REM Sleep Behavior Disorder Research Articles

Intersection of Sleep Disorders and Parkinson Disease: Unveiling the Bidirectional Relationship

AbstractBackgroundPatients with Parkinson's Disease (PD) frequently exhibit non‐motor symptoms, particularly sleep disturbances. Sleep disorders in PD patients are intricately linked to the pathogenesis and progression of PD itself, exacerbating neurodegenerative processes and worsening patient quality of life.ObjectivesThis review underscores the significance of sleep disorders in PD, highlighting their prevalence, impact on disease progression, and the bidirectional relationship between sleep disruption and neurodegeneration. It aims to enhance clinician awareness for better diagnosis and management of sleep‐related comorbidities in PD.MethodsA comprehensive literature search was conducted in PubMed and Scopus using key terms such as “sleep disorders”, “Parkinson's disease”, “REM sleep behavior disorder”, “restless legs syndrome”, “insomnia”, “obstructive sleep apnea”, “excessive daytime sleepiness”, “circadian rhythm disorders”, “sleep and neurodegeneration”.ResultsSleep disorders are prevalent in PD affecting up to 90% of patients. Conditions such as insomnia, REM sleep behavior disorder, restless legs syndrome, obstructive sleep apnea, excessive daytime sleepiness, and circadian rhythm disorders are commonly reported. These disorders are linked to multifactorial biological mechanisms and are associated with more severe disease phenotypes. Of note, several evidence shows that sleep abnormalities may contribute to neuroinflammation and neurodegeneration, further accelerating the disease course.ConclusionsSleep disturbances are critical non‐motor symptoms in PD. Early diagnosis and tailored management of sleep disorders are essential for improving clinical outcomes and potentially offering neuroprotective benefits.

Predicting Post-Mortem α-Synuclein Pathology by the Combined Presence of Probable REM sleep behavior disorder and Hyposmia.

Idiopathic rapid eye movement sleep behavior disorder (RBD) is a strong known predictor of a final clinicopathological diagnosis of a Lewy type α-synucleinopathy (LTS). Olfactory dysfunction is an early symptom of synucleinopathies and has been repeatedly associated with the presence of post-mortem LTS. To assess the combined value of a clinician diagnosis of probable RBD (PRBD) and hyposmia in predicting the post-mortem presence of LTS in a broader, less-selected, volunteer elderly population. We studied 652 autopsied subjects from the Arizona Study of Aging and Neurodegenerative Disorders, which were evaluated for PRBD, had completed annual movement and cognitive assessments, and had at least one the University of Pennsylvania Smell Identification Test (UPSIT) olfactory test. Histological evidence of LTS was significantly more frequent in those who had PRBD (112/152: 73.7%) than those without (177/494: 35.8%) (P < 0.001). LTS was more frequent in cases with PRBD and a low UPSIT score (90.8%) compared to cases with PRBD only (73.7%) (P < 0.001) or cases with a low UPSIT score only (69.4%) (P < 0.001). Sensitivity of PRBD diagnosis for predicting LTS was 38.8% and specificity 88.8%, whereas sensitivity of a low UPSIT score was 74.4% and specificity 73.4% (Youden's index = 0.276 for PRBD, 0.478 for UPSIT). When combining both measures, sensitivity was 34.3% and specificity increased to 97.2%. PRBD, diagnosed without sleep study confirmation, combined with a reduced olfactory performance is highly specific for predicting post-mortem presence of LTS. The combination of both measures may provide a cost-effective means of predicting LTS in a broader community.

