ABSTRACT
OBJECTIVES - Determine whether bilateral subthalamic nucleus stimulation (STN-DBS) in Parkinson's disease (PD) is associated with an increase in neuropeptide Y (NPY) and/or resistance to inhibition by leptin in relation to post-surgery weight gain. MATERIALS AND METHODS - This prospective study included 20 patients who underwent bilateral STN-DBS and 17 who refused surgery. Data were obtained at baseline, 3 and 6 months on neurological and nutritional status, including determination of body mass index (BMI) and serum NPY and leptin levels. RESULTS - NPY and leptin levels changed over time, with a distinct pattern. The BMI increase at 6 months was greater in the surgical group (5.5 ± 6.3% vs 0.5 ± 3.5%; P = 0.035). Medical group exhibited a reduction in leptin level (-2.0 ± 4.3 ng/ml) and a consequent increase in NPY level (72.4 ± 58.7 pmol/ml). However, STN-DBS patients showed an increase in leptin (3.1 ± 5.0 ng/ml; P = 0.001 vs medical group) and also in NPY (12.1 ± 53.6 pmol/ml; P = 0.022 vs medical group) levels, which suggests resistance to inhibition by leptin. Rise in NPY level correlated with higher stimulation voltages. CONCLUSIONS - Bilateral STN-DBS causes disruption of the melanocortin system, probably related to diffusion of the electric current to the hypothalamus. This mechanism may in part explain the weight gain of patients with PD after surgery.
Subject(s)
Electric Stimulation Therapy/adverse effects , Leptin/blood , Neuropeptide Y/blood , Parkinson Disease/therapy , Subthalamic Nucleus/physiology , Weight Gain/physiology , Aged , Body Mass Index , Female , Humans , Male , Melanocortins/metabolism , Middle Aged , Prospective Studies , Treatment OutcomeABSTRACT
INTRODUCTION: The effectiveness of stimulating the subthalamic nucleus (DBS-STN) in advanced Parkinson's disease (PD) largely depends on the correct placement of the electrodes. Since the sensory-motor region of the STN lies beside the internal capsule (IC), we believe that the motor effectiveness of DBS-STN could be related to the stimulation threshold in which IC signs appear (IC threshold). PATIENTS AND METHODS: An examination of 17 consecutive patients with advanced PD who had been submitted to bilateral DBS-STN (one case was unilateral) was carried out to determine the motor improvement on each side of the body (n = 33) and the energy consumption one year after surgery according to the IC threshold obtained during the programming. RESULTS: A 45% improvement was observed in the UPDRS III in off and there was a 24% reduction in the equivalent dose of levodopa with bilateral DBS-STN. When the electrodes were considered, there was a statistically significant improvement that depended on the IC threshold. Energy consumption differed significantly between electrodes with an IC threshold of 3-7 V (1.5 +/- 1.2 microW) and those with an IC threshold > 7 V (8.3 +/- 9.4 microW). CONCLUSIONS: During the stimulation phase and following the correct location of the STN, which was achieved by neurophysiological recording, the IC threshold has prognostic implications in medium-long term motor effectiveness and in the consumption of the battery in the generator.
Subject(s)
Deep Brain Stimulation , Parkinson Disease/therapy , Subthalamic Nucleus/physiology , Aged , Antiparkinson Agents/therapeutic use , Deep Brain Stimulation/instrumentation , Deep Brain Stimulation/methods , Electrodes, Implanted , Female , Humans , Internal Capsule/physiology , Levodopa/therapeutic use , Male , Middle Aged , Parkinson Disease/physiopathology , Treatment OutcomeABSTRACT
Introducción. La eficacia de la estimulación del núcleo subtalámico (ECP-NST) en la enfermedad de Parkinson (EP) avanzada depende en gran medida de la correcta implantación de los electrodos. Como la región sensitivomotora del NST está junto a la cápsula interna (CI), pensamos que la eficacia motora de ECP-NST podría relacionarse con el umbral de estimulación en el que aparecen signos de CI (umbral de CI). Pacientes y métodos. En 17 pacientes consecutivos con EP avanzada intervenidos mediante ECP-NST bilateral (uno unilateral) determinamos la mejoría motora en cada lado del cuerpo (n = 33) y el consumo de energía un año después de la cirugía en función del umbral de CI obtenido durante la programación. Resultados. Hubo una mejoría de un 45% en la UPDRS III en off y un 24% de descenso en la dosis equivalente de levodopa con la ECP-NST bilateral. Cuando consideramos los electrodos hubo una mejoría estadísticamente significativa que era dependiente del umbral de CI. El consumo energético difirió significativamente entre los electrodos con un umbral de CI 3-7 voltios (1,5 ± 1,2 mW) y aquéllos con un umbral de CI > 7 voltios (8,3 ± 9,4 mW). Conclusión. Durante la fase de estimulación y tras una correcta localización del NST, mediante registro neurofisiológico, el umbral de CI tiene implicaciones pronósticas en la eficacia motora a medio-largo plazo y en el consumo de la batería del generador (AU)
The effectiveness of stimulating the subthalamic nucleus (DBS-STN) in advanced Parkinsons disease (PD) largely depends on the correct placement of the electrodes. Since the sensory-motor region of the STN lies beside the internal capsule (IC), we believe that the motor effectiveness of DBS-STN could be related to the stimulation threshold in which IC signs appear (IC threshold). Patients and methods. An examination of 17 consecutive patients with advanced PD who had been submitted to bilateral DBS-STN (one case was unilateral) was carried out to determine the motor improvement on each side of the body (n = 33) and the energy consumption one year after surgery according to the IC threshold obtained during the programming. Results. A 45% improvement was observed in the UPDRS III in off and there was a 24% reduction in the equivalent dose of levodopa with bilateral DBS-STN. When the electrodes were considered, there was a statistically significant improvement that depended on the IC threshold. Energy consumption differed significantly between electrodes with an IC threshold of 3-7 V (1.5 ± 1.2 μW) and those with an IC threshold > 7 V (8.3 ± 9.4 μW). Conclusions. During the stimulation phase and following the correct location of the STN, which was achieved by neurophysiological recording, the IC threshold has prognostic implications in mediumlong term motor effectiveness and in the consumption of the battery in the generator (AU)
