the gap so to speak until the next dose of levodopa. This is unattractive to me for a number of reasons. Apomorphine is generally administered via a syringe into the belly fat. Don’t get me wrong, I have plenty of belly fat into which to inject. My principal objection, leaving aside my dislike of needles generally, is the practical difficulty of making such an injection while experiencing involuntary movements. And yes, there are other solutions to that such as pumps. But these are cumbersome and, to my way of thinking, equally unattractive. In any case, let’s not forget that apomorphine was initially used and marketed as an emetic agent at a time when drug overdoses were common. And I’m not sure I consider that to be the ideal pharmacological pedigree for use in a condition like Parkinson’s.

There are course other drugs available which can be added to one’s smorgasbord of medication specifically to reduce dyskinesias. And for the most part they’re reasonably effective. But I can’t get away from the feeling that the general concept of adding one drug to treat the side-effects of another is somehow conceptually flawed. Okay it works but where will it end? If drug A causes side effects and drug B reduces the side-effects of drug A, how long before we need drug C to treat the side-effects of drug B? On the whole it seems to me a better strategy to try and keep the total drug payload to a minimum.

Until a decade or so ago these were more or less the entirety of your options. More drugs. More frequent drugs. Additional drugs. Higher doses of drugs. Not a desperately attractive proposition. But fortunately not the only avenue of treatment.

Over the last 10 to 20 years, as the circuitry of the basal ganglia has been more thoroughly elucidated, the focus has shifted away from the pharmacopoeia to the operating theatre. Neurosurgery is becoming (or has become, depending on your perspective) a viable alternative to the usual pharmacological rampage.

Deep Brain Stimulation, or DBS as it is more commonly written has moved from experimental technique via niche treatment to its current status as part of the treatment armametarium in Parkinson’s.

Fundamentally the procedure is simple. Electrodes are inserted into specific areas of the brain, fixed in place and connected via wires to a stimulator/battery pack implanted at the shoulder. A remote-controlled device allows one to program the stimulator and an induction collar charges the battery pack once a week.

Although at first sight rather complex and intimidating, the circuitry of the basal ganglia is now well-established. I’ll go into the wiring of the basal ganglia later in another post but rest assured that the various relay stations and points of intervention are well known. Two electrode implantation sites have proven popular – the internal globus pallidus and the subthalamic nucleus. There is not much to pick between the two implantation sites – both achieve similar effects on tremor, bradykinesia and rigidity after 12 months. STN stimulations appear better after six months. But overall there is little difference and presumably choice of location reflects no more than the preference of individual neurosurgeons.

But what does DBS do? In simple terms it replaces the levodopa or a proportion of it. And less levodopa means less dyskinesias and other side-effects. In essence, it turns back the clock. Many who have had DBS talk about going back five years in terms of symptomatology. Personally I’m a little wary of using those kinds of descriptors. DBS is still only symptomatic treatment. It does not slow or delay the process of neurodegeneration. It merely masks the underlying pathology. You are still losing brain cells at the same rate with or without DBS. But at least the journey should be more pleasant for longer.

Around 18 months ago, I had a good discussion with my neurologist and asked to be considered for DBS. Needless to say, volunteering is the easy bit. Not everybody is suitable for DBS and, like the labours of Hercules, there are many tests to pass. Okay I don’t have to clean the Augean stables or capture Cerberus but, in their own way, the pre-DBS trials are just as challenging. These involve a pretty detailed assessment of motor function All the usual stuff – finger to finger taps, touching one’s nose, repetitive stamping and clenching fists. Basically the behavioural repertoire of the average young toddler. Then there is an assessment of language and psychometric tests (is this a smiling or a frowning face?) Before the dreaded L-dopa challenge. For some reason this makes me think of the ice bucket challenge so popular a couple of years ago. But it’s nothing of the sort. In essence is a series of simple motor tests but with one uniquely horrible twist – the tests have to be completed without medication. Gruesome. Then you get your levodopa and, three-quarter of an hour later, you repeat the tests.

If all goes well and you pass with flying colours, you move onto the next stage – meeting the neurosurgical team. This includes neurosurgeons, neurologists, Parkinson’s nurses and so on. A multidisciplinary team designed to check you over once again and make a final go/no-go decision.

That should have been around August 2020 but, as you’ll recall, we had the tiny little matter of a global viral pandemic to occupy our minds and empty our operating theatres. My own choice of hospital ceased nearly all nonemergency neurosurgery for more than a year as, like many other hospitals, they struggled to maintain any kind of functionality.

So I’ve had a lot of time to think about this and whether it’s right for me. Certainly my symptoms would seem to justify DBS and the surgery is relatively routine. Bad or disastrous outcomes are relatively infrequent and, when all comorbidities are taken into account, the procedure is straightforward. But, balanced against that, it is still a throw of the dice, a leap into the unknown. I reassure myself with the thought that many have gone ahead of me and, on the whole, had good outcomes. Needless to say, being of an anxious mien, I still fret over possibilities.

I just hope that, having steeled myself to have DBS, the surgical team agrees with me on suitability. That meeting is next week. I’ll be in touch again. Bye for now. Let me know your thoughts.

DBS Diary 02: Rolling the dice.