The Lasting Legacy of Charles Fisher (1908-1988), Pioneering Sleep Laboratory Scientist and Sleep Medicine Psychiatrist

Abstract Charles Fisher is a pioneering historical figure in sleep laboratory research and sleep medicine who distinguished himself in nine areas: i) The first documentation of nocturnal sleep-onset REM sleep periods in narcoleptic patients; ii) He published the first case of polysomnography (PSG) documented acute REM sleep behavior disorder (RBD) that was triggered by sudden withdrawal from a monoamine oxidase inhibitor (MAOI) in 1978, 8 years before the formal identification of RBD; iii) He worked with Roffwarg and Dement on the early delineation of the ontogeny of the human sleep cycle; iv) He first demonstrated that benzodiazepine (diazepam) therapy was effective in controlling night terrors together with suppression of Stage 4 NREM sleep, and he was also an early investigator of night terrors as phenomena emerging from Stage 4 NREM sleep, without dreaming, as had been traditionally assumed; v) He collaborated with another pioneering sleep medicine physician, William C. Dement on studies focused on REM sleep deprivation and dreaming at Fisher’s Mt. Sinai Hospital sleep laboratory; vi) He published the first PSG-documented case of Sleep Related (Psychogenic) Dissociative Disorder (SRDD) in 1976; vii) He first documented that typical nightmares (“anxiety dreams”) occurred during REM sleep; viii) He conducted some of the earliest research, beginning in 1965, that documented cycles of nocturnal penile tumescence emerging in conjunction with REM sleep cycles; ix) He conducted similar early studies of female sexual arousal during sleep that occurred predominantly in REM sleep.

Enhanced Delta-gamma Phase Amplitude Coupling during Phasic REM Sleep in isolated REM Sleep Behavior Disorder.

This study aims to analyze phase-amplitude coupling (PAC) patterns during rapid eye movement (REM) sleep in patients with isolated REM sleep behavior disorder (iRBD), compared with demography-matched healthy control (HC) participants. At baseline, electroencephalogram data from 13 iRBD patients and 10 HCs during REM sleep were analyzed. During follow-up, 4 patients (converters) later converted to alpha-synucleinopathies. Phasic and tonic REM states were determined by eye movement in 3-second epochs. PAC was compared between the groups, and correlations with clinical indicators were investigated. Additionally, the contribution of each electrode to PAC components was assessed. Patients with iRBD exhibited increased delta (1-3 Hz)-gamma (30-50 Hz) PAC only during the phasic REM state, but not during the tonic state, compared to the HCs (p < 0.05). Elevated PAC in patients negatively correlated with the REM atonia index (p = 0.011) and olfactory function (p = 0.038). Increase PACs were predominent in the fronto-temporo-occipital regions (corrected p < 0.05). Furthermore, patients showed reduced gamma-amplitude contributions of the parietal region (corrected p < 0.05). This reduction exhibited a progressively decreasing trend from HC to non-converters, and further to converters (p for trend = 0.044). Our findings suggest PAC patterns during REM sleep could provide pathophysiological insights for iRBD. The widespread increase of PAC and reduced gamma-amplitude contribution in the parietal region suggest PAC during phasic REM sleep as potential biomarkers for disease progression in iRBD.

IGLON5 Frequency in Idiopathic REM Sleep Behavior Disorder: A Multicenter Study.

Idiopathic/isolated REM sleep behavior disorder (iRBD) has been strongly linked to neurodegenerative synucleinopathies such as Parkinson disease, dementia with Lewy bodies, and multiple system atrophy. However, there have been increasing reports of RBD as a presenting feature of serious and treatable autoimmune syndromes, particularly IGLON5. This study's objective was to investigate the frequency of autoantibodies in a large cohort of participants with iRBD. Participants were enrolled in the North American Prodromal Synucleinopathy cohort with polysomnography-confirmed iRBD, free of parkinsonism and dementia. Plasma samples were systematically screened for the autoantibodies IGLON5, DPPX, LGI1, and CASPR2 using plasma IgG cell-based assay. Positive or equivocal results were confirmed by repeat testing, plus tissue-based indirect immunofluorescence assay for IGLON5. Of 339 samples analyzed, 3 participants (0.9%) had confirmed positive IGLON5 autoantibodies in the cell-based assay, which were confirmed by the tissue-based assay. An additional participant was positive for CASPR2 with low titer by cell-based assay only (of lower clinical certainty). These cases exhibited a variety of symptoms including dream enactment, cognitive decline, autonomic dysfunction, and motor symptoms. In 1 IGLON5 case and the CASPR2 case, evolution was suggestive of typical synucleinopathy, suggesting the possibility that findings were incidental. However, 2 participants with IGLON5 died before diagnosis was clinically suspected, with a final clinical picture highly suggestive of autoimmune disease. Our finding that nearly 1% of a large iRBD cohort may have a serious but potentially treatable autoantibody syndrome has important clinical implications. In particular, it raises the question of whether autoantibody testing for IGLON-5-IgG should be widely implemented for participants with iRBD, considering the difficulty in diagnosis of autoimmune diseases, their response to treatment, and the potential for rapid disease progression. However, any routine testing protocol will also have to consider costs and potential adverse effects of false-positive findings. NCT03623672.

