A 24% prevalence of excessive fragmentary myoclonus in 500 consecutive sleep laboratory patients

Excessive fragmentary myoclonus (EFM) is a frequent finding during routine video-polysomnography (VPSG). We aimed to automatically measure the prevalence of EFM according to current American Academy of Sleep Medicine (AASM) criteria, and the fragmentary myoclonus index (FMI) in sleep stage N1, N2, N3, rapid eye movement (REM) sleep and wake in a large patient population. A total of 500 VPSG recordings of patients admitted to the Sleep Laboratory, Department of Neurology, Medical University of Innsbruck, Austria, between May 1, 2022 and February 28, 2023, were included. EFM according to AASM criteria and FMI were computed by applying a previously validated algorithm. EFM was automatically detected in 121 of the 500 Sleep Laboratory patients (24.2%, 95% confidence interval 20.1%-28.9%). FMI increased with age, male gender, apnea-hypopnea-index (AHI), oxygen desaturation index (ODI), and periodic leg movements of sleep (PLMS) index. FMI was highest in REM sleep behaviour disorder (RBD), followed by neurodegenerative and internal medicine diseases, but the increase in the FMI was not explained by the disease itself but rather by the age and sex of the patients. Almost a quarter of our patient population had EFM. However, the prevalence of EFM does not allow the drawing of any conclusions about the pathophysiology of EFM or even the determination of a pathological FMI cut-off value. Associations of the FMI with age, sex, AHI, ODI and PLMS are in line with previous studies, but the FMI needs to be evaluated in different disease entities to learn more about its pathophysiology.

Sleep features and long-term incident neurodegeneration: a polysomnographic study

STUDY OBJECTIVES

Sleep is altered early in neurodegenerative diseases (NDDs) and may contribute to neurodegeneration. Long-term, large sample-size studies assessing NDDs association with objective sleep measures are scant. We aimed to investigate whether video-polysomnography (v-PSG)-based sleep features are associated with long-term NDDs incidence.

METHODS

Retrospective cohort study of patients referred 2004-2007 to the Sleep Disorders Unit, Neurology, Medical University Innsbruck, Austria. All patients ≥ 18 years undergoing v-PSG and without NDDs at baseline or within 5 years were included. Main outcome was NDDs diagnosis ≥5 years after v-PSG.

RESULTS

Of 1454 patients assessed for eligibility, 999 (68.7%) met inclusion criteria (68.3% men; median age 54.9 (IQR 33.9-62.7) years). Seventy-five patients (7.5%) developed NDDs and 924 (92.5%) remained disease-free after a median of 12.8 (IQR 9.9-14.6) years. After adjusting for demographic, sleep, and clinical covariates, a one-percentage decrease in sleep efficiency, N3-, or rapid-eye-movement (REM)-sleep was associated with 1.9%, 6.5%, or 5.2% increased risk of incident NDDs (HR 1.019, 1.065, and 1.052). One-percentage decrease in wake within sleep period time represented a 2.2% reduced risk of incident NDDs (HR 0.978). Random-forest analysis identified wake, followed by N3 and REM-sleep percentages, as the most important feature associated with NDDs diagnosis. Additionally, multiple sleep features combination improved discrimination of incident NDDs compared to individual sleep stages (concordance-index 0.72).

CONCLUSIONS

These findings support contribution of sleep changes to NDDs pathogenesis and provide insights into the temporal window during which these differences are detectable, pointing to sleep as early NDDs marker and potential target of neuroprotective strategies.

A reliable automatic algorithm to score fragmentary myoclonus

Excessive fragmentary myoclonus (EFM) is an incidental polysomnographic finding requiring documentation of ≥20 minutes of NREM sleep with ≥5 fragmentary myoclonus (FM) potentials per minute. Manual FM scoring is time-consuming and prone to inter-rater variability. This work aimed to validate an automatic algorithm to score FM in whole-night recordings. One expert scorer manually scored FM in the anterior tibialis muscles in 10 polysomnographies of as many subjects. The algorithm consisted of two steps. First, parameters of the automatic leg movement identification algorithm of the BrainRT software (OSG, Belgium) were modified to identify FM-like activity. Second, a post-processing algorithm was implemented to remove FM activity not meeting sufficient amplitude criteria. The parameter choice and the post-processing were optimised with leave-one-out cross-validation. Agreement with the human scorer was measured with Cohen's kappa (k) and correlation between manual and automatic FM indices in different sleep stages was evaluated. Agreement in identifying patients with EFM was computed. The algorithm showed substantial agreement (average k > 0.62) for all sleep stages, except for W, where a moderate agreement was observed (average k = 0.58). Nonetheless, the agreement between human scorer and the algorithm was similar to previously reported values of inter-rater variability for FM scoring. Correlation coefficients were over 0.96 for all sleep stages. Furthermore, the presence/absence of EFM was correctly identified in 80% of the subjects. In conclusion, this work presents a reliable algorithm for automatic scoring of FM and EFM. Future studies will apply it to objectively and consistently evaluate FM indices and the presence of EFM in large populations.

