Parkinsonism & related disorders
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Although Parkinson's disease (PD) is considered mainly a movement disorder, robust information accumulated during the last 30 years has shown that about 30% of PD patients may also suffer from psychosis, which deeply affects their quality of life and eventually brings them to permanent hospitalization in nursing homes. PD psychosis (PDPsy) mainly occurs after 10 or more years of treatment. The main features of PDPsy include recurrent and continuous hallucinations and delusions for at least 1 month. ⋯ Therefore, new atypical antipsychotic drugs with serotonin 5-HT2A receptor inverse agonist properties have been developed. Recently, pimavanserin--a 5-HT2A inverse agonist--has been studied. We hope that soon we will have the possibility to include new agents for the management of PDPsy.
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Hallucinations and psychotic behaviors are a frequent non-motor aspect of Parkinson's disease and its treatment. These behaviors usually do not occur in the presence of the physician and are therefore difficult to rate. Further, because of their bizarre nature, hallucinations are frequently underreported by patients, and caregivers are often unaware of them until they become problematic. ⋯ However, the Task Force felt that each of these scales has significant weaknesses and is insufficient to be considered a definitive rating tool. The Task Force officially recommended the development of a new scale to assess hallucinations and psychosis in Parkinson's disease. This effort is now ongoing with official endorsement by the Movement Disorder Society.
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Parkinsonism Relat. Disord. · Dec 2009
Subthalamic nucleus stimulation applied in the earlier vs. advanced stage of Parkinson's disease - retrospective evaluation of postoperative independence in pursuing daily activities.
While bilateral stimulation of the subthalamic nucleus (STN) has been commonly applied for patients with advanced Parkinson's disease (PD), surgery in the earlier stage of the disease may yield a better prognosis. We retrospectively analyzed the pre- and postoperative activities of daily living (ADL) of 38 PD patients who had undergone bilateral STN stimulation 3 months earlier. Preoperative Unified Parkinson's Disease Rating Scale (UPDRS) scores for neuropsychiatric, axial and ADL impairments were negatively correlated with the postoperative Schwab & England ADL (S-E) scale in the off-medication status (p < 0.01). ⋯ Patients with a preoperative on-medication S-E scale
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Parkinsonism Relat. Disord. · Dec 2009
The placebo-reward hypothesis: dopamine and the placebo effect.
Based on the observation that the placebo effect in Parkinson's disease was mediated by the release of endogenous dopamine in both the dorsal and ventral striatum, in 2002 we formally proposed the placebo-reward hypothesis. This hypothesis establishes a link between the placebo effect and reward mechanisms, and predicts that the activation of the ventral striatum should be present in any placebo response, in any medical condition. In keeping with this prediction, functional neuroimaging studies have shown placebo-induced activation of the reward circuitry in Parkinson's disease, depression, and pain. ⋯ The placebo-reward hypothesis also supports the notion that the expectation of clinical benefit plays a major role in the placebo effect. Probability and trust, two key factors involved in shaping expectations, must therefore be essential to the development of placebo responses. The ventral loop of the basal ganglia circuitry (anterior cingulate cortex-ventral striatum-ventral pallidum- mediodorsal nucleus of the thalamus -anterior cingulate cortex) is a fundamental component of the neuroanatomy of the placebo effect.