Brainstem changes causing reversible RBD in patients with spontaneous intracranial hypotension: a longitudinal neuroimaging study.

This study aimed to investigate the prevalence of REM sleep behavior disorder (RBD) in patients with spontaneous intracranial hypotension (SIH) and longitudinally assess the effects of epidural blood patch (EBP) treatment on brainstem structures using a neuroimaging approach. Twenty-two participants (10 SIH patients and 12 controls) underwent 3-Tesla Magnetic Resonance Imaging (MRI) scans. Midbrain and pons areas were measured on T1-weighted scans at baseline in both groups and three months after the first EBP in SIH patients to determine any MRI structural changes. The RBD Single-Questionnaire was used to screen SIH patients with symptoms suggestive of RBD for polysomnographic (PSG) recording. Half of the SIH patients (5/10) exhibited PSG-confirmed RBD. Baseline evaluation revealed deep brain swelling (DBS) on MRI scans in SIH-RBD patients. Following EBP treatment, significant changes in midbrain and pons morphometry were associated with complete clinical remission of RBD. Cross-sectional analysis showed larger midbrain and pons areas in SIH patients (with and without RBD) compared to controls. A midbrain area of 200 mm2 was identified as a cut-off value distinguishing SIH patients (with and without RBD) from controls individually. Longitudinal analysis demonstrated lower midbrain areas at follow-up compared to baseline in SIH patients. The study suggests that brainstem morphometric changes may underlie reversible RBD in SIH patients. Midbrain area measurement could serve as a dynamic biomarker for SIH, particularly in the presence of RBD, offering insights for clinical practice.

Polysomnographic Findings into Sleep Disorders in Essential Tremor and Essential Tremor Plus: A Comparison with Healthy Controls.

To explore sleep patterns in individuals with Essential Tremor (ET) and Essential Tremor Plus (ET-Plus), compared to healthy controls, and assess differences between ET and ET-Plus, given the lack of established polysomnography (PSG) data on these groups and the potential for sleep disturbances to serve as clinical markers. We conducted a prospective cross-sectional study at NIMHANS, Bengaluru, from November 2021 to August 2023 on 45 patients (26 ET, 19 ET-Plus) and 45 controls. Tremor severity was assessed using TETRAS and FTMTRS, and sleep symptoms with ESS, PSQI, Mayo Sleep Questionnaire, RLS-Q, BQ, GAD-7 and PHQ-9. All cases and controls underwent overnight video PSG. Sleep scoring was manually done by a technically adequate sleep researcher and the first author following AASM (2022) guidelines with data analysed using R studio. ET patients exhibited younger onset age (30.8 ± 16.7 years) compared to ET-Plus patients (46.8 ± 11.1 years). ET-Plus had higher TETRAS and FTMRS scores (P < 0.001) than ET. Both ET and ET-Plus patients exhibited poorer sleep quality, excessive daytime sleepiness, REM sleep behavior disorder (RBD), and Restless Legs Syndrome (RLS) symptoms compared to controls. PSG findings supported these clinical observations, showing elevated Apnea-Hypopnea Index (AHI), reduced Total Sleep Time (TST), prolonged REM latency, decreased sleep efficiency, increased N1 stage duration, and reduced N2/N3 durations and percentages in patients versus controls. The study highlights significant sleep architecture abnormalities in both ET and ET-Plus patients as compared to healthy controls, with no differences between the ET groups.

Behavioral disorders in Parkinson disease: current view.

