Clinical manifestations of Parkinson disease and the onset of rapid eye movement sleep behavior disorder

ObjectiveTo identify whether the presence and/or timing of rapid eye movement (REM) sleep behavior disorder (RBD) onset were associated with differences in clinical features and sleep parameters of Parkinson disease (PD).MethodsIn all, 112 PD patients were enrolled and all underwent extensive clinical evaluations and video-polysomnography (PSG). Clinical features and PSG parameters were compared in PD patients with (PD + RBD) or without (PD − RBD) RBD, RBD preceding (RBD > PD), or not (PD ⩾ RBD) PD onset.ResultsSixty-three of the 112 PD patients were affected by RBD. Adjusted for age, gender, education, body mass index (BMI), levodopa equivalent daily dose (LED) and PD duration, PD + RBD patients had higher Hoehn & Yahr stage, higher scores for UPDRS parts I, II and III, more dyskinesia, higher ratio of axial/limb manifestations, and more hallucinations. Their cognitive and quality-of-life status was significantly lower (all P < 0.05). For PSG, PD + RBD patients exhibited higher percentages of phasic and tonic EMG activities, lower apnea hypopnea (AHI) and oxygen desaturation index (ODI), and less time in arterial oxygen saturation (SaO₂) <90% during REM sleep (all P < 0.05). PD ⩾ RBD (n = 22) patients did not significantly differ from RBD > PD (n = 41) patients in clinical manifestations, whereas the PD ⩾ RBD subgroup had significantly higher UPDRS part I score, lower PDQ score and lower AHI during REM than the PD − RBD group (all P < 0.05), but not RBD > PD subgroup. Correlation analysis showed that worse cognition was associated with shorter interval of RBD preceding PD onset (r = 0.297, P = 0.018), but not RBD duration (P = 0.202).ConclusionsClinical manifestations of PD may vary depending on the presence and timing of RBD onset. These findings are compatible with the hypothesis that RBD may be a marker of complex subtypes of PD.     

Functional neuroimaging and clinical features of drug naive patients with de novo Parkinson’s disease and probable RBD

IntroductionThe association between Parkinson Disease (PD) and REM sleep behavior disorder (RBD) has been related to a specific, malignant clinical phenotype. Definite RBD diagnosis requires video-polysomnography that is often unfeasible. A malignant clinical PD-RBD phenotype could be expected also in PD patients with probable RBD. Aim of this cross-sectional study was to evaluate whether a more severe neuropsychological and functional neuroimaging phenotype can be identified in PD patients with probable RBD.MethodsThirty-eight de novo, drug naïve PD patients underwent a first-line clinical assessment and a second-line multimodal assessment, including neuropsychological evaluation, ¹²³I-FP-CIT-SPECT and ¹⁸F-FDG-PET, which were compared between PD patients with (PD + RBD+) and without (PD + RBD-) probable RBD.ResultsOn first-line assessment, PD + RBD + patients had significantly more constipation (p = 0.02) and showed worse olfaction (p = 0.01) compared with PD + RBD-while the two groups were similar as for age, presence of orthostatic hypotension, UPDRS-III and MMSE scores. On second-line assessment, PD + RBD + patients showed a worse neuropsychological test profile, more severe nigro-striatal dopaminergic impairment, mainly at caudate level in the less affected hemisphere (p = 0.004) and impaired brain glucose metabolism, with relative hypometabolism in posterior cortical regions and relative hypermetabolism mainly in anterior regions of the more affected hemisphere (p = 0.015).ConclusionsPD patients with probable RBD are likely to have a more severe neuropsychological and functional brain-imaging phenotype already at the time of diagnosis.     

