Mild cognitive impairment in rapid eye movement sleep behavior disorder and Parkinson's disease

Centre d'étude du Sommeil et des Rythmes Biologiques, Hôpital du Sacré-Coeur de Montréal, Montréal, Québec, Canada.
Annals of Neurology (Impact Factor: 11.91). 07/2009; 66(1):39-47. DOI: 10.1002/ana.21680
Source: PubMed

ABSTRACT To investigate the frequency and subtypes of mild cognitive impairment (MCI) in idiopathic rapid eye movement sleep behavior disorder (RBD) and Parkinson's disease (PD) in association with RBD.
One hundred and twelve subjects without dementia or major depression including 32 idiopathic RBD patients, 22 PD patients with polysomnography-confirmed RBD, 18 PD patients without RBD, and 40 healthy control subjects, underwent a comprehensive neuropsychological evaluation. We compared the proportion of patients with MCI between groups using standard diagnostic criteria.
MCI was found in 50% of idiopathic RBD patients and 73% of PD patients with RBD. In contrast, only 11% of PD patients without RBD and 8% of control subjects had MCI. The presence of MCI was significantly greater in idiopathic RBD patients and PD patients with RBD than in PD patients without RBD and control subjects. PD patients with RBD also performed worse than idiopathic RBD patients on neuropsychological tests assessing visuoconstructional and visuoperceptual abilities.
In both its association with PD and its idiopathic form, RBD is an important risk factor for MCI. Except for visuoconstructional and visuoperceptual problems, RBD may be an important determinant of cognitive impairment in PD. Ann Neurol 2009;66:39-47.

