Determinants of Functional Independence or Its Loss following Subthalamic Nucleus Stimulation in Parkinson's Disease

Gender discrepancies and differences in motor and non-motor symptoms, cognition, and psychological outcomes in the treatment of Parkinson's disease with subthalamic deep brain stimulation

Available data suggest that there may be gender differences in the effect of STN-DBS in the treatment of Parkinson's disease (PD). The aim of this study was to review data on gender discrepancies and gender differences in clinical outcomes in PD patients treated with deep brain stimulation of the subthalamic nucleus (STN-DBS). Included were original studies that specifically examined gender discrepancies or gender differences in PD patients with STN-DBS. Men receive more DBS than women, for various indications. The decision-making process for DBS in women compared to men is more influenced by personal preferences and external factors. Motor symptoms improve in both genders, but bradykinesia improves more in men. The postoperative reduction of the levodopa equivalent daily dose seems to be more pronounced in men. Men show more cognitive deterioration and less improvement than women after STN-DBS. Women show more depressive symptoms before surgery, but they improve similarly to men. Men show more improvement in impulsivity and less decrease in impulsive behaviour symptoms than women. Anxiety and personality traits remain unchanged in both genders. Voice quality improves more in men and deteriorates less often than in women. Men gain fat-free mass and fat mass, but women only gain fat mass. Regarding sexual function the evidence is inconsistent. More urinary symptoms improve in women than in men. Pain and restless leg syndrome seems to improve more in men. Regarding quality of life, the evidence seems to be inconsistent, and activities of daily living seems to improve in both genders. Better prospective controlled studies, focusing directly on gender differences in PD patients treated with STN-DBS, are needed to better explain gender differences in STN-DBS for PD.

Development of Clinical Milestones in Parkinson’s Disease After Bilateral Subthalamic Deep Brain Stimulation

Objective

Deep brain stimulation of the subthalamic nucleus (STN-DBS) in Parkinson’s disease (PD) patients does not halt disease progression, as these patients will progress and develop disabling non-levodopa responsive symptoms. These features may act as milestones that represent the overall functionality of patients after DBS. The objective of this study was to investigate the development of clinical milestones in advanced PD patients who underwent bilateral STN-DBS.

Methods

The study evaluated PD patients who underwent STN-DBS at baseline up to their last follow-up using the Unified Parkinson’s Disease Rating Scale and Hoehn and Yahr scale. The symptoms of hallucinations, dysarthria, dysphagia, frequent falls, difficulty walking, cognitive impairment and the loss of autonomy were chosen as the clinical milestones.

Results

A total of 106 patients with a mean age of 47.21 ± 10.52 years at disease onset, a mean age of 58.72 ± 8.74 years at surgery and a mean disease duration of 11.51 ± 4.4 years before surgery were included. Initial improvement of motor symptoms was seen after the surgery with the appearance of clinical milestones over time. Using the moderately disabling criteria, 81 patients (76.41%) developed at least one clinical milestone, while 48 patients (45.28%) developed a milestone when using the severely disabling criteria.

Conclusion

STN-DBS has a limited effect on axial and nonmotor symptoms of the PD patients, in contrast to the effect on motor symptoms. These symptoms may serve as clinical milestones that can convey the status of PD patients and its impact on the patients and their caregivers. Therefore, advanced PD patients, even those treated with bilateral STN-DBS, will still require assistance and cannot live independently in the long run.

Impact of Overweight and Obesity on Functional and Clinical Outcomes of Early Parkinson's Disease

OBJECTIVE

To determine whether being overweight or obese contributes to disease progression and functional status in Parkinson's disease (PD).

DESIGN

Cohort study using data from the Parkinson Progression Markers Initiative (PPMI).

SETTING AND PARTICIPANTS

A total of 399 drug-naive patients with early PD were classified into normal weight (body mass index of 18.5-24.9, n = 139), overweight (25.0-29.9, n = 167), and obese (30.0 or more, n = 93) groups.

METHODS

The primary outcome was the development of functional dependency. Functional dependency was defined as a Schwab and England score of less than 80% at any time point that remained throughout follow-up. The secondary outcomes were the changes in the Movement Disorders Society Unified Parkinson Disease Rating Scale motor score measured in the off-medication state and the Montreal Cognitive Assessment score across visits.

RESULTS

Over a 5-year follow-up period, the incidence of functional dependency was higher in the obese group than in the normal weight group (P = .001). No difference was observed between the overweight and normal weight groups (P = .429). The multivariable Cox model confirmed that obesity, but not overweight, increased the risk of dependency (hazard ratio 2.63, 95% confidence interval 1.32-5.23, P = .006). The increase in the Movement Disorders Society Unified Parkinson Disease Rating Scale motor score was greater in the obesity (P < .001) and overweight (P = .004) groups than in the normal weight group. Changes in the Montreal Cognitive Assessment score did not differ among the groups (P = .978).

CONCLUSIONS AND IMPLICATIONS

We found that obesity is related to an increased risk of functional dependency and rapid motor progression in patients with early PD. Although being overweight did not increase the risk of dependency, this condition was associated with rapid motor progression.