Patients with Parkinson disease (PD) frequently experience several behavioral symptoms, such as anxiety, apathy, irritability, agitation, impulsive control and obsessive-compulsive or REM sleep behavior disorders, which can cause severe psychosocial problems and impair quality of life. Occurring in 30-70% of PD patients, these symptoms can manifest at early stages of the disease, sometimes even before the appearance of classic motor symptoms, while others can develop later. Behavioral changes in PD show distinct patterns of brain atrophy, dopaminergic and serotonergic deterioration, altered neuronal connectivity in frontostriatal, corticolimbic, default mode and other networks due to a cascade linking molecular pathologies and deficits in multiple behavior domains. The changes suggest a multi-system neurodegenerative process in the context of a specific α-synucleinopathy inducing a variety of biochemical and functional changes, the neurobiological basis and clinical relevance of which await further elucidation. This paper is intended to review the recent literature with focus on the main behavioral disturbances in PD patients, their epidemiology, clinical features, risk factors, animal models, neuroimaging findings, pathophysiological backgrounds, and treatment options of these deleterious lesions.

Sleep Quality in Parkinson Disease: Clinical Insights and PSQI Reliability Assessment

AbstractSleep disturbances are prevalent in Parkinson disease (PD), encompassing a spectrum from parasomnias like REM sleep behavior disorder to symptoms of sleep-wake cycle dysregulation, such as insomnia and daytime sleepiness. This research investigates sleep quality in PD patients compared with a matched healthy control group and explores the relationships between PD clinical characteristics and sleep parameters. Additionally, the study assesses the reliability of the Pittsburgh Sleep Quality Index (PSQI) for PD patients by examining internal consistency. The study comprises 52 participants, 27 in the PD group and 25 in the healthy control group, matched for sex and age. Sleep quality revealed that PD patients experienced significantly poorer sleep quality than the control group (p = 0.009). Weak correlations were found between PSQI scores and the modified Hoehn and Yahr scale (p = 0.062), with no correlation observed with the daily equivalent dose of levodopa (L-DOPA). The prevalence of poor sleep quality (PSQI score &gt; 5) was 85.1% for PD patients and 68% for the control group. The internal consistency analysis of the PSQI yielded a Cronbach's α of 0.588 for the PD group. While the PSQI demonstrates utility in detecting general sleep abnormalities and gauging patient perceptions of sleep quality in PD, its limitation as a global score is emphasized. The index prioritizes sleep habits and may not fully capture important sleep disorders in this population. These findings underscore the complex relationship between PD and sleep quality, suggesting the need for a comprehensive approach to assess and address sleep disturbances in PD patients.

A prediction model for the walking and balance milestone in Parkinson's disease

BackgroundWalking and balance impairments, represented by freezing of gait and falls, are significant contributors to disability in advanced Parkinson's disease (PD) patients. However, the composite measure of the Walking and Balance Milestone (WBMS) has not been thoroughly investigated. MethodsThis study included 606 early-stage PD patients from the Parkinson's Progression Markers Initiative (PPMI) database, with a disease duration of less than 2 years and no WBMS at baseline. Patients were divided into a model development cohort (70 %) and a validation cohort (30 %) according to the enrollment site. Longitudinal follow-up data over a period of 12 years were analyzed. ResultsAmong all 606 patients, the estimated probability of being WBMS-free at the 5th and 10th year was 88 % and 60 %, respectively. Five clinical variables (Age, Symbol Digit Modalities Test (SDMT), postural instability and gait difficulty (PIGD) score, Movement Disorder Society-Unified Parkinson's Disease Rating Scale Part I (MDS-UPDRS-I) score, and REM Sleep Behavior Disorder (RBD) were used to construct the Cox predictive model. The C-index of the model was 0.75 in the development cohort and 0.76 in the validation cohort. By optimizing the PIGD and MDS-UPDRS-I variables, an easy-to-use model was achieved with comparable predictive performance. ConclusionA predictive model based on five baseline clinical measures (Age, SDMT, PIGD score, MDS-UPDRS-I score, RBD) could effectively estimate the risk of the WBMS in early PD patients. This model is valuable for prognostic counseling and clinical intervention trials for gait and balance impairment.

