Deep brain stimulation, both at subthalamic nucleus and globus pallidus interna, improved tremor symptoms in patients with Parkinson disease, according to a study published in Parkinsonism and Related Disorders.
Researchers in this meta-analysis evaluated the effects of deep brain stimulation in patients with Parkinson disease using 46 comparison studies and 3267 data points. This data set was comprised of 5 longitudinal, randomized control trials and included records of stimulation targets, ongoing medication treatments, and pre- and post-test scores.
Overall, tremors were less severe, and comparisons had fewer tremor symptoms after deep brain stimulation. Deep brain stimulation was effective at both the subthalamic nucleus and globus pallidus interna sites, whether the patient was taking dopaminergic medications or not, and showed positive effects from 6 months to 60 months post-stimulation. Subthalamic nucleus stimulation showed a greater improvement in symptoms at month 24 than at month 6, while globus pallidus interna had a more stable level of effectiveness throughout follow-up.
Considerations need to be given, as these findings are based on a meta-analysis where the evaluated studies portrayed results in different manners, the study protocols were distinctive for each trial, and follow-up intervals varied between studies.
In conclusion, the researchers felt clinicians should base deep brain stimulation targets on the patient’s desired outcomes. In addition, the study researchers concluded that, “analysis indicates that there are no advantages or disadvantages for either target when considering long-term tremor suppression. Tremor that is unresponsive to levodopa may be adequately treated with neuromodulation based on the differences noted between on or off medications assessments in our study. Our results support that long-term tremor benefit is achieved with both targets. When patients [with Parkinson disease] present with tremor as the primary complaint or as an issue adversely affecting quality of life, practitioners should be aware that current data indicated both the [subthalamic nucleus] and [globus pallidus interna] are equally viable options. ”
Wong JK, Cauraugh JH, Ho KWD, et al. STN vs. GPi deep brain stimulation for tremor suppression in Parkinson disease: A systematic review and meta-analysis [published online August 28, 2018]. Parkinsonism Relate Disord. doi: 10.1016/j.parkreldis.2018.08.017