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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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.
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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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Border forms of multiple sclerosis (MS) can be separated in two groups: either they are variants of MS or they are distinct from MS but they share several characteristics with MS thus representing for some of them a continuum with MS. All these entities are central nervous system demyelinating diseases. Here we describe, for the first group, MS in childhood, MS in elderly subjects, Balò's concentric sclerosis, Schilder's myelinoclastic diffuse sclerosis and MS simulating a mass lesion, and for the second group, acute disseminated encephalomyelitis and Devic's neuromyelitis optica.