Sleep disturbances in probable multiple system atrophy

BackgroundMultiple system atrophy (MSA) is a fatal alpha-synucleinopathy characterized by variable combinations of parkinsonism, autonomic and cerebellar dysfunction. Sleep in MSA is highly compromised due to various sleep disturbances. Disrupted sleep-wake cycles in MSA contribute to poor health-related quality of life and are negative prognostic factors. ObjectivesWe aimed to study the various sleep disturbances; the effect of parkinsonian and cerebellar phenotypes on sleep; and the correlation of sleep parameters with disease severity in an Asian-Indian cohort of probable MSA patients. MethodsWe recruited 60 probable MSA patients (MSA-P = 19; MSA-C = 41). Disease severity was assessed using UPDRS-III, UMSARS-I and UMSARS-II. Detailed history and relevant sleep questionnaires were applied to evaluate the sleep disturbances. ResultsSleep disturbances were universally observed in probable MSA patients in this cohort. These include REM behavior disorder (RBD)-95 %; poor sleep quality-80 %; secondary insomnia and intermittent awakenings-100 %; excessive daytime sleepiness-26 %; risk for obstructive sleep apnea-51.7 % and snoring-85 %. MSA patients reported 38.2 ± 22.9 percentage improvement in sleep with the medications. There was no significant difference between probable MSA-P and MSA-C patients in any of the sleep parameters. Sleep quality was poor in patients with pre-motor RBD than post-motor RBD (p < 0.01). Poor sleep quality had a moderate positive correlation with RBD duration. Disease severity positively correlated with RBD duration and poor sleep quality. ConclusionsSleep disturbances, the negative prognostic factors, were universally observed in this Asian Indian MSA cohort. This study provides supporting evidence that RBD might play a possible role in MSA disease severity, progression, and sleep quality.

T2 MRI visible Perivascular Spaces in Parkinson`s Disease: clinical significance and association with polysomnography measured sleep.

Poor sleep quality might contribute to the risk and progression of neurodegenerative disorders via deficient cerebral waste clearance functions during sleep. In this retrospective cross-sectional study, we explore the link between enlarged perivascular spaces (PVS), a putative marker of sleep-dependent glymphatic clearance, with sleep quality and motor symptoms in Parkinson`s disease (PD) patients. T2-weighted MRI images of 20 patients and 17 healthy control subjects were estimated visually for PVS in the basal ganglia (BG) and centrum semiovale (CSO). The patient group additionally underwent a single-night polysomnography. Readouts included polsyomnographic sleep features and slow-wave activity (SWA), a quantitative EEG marker of sleep depth. Associations between PVS counts, PD symptoms (MDS-UPDRS scores) and sleep parameters were evaluated using correlation and regression analyses. Intra- and inter-rater reproducibility was assessed with weighted Cohen`s kappa coefficient. BG and CSO PVS counts in both patients and controls did not differ significantly between groups. In patients, PVS in both brain regions were negatively associated with SWA (1-2Hz) (BG: r(15)=-0.58, padj=0.015 and CSO: r(15)=-0.6, padj=0.015). Basal ganglia PVS counts were positively associated with motor symptoms of daily living (IRR=1.05, CI [1.01, 1.09], p=0.007, padj=0.026) and antidepressant use (IRR=1.37, CI [1.05, 1.80], p=0.021, padj=0.043) after controlling for age. Centrum Semiovale PVS counts in patients were positively associated with a diagnosis of REM sleep behaviour disorder (IRR=1.39, CI [1.06 , 1.84]), p=0.018, padj=0.11). These results add evidence that sleep deterioration may play a role in impairing glymphatic clearance via altered perivascular function, potentially contributing to disease severity in PD patients.

Automatic quantification of REM sleep without atonia reliably identifies patients with REM sleep behavior disorder: a possible screening tool?

