Weight changes in subthalamic nucleus vs globus pallidus internus deep brain stimulation: results from the COMPARE Parkinson disease deep brain stimulation cohort

Weight and survival after deep brain stimulation for Parkinson's disease

BACKGROUND

Weight loss in Parkinson's disease (PD) is common and associated with increased mortality. The clinical significance of weight changes following deep brain stimulation (DBS) of the subthalamic nucleus (STN) and globus pallidus internus (GPi) is unclear.

OBJECTIVES

To address (1) whether PD patients exhibit progressive weight loss, (2) whether staged DBS surgery is associated with weight changes, and (3) whether survival after DBS correlates with post-DBS weight.

METHODS

This is a single-center, longitudinal, retrospective cohort study of 1625 PD patients. We examined trends in weight over time and the relationship between weight and years survival after DBS using regression and mixed model analyses.

RESULTS

There was a decline in body weight predating motor symptom onset (n = 756, 0.70 ± 0.03% decrease per year, p < 0.001). Weight decline accelerated in the decade preceding death (n = 456, 2.18 ± 0.31% decrease per year, p < 0.001). DBS patients showed a weight increase of 2.0 ± 0.33% at 1 year following the first DBS lead implant (n = 455) and 2.68 ± 1.1% at 3 years if a contralateral DBS lead was placed (n = 249). The bilateral STN DBS group gained the most weight after surgery during 6 years of follow up (vs bilateral GPi, 3.03 ± 0.45% vs 1.89 ± 0.31%, p < 0.01). An analysis of the DBS cohort with date of death available (n = 72) revealed that post-DBS weight (0-12 months after the first or 0-36 months after the second surgery) was positively associated with survival (R2 = 0.14, p < 0.001).

DISCUSSION

Though PD is associated with significant weight loss, DBS patients gained weight following surgery. Higher post-operative weight was associated with increased survival. These results should be replicated in other cohorts.

Mechanisms and consequences of weight gain after deep brain stimulation of the subthalamic nucleus in patients with Parkinson's disease

Body weight gain in combination with metabolic alterations has been observed after deep brain stimulation (DBS) of subthalamic nucleus (STN) in patients with Parkinson's disease (PD), which potentially counteracts the positive effects of motor improvement. We aimed to identify stimulation-dependent effects on motor activities, body weight, body composition, energy metabolism, and metabolic blood parameters and to determine if these alterations are associated with the local impact of DBS on different STN parcellations. We assessed 14 PD patients who underwent STN DBS (PD-DBS) before as well as 6- and 12-months post-surgery. For control purposes, 18 PD patients under best medical treatment (PD-CON) and 25 healthy controls (H-CON) were also enrolled. Wrist actigraphy, body composition, hormones, and energy expenditure measurements were applied. Electrode placement in the STN was localized, and the local impact of STN DBS was estimated. We found that STN DBS improved motor function by ~ 40% (DBS ON, Med ON). Weight and fat mass increased by ~ 3 kg and ~ 3% in PD-DBS (all P ≤ 0.005). fT3 (P = 0.001) and insulin levels (P = 0.048) increased solely in PD-DBS, whereas growth hormone levels (P = 0.001), daily physical activity, and VO2 during walking were decreased in PD-DBS (all P ≤ 0.002). DBS of the limbic part of the STN was associated with changes in weight and body composition, sedentary activity, insulin levels (all P ≤ 0.040; all r ≥ 0.56), and inversely related to HOMA-IR (P = 0.033; r = - 0.62). Daily physical activity is decreased after STN DBS, which can contribute to weight gain and an unfavorable metabolic profile. We recommend actigraphy devices to provide feedback on daily activities to achieve pre-defined activity goals.

The Thermodynamic Consequences of Parkinson's Disease

Several lines of evidence point to a pervasive disturbance of energy balance in Parkinson's disease (PD). Weight loss, common and multifactorial, is the most observable sign of this. Bradykinesia may be best understood as an underinvestment of energy in voluntary movement. This accords with rodent experiments that emphasise the importance of dopamine in allocating motor energy expenditure. Oxygen consumption studies in PD suggest that, when activities are standardised for work performed, these inappropriate energy thrift settings are actually wasteful. That the dopaminergic deficit of PD creates a problem with energy efficiency highlights the role played by the basal ganglia, and by dopamine, in thermodynamic governance. This involves more than balancing energy, since living things maintain their internal order by controlling transformations of energy, resisting probabilistic trends to more random states. This review will also look at recent research in PD on the analysis of entropy-an information theory metric of predictability in a message-in recordings from the basal ganglia. Close relationships between energy and information converge around the concept of entropy. This is especially relevant to the motor system, which regulates energy exchange with the outside world through its flow of information. The malignant syndrome in PD, a counterpart of neuroleptic malignant syndrome, demonstrates how much thermodynamic disruption can result from breakdown of motor signalling in an extreme hypodopaminergic state. The macroenergetic disturbances of PD are consistent with a unifying hypothesis of dopamine's neurotransmitter actions-to adapt energy expenditure to prevailing economic circumstances.