Two polysomnographic features of REM sleep behavior disorder: Clinical variations insight for Parkinson's disease

IntroductionLoss of REM sleep muscle atonia (RWA) and dream-enactment behavior (DEB) are two associated features of REM sleep behavior disorder (RBD), which is frequently associated with Parkinson's disease (PD). Few studies have examined both DEB and RWA simultaneously in patients with PD. This study aimed to evaluate relationships between RWA, DEB and clinical characteristics of PD.MethodsWe conducted overnight polysomnography in 145 patients with PD. DEB (motor behaviors and/or vocalizations during REM) and increased RWA (IRWA; tonic and phasic chin EMG density ≥ 30% and ≥15%, respectively) were identified. Patients were categorized as clinical RBD (DEB and IRWA), sub-DEB positive (DEB only), subclinical RBD (IRWA only), or normal REM sleep.ResultsPatients with DEB had higher Hoehn and Yahr (H&Y) stage, Unified Parkinson's Disease Rating Scale (UPDRS) III score, levodopa equivalent dose(LEDs), and worse cognition. RWA was associated with H&Y stage, LEDs, cognition, and sleep structure in all patients. PD duration was associated with RWA, but not DEB. The PD patients who exhibited clinical or subclinical RBD, compared to sub-DEB positive, had higher H&Y stage, UPDRS III score and LEDs, lower cognitive score, worse sleep structure than the PD + cREM group.ConclusionBoth DEB and RWA were associated with severity of PD illness. Subclinical RBD might have different disease progression from sub-DEB positive. DEB symptoms may fluctuate or disappear whereas RWA may continue to develop as PD progresses. Differences in the course of DEB and RWA may reflect the difference in the degeneration process of neurodegenerative disorders.     

Surface EMG activity during REM sleep in Parkinson's disease correlates with disease severity

ObjectivesOver 40% of individuals with Parkinson's disease (PD) have rapid eye movement sleep behavior disorder (RBD). This is associated with excessive sustained (tonic) or intermittent (phasic) muscle activity instead of the muscle atonia normally seen during REM sleep. We examined characteristics of manually-quantitated surface EMG activity in PD to ascertain whether the extent of muscle activity during REM sleep is associated with specific clinical features and measures of disease severity.MethodsIn a convenience sample of outpatients with idiopathic PD, REM sleep behavior disorder was diagnosed based on clinical history and polysomnogram, and severity was measured using the RBD sleep questionnaire. Surface EMG activity in the mentalis, extensor muscle group of the forearms, and anterior tibialis was manually quantitated. Percentage of REM time with excessive tonic or phasic muscle activity was calculated and compared across PD and RBD characteristics.ResultsAmong 65 patients, 31 had confirmed RBD. In univariate analyses, higher amounts of surface EMG activity were associated with longer PD disease duration (srho = 0.34; p = 0.006) and greater disease severity (p < 0.001). In a multivariate regression model, surface EMG activity was significantly associated with RBD severity (p < 0.001) after adjustment for age, PD disease duration, PD severity and co-morbid sleep abnormalities.ConclusionSurface EMG activity during REM sleep was associated with severity of both PD and RBD. This measure may be useful as a PD biomarker and, if confirmed, may aid in determining which PD patients warrant treatment for their dream enactment to reduce risk of injury.     

Revisiting the impact of REM sleep behavior disorder on motor progression in Parkinson's disease

BackgroundEstimation of progression in Parkinson's disease (PD) is useful to guide clinical decisions and to enable patients to plan and manage their life with PD. Rapid eye movement (REM) sleep behavior disorder (RBD) and REM sleep without atonia (RWA) are recognized as early harbingers of neurodegeneration and may precede motor symptoms by years. However, their impact on motor progression remains elusive.MethodsWe retrospectively analyzed polysomnographic and clinical data of 59 PD patients, grouping them into patients with RBD (n = 15), RWA (n = 22) and those with normal muscle atonia (n = 22). We compared the three groups with regard to motor progression, defined as changes in Unified Parkinson's Disease Rating Scale (UPDRS) III values per year, and selected PD specific characteristics.ResultsMotor disability at first visit and time interval between first and last visits were similar between groups. We observed a significantly faster motor progression in PD patients with RBD and RWA than in those with preserved REM sleep atonia.ConclusionOur findings suggest that impaired muscle atonia during REM sleep might represent a marker of faster motor progression in PD.     