Is REM Sleep Behavior Disorder Changing? Secular Changes Versus Referral Patterns

Background

Since 2014, there has been increasing public outreach effort regarding isolated/idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) in Montreal.

Objective

To assess if, over time, milder iRBD cases are presenting earlier.

Methods

Disease-free survival was compared in two iRBD recruitment epochs: 2004 to 2013 ("earlier") versus 2014to 2022 ("later") and by referral type ("self-referral" vs. "conventional-referral") in three large centers.

Results

In Montreal, among 209 subjects followed prospectively, shorter time to phenoconversion was observed in the earlier epoch (5-year phenoconversion = 42% earlier vs. 23% later); diagnosis before 2014 had a 1.8-fold phenoconversion hazard. However, no difference was observed in 248 subjects from Barcelona and 166 from Innsbruck. Analysis of Montreal data found that increased survival in the later epoch was driven by an increasing number of self-referrals, who phenoconverted at 1/3 the rate of physician-referred subjects.

Conclusions

Increased patient awareness of iRBD results in earlier presentation to clinical attention, with a longer time to phenoconversion.

Improved automatic identification of isolated rapid eye movement sleep behavior disorder with a 3D time-of-flight camera

BACKGROUND AND PURPOSE

Automatic 3D video analysis of the lower body during rapid eye movement (REM) sleep has been recently proposed as a novel tool for identifying people with isolated REM sleep behavior disorder (iRBD), but, so far, it has not been validated on unseen subjects. This study aims at validating this technology in a large cohort and at improving its performances by also including an analysis of movements in the head, hands and upper body.

METHODS

Fifty-three people with iRBD and 128 people without RBD (of whom 89 had sleep disorders considered RBD differential diagnoses) were included in the study. An automatic algorithm identified movements from 3D videos during REM sleep in four regions of interest (ROIs): head, hands, upper body and lower body. The movements were divided into categories according to duration: short (0.1-2 s), medium (2-15 s) and long (15-300 s). For each ROI and duration range, features were obtained from the identified movements. Logistic regression models using as predictors the features from one single ROI or a combination of ROIs were trained and tested in a 10-runs 10-fold cross-validation scheme on the task of differentiating people with iRBD from people without RBD.

RESULTS

The best differentiation was achieved using short movements in all four ROIs (test accuracy 0.866 ± 0.007, test F1 score = 0.783 ± 0.010). Single group analyses showed that people with iRBD were distinguished successfully from subjects with RBD differential diagnoses.

CONCLUSIONS

Automatic 3D video analysis might be implemented in clinical routine as a supportive screening tool for identifying people with RBD.

Low Specificity of Rapid Eye Movement Sleep Behavior Disorder Questionnaires: Need for Better Screening Methods

BACKGROUND

Correct diagnosis of rapid eye movement sleep behavior disorder (RBD) is critical due to its link to α-synucleinopathies and risk of injuries and requires video-polysomnography (V-PSG). Usefulness of screening questionnaires outside the context of validation studies is limited.

OBJECTIVE

The aim was to assess the performance of three validated RBD screening questionnaires compared with gold-standard V-PSG.

METHODS

In this bicentric prospective study, 400 consecutive subjects referred to a sleep center for the first time filled three RBD questionnaires (RBD Screening Questionnaire, RBD Single Question, and Innsbruck RBD Inventory) in random order before sleep experts' interview. Subjects positive for at least one questionnaire were invited to undergo V-PSG. Data from patients negative for all questionnaires undergoing V-PSG for other reasons were also evaluated. Questionnaire performances were compared to gold-standard V-PSG RBD diagnosis.

RESULTS

Three hundred ninety-nine patients (median age: 51 [interquartile range: 37-64] years, 54.9% men) participated. Two hundred thirty-eight (59.6%) were positive for at least one questionnaire, and RBD was diagnosed using V-PSG in 30 patients (7.5%). Questionnaire specificity was 48.1% to 67.4%, sensitivity 80% to 92%, accuracy 51% to 68.3%, negative predictive value 94.2% to 98%, and positive predictive value 14.1% to 20.7%, with no relevant differences in performances among the evaluated questionnaires.

CONCLUSIONS

RBD questionnaires have low specificity and low positive predictive value and should not be used as a standalone tool for the diagnosis of RBD. Further development of RBD screening methods is needed, particularly for upcoming neuroprotective trials. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

A prospective case-control study of excessive fragmentary myoclonus in the upper and lower extremities: Clinical characteristics and electrophysiological correlates

BACKGROUND

Excessive fragmentary myoclonus (EFM) is an incidental finding in video-polysomnography (VPSG) and listed among "Sleep Related Movement Disorders - Isolated symptoms and normal variants" in the ICSD-3. We aimed to prospectively evaluate EFM in the upper and lower extremities in a large sleep laboratory cohort and to investigate clinical characteristics and peripheral nerve pathology in patients with and without EFM.