Anticipatory human subthalamic area beta-band power responses to dissociable tastes correlate with weight gain

The availability of enticing sweet, fatty tastes is prevalent in the modern diet and contribute to overeating and obesity. In animal models, the subthalamic area plays a role in mediating appetitive and consummatory feeding behaviors, however, its role in human feeding is unknown. We used intraoperative, subthalamic field potential recordings while participants (n = 5) engaged in a task designed to provoke responses of taste anticipation and receipt. Decreased subthalamic beta-band (15-30 Hz) power responses were observed for both sweet-fat and neutral tastes. Anticipatory responses to taste-neutral cues started with an immediate decrease in beta-band power from baseline followed by an early beta-band rebound above baseline. On the contrary, anticipatory responses to sweet-fat were characterized by a greater and sustained decrease in beta-band power. These activity patterns were topographically specific to the subthalamic nucleus and substantia nigra. Further, a neural network trained on this beta-band power signal accurately predicted (AUC ≥ 74%) single trials corresponding to either taste. Finally, the magnitude of the beta-band rebound for a neutral taste was associated with increased body mass index after starting deep brain stimulation therapy. We provide preliminary evidence of discriminatory taste encoding within the subthalamic area associated with control mechanisms that mediate appetitive and consummatory behaviors.

Weight Change After Subthalamic Nucleus Deep Brain Stimulation in Patients With Isolated Dystonia

Purpose: Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an effective treatment method for advanced Parkinson's disease (PD) and isolated dystonia and provides marked improvement of major motor symptoms. In addition, non-motor effects have been reported including weight gain (WG) in patients with PD after STN-DBS. However, it is still unclear whether patients with isolated dystonia also experience WG.

Methods: Data from 47 patients with isolated dystonia who underwent bilateral STN-DBS surgery between October 2012 and June 2019 were retrospectively collected. The severity of dystonia was assessed via the Burke–Fahn–Marsden Dystonia Rating Scale (BFMDRS). Changes in the body mass index (BMI) and BFMDRS score were analyzed using paired Student's t-tests. Regression analysis was performed to identify factors that affected the BMI after surgery.

Results: Postoperative WG was observed in 78.7% of patients. The percentage of overweight and obese patients increased from 25.5% (before STN-DBS) to 48.9% (at the last follow-up). The mean BMI and mean percentage change in BMI increased by 1.32 ± 1.83 kg/m² (P < 0.001) and 6.28 ± 8.34%, respectively. BMI increased more in female than in male patients. At the last follow-up, BFMDRS movement and disability scores improved by 69.76 ± 33.23% and 65.66 ± 31.41%, respectively (both P < 0.001). The final regression model analysis revealed that sex and preoperative BMI alone were independently associated with BMI change (P < 0.05).

Conclusions: STN-DBS is associated with postoperative WG with patients with isolated dystonia. WG is more prominent in female patients and is associated with preoperative weight but not with the efficacy of STN-DBS on motor symptoms.

Factors Associated With Postoperative Confusion and Prolonged Hospital Stay Following Deep Brain Stimulation Surgery for Parkinson Disease

BACKGROUND

Several patient and disease characteristics are thought to influence DBS outcomes; however, most previous studies have focused on long-term outcomes with only a few addressing immediate postoperative course.

OBJECTIVE

To evaluate predictors of immediate outcomes (postoperative confusion and length of postoperative hospitalization) following deep brain stimulation surgery (DBS) in Parkinson disease (PD) patients.

METHODS

We conducted a retrospective study of PD patients who underwent DBS at our institution from 2006 to 2011. We computed the proportion of patients with postoperative confusion and those with postoperative hospitalization longer than 2 d. To look for associations, Fisher's exact tests were used for categorical predictors and logistic regression for continuous predictors.

