Deep brain stimulation in Parkinson’s disease: state of the art and future perspectives

Abstract

For more than 30 years, Deep Brain Stimulation (DBS) has been a therapeutic option for Parkinson’s disease (PD) treatment. However, this therapy is still underutilized mainly due to misinformation regarding risks and clinical outcomes. DBS can ameliorate several motor and non-motor symptoms, improving patients’ quality of life. Furthermore, most of the improvement after DBS is long-lasting and present even in advanced PD. Adequate patient selection, precise electric leads placement, and correct DBS programming are paramount for good surgical outcomes. Nonetheless, DBS still has many limitations: axial symptoms and signs, such as speech, balance and gait, do not improve to the same extent as appendicular symptoms and can even be worsened as a direct or indirect consequence of surgery and stimulation. In addition, there are still unanswered questions regarding patient’s selection, surgical planning and programming techniques, such as the role of surgicogenomics, more precise imaging-based lead placement, new brain targets, advanced programming strategies and hardware features. The net effect of these innovations should not only be to refine the beneficial effect we currently observe on selected symptoms and signs but also to improve treatment resistant facets of PD, such as axial and non-motor features. In this review, we discuss the current state of the art regarding DBS selection, implant, and programming, and explore new advances in the DBS field.

The Therapeutic Potential of Non-Invasive and Invasive Cerebellar Stimulation Techniques in Hereditary Ataxias

“…Stimulation frequency is a pivotal aspect of DBS in various movement disorders. In Parkinson’s disease, STN DBS is typically applied with high frequencies (i.e., >100 Hz), but lower frequencies above 60 Hz have already been shown to effectively reduce bradykinesia and decrease stimulation-induced side effects regarding gait and speech [ 170 , 171 ]. In addition, symptom control in essential tremor is usually better when higher frequencies are administered [ 172 ].…”

Tailoring and personalizing deep brain stimulation for Parkinson's disease

“…In this sense, tractography can provide additional information for surgical planning. 9 After good patient selection and adequate lead positioning, correct DBS programming is the final step responsible for good motor and non-motor outcomes. Considering that DBS programming is a time-consuming task, mainly based on electrophysiological and neuroanatomical notions, as well as trial-and-error, much effort is now being directed toward making this process quicker and easier.…”

“… 7 8 Vascular changes, smaller middle and superior frontal cortical thickness, preoperative lower parieto-occipital glycolytic uptake, and higher primary motor cortex glycolytic uptake are some of the imaging findings that predict a worse motor outcome. 9 Although a minority of PD patients have genetic abnormalities, it is well known that PRKN mutation carriers have good motor outcomes and minimal cognitive decline, whereas GBA mutation carriers usually have worse cognitive and neuropsychiatric outcomes. Carriers of LRRK2 mutations may have different outcomes, depending on the specific type of mutation.…”

“…Carriers of LRRK2 mutations may have different outcomes, depending on the specific type of mutation. 9 While these findings should not be the main reason to refer or exclude patients from a DBS referral, they should be considered as additional tools to help both patients and physicians manage surgical expectations.…”

“…In this regard, direct target visualization is greatly improved with ultra-high-field MRI (7T and above), although this technique is prone to higher distortion susceptibility. 9 Alternative MRI sequences can also help improve surgical planning, such as susceptibility weighted imaging (SWI), Fast Gray Matter Acquisition T1 Inversion Recovery (FGATIR), and Quantitative Susceptibility Mapping (QSM) applied to multi-echo gradient-recalled echo (GRE) acquisitions. 9 A novel approach to DBS targets is to think not about gray matter nuclei, but about networks.…”