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Item does not contain fulltext, Pedunculopontine nucleus region deep brain stimulation (DBS) is a promising but experimental therapy for axial motor deficits in Parkinson's disease (PD), particularly gait freezing and falls. Here, we summarise the clinical application and outcomes reported during the past 10 years. The published dataset is limited, comprising fewer than 100 cases. Furthermore, there is great variability in clinical methodology between and within surgical centers. The most common indication has been severe medication refractory gait freezing (often associated with postural instability). Some patients received lone pedunculopontine nucleus DBS (unilateral or bilateral) and some received costimulation of the subthalamic nucleus or internal pallidum. Both rostral and caudal pedunculopontine nucleus subregions have been targeted. However, the spread of stimulation and variance in targeting means that neighboring brain stem regions may be implicated in any response. Low stimulation frequencies are typically employed (20-80 Hertz). The fluctuating nature of gait freezing can confound programming and outcome assessments. Although firm conclusions cannot be drawn on therapeutic efficacy, the literature suggests that medication refractory gait freezing and falls can improve. The impact on postural instability is unclear. Most groups report a lack of benefit on gait or limb akinesia or dopaminergic medication requirements. The key question is whether pedunculopontine nucleus DBS can improve quality of life in PD. So far, the evidence supporting such an effect is minimal. Development of pedunculopontine nucleus DBS to become a reliable, established therapy would likely require a collaborative effort between experienced centres to clarify biomarkers predictive of response and the optimal clinical methodology. (c) 2017 International Parkinson and Movement Disorder Society.

Item does not contain fulltext, BACKGROUND: Subthalamic nucleus deep brain stimulation (STN-DBS) improves motor symptoms of Parkinson's disease (PD) and motor complications of dopaminergic treatment. Whether STN-DBS should be considered when PD patients experience neuropsychiatric symptoms is controversial. Lack of systematic behavioral evaluation at baseline hampers the understanding of postoperative neuropsychiatric outcomes. OBJECTIVE: This study compares the behavioral profile of a surgical population to that in general PD. METHODS: Single center data from 234 PD surgical candidates were compared to data from 260 non-demented PD patients consulting in 13 PD expert centers at different stages of disease. The latter were considered representative of the general PD population. Neuropsychiatric symptoms were assessed using the Ardouin Scale of Behavior in PD, a guided interview quantifying changes in severity of 21 neuropsychiatric symptoms, classified into psychic non-motor fluctuations, hypo- and hyperdopaminergic behaviors. Multivariate analyses were performed to study differences in behavioral items between the two groups. Results : Surgical candidates were younger, had longer disease duration and used significantly higher doses of dopaminergic drugs. After adjustment for covariates, dopaminergic addiction (OR 10.83; p = 0.002), nocturnal hyperactivity (OR 1.87; p = 0.04), excessive hobbyism (OR 2.37; p = 0.008), "excess in motivation" (OR 4.02; p < 0.001), psychic OFF (2.87; p < 0.001) and psychic ON (2.10; p = 0.001) fluctuations were more frequent in the surgical candidates. Depressed mood prevailed in the general PD population (OR 0.53; p = 0.045). CONCLUSION: Behavioral complications of dopaminergic treatment are frequent in PD patients candidates for STN-DBS. They cannot be considered as contraindications for STN-DBS but must be taken into account in postoperative management.

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Item does not contain fulltext, BACKGROUND: Impulse control disorders (ICD), including pathological gambling, are common in Parkinson's disease (PD) and tend to improve after subthalamic (STN) stimulation after a marked reduction of dopaminergic medication. In order to investigate the effect of STN stimulation on impulsive decision making, we used the Iowa Gambling task (IGT). METHODS: We investigated IGT performance in 20 patients with PD before STN surgery with and without dopaminergic treatment and in 24 age-matched controls. All patients underwent an extensive neuropsychological interview screening for behavioural disorders. Assessment in patients was repeated 3 months after surgery without dopaminergic treatment with and without stimulation. RESULTS: Chronic antiparkinsonian treatment was drastically reduced after surgery (-74%). At baseline, on high chronic dopaminergic treatment 8/20 patients with PD presented with pathological hyperdopaminergic behaviours, which had resolved in 7/8 patients 3 months after surgery on low chronic dopaminergic treatment. Preoperative performance on the IGT was significantly impaired compared to after surgery. CONCLUSIONS: Dopaminergic medication likely contributes to the impairment in decision making underlying ICDs. Deep brain stimulation allows drastic reduction of dopaminergic medication and, thus, concomitant remediation of medication-induced impairment in decision making.

Item does not contain fulltext, OBJECTIVE: To compare the influence of low-frequency (10-25 Hz) versus higher (60-80 Hz) frequency stimulation of the pedunculopontine nucleus area (PPNa) on akinaesia, freezing of gait and daytime sleepiness. METHOD: We included nine patients with Parkinson's disease (PD) and severe gait disorders. In this double-blind randomised cross-over study, patients were assessed after 24 h of PPNa stimulation. Assessments included the motor part of the Unified Parkinson's Disease Rating Scale, the Epworth Sleepiness Scale and a behavioural gait assessment. RESULTS: Compared with 60-80 Hz, 10-25 Hz PPNa stimulation led to decreased akinaesia, gait difficulties and daytime sleepiness in 7/9 patients. In one patient, these symptoms were aggravated under 10-25 Hz stimulation compared with 60-80 Hz. CONCLUSION: These results are in keeping with the benefits of chronic PPNa stimulation for gait and postural difficulties in patients with PD, and with regard to the influence of patients' clinical characteristics, differential neuronal loss in the PPNa and electrode location. We conclude that in patients with PPNa stimulation, low frequency provides a better outcome than high-frequency stimulation.

Contains fulltext : 153489.pdf (Publisher’s version ) (Closed access), Gait disturbances, including freezing of gait, are frequent and disabling symptoms of Parkinson's disease. They often respond poorly to dopaminergic treatments. Although recent studies have shed some light on their neural correlates, their modulation by dopaminergic treatment remains quite unknown. Specifically, the influence of levodopa on the networks involved in motor imagery (MI) of parkinsonian gait has not been directly studied, comparing the off and on medication states in the same patients. We therefore conducted an [H2 (15) 0] Positron emission tomography study in eight advanced parkinsonian patients (mean disease duration: 12.3 +/- 3.8 years) presenting with levodopa-responsive gait disorders and FoG, and eight age-matched healthy subjects. All participants performed three tasks (MI of gait, visual imagery and a control task). Patients were tested off, after an overnight withdrawal of all antiparkinsonian treatment, and on medication, during consecutive mornings. The order of conditions was counterbalanced between subjects and sessions. Results showed that imagined gait elicited activations within motor and frontal associative areas, thalamus, basal ganglia and cerebellum in controls. Off medication, patients mainly activated premotor-parietal and pontomesencephalic regions. Levodopa increased activation in motor regions, putamen, thalamus, and cerebellum, and reduced premotor-parietal and brainstem involvement. Areas activated when patients are off medication may represent compensatory mechanisms. The recruitment of these accessory circuits has also been reported for upper-limb movements in Parkinson's disease, suggesting a partly overlapping pathophysiology between imagined levodopa-responsive gait disorders and appendicular signs. Our results also highlight a possible cerebellar contribution in the pathophysiology of parkinsonian gait disorders through kinesthetic imagery.