METHODS

Two-hundred consecutive sleep laboratory patients with EFM according to ICSD-3 criteria were included and matched to 100 patients without EFM for age, sex and presence or absence of sleep-related breathing disorder. Patients additionally underwent peripheral neurophysiological work-up.

RESULTS

In 31/200 (15.5%) patients EFM was present not only in the lower extremities, but also in the upper extremities. Patients with EFM had less REM sleep (%/SPT; median (IQR); 13.8 (9.1-18.2) vs. 17.1 (10.1-20.5); p = 0.008) and the PLMS-Index was higher in patients with EFM than in those without (16.2 vs. 8.8/h; p = 0.009). Polyneuropathy (PNP) and nerve root lesions L5 and S1 were more frequent in patients with than in those without EFM (31.5% vs. 21% and 5% vs. 0%; p = 0.003).

CONCLUSIONS

In this large cohort we systematically investigated upper and lower extremities with surface electromyography during sleep and show that EFM is much more frequent in the lower extremities than in the upper extremities and corroborate the association of EFM with peripheral nerve pathology and PLMS.

Automatic analysis of muscular activity in the flexor digitorum superficialis muscles: a fast screening method for rapid eye movement sleep without atonia

STUDY OBJECTIVES

To identify a fast and reliable method for rapid eye movement (REM) sleep without atonia (RWA) quantification.

METHODS

We analyzed 36 video-polysomnographies (v-PSGs) of isolated REM sleep behavior disorder (iRBD) patients and 35 controls' v-PSGs. Patients diagnosed with RBD had: i) RWA, quantified with a reference method, i.e. automatic and artifact-corrected 3-s Sleep Innsbruck Barcelona (SINBAR) index in REM sleep periods (RSPs, i.e. manually selected portions of REM sleep); and ii) v-PSG-documented RBD behaviors. We quantified RWA with other (semi)-automated methods requiring less human intervention than the reference one: the indices proposed by the SINBAR group (the 3-s and 30-s phasic flexor digitorum superficialis (FDS), phasic/"any"/tonic mentalis), and the REM atonia, short and long muscle activity indices (in mentalis/submentalis/FDS muscles). They were calculated in whole REM sleep (i.e. REM sleep scored following international guidelines), in RSPs, with and without manual artifact correction. Area under curves (AUC) discriminating iRBD from controls were computed. Using published cut-offs, the indices' sensitivity and specificity for iRBD identification were calculated. Apnea-hypopnea index in REM sleep (AHIREM) was considered in the analyses.

RESULTS

RWA indices from FDS muscles alone had the highest AUCs and all of them had 100% sensitivity. Without manual RSP selection and artifact correction, the "30-s phasic FDS" and the "FDS long muscle activity" had the highest specificity (85%) with AHIREM < 15/h. RWA indices were less reliable when AHIREM≥15/h.

CONCLUSIONS

If AHIREM<15/h, FDS muscular activity in whole REM sleep and without artifact correction is fast and reliable to rule out RWA.

Differentiation of central disorders of hypersomnolence with manual and artificial-intelligence-derived polysomnographic measures

Differentiation of central disorders of hypersomnolence (DOH) is challenging but important for patient care. This study aimed to investigate whether biomarkers derived from sleep structure evaluated both by manual scoring as well as with artificial intelligence (AI) algorithms allow distinction of patients with different DOH. We included video-polysomnography data of 40 narcolepsy type 1 (NT1), 26 narcolepsy type 2 (NT2), 23 patients with idiopathic hypersomnia (IH) and 54 participants with subjective excessive daytime sleepiness (sEDS). Sleep experts manually scored sleep stages. A previously validated AI algorithm was employed to obtain automatic hypnograms and hypnodensity graphs (where each epoch is represented as a mixture of sleep stage probabilities). One-thousand-three features describing sleep architecture and instability were extracted from manual/automatic hypnogram and hypnodensity graphs. After feature selection, random forest classifiers were trained and tested in a 5-fold-cross-validation scheme to distinguish groups pairwise (NT1-vs-NT2, NT1-vs-IH, …) and single groups from the pooled remaining ones (NT1-vs-rest, NT2-vs-rest,…). The accuracy/F1-score values obtained in the test sets were: 0.74 ± 0.04/0.79 ± 0.05 (NT1-vs-NT2), 0.89 ± 0.09/0.91 ± 0.08 (NT1-vs-IH), 0.93 ± 0.06/0.91 ± 0.07 (NT1-vs-sEDS), 0.88 ± 0.04/0.80 ± 0.07 (NT1-vs-rest), 0.65 ± 0.10/0.70 ± 0.09 (NT2-vs-IH), 0.72 ± 0.12/0.60 ± 0.10 (NT2-vs-sEDS), 0.54 ± 0.19/0.38 ± 0.13 (NT2-vs-rest), 0.57 ± 0.11/0.35 ± 0.18 (IH-vs-sEDS), 0.71 ± 0.08/0.35 ± 0.10 (IH-vs-rest) and 0.76 ± 0.08/0.71 ± 0.13 (sEDS-vs-rest). The results confirm previous findings on sleep instability in patients with NT1 and show that combining manual and automatic AI-based sleep analysis could be useful for better distinction of NT2 from IH, but no precise sleep biomarker of NT2 or IH could be identified. Validation in a larger and multi-centric cohort is needed to confirm these findings.

