4

Recently, a relative of mine has been diagnosed with Parkinson's Disease.

Doctors have prescribed him dopamine agonists. However, they mentionned that with time, those drugs may loose their efficacy and may lead to increased side effects.

By browsing the internet, I came across deep brain stimulation as promising therapy for PD patients. http://www.parkinson.org/understanding-parkinsons/treatment/surgery-treatment-options/Deep-Brain-Stimulation

My question is: considering that these dopamine agonists are associated with side effects and loose their effect over time, why isn't deep brain stimulation used in the first instance?

4

This is an interesting question. The role of deep brain stimulation in Parkinson's disease has increased in the last years.

Recently, de Souza et al adressed your concern and reviewed studies investigating the timing of DBS in PD. Here are their conclusion:

From the evidence available, we conclude that surgical management of PD alone or in combination with medical therapy results in greater improvement of motor symptoms and quality of life than medical treatment alone. There is evidence to support the use of DBS in less advanced PD and that it may be appropriate for earlier stages of the disease than for which it is currently used. The improving short and long-term safety profile of DBS makes early application a realistic possibility.

To your question regarding why DBS is not used as first line therapy: Well, while various studies have shown a significant reduction of dyskinesias, improvement of motor symptoms and significant improvement of quality of life when compared with best medical treatment, DBS is also associated with side effects (surgery related, device related and stimulus related).

Concerning stimulus related side effects (ie other structures than the targeted Subthalamic Nucleus or Globus Pallidus Interna get stimulated through the produced electric potential), you have to imagine, that the electrical field produced by DBS can propagate to other brain regions and may therefore lead to psychological symptoms or motor symptoms. Research on this field is ongoing but because "in vivo" testing can't be undertaken (it would not be unethical), bioengineers are creating "models" than enable to stimulate DBS electrical field distribution.

Overall, yes, DBS is promising and current debate suggests it should be used earlier. BUT our current understanding on how DBS works (on neuronal level) is still poor and further research is needed.

Sources (both are open access):

Groiss SJ, Wojtecki L, Südmeyer M, Schnitzler A. Deep Brain Stimulation in Parkinson’s Disease. Therapeutic Advances in Neurological Disorders. 2009;2(6):20-28. doi:10.1177/1756285609339382.

deSouza R-M, Moro E, Lang AE, Schapira AHV. Timing of Deep Brain Stimulation in Parkinson Disease: A Need for Reappraisal? Annals of Neurology. 2013;73(5):565-575. doi:10.1002/ana.23890.

| improve this answer | |
  • Thank you very much @M.Arrowsmith! Your answers are always very useful and clear, in particular for a layperson. I really appreciate that. Let's hope research will be progressing rapidly on this field... Cheers! – Richard Callahan Aug 27 '16 at 18:54

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.