RESULTS

We identified 130 patients [71% male, mean age: 63 ± 9.1, mean PD duration: 10.7 ± 5.1]. There were 7 cases of postoperative confusion and 19 of prolonged postoperative hospitalization. Of the 48 patients with tremors, none had postoperative confusion, whereas 10.1% of patients without tremors had confusion (P = .0425). Also, 10.2% of patients with preoperative falls/balance-dysfunction had postoperative confusion, whereas only 1.6% of patients without falls/balance-dysfunction had postoperative confusion (P = .0575). For every one-unit increase in score on the preoperative on-UPDRS III/MDS-UPDRS III score, the odds of having postoperative confusion increased by 10% (P = .0420). The following factors were noninfluential: age, disease duration, dyskinesia, gait freezing, preoperative levodopa-equivalent dose, number of intraoperative microelectrode passes, and laterality/side of surgery.

CONCLUSION

Absence of tremors and higher preoperative UPDRS III predicted postoperative confusion after DBS in PD patients. Clinicians' awareness of these predictors can guide their decision making regarding patient selection and surgical planning.

Effects of implantation of a deep brain stimulation device on patient weight in Parkinson's disease and essential tremor

OBJECTIVE

Deep brain stimulation (DBS) is a well-established therapy for treating neurological movement disorders. Some patients who have received DBS therapy have noticed significant weight gain. Further investigation into correlations between patient characteristics and weight gain following DBS device implantation, which the authors here have done, will provide physicians with useful clinical information.

METHODS

The authors performed a retrospective study of patients with Parkinson's disease (PD) and essential tremor (ET) who had received DBS therapy in the period from 2012 to 2017. Patient weights had been recorded preoperatively and at 3, 6, and 12 months postoperatively. These data were used to compare patient characteristics, including diagnosis, body mass index (BMI), sex, levodopa equivalent dose (LED), and change in Unified Parkinson's Disease Rating Scale (UPDRS) score. For PD patients, a quantile multivariate regression analysis was used to examine whether significant correlations existed between several of these patient characteristics, as well as age and weight gain following implantation.

RESULTS

PD patients had gained a significant amount of weight at 3 months (mean [SE] 2.66 [0.428] kg, p < 0.001), 6 months (3.64 [0.492] kg, p < 0.001), and 12 months (4.18 [0.540] kg, p < 0.001) after DBS placement. Patients who had undergone subthalamic nucleus (STN) DBS device placement gained, on average, more weight than the patients with globus pallidus internus (GPi) placement at both 6 months (mean 2.558 [1.020] kg, p = 0.01) and 12 months (2.358 [1.130] kg, p = 0.04). BMI in the STN cohort was greater than that in the GPi cohort at 6 months (mean difference [SE] 2.60 [1.127] kg/m2, p = 0.02) and at 12 months (2.36 [1.112] kg/m2, p = 0.04). A reduction in LED was negatively correlated with weight change at 6 months (r = -0.33, p < 0.001) and 12 months (r = -0.41, p < 0.001). There was no weight gain correlated with DBS therapy for ET.

CONCLUSIONS

PD patients experienced a significant change in weight over time after DBS therapy, whereas ET patients did not. PD patients with an STN target site experienced greater weight gain, on average, than those with a GPi target site. Furthermore, there was a significant increase in BMI at 6 and 12 months in patients with an STN target compared to that in patients with a GPi target. PD patients whose LED was reduced after DBS gained more weight at 6 and 12 months after surgery than the patients whose LED was kept at the same level or increased.

A systematic review of body mass gain after deep brain stimulation of the subthalamic nucleus in patients with Parkinson's disease

This systematic review investigated the effects of deep brain stimulation of the subthalamic nucleus on extent and time course of body mass changes in patients with Parkinson's disease. A computerized search identified relevant articles using a priori defined inclusion and exclusion criteria. A descriptive analysis was calculated for the main outcome parameters body mass and BMI. Thirty-eight out of 206 studies fulfilled the inclusion criteria (979 patients aged 59.0±7.5 years). Considering the longest follow-up time for each study, body mass and BMI showed a mean increase across studies of +5.71kg (p < .0001; d = 0.64) and +1.8kg/m² (p < .0001; d = 1.61). The time course of body mass gain revealed a continuous increase ranging from +3.25kg (d = 0.69) at 3 months, +3.88kg (d = 0.21) at 6 months, +6.35kg (d = 0.72) at 12 months, and +6.11kg (d = 1.02) greater than 12 months. Changes in BMI were associated with changes in disease severity (r = 0.502, p = .010) and pharmacological treatment (r = 0.440, p = .0231). Data suggest that body mass gain is one of the most common side effects of deep brain stimulation going beyond normalization of preoperative weight loss. Considering the negative health implications of overweight, we recommend the development of tailored therapies to prevent overweight and associated metabolic disorders following this treatment.

