Two studies have looked into the long-term effects of subthalamic deep brain stimulation as a treatment for Parkinson’s disease. For more detailed information on this topic, you can find the source studies on pages 11 and 13 of this document from the World Congress on Parkinson’s Disease and Related Disorders. Additionally, Parkinson’s News Today has released a useful summary of the articles, which you can find here.
About Parkinson’s Disease
Parkinson’s disease (PD) is a condition that causes progressive damage to the brain. According to the NHS, PD is characterised by three symptoms; tremors, slow movement, and stiff and inflexible muscles. However, people affected by the condition may experience a wide range of other symptoms, such as depression, sleeping problems, and memory problems, amongst others. PD is caused by a loss of nerve cells in the substantia nigra, an area of the brain. As a result, dopamine levels may fall, which can cause many of the symptoms linked to PD. However, what causes the loss of nerve cells remains poorly understood.
About Subthalamic Deep Brain Stimulation
Deep brain stimulation (DBS) is a surgical treatment option for some patients with PD. According to Oxford University Hospitals, DBS involves placing fine wires into certain areas of the brain. One of the more common areas involved is the subthalamic nucleus (STN). The wire is then used to send a constant electrical pulse to the brain.
The two studies outlined in this article investigated the long-term effects of subthalamic deep brain stimulation (STN-DBS).
(1) The Long-Term Outcomes of STN-DBS for Young and Late-Onset PD
One of the studies, titled ‘Long-term effect of subthalamic deep brain stimulation in young- and late-onset Parkinson’s disease: 10-year follow-up study’ (p.13), investigated the link between the outcomes of patients who underwent STN-DBS and their age of symptom onset. To do this, the researchers retrospectively analysed ten years of clinical data from 24 patients from the Asan Medical Centr in Korea. Of these, 13 were ‘young-onset’ (symptoms began before age 40), and 11 were ‘late-onset’ (symptoms began after age 40).
The results of the investigation showed that at baseline there was no significant difference between the two groups in clinical motor and non-motor features. Ten years after the operation the two groups of patients still showed similar levels of motor symptoms, visual hallucinations, and adverse effects to each other. However, the group of young-onset patients were found to have a greater reduction in levodopa equivalent dose (an approximate way to compare drugs) and levodopa-induced dyskinesia (side effects of the drug levodopa, often used to treat PD) scores compared to the late-onset group. The researchers concluded, “These results may have clinical implications for tailored application of STN DBS in patients with PD.”
(2) Long-Term Follow-Up of Patients With Advanced PD Who Underwent STN-DBS
In the second study (‘Subthalamic deep brain stimulation for advanced Parkinson’s disease beyond the 5-year follow-up’, p.11), researchers aimed to investigate how effective and safe STN-DBS was in the long-term. The researchers collected data from 33 patients with PD who underwent STN-BS and were followed up for over five years. They included information on motor and functional outcomes, daily living activities, quality of life, antiparkinsonian medication regimens, complications, and side-effects.
The results of the analysis found that after seven years, patients showed improvements in some measures of motor and functional outcome and quality of life, and many patients had reduced L-dopa dosage.