Subthalamic deep brain stimulation for Parkinson's disease outcome

Numerous studies have investigated the outcomes of subthalamic deep brain stimulation patients, and overall, the results have been positive. Some of the key outcomes that have been observed include:

Improved motor function: Subthalamic DBS has been shown to improve motor symptoms such as tremors, rigidity, and bradykinesia (slowness of movement).

Reduced medication requirements: Many patients who undergo subthalamic DBS are able to reduce or eliminate their medication use, which can reduce the risk of medication-related side effects.

Improved quality of life: Patients who receive subthalamic DBS often report improvements in their quality of life, including better mood, greater independence, and improved ability to perform daily activities.

Long-term efficacy: Studies have demonstrated that the beneficial effects of subthalamic DBS can last for several years, with many patients experiencing sustained improvements in motor function and quality of life.

However, subthalamic DBS is not without risks, and potential complications include infection, bleeding, and device malfunction. Patients must also be carefully selected for the procedure based on a thorough evaluation of their medical history, PD symptoms, and other factors.

Overall, subthalamic DBS can be an effective treatment option for carefully selected PD patients who are experiencing significant motor symptoms and have not responded well to medication alone.

Chen et al. found that the initial outcome of subthalamic deep brain stimulation was associated with functional/structural connectivities between the volume of tissue activated and multiple brain regions, including the supplementary motor area, precentral and frontal areas, cingulum, temporal cortex, and striatum. These factors could be used to predict the initial outcome, with an r-value of 0.4978 (P = 0.0255). The study demonstrates a correlation between a specific connectivity pattern and the initial outcome of STN-DBS, which could be used to predict the initial outcome of DBS ¹⁾.

The surgical and clinical outcomes of asleep DBS for Parkinson's disease are comparable to those of awake DBS ²⁾.

Suboptimal targeting within the STN can give rise to intolerable sensorimotor side effects, such as dysarthria, contractions and paresthesias ^{3) 4) 5)}. eye movement perturbations, and psychiatric symptoms ^{6) 7) 8)}, limiting the management of motor symptoms. The small size of the STN motor territory and the consequences of spreading current to immediately adjacent structures obligate precise targeting. Neurosurgeons therefore rely on a combination of imaging, electrophysiology, kinesthetic responses, and stimulation testing to accurately place the DBS lead into the sensorimotor domain of STN ^{9) 10) 11)}.

Deep Brain Stimulation has been associated with post-operative neuropsychology changes, especially in verbal memory.

Deep brain stimulation (DBS) of subthalamic nucleus (STN) is widely accepted to treat advanced Parkinson's disease (PD). However, published studies were mainly conducted in Western centers ¹²⁾.

High frequency subthalamic nucleus (STN) deep brain stimulation (DBS) improves the cardinal motor signs of Parkinson's disease (PD) and attenuates STN alpha/beta band neural synchrony in a voltage-dependent manner. While there is a growing interest in the behavioral effects of lower frequency (60 Hz) DBS, little is known about its effect on STN neural synchrony.

Low-frequency stimulation of the subthalamic nucleus via the optimal contacts is effective in improving overall motor function of patients with Parkinson's disease ¹³⁾. In Parkinson's disease significantly improved important aspects of QoL as measured by PDQ-39. The improvements were maintained at 2 years follow-up except for social support and communication. Sobstyl et al., demonstrated a positive correlation between changes in the off condition of motor UPDRS scores and Unified Dyskinesia Rating Scale in several PDQ-39 dimensions, whereas fluctuation UPDRS scores were negatively correlated with PDQ-39 mobility scores ¹⁴⁾.

The degree of clinical improvement achieved by deep brain stimulation (DBS) is largely dependent on the accuracy of lead placement.

A study reports on the evaluation of intraoperative MRI (iMRI) for adjusting deviated electrodes to the accurate anatomical position during DBS surgery and acute intracranial changes ¹⁵⁾.

In 82 postural instability and gait difficulty (PIGD) and 33 tremor-dominant patients included in a study, baseline Non-Motor Symptom Scale (NMSS) total scores were worse in PIGD patients, both groups experienced postoperative improvements of the NMSS sleep/fatigue domain, and between-group differences in postoperative outcomes were favourable in the PIGD group for the NMSS total and miscellaneous domain scores.

This study provides evidence of a favourable outcome of total non-motor burden in PIGD compared to tremor-dominant patients undergoing DBS for PD. These differences of clinical efficacy on non-motor aspects should be considered when advising and monitoring patients with PD undergoing DBS ¹⁶⁾.

The bilateral effects of deep brain stimulation (DBS) on motor and non-motor symptoms of Parkinson's disease (PD) have been extensively studied and reviewed. However, the unilateral effects-in particular, the potential lateralized effects of left- versus right-sided DBS-have not been adequately recognized or studied.

Lin et al. summarized the current evidence and controversies in the literature regarding the lateralized effects of DBS on motor and non-motor outcomes in PD patients. Publications in the English language before February 2021 were obtained from the PubMed database and included if they directly compared the effects of unilateral versus contralateral side DBS on the motor or non-motor outcomes in PD. The current literature is overall of low-quality and is biased by various confounders. Researchers have investigated mainly PD patients receiving subthalamic nucleus (STN) DBS while the potential lateralized effects of globus pallidus internus (GPi) DBS have not been adequately studied. Evidence suggests potential lateralized effects of STN DBS on axial motor symptoms and deleterious effects of left-sided DBS on language-related functions, in particular, the verbal fluency, in PD. The lateralized DBS effects on appendicular motor symptoms as well as other neurocognitive and neuropsychiatric domains remain inconclusive. Future studies should control for varying methodological approaches as well as clinical and DBS management heterogeneities, including symptom laterality, stimulation parameters, location of active contacts, and lead trajectories. This would contribute to improved treatment strategies such as personalized target selection, surgical planning, and postoperative management that ultimately benefit patients ¹⁷⁾.

The ability of serum biomarkers to predict the prognosis and response to deep brain stimulation (DBS) therapy in Parkinson's disease (PD) patients is promising. Sanmartino et al. showed that NfL differed between healthy individuals and PD patients and that changes in NfL, GFAP, and BDNF occurred only transiently after DBS surgery. Therefore, subthalamic deep brain stimulation does not promote neurodegeneration, and these biomarkers do not serve as clinical improvement endpoints in PD DBS patients ¹⁸⁾