Challenges in PD Patient Management After DBS: A Pragmatic Review

BACKGROUND

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) or internal globus pallidus (GPi) represents an effective and universally applied therapy for Parkinson's disease (PD) motor complications. However, certain procedure-related problems and unrealistic patient expectations may detract specialists from indicating DBS more widely despite significant clinical effects.

METHODS

This review provides a pragmatic educational summary of the most conflicting postoperative management issues in patients undergoing DBS for PD.

RESULTS

DBS in PD has been associated with certain complications and post-procedural management issues, which can complicate surgical outcome interpretation. Many PD patients consider DBS outcomes negative due to unfulfilled expectations, even when significant motor symptom improvement is achieved. Speech, gait, postural stability, and cognition may worsen after DBS and body weight may increase. Although DBS may induce impulse control disorders in some cases, in others, it may actually improve them when dopamine agonist dosage is reduced after surgery. However, apathy may also arise, especially when dopaminergic medication tapering is rapid. Gradual loss of response with time suggests disease progression, rather than the wearing off of DBS effects. Furthermore, implantable pulse generator expiration is considered a movement disorder emergency, as it may worsen parkinsonian symptoms or cause life-threatening akinetic crises due to malignant DBS withdrawal syndrome.

CONCLUSION

Major unsolved issues occurring after DBS therapy preclude complete patient satisfaction. Multidisciplinary management at experienced centers, as well as careful and comprehensive delivery of information to patients, should contribute to make DBS outcome expectations more realistic and allow post procedural complications to be better accepted.

Subthalamic and Pallidal Deep Brain Stimulation for Parkinson's Disease

Deep brain stimulation (DBS) is a surgical treatment in which stimulation electrodes are permanently implanted in basal ganglia to treat motor fluctuations and symptoms of Parkinson's disease (PD). Subthalamic nucleus (STN) and globus pallidus internus (GPi) are the commonly used targets for DBS in PD. Many studies have compared motor and non-motor outcomes of DBS in both targets. However, the selection of PD patients for DBS targets is still poorly studied. Therefore, we performed this narrative review to summarize published studies comparing STN DBS and GPi DBS. GPi DBS is better for patients with problems in speech, mood, or cognition while STN DBS is better from an economic point of view as it allows much reduction in antiparkinson medications and less battery consumption.

Weight Gain following Pallidal Deep Brain Stimulation: A PET Study

The mechanisms behind weight gain following deep brain stimulation (DBS) surgery seem to be multifactorial and suspected depending on the target, either the subthalamic nucleus (STN) or the globus pallidus internus (GPi). Decreased energy expenditure following motor improvement and behavioral and/or metabolic changes are possible explanations. Focusing on GPi target, our objective was to analyze correlations between changes in brain metabolism (measured with PET) and weight gain following GPi-DBS in patients with Parkinson's disease (PD). Body mass index was calculated and brain activity prospectively measured using 2-deoxy-2[18F]fluoro-D-glucose PET four months before and four months after the start of GPi-DBS in 19 PD patients. Dopaminergic medication was included in the analysis to control for its possible influence on brain metabolism. Body mass index increased significantly by 0.66 ± 1.3 kg/m2 (p = 0.040). There were correlations between weight gain and changes in brain metabolism in premotor areas, including the left and right superior gyri (Brodmann area, BA 6), left superior gyrus (BA 8), the dorsolateral prefrontal cortex (right middle gyrus, BAs 9 and 46), and the left and right somatosensory association cortices (BA 7). However, we found no correlation between weight gain and metabolic changes in limbic and associative areas. Additionally, there was a trend toward a correlation between reduced dyskinesia and weight gain (r = 0.428, p = 0.067). These findings suggest that, unlike STN-DBS, motor improvement is the major contributing factor for weight gain following GPi-DBS PD, confirming the motor selectivity of this target.

Deep Brain Stimulation for Movement Disorders of Basal Ganglia Origin: Restoring Function or Functionality?

