Int Rev Neurobiol
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Parkinson's disease (PD) is a neurodegenerative disease characterized by the degeneration of dopaminergic nigrostriatal connections which is recognized as the major pathophysiological event underlying the onset of motor symptoms. Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) imaging allow the study of these connections in vivo at a molecular level. ⋯ PET molecular imaging could be a reliable biomarker to aid earlier diagnosis and for monitoring disease progression. Furthermore, PET imaging could be used as outcome measure in the design of clinical trials testing novel pharmacological compounds aiming to slow, and ultimately halt, disease progression.
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There is strong behavioral evidence that placebo and nocebo effects can influence aspects of motor performance like speed, force, and resistance to fatigue in athletes and non-athletes alike. These behavioral studies were essential for extending experimental investigation of the placebo and nocebo effects from the pain to the motor domain and to reveal how verbal suggestions and experiential learning are involved in shaping modulatory systems and related behavioral responses. ⋯ Further evidence derives from studies in patients with Parkinson's disease that have directly demonstrated that placebo-induced improvements in motor symptoms are related to changes in subcortical neural firing activity and dopamine release. Future investigations are needed to better clarify the complex neural architecture underpinning the placebo and nocebo effects in the motor domain.
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Learning is a key mechanism underpinning the development of the nocebo effect. The learning literature has cataloged and explored numerous ways in which the environment can be manipulated to prevent, reduce, or eradicate learning. ⋯ These learning strategies include overshadowing, latent inhibition, extinction, and contingency degradation. These strategies represent important new avenues for investigation and should be used by researchers to design and test interventions to reduce nocebo effects.
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The clinical surveillance and active management of Tourette syndrome (TS) and other primary chronic tic disorders cannot be limited to tics, as these patients manifest a spectrum of sensory-, behavioral-, cognitive-, and sleep-related problems that have a major impact on their functioning and quality of life, influencing enormously clinical decision making on a routine basis. The sensory phenomena of primary tic disorders consist of premonitory urges and heightened sensitivity to external somatosensory and interoceptive stimuli. Recent evidence suggests that raised interoceptive awareness may be related to the classical premonitory urges associated with tics. ⋯ Mood and anxiety disorders, impulse control disorders, rage attacks, "impulsive" tic-like behaviors (e.g., nonobscene socially inappropriate behaviors, and self-injurious behaviors), and autism spectrum disorders complete the wide psychopathological spectrum of primary chronic tic disorders. Moreover, specific sleep abnormalities have been reported in TS patients, although more research is needed on this specific clinical problem. As in other areas of clinical neuroscience, a comprehensive approach to both motor and nonmotor aspects of this group of disorders will help personalizing treatment interventions and, ultimately, improve quality of care.
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The spectrum of sleep problems in Parkinson's disease (PD) is broad. These symptoms are recognized as being clinically relevant by the PD patients and may seriously affect their quality of life. Some studies reveal the occurrence of sleep disorders in more than half of the PD patients. ⋯ Further assessment can be done using sleep recording techniques, like actigraphy or polysomnography. All types of sleep disturbances may be encountered in PD: insomnia, excessive daytime sleepiness, rapid eye movement sleep behavior disorders, and restless legs syndrome. This chapter will focus on reviewing the main characteristics, pathophysiology, assessment, and management of the most frequent sleep disturbances encountered in PD.