Decreased sleep spindle density in patients with idiopathic REM sleep behavior disorder and patients with Parkinson’s disease

ObjectiveTo determine whether sleep spindles (SS) are potentially a biomarker for Parkinson’s disease (PD).MethodsFifteen PD patients with REM sleep behavior disorder (PD + RBD), 15 PD patients without RBD (PD − RBD), 15 idiopathic RBD (iRBD) patients and 15 age-matched controls underwent polysomnography (PSG). SS were scored in an extract of data from control subjects. An automatic SS detector using a Matching Pursuit (MP) algorithm and a Support Vector Machine (SVM) was developed and applied to the PSG recordings. The SS densities in N1, N2, N3, all NREM combined and REM sleep were obtained and evaluated across the groups.ResultsThe SS detector achieved a sensitivity of 84.7% and a specificity of 84.5%. At a significance level of α = 1%, the iRBD and PD + RBD patients had a significantly lower SS density than the control group in N2, N3 and all NREM stages combined. At a significance level of α = 5%, PD − RBD had a significantly lower SS density in N2 and all NREM stages combined.ConclusionsThe lower SS density suggests involvement in pre-thalamic fibers involved in SS generation. SS density is a potential early PD biomarker.SignificanceIt is likely that an automatic SS detector could be a supportive diagnostic tool in the evaluation of iRBD and PD patients.     

Proof of concept: Screening for REM sleep behaviour disorder with a minimal set of sensors

ObjectiveRapid-Eye-Movement (REM) sleep behaviour disorder (RBD) is an early predictor of Parkinson’s disease, dementia with Lewy bodies, and multiple system atrophy. This study investigated the use of a minimal set of sensors to achieve effective screening for RBD in the population, integrating automated sleep staging (three state) followed by RBD detection without the need for cumbersome electroencephalogram (EEG) sensors.MethodsPolysomnography signals from 50 participants with RBD and 50 age-matched healthy controls were used to evaluate this study. Three stage sleep classification was achieved using a random forest classifier and features derived from a combination of cost-effective and easy to use sensors, namely electrocardiogram (ECG), electrooculogram (EOG), and electromyogram (EMG) channels. Subsequently, RBD detection was achieved using established and new metrics derived from ECG and EMG channels.ResultsThe EOG and EMG combination provided the optimal minimalist fully-automated performance, achieving 0.57 ± 0.19 kappa (3 stage) for sleep staging and an RBD detection accuracy of 0.90 ± 0.11, (sensitivity and specificity of 0.88 ± 0.13 and 0.92 ± 0.098, respectively). A single ECG sensor achieved three state sleep staging with 0.28 ± 0.06 kappa and RBD detection accuracy of 0.62 ± 0.10.ConclusionsThis study demonstrates the feasibility of using signals from a single EOG and EMG sensor to detect RBD using fully-automated techniques.SignificanceThis study proposes a cost-effective, practical, and simple RBD identification support tool using only two sensors (EMG and EOG); ideal for screening purposes.     

REM sleep behavior disorder: Association with motor complications and impulse control disorders in Parkinson's disease

ObjectiveClinical phenotypes such as old age, longer disease duration, motor disability, akineto-rigid type, dementia and hallucinations are known to be associated with REM sleep behavior disorder (RBD) in Parkinson's disease (PD). However, the relationship between motor fluctuations/impulse control and related behaviors (ICRB) and RBD is not clear. We designed this study to elucidate the clinical manifestations associated with RBD to determine the implications of RBD in PD.DesignIn a cross-sectional study, a total of 994 patients with PD were interviewed to determine the presence of RBD and their associated clinical features including motor complications and ICRB.ResultsOf the 944 patients, 578 (61.2%) had clinical RBD. When comparing the clinical features between patients with RBD (RBD group) and without RBD (non-RBD group), older age, longer disease duration, higher Hoehn and Yahr stage (H&Y stage), higher levodopa equivalent daily dose (LEDD), and the existence of wearing off, dyskinesia, freezing, and ICRB, especially punding, were associated with the RBD group compared to the non-RBD group (P < .05 in all). Multivariate analysis showed that motor complications including wearing off, peak dose dyskinesia, and diphasic dyskinesia were the only relevant factors for RBD after adjusting for age and disease duration.ConclusionMotor complications and ICRB are more frequent in patients with RBD than in patients without RBD. In addition, motor complications are related to RBD even after adjusting for age and disease duration.     

