|Globus Pallidus Region of Brain Targeted in DBS in Yellow|
The first post can be located here and was limited to the drug treatment of the motor symptoms of Parkinson's disease.
In part II, I want to focus on deep brain stimulation and the treatment of non-motor symptoms.
The authors of the review note the following key points regarding deep brain stimulation:
- Deep brain stimulation (DBS) therapy for Parkinson's disease is considered most effective when the anatomical target is a small area known as the subthalamic nucleus (STN)
- STN deep brain stimulation improves all the cardinal symptoms of Parkinson's disease
- However, compared to previous DBS targets, STN brings with it new short-term adverse effects including "postoperative dysphoria, hypomania and a higher risk of suicide"
- Adverse effects of STN-DBS appear greater in older patients making this intervention most effective when used in younger patients with severe motor symptoms
- An alternative to STN-DBS is surgery targeting the inferior globus pallidus--this target had been felt by some to be less effective than STN-DBS in treating motor symptoms
- However, globus pallidus DBS is regaining some advocates because it is easier to target and appears to cause less psychiatric and cognitive side effects than STN-DBS
- Globus pallidus DBS might be best used in older patients with non-motor symptom predominance
- Although DBS in Parkinson's disease is generally accepted due to clinical experience with thousands of subjects, there is still some debate on whether to use unilateral or bilateral approaches-the authors favor bilateral treatment
- DBS is typically reserved for patients with inadequate response to drug treatment
- Earlier use of DBS holds promise as a potential boost to quality of life
- A randomized trial of earlier use of DBS, the EARLYSTIM study will soon be published and will be important in providing guidance on the timing of DBS
- The decision to use DBS should be made by patients and their families after a comprehensive assessment from an interdisciplinary team of neurologists, neurosurgeons, psychiatrists, physical, occupational and speech therapists
Readers with more interest in DBS for Parkinson's disease may find a recent consensus manuscript on the topic that I have previously reviewed here.
The current review also includes a detailed discussion of the treatment of non-motor symptoms including sleep disorders (insomnia, REM sleep behavior disorder and restless leg syndrome), excessive daytime sleepiness, autonomic dysfunction (orthostatic hypotension, gastrointestional motility dysfucntion, and urinary dysfunction), erectile dysfunction, impulse control disorders, medication-induced psychosis, dementia and depression.
It outside the scope of this post to review the author's recommendations for management of all of the non-motor symptoms of Parkinson's disease. I did find interesting the author's recommendation for use of low-dose clozapine 12.5 mg to 50 mg or quetiapine 25 to 75 mg at bedtime for the management of psychosis. They also noted donepezil at 5 to 10 mg per day may improve psychosis in patients with Lewy body dementia.
Additionally, the review highlighted the use of pramipexole 0.35 to 0.7 mg three times daily for the treatment of depression in Parkinson's disease with lower evidence of the effectiveness for standard tricyclic antidepressants or selective serotonin reuptake inhibitors.
Readers with more interest in specific non-motor symptom treatment in Parkinson's disease are directed to the free full text manuscript that can be access by clicking on the reference below.
Image of globus pallidus is an iPad screen shot from the app Brain Tutor.Pedrosa, D., & Timmermann, . (2013). Review: management of Parkinson's disease Neuropsychiatric Disease and Treatment DOI: 10.2147/NDT.S32302