TeaSpam: A Novel Method of TEmporal And SPAtial Movement Encoding during Sleep

Movements during sleep characterize sleep disorders, which can disturb sleep or its onset, impacting sleep quantity and quality. Video-polysomnography is the current gold standard to assess movements during sleep, but its availability is limited. Using data recorded with a 3D time of flight sensor, we developed a novel method of encoding temporal and spatial information of automatically identified movements during sleep. In a cohort of 20 insomnia patients and 18 controls, we showed that this novel method holds important information able to discriminate the groups. Future studies will explore the methodology in the context of other sleep disorders.

The additional diagnostic benefits of performing both video-polysomnography and prolonged video-EEG-monitoring: when and why

•

Video-polysomnography (VPSG) and prolonged video-EEG-monitoring (pVEEG-M) are indicated for different suspected diagnoses.

•

Here, we report on 109 patients who underwent both, VPSG and pVEEG-M, within a 10 year period.

•

Both examinations were performed in case of comorbidities, to achieve a final diagnosis or to refute differential diagnoses.

Objective

Video-polysomnography (VPSG) and prolonged video-EEG-monitoring (pVEEG-M) are neurophysiological investigation modalities. Depending on indication either is performed, but occasionally patients undergo both (during the same or separate stays). We sought to assess the reasons and potential benefits of dual diagnostic assessments with both modalities.

Methods

A retrospective chart-review was performed to identify patients who underwent both VPSG and pVEEG-M during the 10 year period between 2007 and 2017. One-hundred-nine patients were identified who had undergone both studies. Patients were grouped according to indication and outcome.

Results

One-hundred-nine patients had both, a VPSG and pVEEG-M, in 62 (56.9%) the studies were performed because of separate diagnoses independent from each other. In 47 patients (43.1%) investigation with both modalities was needed to clarify the suspected diagnosis or to refute differential diagnoses. Out of these 47, 11 (10.1% of the whole group) arrived a new final diagnosis whereas in 36 (33%) the primary diagnosis was corroborated with the second modality.

Conclusions

In the majority of cases VPSG plus pVEEG-M were indicated to diagnose or monitor different comorbid diseases (e.g. sleep-related breathing disorder and epilepsy). In the other cases, performing both modalities was useful to achieve a higher diagnostic accuracy or to refute differential diagnoses.

Significance

VPSG and pVEEG-M are neurophysiological investigations which complement each other, especially in case of two different comorbid diseases in a single patient, to rule out differential diagnosis or when a higher diagnostic certainty is seeked.

Factors associated with augmentation in patients with restless legs syndrome

Background and purpose

Augmentation is a paradoxical reaction mainly to dopaminergic medication in patients with restless legs syndrome (RLS), but the exact pathomechanism remains unclear. The aim of this study was to identify factors associated with augmentation in RLS patients.

Methods

RLS patients with and without current or previous augmentation were recruited. Demographic characteristics, history of smoking, questionnaires for depression, alexithymia, and impulsivity, and RLS severity were obtained.

Results

We included 122 patients, of whom half had a history of augmentation. Patients with augmentation had a longer disease duration (p = 0.001), had higher RLS severity scores (p = 0.013), had higher levodopa equivalent doses (p < 0.001), had higher scores for alexithymia (p = 0.028), had higher prevalence of impulse control disorders (p < 0.001), more often had a history of smoking (p = 0.039), were more often currently smoking (p = 0.015), and had more average pack‐years (p = 0.016).

Conclusions

Here, we describe several factors commonly associated with augmentation in RLS. These may help clinicians to screen and treat patients carefully to avoid the challenging side effect of augmentation.

Automatic 3D Video Analysis of Upper and Lower Body Movements to Identify Isolated REM Sleep Behavior Disorder: A Pilot Study. Annu Int Conf IEEE Eng Med Biol Soc 2021;2021:7050-7053. [PMID: 34892726 DOI: 10.1109/embc46164.2021.9630011]

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by dream enactment, abnormal jerks and movements during REM sleep. Isolated RBD (iRBD) is recognized as the early stage of alpha-synucleinopathies, i.e. dementia with Lewy bodies, Parkinson's disease and multiple system atrophy. The certain diagnosis of iRBD requires video-polysomnography, evaluated by experts with time-consuming visual analyses. In this study, we propose automatic analysis of movements detected with 3D contactless video as a promising technology to assist sleep experts in the identification of patients with iRBD. By using automatically detected upper and lower body movements occurring during REM sleep with a duration between 4s and 5s, we could discriminate 20 iRBD patients from 24 patients with sleep-disordered breathing with an accuracy of 0.91 and F1-score of 0.90. This pilot study shows that 3D contactless video can be successfully used as a non-invasive technology to assist clinicians in identifying abnormal movements during REM sleep, and therefore to recognize patients with iRBD. Future investigations in larger cohorts are needed to validate the proposed technology and methodology.