REM sleep behavior disorder in Parkinson disease: Association with abnormal ocular motor findings

BackgroundThe anatomical substrates associated with generalized muscle atonia during REM sleep are located on the pontine tegmentum and medial medulla oblongata. We examined whether patients with REM sleep behavior disorder (RBD) have abnormal ocular movements suggesting brainstem or cerebellar dysfunction in Parkinson's disease (PD).MethodsCross-sectional survey for the existence of RBD and abnormal ocular movements. Ocular movements were examined by video-oculography (VOG).ResultsA total of 202 patients were included in this study. One hundred and sixteen (57.4%) of the 202 patients have clinically probable RBD, and 28 (24.1%) of the 116 with clinically probable RBD patients had abnormal VOG findings suggesting brainstem or cerebellar dysfunction; whereas 86 of the 202 patients did not have clinically probable RBD, and only 7 (8.1%) of the 86 patients had abnormal VOG findings suggesting brainstem or cerebellar dysfunction (P = 0.001).ConclusionThis study suggests that the presence of RBD is associated with more severe or extensive brainstem pathology or different distribution of pathology in PD.     

REM sleep behavior disorder and motor dysfunction in Parkinson's disease – A longitudinal study

ObjectivesLongitudinal assessment of a Parkinson's disease (PD) cohort, to investigate the evolution or REM sleep behavior symptoms (RBD) over time and to test the relation between RBD at onset and motor dysfunction progression.MethodsAn early stage PD cohort (n = 61) was assessed at two time points, separated by a two years interval. Diagnostic criteria for RBD were: violent behavior during sleep and body movements or vocalization indicative of dream enacting and at least six affirmative answers in the REM sleep behavior disorder screening questionnaire. Motor function assessment was performed with the Unified Parkinson's Disease Scale part II and III (total and partial scores for tremor, bradykinesia, rigidity, gait/postural instability and dysarthria).Results25 Patients had RBD at baseline, vs. 35 at follow-up. Three RBD changed to non-RBD at follow-up, while 10 non-RBD patients developed RBD at follow-up (annual incidence of 12.5%). RBD and non-RBD patients did not differ significantly at baseline or follow-up. The presence of RBD at baseline was significantly related to an increase in UPDRS total and bradykinesia scores over time.DiscussionRBD symptoms can vary over time and have a tendency to increase during the early stages of disease. The presence of RBD symptoms could be a risk factor for motor function deterioration and particularly for bradykinesia worsening.     

Does REM sleep behavior disorder change in the progression of Parkinson’s disease?

Objectives/backgroundRapid eye movement (REM) Sleep Behavior Disorder (RBD) in Parkinson's disease (PD) may be associated with a malignant phenotype. Despite its prognostic value, little is known about the time course of RBD in PD. In this study, we aimed to ascertain whether or not RBD is a stable feature in PD. In this study, we prospectively evaluated clinical and neurophysiological features of RBD, including REM Sleep Without Atonia (RSWA), in PD patients with RBD at baseline and after three years then assessed whether the changes in measures of RSWA parallel the progression of PD.Patients/methodsIn sum, 22 (17M, mean age 64.0 ± 6.9 years) moderate-to-advanced PD patients (mean PD duration at baseline:7.6±4.8 years) with RBD, underwent a video-polysomnography (vPSG) recording and clinical and neuropsychological assessment at baseline and after three years.ResultsAt follow-up, the self-assessed frequency of RBD symptoms increased in six patients, decreased in six and remained stable in 10, while RSWA measures significantly increased in all subjects. At follow-up, patients showed worse H&Y stage (p = 0.02), higher dopaminergic doses (p = 0.05) and they performed significantly worse in phonetic and semantic fluency tests (p = 0.02; p = 0.04). Changes in RSWA correlated significantly with the severity in levodopa-induced dyskinesia (r = 0.61,p = 0.05) and motor fluctuation (r = 0.54,p = 0.03) scores, and with the worsening of executive functions (r = 0.78,p = 0.001) and visuo-spatial perception (r = −0.57,p = 0.04).ConclusionDespite the subjective improvement of RBD symptoms in one-fourth of PD patients, all RSWA measures increased significantly at follow-up, and their changes correlated with the clinical evolution of motor and non-motor symptoms. RBD is a long-lasting feature in PD and RSWA is a marker of the disease's progression.     