REM Sleep Behavior Disorder (RBD) is characterized by absence of physiological muscle atonia during REM sleep (REM sleep without atonia, RWA). Nigro-striatal dopaminergic impairment is a feature of Parkinson disease (PD) and can be identified in prodromal stages as well, such as idiopathic RBD (iRBD). Aims of this study are to explore the efficacy of an automatic RWA quantification in identifying RBD patients and the correlation between RWA and nigro-striatal dopaminergic function. Forty-five iRBD, 46 PD with RBD, 24 PD without RBD patients and 11 healthy controls were enrolled in the Genoa Center (group A) and 25 patients with iRBD (group B) were enrolled in the Danish Center. Group A underwent brain [123I]FP-CIT-SPECT and group B underwent brain [18F]PE2I-PET as measures of nigro-striatal dopaminergic function. Chin muscle activity was recorded in all subjects and analyzed by applying a published automatic algorithm. Correlations between RWA and nigro-striatal dopaminergic function were explored. The automatic quantification of RWA significantly differentiated RBD from non-RBD subjects (AUC = 0.86), although with lower accuracy compared with conventional visual scoring (AUC = 0.99). No significant correlation was found between RWA and nigro-striatal dopaminergic function. The automatic quantification of RWA is a reliable tool to identify subjects with RBD and may be used as a first-line screening tool, but without correlations with nigro-striatal dopaminergic functioning.

Biofluid Markers and Tissue Biopsies Analyses for the Prodromal and Earliest Phase of Parkinson's Disease.

The recent development of new methods to detect misfolded α-synuclein (αSyn) aggregates in biofluids and tissue biopsies in the earliest Parkinson's disease (PD) phases is dramatically challenging the biological definition of PD. The αSyn seed amplification methods in cerebrospinal fluid (CSF) showed high sensitivity and specificity for early diagnosis of PD and Lewy bodies disorders. Several studies in isolated REM sleep behavior disorders and other at-risk populations also demonstrated a high prevalence of CSF αSyn positivity and its potential value in predicting the phenoconversion to clinically manifested diseases. Growing evidence exists for αSyn aggregates in olfactory mucosa, skin, and other tissues in subjects with PD or at-risk subjects. DOPA decarboxylase and numerous other candidates have been additionally proposed for either diagnostic or prognostic purposes in earliest PD phases. The newly described αSyn detection in blood, through its quantification in neuronally-derived exosome vesicles, represents a technical challenge that could open a new scenario for the biological diagnosis of PD. Despite this growing evidence in the field, most of method of αSyn detection and markers still need to be validated in ongoing longitudinal studies through an accurate assessment of different prodromal disease subtypes and scenarios before being definitively implemented in clinical settings.

Brain-first forms of Parkinson's disease are over-represented in patients with non-responsive resting tremor

Motor subtypes in Parkinson's Disease (PD) are unstable over time, limiting mechanistic insights and biomarker discovery. We focused on Rest Tremor (RT) as a symptom to test for phenotype stability and link it to specific circuits and disease mechanisms. Using the PPMI cohort data over 5 years we found that RT is more stable than classical Tremor-Dominant definitions, a stability also seen for RT response to therapy. At time of diagnosis, the population of therapy-resistant RT patients was enriched with a brain-first PD profile as predicted by a-Synuclein origin site and connectome (SOC) model. Resistant-RT patients have lower gastrointestinal and cardiovascular symptoms, lower prevalence of probable REM-Sleep behaviour disorder, and higher dopaminergic asymmetry compared to therapy-responsive or no tremor patients. Treating RT as a distinct phenomenon revealed a relative phenotypic stability with treatment response being linked to different patterns of disease progression.

The paradoxical impact of periodic limb movements on isolated REM sleep behavior disorder patients.