Language analysis of spontaneous descriptions of restless legs syndrome: Gender differences?

Patients with restless legs syndrome (RLS) use various terms when describing their symptoms. Whether gender might influence this has not been investigated so far. The aim of this study was to evaluate possible gender differences in spontaneous descriptions of RLS symptoms. This prospective study, conducted in 100 consecutive German‐speaking RLS patients, used a single standardized question. Answers were digitally recorded and transcribed. A content‐related linguistic analysis of the transcripts was performed by two independent blinded raters. The lengths of the answers and content‐related linguistic features were compared between women and men. Ninety‐eight patients were included in the final analysis, 59 women (60.2%) and 39 men (39.8%), with a median age of 62 (23–94) and 63 (31–82) years, respectively (p = 0.602). Demographic and clinical features, including educational level and RLS treatment class, did not differ between genders (p > 0.05). Total word or sentence count showed no gender differences (p = 0.159 and 0.259, respectively), although men used more words per sentence than women (p = 0.018). More men than women described quiescegenic (i.e., triggered by rest or inactivity) symptoms (p = 0.006) and successful attempts at relief (p = 0.039). There was a non‐significant trend toward a more frequent use of the first‐person perspective in men (median times used = 5 [0–10.5] vs. 3.8 [0–17.5], p = 0.068). The more frequent mention of quiescegenic symptoms and successful attempts at relief in men could indicate differences in phenotypic presentation of RLS between genders, a more precise description of RLS symptoms or a higher experience of self‐efficacy in men compared to women.

Signs of sympathetic and endothelial cell activation in the skin of patients with restless legs syndrome

OBJECTIVES

To evaluate skin biopsies of patients with early- and late onset restless legs syndrome (RLS) for concomitant small fiber neuropathy (SFN) and to determine cutaneous sympathetic innervation and microvascularization in comparison to healthy individuals.

METHODS

Density of intraepidermal nerve fibers (IENFD), adrenergic nerve fibers and dermal capillaries was analyzed by immunofluorescence for PGP9.5, tyrosine hydroxylase and endothelial markers CD31 and CD105 in skin biopsies of 11 individuals with RLS and 8 age- and sex-matched controls.

RESULTS

IENFD did not differ between RLS and controls, but two RLS patients with comorbid impaired glucose metabolism fulfilled morphometric criteria of SFN according to published normative values. In contrast, dermal nerve bundles of RLS patients showed an increased density of tyrosine hydroxylase⁺ adrenergic nerve fibers (p < 0.005). Moreover, an increased ratio between immature CD105⁺ and mature CD31⁺ endothelial cells within dermal capillaries was observed in RLS (p < 0.02).

CONCLUSIONS

SFN, as a potential contributing factor for RLS, should be considered in patients with predisposing comorbidities presenting with burning or shooting pain, dysesthesias and impaired sensory and temperature perception. Evidence of an increased adrenergic innervation of the skin in RLS patients is in accordance with sympathetic hyperactivity while signs of endothelial cell activation may reflect an adaptive response to tissue hypoxia.

Birds of a Feather Flock Together: Disadvantageous Decision Making in Augmented Restless Legs Syndrome Patients with and without Impulse Control Disorders

Background: Augmentation (AUG) in patients with restless legs syndrome (RLS) can be associated with impulse control disorder (ICD) symptoms, such as compulsive sexual behavior, gambling disorder or compulsive shopping. In this study, we wanted to assess whether RLS patients with AUG differ in decision making from those patients who have augmentation and in addition ICD symptoms (AUG + ICD) in a post hoc analysis of a patient cohort assessed in a previous study. Methods: In total, 40 RLS patients with augmentation (19 AUG + ICD, 21 AUG without ICDs) were included. RLS diagnosis, severity, and diagnosis of augmentation were made by sleep disorder specialists. ICD symptoms were assessed using semi-structured interviews. All patients performed the beads task, which is an information sampling task where participants must decide from which of the two cups colored beads were drawn. Results were compared to 21 healthy controls (HC). Results: There was no difference in information sampling or irrational decision making between AUG and AUG + ICD patients (p = 0.67 and p = 1.00, respectively). Both patient groups drew less beads and made more irrational decisions than HC (all p-values < 0.03, respectively). Conclusions: Our results suggest that augmentation itself is associated with poorer decision making even in the absence of ICD symptoms. Further studies are necessary to explore whether rapid and hasty decision making are a harbinger of augmentation in RLS.