Parkinson’s disease and REM sleep behavior disorder result in increased non-motor symptoms

ObjectiveRapid eye movement (REM)-sleep behavior disorder (RBD) is often comorbid with Parkinson’s disease (PD). The current study aimed to provide a detailed understanding of the impact of having RBD on multiple non-motor symptoms (NMS) in patients with PD.MethodsA total of 86 participants were evaluated for RBD and assessed for multiple NMS of PD. Principal component analysis was utilized to model multiple measures of NMS in PD, and a multivariate analysis of variance was used to assess the relationship between RBD and the multiple NMS measures. Seven NMS measures were assessed: cognition, quality of life, fatigue, sleepiness, overall sleep, mood, and overall NMS of PD.ResultsAmong the PD patients, 36 were classified as having RBD (objective polysomnography and subjective findings), 26 as not having RBD (neither objective nor subjective findings), and 24 as probably having RBD (either subjective or objective findings). RBD was a significant predictor of increased NMS in PD while controlling for dopaminergic therapy and age (p = 0.01). The RBD group reported more NMS of depression (p = 0.012), fatigue (p = 0.036), overall sleep (p = 0.018), and overall NMS (p = 0.002).ConclusionIn PD, RBD is associated with more NMS, particularly increased depressive symptoms, sleep disturbances, and fatigue. More research is needed to assess whether PD patients with RBD represent a subtype of PD with different disease progression and phenomenological presentation.     

Rapid eye movement sleep behaviour disorder in young- and older-onset Parkinson disease: a questionnaire-based study

BackgroundRapid eye movement sleep behavior disorder (RBD) is common in Parkinson disease (PD).ObjectivesTo determine the frequency of clinically probable RBD (cpRBD) in young-onset (21 to ⩽40 years; YOPD) and older-onset PD (>40 years; OOPD) and characterize its pattern.MethodsA total of 156 patients with PD (YOPD-51, OOPD-105) were clinically examined and the presence of RBD was diagnosed using the minimal criteria for diagnosis of RBD (International Classification of Sleep Disorders, ICSD-1). RBD screening questionnaire based on the minimal criteria was used. The bed-partners were also interviewed with Mayo sleep questionnaire. Other scales included Unified Parkinson Disease Rating Scale part III (UPDRS III), Hoehn & Yahr stage, Mini Mental Status Examination, Pittsburgh Sleep Quality Index, Parkinson Disease Sleep Scale, Epworth Sleep Scale, Hamilton Anxiety Rating Scale and Hamilton Depression Rating Scale.ResultscpRBD was diagnosed in 30 (19.2%) patients, majority being OOPD rather than YOPD (86.7% vs 13.3%; P = 0.01). The frequency of RBD was significantly higher (P = 0.016) in OOPD (24.8%) compared to those with YOPD (7.8%). Most often (72.4%) RBD occurred after the onset of parkinsonian symptoms. RBD was independently associated with higher global PSQI scores, total ESS scores and total PDSS scores after adjusting for the effects of age, gender, Hoehn & Yahr stage and duration of illness.ConclusionsPatients with RBD were older with later-onset motor symptoms, a more advanced stage, poorer sleep quality, and more frequent daytime sleepiness. Older-onset PD had a higher frequency of RBD than young-onset PD.     

Cardiac sympathetic index identifies patients with Parkinson's disease and REM behavior disorder

