November 13, 2014

New Questions about Deep Brain Stimulation for Parkinson’s

Deep brain stimulation (DBS) has become a standard treatment for people with Parkinsons (PWPs) who experience dyskenesia (uncontrolled trashing about) and have trouble with precipitous off-times, when their levodopa – the standard medication for PWPs – suddenly wears off.

As reported in the November 4 edition of the Parkinson's Disease Foundation, a recent clinical study from the University of Toronto takes a new look at the procedure and reaches some new conclusions, too – especially concerning which PWPs should think about undergoing DBS… and when.

Not long ago, another study considered PWPs who were still within three years of the first mild symptoms of motor complications. Researchers administered DBS on half of those subjects. The other half – also PWPs with the same early manifestations of the disease – did not have the surgery.

The results seemed compelling: after two years, subjects who had undergone DBS were showing movement improvements. Their counterparts in the second group were not.

However, the most recent study from Toronto  -- while not disputing the results of the earlier results on PWPs with recent, mild symptoms – concludes that the most important consideration in the decision to undergo DBS is WHO, and not WHEN. Earlier is not necessarily better.

Risk and Benefit Assessment
When IS the time for DBS? Only when the needs and expected benefits clearly outweigh the risks for PWPs who have received objective, comprehensive information about their own individual situation… according to study leader DR. Anthony E. Lang. M.D.

And what are those risks?

For some DBS patients, certain PD symptoms – like unusual speech – have gotten worse after surgery. Others have gone through lengthy and frustrating delays as the complex electrical process is fine-tuned.

In addition, there are troubling, still-unanswered questions about DBS patients who underwent the surgery soon after symptoms emerged. Since many of them will presumably live a long time with the implanted device, how will they fare over the long haul?

Lang and his team also suggest that there are new therapies in development – there always are – that might bring benefits similar to those after DBS, but with fewer risks.

The Considerations
In drawing their conclusions, the researchers kept these considerations in mind:
  • A diagnosis of PD is difficult to make, especially early in the course of disease. There is a risk that individuals may have an atypical parkinsonism that does not respond to DBS, rather than true PD.
  • People with the mild symptoms of early-stage PD receive a lesser benefit from DBS than those with more severe, later-stage symptoms, even though the risks of surgery are the same.
  • Motor complications can remain stable for years — it is impossible to predict, but a person could undergo early DBS, and be subject to its risks, even though their symptoms may not have changed much without the treatment.
  • DBS does not help all PD symptoms, such as cognitive issues, some of which take time to develop. By waiting until later in the course of PD to do DBS, doctors can better predict who will benefit from it.
  • Not all treatment centers have the teams of experts needed to safely follow-up with younger people, who have a greater risk of suicide after DBS.
  • Having DBS at a younger age means that people will live longer with the implants, increasing the chance of a malfunction, and making them subject to the risks of additional surgery.
  • In economic terms, the benefits of early DBS vary by individual – for some, early DBS reduces later health care costs, for others it may not.
  • The placebo effect may have exaggerated the benefits of early DBS. Participants knew they were getting the implants. A high expectation that DBS would help may have contributed to improvement in their symptoms.
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I've written often about this topic. To see earlier posts, just enter DBS in the search bar above.

1 comment:

Michael G Hagan said...

NeuroDerm's subcutaneous pump patch going into phase III may eventually replace DBS and LCIG surgical procedures. The patch is not surgery.