REM Sleep Behavior Disorder and REM Sleep Without Atonia are More Frequent in Advanced versus Early Parkinson's Disease

STUDY OBJECTIVES

To evaluate macro sleep architecture and characterize REM sleep without atonia (RWA) by using the SINBAR EMG montage including mentalis and upper extremity muscles in early and advanced Parkinson's disease (PD).

METHODS

We recruited 30 patients with early- and advanced-stage of PD according to Movement Disorder Society (MDS) Clinical Diagnostic Criteria. Participants were classified as early-stage PD if they were treatment-naïve or had no motor complications and had been diagnosed with PD within the previous 6 years. Advanced PD was defined as a disease duration equal to or more than 6 years with or without motor complications.

RESULTS

There was significantly shorter REM sleep latency in early as compared to advanced stage of PD. We found that the SINBAR EMG index and tonic EMG activity of the mentalis muscle in advanced-stage PD were significantly higher than in early-stage PD with a trend in phasic EMG activity of the flexor digitorum superficialis muscles. The SINBAR EMG index, tonic and any EMG activity of the mentalis muscle, and phasic EMG activity of flexor digitorum superficialis muscles significantly correlated with disease duration.

CONCLUSIONS

This study analyzed RWA using the SINBAR EMG montage in early- and advanced-stage of PD and showed higher RWA in mentalis and flexor digitorum superficialis muscles and SINBAR EMG index in advanced-PD patients compared to patients in the early stage. Also, PSG-confirmed RBD was more common in advanced versus early-stage patients. Our findings suggest that RWA worsens or is more intense or more frequent with disease progression.

Central Sleep Apnea and Pacing-Induced Cardiomyopathy

The role of central sleep apnea (CSA) in pacing-induced cardiomyopathy (PICM) remains speculative. In a prospective trial entitled UPGRADE, the presence of CSA was assessed by single-night polysomnography (PSG) in 54 PICM patients within 1 month after left ventricular lead implantation (with biventricular stimulation still not activated). CSA was diagnosed in half of patients (n = 27). Patients with moderate or severe CSA were randomized to cardiac resynchronization therapy (CRT) versus right ventricular pacing (RVP) in a double-blinded cross-over design and re-scheduled for a follow-up PSG within 3 to 5 months. After crossing-over of stimulation mode another PSG was conducted 3 to 5 months later. CRT led to a significant increase in left ventricular ejection fraction and significant reduction in left ventricular end systolic volumes and N-terminal pro brain natriuretic peptide plasma levels, whereas no significant effects were observed with ongoing RVP. CSA was significantly improved after 3.9 (3.2 to 4.4) months of CRT: apnea-hypopnea index decreased from 39.1 (32.1 to 54.0) events per hour at baseline to 22.2/h (10.9 to 36.7) by CRT (p <0.001). Central apnea index decreased from 27.1/h (17.7 to 36.1) at baseline to 6.8/h (1.1 to 14.4) after CRT activation (p <0.001). Ongoing RVP yielded only a minor improvement in apnea-hypopnea index and central apnea index. Pre-existent CSA did not affect structural response rate and had no impact on mid-term follow-up (median 2.8 years). In conclusion, CSA is highly prevalent in patients with PICM. CRT upgrading significantly improves CSA leading to a similar outcome in PICM patients without pre-existent CSA.

Augmentation in restless legs syndrome: an eye tracking study on emotion processing

Objective

To assess emotional processing and alexithymia in patients with restless legs syndrome (RLS) with augmentation versus those who never had augmentation.

Methods

We recruited 26 patients who had a history of augmentation (AUG), either current or past, 27 RLS patients treated with dopamine agonists who never had augmentation (RLS controls), and 21 healthy controls (HC). All participants were screened for impulse control disorders (ICDs). Alexithymia was assessed by means of the Toronto Alexithymia Scale – 20 (TAS‐20). Facial emotion recognition was tested through an eye‐tracking task. Furthermore, all participants performed neuropsychological tests assessing global cognitive status, impulsivity, anxiety, and depression.

Results

ICD symptoms occurred more frequently in AUG patients than in RLS controls (P = 0.047). Patients with AUG scored higher on the TAS‐20 (P = 0.007) and the attentional subdomain of an impulsivity scale (BIS‐11; P = 0.015) compared to HC. Patients with AUG also performed worse on the facial emotion recognition task relative to RLS controls (P = 0.009) and HC (P = 0.003). We found a group difference for the time to first fixation and the fixation count in the mouth region (P = 0.019 and P = 0.021, respectively). There were no other differences in the eye tracking examination.

Interpretation

This study showed evidence of poorer emotional processing in patients who had augmentation compared to RLS patients without augmentation and healthy controls. The altered exploration pattern of faces and the higher alexithymia scores suggest abnormalities in emotion processing in patients with augmentation.