ObjectiveTo compare circadian autonomic fluctuations in patients with Parkinson's Disease (PD) with or without REM sleep behavior disorder (RBD) by using heart rate variability (HRV) analysis.MethodsThis is a case-control study including 20 PD patients with RBD (PD-RBD) and 20 PD patients without RBD (PD). In all patients, we measured the components of HRV in the frequency domain during 24-h with daytime and night time recordings. Selected variables considered were low-frequency (LF) influenced by the sympathetic system and high-frequency (HF) influenced by the parasympathetic system. Moreover, we calculated night-to-day ratio for both LF (cardiac sympathetic index) and HF (cardiac parasympathetic index) spectral components. Video-polysomnography was performed in all patients to diagnose RBD.ResultsBoth nocturnal LF and HF spectral power values were significantly higher in PD-RBD patients than in PD patients (P < 0.001 and P = 0.004 respectively). Moreover, in PD-RBD patients LF and HF values were higher at night than during the day while no difference between night time and daytime values was observed in patients with PD. Cardiac sympathetic index value was significantly higher in PD-RBD patients (median 1.83, range 1.65–3.66) than in PD patients (median 0.93, range 0.44–1.3) without overlap of individual values between groups (accuracy 100%). By contrast, cardiac parasympathetic index had sensitivity of 45% and specificity of 100% for differentiating between PD groups.ConclusionsCardiac sympathetic index distinguishes PD-RBD patients from those with PD on an individual basis, thus representing a valid help in everyday clinical practice for screening of RBD in PD patients.     

Comparative study of the substantia nigra echogenicity and 123I-Ioflupane SPECT in patients with synucleinopathies with and without REM sleep behavior disorder

ObjectivesHyperechogenicity of the substantia nigra (SN) and abnormal dopamine transporter-single-photon emission computed tomography (DAT-SPECT) are biomarkers commonly used in the assessment of prodromal synucleinopathy. Our goals were as follows: (1) to compare echogenicity of SN in idiopathic rapid eye movement (REM) behavior disorder (iRBD), Parkinson's disease (PD) without RBD (PD-noRBD), PD with RBD (PD + RBD), and control subjects; and (2) to examine association between SN degeneration assessed by DAT-SPECT and SN echogenicity.Patients/methodsA total of 61 subjects with confirmed iRBD were examined using Movement Disorders Society-unified PD rating scale (MDS-UPDRS), TCS (transcranial sonography) and DAT-SPECT. The results were compared with 44 patients with PD (25% PD + RBD) and with 120 age-matched healthy subjects.Results and conclusionThe abnormal SN area was found in 75.5% PD, 23% iRBD and 7.3% controls. Median SN echogenicity area in PD (0.27 ± 0.22 cm²) was higher compared to iRBD (0.07 ± 0.07 cm²; p < 0.0001) and controls (0.05 ± 0.03 cm²; p < 0.0001). SN echogenicity in PD + RBD was not significantly different from PD-noRBD (0.30 vs. 0.22, p = 0.15).Abnormal DAT-SPECT was found in 16 iRBD (25.4%) and 44 PD subjects (100%). No correlation between the larger SN area and corresponding putaminal binding index was found in iRBD (r = −0.13, p = 0.29), nor in PD (r = −0.19, p = 0.22).The results of our study showed that: (1) SN echogenicity area in iRBD was higher compared to controls, but the hyperechogenicity was present only in a minority of iRBD patients; (2) SN echogenicity and DAT-SPECT binding index did not correlate in either group; and (3) SN echogenicity does not differ between PD with/without RBD.     

REM sleep behavior disorder in Parkinson's disease – Is there a gender difference?

BackgroundREM sleep behavior disorder (RBD) is common in Parkinson's disease (PD). While previous studies of idiopathic RBD have reported a striking male preponderance, little information exists about potential gender differences of RBD in PD.MethodsWe performed a cross sectional study of 107 PD patients. Probable RBD (pRBD) was diagnosed using the RBD Screening Questionnaire.ResultsMen had more fights (96% versus 54%, p < 0.001), violent behavior (71% versus 39%, p = 0.04) and awakening by own movements (89% versus 62%, p = 0.04). More women experienced disturbed sleep (85% versus 32%, p = 0.02). The frequency of pRBD was 31% in women and 43% in men (p = 0.2), total frequency 38%.ConclusionsWe found no clear differences in the frequency of pRBD among men and women with PD, but demonstrated significant gender differences in its clinical expression. Female PD patients reported significantly less fights and aggressive behavior during dreams, but had more disturbed sleep.     