Deep brain stimulation (DBS) is highly effective for both hypo- and hyperkinetic movement disorders of basal ganglia origin. The clinical use of DBS is, in part, empiric, based on the experience with prior surgical ablative therapies for these disorders, and, in part, driven by scientific discoveries made decades ago. In this review, we consider anatomical and functional concepts of the basal ganglia relevant to our understanding of DBS mechanisms, as well as our current understanding of the pathophysiology of two of the most commonly DBS-treated conditions, Parkinson's disease and dystonia. Finally, we discuss the proposed mechanism(s) of action of DBS in restoring function in patients with movement disorders. The signs and symptoms of the various disorders appear to result from signature disordered activity in the basal ganglia output, which disrupts the activity in thalamocortical and brainstem networks. The available evidence suggests that the effects of DBS are strongly dependent on targeting sensorimotor portions of specific nodes of the basal ganglia-thalamocortical motor circuit, that is, the subthalamic nucleus and the internal segment of the globus pallidus. There is little evidence to suggest that DBS in patients with movement disorders restores normal basal ganglia functions (e.g., their role in movement or reinforcement learning). Instead, it appears that high-frequency DBS replaces the abnormal basal ganglia output with a more tolerable pattern, which helps to restore the functionality of downstream networks.

Association between subthalamic nucleus deep brain stimulation and weight gain: Results of a case-control study

OBJECTIVE

To evaluate whether weight change in patients with Parkinson's disease (PD) is different in those undergoing deep brain stimulation (DBS) of the subthalamic nucleus (STN) compared to those not undergoing DBS.

PATIENTS AND METHODS

A retrospective case-control study was performed in PD patients who had undergone STN DBS (cases) compared to matched PD patients without DBS (controls). Demographic and clinical data including Unified Parkinson's Disease Rating Scale (UPDRS) motor scores were collected. Repeated measures mixed model regression was used to identify variables associated with weight gain.

RESULTS

Thirty-five cases and 34 controls were identified. Baseline age, gender, diagnosis and weight were similar. Duration of diagnosis was longer in cases (6.3 vs 4.9 years, p=0.0015). At 21.3 months, cases gained 2.9 kg (+4.65%) while controls lost 1.8 kg (-3.05%, p<0.02). Postoperative UPDRS motor scores improved by 49% indicating surgical efficacy. Only younger age (p=0.0002) and DBS (p=0.008) were significantly associated with weight gain.

CONCLUSION

In this case-control study, PD patients undergoing STN DBS experienced post-operative weight gain that was significantly different from the weight loss observed in non-DBS PD controls. Patients, especially overweight individuals, should be informed that STN DBS can result in weight gain.

Update on deep brain stimulation in Parkinson's disease

Deep brain stimulation (DBS) is considered a safe and well tolerated surgical procedure to alleviate Parkinson’s disease (PD) and other movement disorders symptoms along with some psychiatric conditions. Over the last few decades DBS has been shown to provide remarkable therapeutic effect on carefully selected patients. Although its precise mechanism of action is still unknown, DBS improves motor functions and therefore quality of life. To date, two main targets have emerged in PD patients: the globus pallidus pars interna and the subthalamic nucleus. Two other targets, the ventralis intermedius and zona incerta have also been selectively used, especially in tremor-dominant PD patients. The main indications for PD DBS have traditionally been motor fluctuations, debilitating medication induced dyskinesias, unpredictable “off time” state, and medication refractory tremor. Medication refractory tremor and intolerable dyskinesia are potential palliative indications. Besides aforementioned targets, the brainstem pedunculopontine nucleus (PPN) is under investigation for the treatment of ON-state freezing of gait and postural instability. In this article, we will review the most recent literature on DBS therapy for PD, including cutting-edge advances and data supporting the role of DBS in advanced neural-network modulation.

Neuroimaging and neuromodulation approaches to study eating behavior and prevent and treat eating disorders and obesity