Automated 3D video analysis of lower limb movements during REM sleep: a new diagnostic tool for isolated REM sleep behavior disorder

STUDY OBJECTIVES

The differentiation of isolated rapid eye movement (REM) sleep behavior disorder (iRBD) or its prodromal phase (prodromal RBD) from other disorders with motor activity during sleep is critical for identifying α-synucleinopathy in an early stage. Currently, definite RBD diagnosis requires video polysomnography (vPSG). The aim of this study was to evaluate automated 3D video analysis of leg movements during REM sleep as objective diagnostic tool for iRBD.

METHODS

A total of 122 participants (40 iRBD, 18 prodromal RBD, 64 participants with other disorders with motor activity during sleep) were recruited among patients undergoing vPSG at the Sleep Disorders Unit, Department of Neurology, Medical University of Innsbruck. 3D videos synchronous to vPSG were recorded. Lower limb movements rate, duration, extent, and intensity were computed using a newly developed software.

RESULTS

The analyzed 3D movement features were significantly increased in subjects with iRBD compared to prodromal RBD and other disorders with motor activity during sleep. Minor leg jerks with a duration < 2 seconds discriminated with the highest accuracy (90.4%) iRBD from other motor activity during sleep. Automatic 3D analysis did not differentiate between prodromal RBD and other disorders with motor activity during sleep.

CONCLUSIONS

Automated 3D video analysis of leg movements during REM sleep is a promising diagnostic tool for identifying subjects with iRBD in a sleep laboratory population and is able to distinguish iRBD from subjects with other motor activities during sleep. For future application as a screening, further studies should investigate usefulness of this tool when no information about sleep stages from vPSG is available and in the home environment.

P534Central sleep apnea in pacing-induced cardiomyopathy: prevalence, improvement by upgrading to cardiac resynchronisation therapy and impact on structural responder rates and long-term outcome

Funding Acknowledgements

ÖNB Jubiläumsfondsprojekt Nr. 15974, ISR grant by Boston Scientific, St. Paul, MN, USA

Background

Central sleep apnea (CSA) in pacing induced cardiomyopathy (PICM) is poorly studied. Specifically, it is unknown whether upgrading from right ventricular pacing (RVP) to cardiac resynchronisation therapy (CRT) improves CSA.

Methods

Fifty-three patients with impaired left ventricular ejection fraction, frequent right ventricular pacing due to high-grade atrioventricular block and heart failure symptoms despite optimal medical therapy underwent upgrading to CRT. Within one month after left ventricular lead implantation (but still not activated), sleep apnea was assessed in all participants by single-night polysomnography (PSG). Nineteen patients with moderate or severe CSA defined by an apnea hypopnea index (AHI) &gt; 15 events per hour were re-scheduled for a follow up PSG 3-5 months after initiation of cardiac resynchronization therapy. Of this cohort, thirteen patients with stable mild heart failure agreed to be randomized to CRT versus RVP in a cross-over design.

Results

CSA (AHI &gt; 5 events per hour) was diagnosed in 26 (49.1%), OSA in 16 (30.2%) patients suffering from PICM . Eleven (20.8%) patients did not have any form of sleep apnea. Moderate to severe CSA (AHI &gt; 15 events per hour) was significantly improved (without specific CPAP therapy) by 102 (96-172) days of CRT: AHI decreased from 39.4 events per hour at baseline to 21.6 by CRT (p &lt; 0.001). Furthermore, CRT led to a substantial decrease in left ventricular endsystolic volumes: baseline 141 ml (103-155), significant improvement under CRT (102 ml, 65-138; p &lt; 0.001), whereas no effect with ongoing RV-pacing (147 ml, 130-161; p = 0.865). Preexistent CSA did not affect the structural response of CRT (56.5% in patients with CSA, 62.5% of patients with obstructive sleep apnea and 54.5% in patients without sleep apnea; p = 0.901) and had no impact on major adverse cardiac events (p = 0.412) and/or survival (p = 0.623) during long-term follow-up.

Conclusions

CSA is highly prevalent in patients with PICM and is significantly improved by upgrading to CRT. Preexistent CSA does not hamper structural improvement and long-term outcome after upgrading to CRT. Thus, CSA seems to occur as a consequence of PICM, rather than as a pathophysiological mediator.

Abstract Figure.

Screening for idiopathic REM sleep behavior disorder: usefulness of actigraphy

Study Objectives

To evaluate the utility of multimodal low-cost approaches including actigraphy, a wrist-worn device monitoring rest/activity cycles, in identifying patients with idiopathic REM sleep behavior disorder (iRBD).

Methods

Seventy patients diagnosed with sleep disorders causing different motor manifestations during sleep (iRBD, sleep apnea, restless legs syndrome) and 20 subjects without any relevant motor manifestation during sleep, underwent video-polysomnography (vPSG) and 2 week actigraphy, completed six validated RBD screening questionnaires, and sleep apps use was assessed. Actigraphy was analyzed automatically, and visually by seven blinded sleep medicine experts who rated as "no," "possible," and "probable" RBD.

