Weight Gain following Pallidal Deep Brain Stimulation: A PET Study

Abstract

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.

Cellular, molecular, and clinical mechanisms of action of deep brain stimulation—a systematic review on established indications and outlook on future developments

“…This was shown in in vitro experiments: When neuronal synaptic activity was blocked in the thalamus, vesicular glutamate release was still found via astrocytes (Tawfik et al , ). Furthermore, astrocytes will shift potassium into the extracellular space and therefore contribute to a microenvironment that supports depolarization block‐like states (Sasaki et al , ; Barat et al , ; Sauleau et al , ). The change in the microenvironment of non‐neural cells might lead to prolonged plasticity‐associated effects even when stimulation is turned off.…”

Clinical Impact of Deep Brain Stimulation on the Autonomic System in Patients with Parkinson's Disease

“…51 The Aiello study further highlighted that weight gain postoperatively negatively correlated with levodopa therapy reduction, that is, the greater the medication reduction the more weight gain, and this also corresponded to disease duration. 50 Concerning GPi-DBS, Sauleau and colleagues 52 performed a PET study of PD patients following surgery. As with studies focusing on STN-DBS, they found that body mass index increased significantly following surgery.…”

Deep Brain Stimulation in Non-motor Symptoms of Neurodegenerative Diseases

“…Generally, the pulses inhibit cell body activity while creating action potentials in the axons [20]. The pulses also act on astrocytes and microglia in the area of stimulation, causing a change in glial activity and complete changes in ion concentrations such as potassium and calcium, which in turn influences the changes in action potentials of neurons [21]. Immediate effects of DBS are a consequence of the function of individual neurons that are stimulated in the vicinity of the placed electrode and vary greatly depending on the selected target.…”