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    • "Moreover, the absence of these associations in the controls suggests that the associations between EEG measures and cognitive performance found in our study are specific to iRBD patients. Poor performance on the Trail Making Test Part B and the Block Design subtest has been reported in DLB and PD with cognitive impairment [6] [29] [30]. This observation suggests that both EEG slowing and impaired performance on these tasks could be early manifestations of cognitive decline in iRBD patients. "
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    ABSTRACT: Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) is a well-documented risk factor for synucleinopathies such as Parkinson disease (PD) and dementia with Lewy bodies (DLB). Moreover, approximately 50% of iRBD patients have mild cognitive impairment (MCI). The purpose of our study was to investigate waking electroencephalogram (EEG) abnormalities specific to iRBD patients with MCI. Forty-two polysomnographically confirmed iRBD patients, including 23 iRBD [+]MCI patients 19 patients without MCI (iRBD [-]MCI), and 37 healthy subjects participated in the study. All participants underwent a complete neuropsychologic assessment for MCI diagnosis and a waking quantitative EEG recording. iRBD [+]MCI patients had a higher slow-to-fast frequency ratio than iRBD [-]MCI patients and controls in the parietal, temporal, and occipital regions. iRBD [+]MCI patients also had higher relative θ power in the parietal, temporal, and occipital regions and lower relative α power in the occipital region compared to iRBD [-]MCI patients and controls. Moreover, iRBD [+]MCI patients had higher relative θ power in the frontal and central areas and lower relative β power in the central, parietal, and temporal regions compared to controls. The dominant occipital frequency also was slower in iRBD [+]MCI patients compared to controls. No between-group differences were observed between iRBD [-]MCI patients and controls. In iRBD patients, only those with concomitant MCI showed waking EEG slowing in the posterior cortical regions, providing a potential marker for an increased risk for developing DLB or PD.
    Sleep Medicine 09/2013; 14(11). DOI:10.1016/j.sleep.2013.06.013 · 3.10 Impact Factor
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    • "Criteria should be developed for how iRBD patients are tested and how the results can influence entry into the study. (F) RBD patients with mild cognitive impairment [34] [35] [36]. This inclusion is in line with the previous inclusion of RBD patients with soft neurologic dysfunction. "
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    ABSTRACT: We aimed to provide a consensus statement by the International Rapid Eye Movement Sleep Behavior Disorder Study Group (IRBD-SG) on devising controlled active treatment studies in rapid eye movement sleep behavior disorder (RBD) and devising studies of neuroprotection against Parkinson disease (PD) and related neurodegeneration in RBD. The consensus statement was generated during the fourth IRBD-SG symposium in Marburg, Germany in 2011. The IRBD-SG identified essential methodologic components for a randomized trial in RBD, including potential screening and diagnostic criteria, inclusion and exclusion criteria, primary and secondary outcomes for symptomatic therapy trials (particularly for melatonin and clonazepam), and potential primary and secondary outcomes for eventual trials with disease-modifying and neuroprotective agents. The latter trials are considered urgent, given the high conversion rate from idiopathic RBD (iRBD) to Parkinsonian disorders (i.e., PD, dementia with Lewy bodies [DLB], multiple system atrophy [MSA]). Six inclusion criteria were identified for symptomatic therapy and neuroprotective trials: (1) diagnosis of RBD needs to satisfy the International Classification of Sleep Disorders, second edition, (ICSD-2) criteria; (2) minimum frequency of RBD episodes should preferably be ⩾2 times weekly to allow for assessment of change; (3) if the PD-RBD target population is included, it should be in the early stages of PD defined as Hoehn and Yahr stages 1-3 in Off (untreated); (4) iRBD patients with soft neurologic dysfunction and with operational criteria established by the consensus of study investigators; (5) patients with mild cognitive impairment (MCI); and (6) optimally treated comorbid OSA. Twenty-four exclusion criteria were identified. The primary outcome measure for RBD treatment trials was determined to be the Clinical Global Impression (CGI) efficacy index, consisting of a four-point scale with a four-point side-effect scale. Assessment of video-polysomnographic (vPSG) changes holds promise but is costly and needs further elaboration. Secondary outcome measures include sleep diaries; sleepiness scales; PD sleep scale 2 (PDSS-2); serial motor examinations; cognitive indices; mood and anxiety indices; assessment of frequency of falls, gait impairment, and apathy; fatigue severity scale; and actigraphy and customized bed alarm systems. Consensus also was established for evaluating the clinical and vPSG aspects of RBD. End points for neuroprotective trials in RBD, taking lessons from research in PD, should be focused on the ultimate goal of determining the performance of disease-modifying agents. To date no compound with convincing evidence of disease-modifying or neuroprotective efficacy has been identified in PD. Nevertheless, iRBD patients are considered ideal candidates for neuroprotective studies. The IRBD-SG provides an important platform for developing multinational collaborative studies on RBD such as on environmental risk factors for iRBD, as recently reported in a peer-reviewed journal article, and on controlled active treatment studies for symptomatic and neuroprotective therapy that emerged during the 2011 consensus conference in Marburg, Germany, as described in our report.
    Sleep Medicine 07/2013; 15(1). DOI:10.1016/j.sleep.2013.02.016 · 3.10 Impact Factor
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    • "Cognitive impairment has been associated with nocturnal psychosis, hallucination, depressive symptoms and excessive daytime sleepiness [3] [4]. Furthermore, it has been reported that patients with PD and RBD showed more frequent mild cognitive impairment [5] and poorer performance on tests of episodic verbal memory, executive functions and visuospatial and visuoperceptual processing compared with patients with PD without RBD [6]. Although the coexistence of RLS in PD patients has been reported with a frequency ranging from 0 to 50% [7], a relationship between RLS and PD is still controversial [8] [9] [10] [11]. "
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    ABSTRACT: The aim of this study was to assess the validity and the reliability of the Japanese version of the Parkinson's disease sleep scale (PDSS)-2 and to use this scale to identify nocturnal symptoms and their impact on patient's quality of life. A cross-sectional, case-controlled study was conducted consisting of 93 patients with Parkinson's disease (PD) and 93 age- and gender-matched control subjects. The Japanese version of the PDSS-2 was used for the evaluation of nocturnal disturbances. The patient's quality of life was evaluated with the Parkinson's Disease Quality of Life questionnaire (PDQ-39) and their depressive symptoms were assessed with the Beck Depression Inventory-II (BDI-II), respectively. In addition, the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and Parkinson Fatigue Scale (PFS) were administered. As assessed using the PDSS-2, PD patients had significantly impaired scores compared with control subjects (15.0±9.7 vs. 9.1±6.6, p<0.001). The ESS, BDI-II and PFS scores were significantly impaired in PD patients compared with controls. A satisfactory internal consistency and test-retest reliability score were obtained for the PDSS-2 total score (Cronbach's alpha=0.86). The PDSS-2 was correlated with the PSQI, ESS, BDI-II, PFS, PDQ-39 summary index, all of the PDQ-39 domains and Unified Parkinson's Disease Rating Scale part III. The frequency of restless legs syndrome (RLS) was not significantly different between PD patients and controls (5.5% vs. 2.2%), but nocturnal restlessness was significantly more frequent in PD patients than controls. Stepwise linear regression analyses revealed the PDQ-39 summary index and the PSQI global score as significant predictors for the PDSS-2 total score. Our study confirmed the usefulness of the Japanese version of the PDSS-2 that enables the comprehensive assessment of nocturnal disturbances in PD. The association between RLS and nocturnal restlessness in PD requires further study.
    Journal of the neurological sciences 04/2012; 318(1-2):76-81. DOI:10.1016/j.jns.2012.03.022 · 2.26 Impact Factor
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