Rev Neurol France
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During the past 10 years, there has been an increasing interest in the study of rapid-eye-movement (REM) sleep in neurodegenerative diseases and more particulary in Parkinson's disease (PD). This interest is justified by the strong association observed between these diseases and REM sleep behavior disorder (RBD). In the first section of this paper, a critical review of the literature on the presence of REM sleep disorders in PD is presented. ⋯ Emphasis is placed on the role of cholinergic neurons of the pedunculopontine and laterodorsal tegmental nuclei, structures shown to be particularly impaired in PD. Neurophysiological, neuroanatomical and neuropharmacological studies demonstrate that these neurons are strongly implicated in the different REM sleep parameters (muscular atonia, electroencephalographic desynchronisation, ponto-geniculo-occipital spikes). Finally, future research directions are proposed.
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The effects of deep brain stimulation (DBS) of the subthalamic nucleus (STN) or the internal pallidum (GPi) on the parkinsonian triad and on levodopa-induced dyskinesias are very similar. The antiakinetic effect of STN DBS seems to be slightly better. On the contrary to pallidal DBS, stimulation of the STN allows to reduce dopaminergic treatment by more than 50p.100 on average. ⋯ It is the responsibility of the operating centre to determine the levodopa response, to confirm the diagnosis, to rule out contraindications and to make sure that the medical treatment cannot be further optimised. Severe surgical complications with permanent sequels are relatively rare, about 1p.100 per implanted side. The patient selection, the precision of the surgery and the quality of the postoperative follow-up are the three main determinants of success.
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Mild Cognitive Impairment (MCI) is an emerging concept used to describe memory decline and probably attention disturbances in otherwise intellectually intact individuals. MCI may be considered in 12 to 15 p. 100 of the cases as announcing an Alzheimer's Disease (AD). Although still speculative, the debate concerning the drugs susceptible to normalize symptoms of MCI or to stop conversion to AD must be raised. For that purpose, several long term clinical trials are running (antioxidants, nootropics, anticholinesterasics.) and new molecules in the pipe-line should be assessed in patients with the diagnosis of MCI.
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Cognitive impairment without dementia is common in elderly persons and causes significant impairment in capacity to perform everyday activities. A number of nosological entities have been proposed for the classification of sub-clinical cognitive dysfunction. ⋯ While prospective studies suggest that persons with mild cognitive disorder have a high risk of developing dementia, long-term follow-up of subjects with mild cognitive impairment suggests that dementia alone does not explain all cases. Cognitive disorder in the elderly must be construed as a common outcome for a number of interacting pathologies whose expression is also mediated by genetic, environmental and social factors.