Recently, the α-synuclein origin and connectome model described two types of Parkinson's disease: "brain-first" and "body-first" subtypes. We aimed to investigate the role of periodic limb movements during sleep (PLMS) in identifying these subtypes starting from a prodromal stage of α-synucleinopathies. 191 patients with isolated REM sleep behavior disorder (iRBD) underwent video-polysomnography (vPSG), questionnaires, clinical interview, and neuropsychological battery. Patients who presented PLMS index (PLMSi) > 15 were compared with patients presenting PLMSi ≤ 15 on clinical questionnaires, vPSG, and neuropsychological domains with age as a covariate. Correlations were performed between PLMSi and vPSG and neuropsychological domains in both groups of iRBD. 48.2% of patients presented PLMSi > 15. iRBD subgroup with PLMSi > 15 performed better than the iRBD subgroup with PLMSi ≤ 15 in the executive function domain. In patients with PLMSi > 15 negative correlations were observed between PLMSi and some neuropsychological domains (memory, language, and executive function). Moreover, this subgroup was older and their PLMSi was positively correlated with wake-after-sleep onset and inversely correlated with total sleep time and sleep efficiency, suggesting a detrimental effect of PLM on sleep also in this cohort. Patients with PLMSi > 15 are characterized by a more preserved cognitive status, despite a more disrupted sleep. PLMSi could be explored in longitudinal studies concerning the "brain-first" and "body-first" model.

History of symptoms consistent with REM sleep behavior disorder in a population with Parkinson's Disease

REM Sleep Behavioral Disorder (RBD) is a parasomnia marked by the maintenance of muscle tone during REM sleep. Evidence has placed RBD as one of the possible prodromal stages of Parkinson's Disease (PD), but data on the proportion of people with PD who have had symptoms of RBD are limited. This study aimed to investigate the history of symptoms compatible with RBD in a population with PD. The sample was composed by 73 patients with clinically diagnosed PD being followed up at a reference outpatient setting, compared to 73 age- and sex-matched individuals with no PD. The evaluation of symptoms compatible with RBD was performed using the Brazilian version of the RBD Screening Questionnaire (RBDSQ). The prevalence of symptoms compatible with RBD was 65 % for PD and 10.09 % for controls. The RBDSQ score was significantly higher in the PD group (6.03 ± 0.35) in comparison to the control group (2.38 ± 0.23). The odds ratio for presenting previous RBD-compatible symptoms was 12.09 in favor of positive PD cases. PD diagnosis has the following diagnostic properties in relation to presenting RBD symptoms: sensitivity of 0.65, specificity of 0.86, positive predictive value of 0.82 and negative predictive value of 0.71. In conclusion, the proportion of PD patients showing RBD symptoms is high, corroborating the expected neuroprogression of the disease on a case-control design comprising outpatient PD cases. Clinical practitioners should include evaluations of RBD-compatible symptoms during the PD assessment and, if positive, forward to a sleep specialist.

Not All Antihistamines Are Created Equal: Alimemazine As A Cause Of Drug Induced Parkinsonism

Abstract Background A 67year old female presented to a Movement Disorder Service for assessment of tremor. She had a history of presbycusis, dermatitis herpetiformis, bronchiectasis, osteoporosis and stage A chronic lymphocytic leukaemia. History elucidated hypophonia, somniloquy, REM-sleep behaviour disorder, bruxism, presence hallucinosis, insidious bradykinesia and of titubation of increasing prevalence and amplitude over 20years. Examination demonstrated cognitive impairment (Montreal Cognitive Assessment 12+1/30) in the domains of visuospatial function, executive thinking, naming, attention, language, abstraction and anterograde recall. Luria test was 0/6. Also found was: micrographia, left exotropia, reduced left arm and leg swing, kinetic tremor asymmetry, decrement of amplitude and frequency of rapid repetitive movements asymmetrically, mandibular and lingual tremor, positive Kinnier-Wilson test and orthostatic deterioration in yes-yes titubation. Drg history identified use of Alimemazine 10mg for insomnia for approximately 20years. Methods Modified Simpson Angus Scale score was 6 indicating a clinically significant degree of extrapyramidal side effects. Unified Parkinson’s Disease Rating Scale part III was 17. Results Functional dopamine uptake imaging did not indicate a parkinsonian syndrome. Drg induced parkinsonism was diagnosed. 0.0097% of the Northern Ireland population were prescribed Alimemazine in 2022 for non-dermatological reasons, representing 73.49% of all dispensed preparations. In the first financial quarter of 2024 in Northern Ireland, all dispensed prescriptions cost £218,395. Conclusion Not all antihistamines are created equal. Alimemazine is an older phenothiazine derivative antihistamine with central sedative effects equivalent to Chlorpromazine but without anti-adrenaline action. It is rarely prescribed and easily overlooked as “just another antihistamine”. It is commonly prescribed by dermatologists for urticaria. It has substantial pharmacoeconomic implications given its cost disparity with other antihistamines. Extrapyramidal features of tremor, akinesia and hypertonicity are more common in older people; usually developing within weeks or months of commencement. Stopping the drug is the first-line intervention. Resolution of symptoms is not guaranteed.