Functional, molecular and genetic neuroimaging has highlighted the existence of brain anomalies and neural vulnerability factors related to obesity and eating disorders such as binge eating or anorexia nervosa. In particular, decreased basal metabolism in the prefrontal cortex and striatum as well as dopaminergic alterations have been described in obese subjects, in parallel with increased activation of reward brain areas in response to palatable food cues. Elevated reward region responsivity may trigger food craving and predict future weight gain. This opens the way to prevention studies using functional and molecular neuroimaging to perform early diagnostics and to phenotype subjects at risk by exploring different neurobehavioral dimensions of the food choices and motivation processes. In the first part of this review, advantages and limitations of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), pharmacogenetic fMRI and functional near-infrared spectroscopy (fNIRS) will be discussed in the context of recent work dealing with eating behavior, with a particular focus on obesity. In the second part of the review, non-invasive strategies to modulate food-related brain processes and functions will be presented. At the leading edge of non-invasive brain-based technologies is real-time fMRI (rtfMRI) neurofeedback, which is a powerful tool to better understand the complexity of human brain-behavior relationships. rtfMRI, alone or when combined with other techniques and tools such as EEG and cognitive therapy, could be used to alter neural plasticity and learned behavior to optimize and/or restore healthy cognition and eating behavior. Other promising non-invasive neuromodulation approaches being explored are repetitive transcranial magnetic stimulation (rTMS) and transcranial direct-current stimulation (tDCS). Converging evidence points at the value of these non-invasive neuromodulation strategies to study basic mechanisms underlying eating behavior and to treat its disorders. Both of these approaches will be compared in light of recent work in this field, while addressing technical and practical questions. The third part of this review will be dedicated to invasive neuromodulation strategies, such as vagus nerve stimulation (VNS) and deep brain stimulation (DBS). In combination with neuroimaging approaches, these techniques are promising experimental tools to unravel the intricate relationships between homeostatic and hedonic brain circuits. Their potential as additional therapeutic tools to combat pharmacorefractory morbid obesity or acute eating disorders will be discussed, in terms of technical challenges, applicability and ethics. In a general discussion, we will put the brain at the core of fundamental research, prevention and therapy in the context of obesity and eating disorders. First, we will discuss the possibility to identify new biological markers of brain functions. Second, we will highlight the potential of neuroimaging and neuromodulation in individualized medicine. Third, we will introduce the ethical questions that are concomitant to the emergence of new neuromodulation therapies.

Body weight and food intake in Parkinson's disease. A review of the association to non-motor symptoms

Research on eating behaviours has extensively highlighted that cognitive systems interact with the metabolic system in driving food intake and in influencing body weight regulation. Parkinson's disease is a good model for studying these complex interactions since alterations in both body weight and cognitive domains have been frequently reported among these patients. Interestingly, even if different non-motor symptoms may characterize the course of the disease, their contribution to weight and food preference has been poorly investigated. This review describes body weight alterations and eating habits in patients with Parkinson's disease, including those who underwent deep brain stimulation surgery. In particular, the review considers the link between non-motor symptoms, affecting sensory perception, cognition, mood and motivation, and food intake and weight alterations. The take home message is twofold. First, we recommend a comprehensive approach in order to develop effective strategies in the management of patients' weight. Second, we also suggest that investigating this issue in patients with Parkinson's disease may provide some useful information about the mechanisms underlying food and weight regulation in healthy subjects.

Mechanisms of body weight fluctuations in Parkinson's disease

Typical body weight changes are known to occur in Parkinson’s disease (PD). Weight loss has been reported in early stages as well as in advanced disease and malnutrition may worsen the clinical state of the patient. On the other hand, an increasing number of patients show weight gain under dopamine replacement therapy or after surgery. These weight changes are multifactorial and involve changes in energy expenditure, perturbation of homeostatic control, and eating behavior modulated by dopaminergic treatment. Comprehension of the different mechanisms contributing to body weight is a prerequisite for the management of body weight and nutritional state of an individual PD patient. This review summarizes the present knowledge and highlights the necessity of evaluation of body weight and related factors, as eating behavior, energy intake, and expenditure in PD.

The "brittle response" to Parkinson's disease medications: characterization and response to deep brain stimulation

OBJECTIVE

Formulate a definition and describe the clinical characteristics of PD patients with a "brittle response" (BR) to medications versus a "non-brittle response" (NBR), and characterize the use of DBS for this population.

METHODS

An UF IRB approved protocol used a retrospective chart review of 400 consecutive PD patients presenting to the UF Center for Movement Disorders and Neurorestoration. Patient records were anonymized and de-identified prior to analysis. SPSS statistics were used to analyze data.

RESULTS

Of 345 included patients, 19 (5.5%) met criteria for BR PD. The BR group was comprised of 58% females, compared to 29% in the NBR group (P = .008). The former had a mean age of 63.4 compared to 68.1 in the latter. BR patients had lower mean weight (63.5 vs. 79.6, P = <.001), longer mean disease duration (12.6 vs. 8.9 years, P = .003), and had been on LD for more years compared to NBR patients (9.8 vs. 5.9, P = .001). UPDRS motor scores were higher (40.4 vs. 30.0, P = .001) in BR patients. No differences were observed regarding the Schwab and England scale, PDQ-39, and BDI-II. Sixty-three percent of the BR group had undergone DBS surgery compared to 18% (P = .001). Dyskinesias were more common, severe, and more often painful (P = <.001) in the BR group. There was an overall positive benefit from DBS.

