Deep brain stimulation: egg in a Parkinsonian brew

Having bored myself into dribbling obscurity with my bloody tedious dissection of Argo (why did I bother writing that, I will never know), I decided to mention a few things in my upcoming posts that have been bugging me for a while – mostly to do with the infallibility of authority, the unavoidable fingers that big business has in government pies, and my embarrassment by the fact that noone in science seems to be able to do basic statistics – to which I will uninspiringly don the mantle of ‘Sciencewipe’.

Sorry, Charlie Brooker. I have hijacked your franchise, but it’s only because I have no wit of my own.

I am writing for the European Brain Council (EBC) at the moment (check me out, namechecking my abstruse beaurocratic pals. The EBC do fantastic work by the way in reducing the stigma of brain disorders, and campaigning for more research to deal with what is one of the biggest health problems we face as a world today.) As part of this work, I have just interviewed the lead author of the EarlyStim clinical trial, results of which were recently published in the New England Journal of Medicine (NEJM). This study looked at Parkinson’s disease (PD) patients, comparing a group of 120ish that underwent deep brain stimulation (DBS) along with the usual PD medication, with a group of 120ish that took only meds. The findings were pretty nicely stacked in favour of the DBS group.

The DBS procedure, incidentally, is a wonder of modern neurosurgery. Ploughing (poor choice of words given that I’ve just had my lunch) what is effectively a pacemaker into the subthalamic nuclei of the brain, an electrical impulse is delivered via a device that is attached to the chest. It is unclear exactly how DBS works to improve symptoms in various conditions (anorexia, depression, OCD, etc), however I am sure a cursory google search will reveal some headless Daily Mail hack declaring the revival of electroshock therapy. I won’t do them the service of linking to such an article. We all know it’s out there.

The much acclaimed NEJM study was impeccably carried out and followed up, based upon a pilot that was carried out ten years ago (those ten-year-old DBS cases now being under further follow-up to look at longer term effects of the procedure). As such a sensational study might, it was given a sensuous rub-down in the NEJM editorial by research spanner, Caroline Tanner, Director of Clinical Research at the Parkinson’s Institute.

Tanner, an insightful and informed therapist no doubt, nonetheless made the worrying claim that suicides were increased in the DBS group of patients. She failed, however, to stipulate that the rates of suicides in the DBS versus the meds-only group were 2 and 1 respectively. This may be statistically significant on paper (I am not sure, I haven’t checked; it is irrelevant), but it is far-removed from the the bleeding obvious, which is that you cannot compare such small numbers and hope to make anything resembling a sound conclusion.

This is revealing in several ways.

First, it tells me that even big cheeses like Tanner are yet to learn about the foundations of statistics.

Second, it is an irresponsible claim to make, and something that can have disastrous consequences given the bloodthirsty state of the media, whose lazy science journalists, somehow having made it onto the science column at Forbes, will willingly regurgitate anything an ‘expert’ says without looking into it for themselves – all the while posing as bespectacled clever cloggses.

Third, it is symptomatic of science today that we cannot acknowledge, as canny lead author Michael Schupbach was able to, that we do not have enough longitudinal data to decide conclusively whether DBS per se is associated with a higher risk of suicide. The fact is that DBS is a highly invasive procedure that is, to put it lightly, not without its risks. Therefore, the patients that undergo the procedure must be suffering from clinical symptoms that pose a morbidity or quality of life risk that is comparable, or higher, than that of the procedure. Such a procedure would not be justifiable under any other circumstances. The fact that DBS patients are associated with a high risk of suicide relative to the general population is perhaps due to the underlying medical condition, and not to DBS itself.

Unfortunately, conditions such as Parkinson’s often come with a hefty bout of depression, as Michael J Fox candidly shared in his C-SPAN appearance several years ago. This is the story of many patients, but not all. PD patients are presently only considered for DBS as a ‘last ditch’ treatment effort, when medication is only effective for short spans of time, when secondary symptoms diminish the benefits of the treatment, and when patients are so old that they may not be in good enough general health to undergo it anyway. Happily, the EarlyStim study is justification for the safe and beneficial use of earlier intervention with DBS than it is at present, with the bonus of extending the active family and work lives of many young PD suffers.

This post has a terrible title. I’m sorry. Please send me something better on a postcard, as someone funny might say.

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2 thoughts on “Deep brain stimulation: egg in a Parkinsonian brew

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