REM sleep behavior disorder in early Parkinson’s disease predicts the rapid dopaminergic denervation

ObjectiveTo test the hypothesis that REM sleep behavior disorder (RBD) in early Parkinson's disease (PD) predicts rapid progression of dopaminergic denervation.Methods123I-FP-CIT single photon emission computed tomography (SPECT) scans were performed sequentially at baseline, 1 year, 2 years, and 4 years in 416 de novo patients with PD. RBD screening questionnaire scores >5 at baseline placed the participant in the likely-RBD group. Temporal changes in the specific binding ratio (SBR; caudate, putamen. sum of both, striatum) were compared between the likely-RBD and the non-likely-RBD groups for more or less affected striatum with a repeated measure ANOVA.ResultsLikely-RBD was reported in 37.7% of the drug-naïve PD patients at baseline. The likely-RBD and non-likely-RBD groups did not have significant differences in the baseline clinical features including gender, age, disease duration, UPDRS motor score, and striatal SBR. Striatal SBR decreased significantly over four years in both groups (P < .001). In the analysis of a more affected striatum, striatal SBR decreased significantly faster in the likely-RBD group than in the non-likely-RBD group (P < .05 for all), whereas it was not statistically significant for the less affected striatum. The mean striatal SBR value (mean value of both striata), especially the caudate SBR, indicated greater acceleration of denervation in the likely-RBD group than in the non-likely-RBD group over time (P < .05).ConclusionLikely-RBD in PD predicts accelerating dopaminergic denervation, thereby implicating it as a marker for a poor prognosis or distinctive subtype in PD.     

Impulse control disorder and rapid eye movement sleep behavior disorder in Parkinson's disease

IntroductionThe relationship between ICD and RBD is still not yet understood and the results from the current literature are contradictory in PD. We aimed to explore the association between rapid eye movement (REM) sleep behavior disorder (RBD) and impulse control disorder in Parkinson's disease.MethodsNinety-eight non-demented patients with Parkinson's disease underwent one night of video-polysomnography recording. The diagnosis of RBD was established according to clinical and polysomnographic criteria. Impulse control disorders were determined by a gold standard, semi-structured diagnostic interview.ResultsHalf of the patients (n = 49) reported clinical history of RBD while polysomnographic diagnosis of RBD was confirmed in 31.6% of the patients (n = 31). At least one impulse control disorder was identified in 21.4% of patients, 22.6% with RBD and 20.9% without. Logistic regression controlling for potential confounders indicated that both clinical RBD (OR = 0.34, 95% CI = 0.07–1.48, P = 0.15) and polysomnographic confirmed RBD diagnoses (OR = 0.1.28, 95% CI = 0.31–5.33, P = 0.34) were not associated with impulse control disorder.ConclusionIn Parkinson's disease, REM Sleep Behavior Disorder is not associated with impulse control disorder. The results of our study do not support the notion that PSG-confirmed RBD and ICD share a common pathophysiology.     

Quantitative evaluation of the microstructure of rapid eye movement sleep in refractory epilepsy: a preliminary study using electroencephalography and heart rate variability analysis

IntroductionPatients with epilepsy have a disturbed sleep architecture. Polysomnographic studies have shown that patients with refractory epilepsy have decreased rapid eye movement (REM) sleep and longer REM latency than those with medically controlled epilepsy. However, little is known about the differences in the REM sleep microstructure between these patient groups.MethodsWe conducted a retrospective case–control study of 20 patients with refractory epilepsy (refractory group) and 28 patients with medically controlled epilepsy (medically controlled group). All patients completed sleep questionnaires and underwent overnight in-lab polysomnography. Five-minute electroencephalogram recordings at the C3 and C4 electrodes from each REM sleep were selected for spectral analysis, and 5-min electrocardiogram segments recorded during REM sleep were used for heart rate variability analysis. The groups’ scores on the sleep questionnaires, polysomnographic sleep parameters, indices of sleep-related breathing disorders, and REM sleep electroencephalogram spectra were compared.ResultsThe refractory group had decreased REM sleep (p < 0.001) and longer REM latency (p = 0.0357) than those of the medically controlled group. Moreover, electroencephalogram spectral analysis revealed that the refractory group had decreased absolute beta power (p = 0.0039) and relative beta power (p = 0.0035) as well as increased relative delta power (p = 0.0015) compared with the medically controlled group.ConclusionsDifferences in the polysomnographic macrostructure and REM sleep microstructure between the study groups suggest REM sleep dysregulation in patients with refractory epilepsy.