CONCLUSION

BR PD occurred more commonly in female patients with a low body weight. Patients with longer disease duration and longer duration of LD therapy were also at risk. The BR group responded well to DBS.

Dyspnea as a side effect of subthalamic nucleus deep brain stimulation for Parkinson's disease

Bilateral subthalamic nucleus deep brain stimulation for Parkinson's disease improves limb function. Unpublished observations from our clinic noted that some subthalamic nucleus deep brain stimulation patients complain of post-operative dyspnea. Therefore, we designed a prospective, longitudinal study to characterize this in greater depth. We used specific questionnaires to assess dyspnea in patients with electrodes in the subthalamic nucleus (n=13) or ventral intermediate thalamus (n=7). St. George's Hospital Respiratory Questionnaire symptom subscale scores were greater in subthalamic nucleus patients (median=18.60, interquartile range=40.80) than ventral intermediate thalamus patients (median = 0.00, interquartile range=15.38) at greater than 6 months post-operatively (p<0.05). Several of the subthalamic nucleus patients exhibited functional impairments as judged by the St. George's Hospital Respiratory Questionnaire impact subscale, the Medical Research Council Dyspnoea Scale, and the Dyspnoea-12 Questionnaire. There was no correlation between limb function ratings, stimulation parameters, or precise electrode position and dyspnea severity. We have shown, for the first time, that dyspnea can be a side effect of subthalamic nucleus deep brain stimulation, and that this dyspnea may be highly disabling.

A systematic review of the effects of neuromodulation on eating and body weight: evidence from human and animal studies

BACKGROUND

Eating disorders (ED) are chronic and sometimes deadly illnesses. Existing treatments have limited proven efficacy, especially in the case of adults with anorexia nervosa (AN). Emerging neural models of ED provide a rationale for more targeted, brain-directed interventions.

AIMS

This systematic review has examined the effects of neuromodulation techniques on eating behaviours and body weight and assessed their potential for therapeutic use in ED.

METHOD

All articles in PubMed, PsychInfo and Web of Knowledge were considered and screened against a priori inclusion/exclusion criteria. The effects of repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation, vagus nerve stimulation (VNS) and deep brain stimulation (DBS) were examined across studies in ED samples, other psychiatric and neurological disorders, and animal models.

RESULTS

Sixty studies were identified. There is evidence for ED symptom reduction following rTMS and DBS in both AN and bulimia nervosa. Findings from studies of other psychiatric and neurological disorders and from animal studies demonstrate that increases in food intake and body weight can be achieved following DBS and that VNS has potential value as a means of controlling eating and inducing weight loss.

CONCLUSIONS

Neuromodulation tools have potential for reducing ED symptomatology and related behaviours, and for altering food intake and body weight. In response to such findings, and emerging neural models of ED, treatment approaches are highly unlikely to remain 'brainless'. More research is required to evaluate the potential of neuromodulation procedures for improving long-term outcomes in ED.

Stereotactic surgery for eating disorders

EATING DISORDERS (EDS) ARE A GROUP OF SEVERELY IMPAIRED EATING BEHAVIORS, WHICH INCLUDE THREE SUBGROUPS: anorexia nervosa (AN), bulimia nervosa (BN), and ED not otherwise specified (EDNOS). The precise mechanism of EDs is still unclear and the disorders cause remarkable agony for the patients and their families. Although there are many available treatment methods for EDs today, such as family therapy, cognitive behavioral therapy, medication, psychotherapy, and so on, almost half of the patients are refractory to all current medical treatment and never fully recover. For treatment-refractory EDs, stereotactic surgery may be an alternative therapy. This review discusses the history of stereotactic surgery, the modern procedures, and the mostly used targets of stereotactic surgery in EDs. In spite of the limited application of stereotactic surgery in ED nowadays, stereotactic lesion and deep brain stimulation (DBS) are promising treatments with the development of modern functional imaging techniques and the increasing understanding of its mechanism in the future.

Postoperative management of deep brain stimulation in Parkinson's disease

Deep brain stimulation has become an established treatment for advanced Parkinson's disease. Its postoperative management is a delicate phase, dedicated to finding the optimal balance between stimulation and dopaminergic treatment. Postoperative management can be divided into an acute phase, aimed at the selection of the best stimulation contact, and a stabilization phase, aimed at the progressive adjustment of stimulation parameters and medications. A good knowledge of the electrophysiological anatomy of the target and surrounding structures, of the potential consequences of dopaminergic treatment modifications, and of the time course and interactions between stimulation and medication effects is mandatory for optimal outcome. This chapter focuses on the main strategies for the acute and chronic management of stimulation parameters and medication in the three main nuclei targeted in Parkinson's disease, namely the subthalamic nucleus, the ventral intermediate thalamic nucleus, and the internal part of the globus pallidus.