Validation of the International REM Sleep Behavior Disorder Study Group Symptoms Severity Scale (IRBD-SSS): a new tool to assess RBD clinical severity.

Currently, no standard scale has been validated to assess overall severity of RBD symptoms in the home environment. We aimed to evaluate the psychometric properties of the International RBD Severity Scale (IRBD-SSS), a new tool designed by the International RBD Study Group. Two versions of the IRBD-SSS were created, one for the patient (IRBD-SSS-PT) and another for the bedpartner (IRBD-SSS-BP), both consisting of 3 components, namely vocalizations, body movements and injury, with a fourth component (patient version only) evaluating dream content. To score each dimension, the frequency and severity/impact of behaviors during the previous month are multiplied. Psychometric properties of the IRBD-SSS were assessed, including reproducibility. A total of 188 subjects including n = 132 RBD patients (n = 94 isolated RBD and n = 38 symptomatic RBD) and n = 52 bedpartners were enrolled from eight Sleep centers across France and Italy. Participants completed the scale at baseline and after one week. Acceptability of the scale was excellent in patients (97%) and bedpartners (98%). Internal consistency was acceptable for IRBD-SSS-PT (Cronbach α = 0.75) while slightly low for IRBD-SSS-BP (Cronbach α = 0.49). Concurrent validity was good for both patient (r = 0.70;p < 0.001, see Figure) and bedpartner (r = 0.69;p < 0.001) IRBD-SSS. Reproducibility was high for IRBD-SSS-PT (Lin's coefficient of agreement = 0.85 [0.81;0.90]) and good for the IRBD-SSS-BP (0.79 [0.68;0.90] (p < 0.001). Both the patient and bedpartner versions of the IRBD-SSS showed excellent acceptability, acceptable internal consistency, good external validity and high reproducibility. IRBD-SSS is a useful tool to test the severity of RBD symptoms in clinical settings and clinical trials. NCT04071899.

Cerebellum and basal ganglia connectivity in isolated REM sleep behaviour disorder and Parkinson's disease: an exploratory study.

REM sleep behaviour disorder (RBD) is a parasomnia characterised by dream-enacting behaviour with loss of muscle atonia during REM sleep and is a prodromal feature of α-synucleinopathies like Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. Although cortical-to-subcortical connectivity is well-studied in RBD, cerebellar and subcortical nuclei reciprocal connectivity is less established. Nonetheless, it could be relevant since RBD pathology involves brainstem structures with an ascending gradient. In this study, we utilised resting-state functional MRI to investigate 13 people with isolated RBD (iRBD), 17 with Parkinson's disease and 16 healthy controls. We investigated the connectivity between the basal ganglia, thalamus and regions of the cerebellum. The cerebellum was segmented using a functional atlas, defined by a resting-state network-based parcellation, rather than an anatomical one. Controlling for age, we found a significant group difference (F4,82 = 5.47, pFDR = 0.017) in cerebellar-thalamic connectivity, with iRBD significantly lower compared to both control and Parkinson's disease. Specifically, cerebellar areas involved in this connectivity reduction were related to the default mode, language and fronto-parietal resting-state networks. Our findings show functional connectivity abnormalities in subcortical structures that are specific to iRBD and may be relevant from a pathophysiological standpoint. Further studies are needed to investigate how connectivity changes progress over time and whether specific changes predict disease course or phenoconversion.