Weight change after globus pallidus internus or subthalamic nucleus deep brain stimulation in Parkinson's disease and dystonia

BACKGROUND

Weight gain has been described in Parkinson's disease (PD) patients after subthalamic nucleus (STN) deep brain stimulation (DBS).

OBJECTIVES

We examined change in weight following DBS in both PD and dystonia patients to further investigate the role of disease and brain target (STN or globus pallidus internus, GPi) specificity.

METHODS

Data was retrospectively collected on 61 PD DBS patients (STN n = 31 or GPi n = 30) and on 36 dystonia DBS patients (STN n = 9 and GPi n = 27) before and after surgery. Annual change in body mass index (BMI) was evaluated with nonparametric tests between groups and multiple quantile regression.

RESULTS

PD patients treated with STN DBS had a small increase in median BMI while those with GPi had a small decrease in BMI. Dystonia patients treated with STN DBS had a greater increase in BMI per year compared to those treated with GPi DBS. Multivariable regression analyses for each disease showed little difference between targets in weight gain in those with PD, but STN target was strongly associated with weight gain in dystonia patients (STN vs. GPi, +7.99 kg, p = 0.012).

CONCLUSIONS

Our results support previous reports of weight gain after DBS in PD. This is the first report to suggest a target-specific increase in weight following STN DBS in dystonia patients.

Free-living energy expenditure reduced after deep brain stimulation surgery for Parkinson's disease

BACKGROUND

The clinical picture in Parkinson's disease (PD) is characterized by bradykinesia, rigidity, resting tremor and postural instability. In advanced stages of the disease, many patients will experience reduced efficacy of medication with fluctuations in symptoms and dyskinesias. Surgical treatment with deep brain stimulation in the subthalamic nucleus (STN-DBS) is now considered the gold standard in fluctuating PD. Many patients experience a gain of weight following the surgery. The aim of this study was to identify possible mechanisms, which may contribute to body weight gain in patients with PD following bilateral STN-DBS surgery.

METHODS

Ten patients with PD were studied before bilateral STN-DBS surgery, and seven patients were studied again 3 and 12 months postoperatively. Clinical examination and resting metabolic rate with and without medical treatment was measured before and after STN-DBS. Furthermore, free-living energy expenditure, body composition, energy intake, peak oxygen consumption, maximal workload and leisure time physical activity were measured before and 3 and 12 months after surgery.

RESULTS

The STN-DBS operated patients had a significant weight gain of 4·7 ± 1·6 kg (mean ± SE) 12 months postoperatively, and the weight gain was in the fat mass. The free-living energy expenditure decreased postoperatively 13 ± 4% even though the reported dietary intake was reduced. A decreased energy expenditure took place in the non-resting energy expenditure. The reported daily leisure time activity, peak oxygen consumption and maximal workload were unchanged.

CONCLUSION

The STN-DBS operated patients have a significant postoperative weight gain, as a result of a decrease in free-living energy expenditure concomitant with an insufficient decrease in energy intake.

Comparison of weight changes following unilateral and staged bilateral STN DBS for advanced PD

Unilateral and bilateral subthalamic nucleus deep brain stimulation (STN DBS) in Parkinson's disease (PD) result in weight gain in the initial postoperative months, but little is known about the changes in weight following unilateral and staged bilateral STN DBS over longer time intervals. A case-control comparison evaluated weight changes over 2 years in 43 consecutive unilateral STN DBS patients, among whom 25 elected to undergo staged bilateral STN DBS, and 21 age-matched and disease severity matched PD controls without DBS. Regression analyses incorporating age, gender, and baseline weight in case or control were conducted to assess weight changes 2 years after the initial unilateral surgery. Unilateral STN DBS and staged bilateral STN DBS patients gained 3.9 ± 2.0 kg and 5.6 ± 2.1 kg versus their preoperative baseline weight (P < 0.001, respectively) while PD controls without DBS lost 0.8 ± 1.1 kg. Although bilateral STN DBS patients gained 1.7 kg more than unilateral STN DBS patients at 2 years, this difference was not statistically significant (P = 0.885). Although there was a trend toward greater weight gain in staged bilateral STN DBS patients versus unilateral patients, we found no evidence for an equivalent or synergistic increase in body weight following placement of the second DBS electrode.