Results

Quantitative actigraphy analysis distinguished patients from controls, but not between patients with different types of motor activity during sleep. Visual actigraphy rating by blinded experts in sleep medicine using pattern recognition identified vPSG confirmed iRBD with 85%-95% sensitivity, 79%-91% specificity, 81%-91% accuracy, 57.7% ± 11.3% positive predictive value, 95.1% ± 3.3% negative predictive value, 6.8 ± 2.2 positive likelihood ratio, 0.14 ± 0.05 negative likelihood ratio and 0.874-0.933 area under the ROC curve (AUC). AUC of the best performing questionnaire was 0.868. Few patients used sleep apps; therefore, their potential utility in the evaluated patients' groups is limited.

Conclusions

Visual analysis of actigraphy using pattern recognition can identify subjects with iRBD, and is able to distinguish iRBD from other motor activities during sleep, even when patients are not aware of the disease in contrast to questionnaires. Therefore, actigraphy can be a reliable screening instrument for RBD potentially useful in the general population.

Sleep apnea detection by a cardiac resynchronization device integrated thoracic impedance sensor: A validation study against the gold standard polysomnography

BACKGROUND

Sleep disordered breathing is a common but often undiagnosed comorbidity in heart failure patients. Cardiac implantable electronic devices used for cardiac resynchronization therapy (CRT) may detect sleep apnea by use of a transthoracic impedance sensor. Validation of the AP scan® algorithm (Boston Scientific®) was performed by using the diagnostic gold standard polysomnography (PSG).

METHODS

Forty-one patients with impaired left ventricular ejection fraction, frequent right ventricular pacing due to atrioventricular block and heart failure symptoms despite optimal medical therapy underwent upgrading to biventricular pacing. Within one month after left ventricular lead implantation, sleep apnea was assessed by single-night PSG and AP scan® measurements.

RESULTS

AP scan® measurements were valid in only 21 of 41 (51.2%) patients in the index night of the PSG. The PSG determined apnea-hypopnea index did not correlate statistically significant with the AP scan® measurements (r = 0.41, 95% confidence interval -0.05-0.72, p = 0.07). The degree of overestimation is displayed by using the Bland-Altman method: mean difference -12.4, standard deviation ± 15.8, 95% confidence interval -43.3-18.6.

CONCLUSIONS

In heart failure patients receiving CRT upgrading, the AP scan® algorithm may need further improvement before it can be recommended for sleep apnea detection.

Reflection impulsivity perceptual decision-making in patients with restless legs syndrome

Objectives

The objective of this study was to investigate perceptual decision‐making and reflection impulsivity in drug naïve patients with restless legs syndrome (RLS) and patients with dopaminergic therapy.

Methods

A total of 35 RLS patients (20 who were drug naïve regarding dopaminergic medication and 15 patients treated with dopaminergic therapy without augmentation or impulse control disorders) were included in this study. We used the Beads task and the Pixel task which assess reflection impulsivity and perceptual decision‐making, respectively. Results were compared to 20 healthy controls.

Results

Both RLS patient groups gathered less evidence than healthy controls in the Beads task before making a decision (P < 0.001), but patients with dopaminergic treatment gathered less information than drug naïve patients (P = 0.026). Moreover, both patient groups made more choices against the evidence than healthy controls (both P < 0.01), but there was no difference between the two patient groups. In the Pixel task, we found an effect of task difficulty on reaction times with patients and controls responding faster with reduced task difficulty. There was neither an effect of group on reaction times nor an effect of group on error rates.

Conclusions

Reflection impulsivity is common in RLS patients, regardless whether they are drug naïve or treated with dopaminergic therapy. Thus, RLS patients tend to gather less information compared to healthy controls which could have a negative effect on decision‐making in daily life and should be investigated further.

Dream Content in Patients With Sleep Apnea: A Prospective Sleep Laboratory Study

STUDY OBJECTIVES

Few studies have addressed dreaming in patients with sleep apnea. We hypothesized that respiratory events and subsequent oxygen desaturation act as an important physiological trigger and may thus influence dream content in patients with a sleep-related breathing disorder.

METHODS

Seventy-six patients (28 women, mean age 54 years, range 20-82) who underwent polysomnography because of suspected sleep apnea participated in this study. Dream reports and dream questionnaires were collected immediately after first morning awakening, at 5:30 AM, at the sleep laboratory. Dream content analysis with respect to possible respiratory-related content was performed. Patients were stratified into primary snoring, mild, moderate, and severe sleep apnea groups.

RESULTS

In 63 patients sleep apnea was diagnosed (mild n = 31, 49.2%, moderate n = 13, 20.6%, severe n = 19, 30.2%), and 13 subjects in whom a sleep-related breathing disorder was not confirmed were included as a control group with primary snoring. There was no significant difference in respiratory-related dream topics between patients and controls. Also, no influence of respiratory parameters measured during polysomnography on dream content was detectable.

CONCLUSIONS

We failed to detect a difference in dream content between patients with sleep apnea and controls. Further studies are required to determine whether these results indicate that the incorporation of respiratory events into dreams is absent in patients with sleep apnea or represents a bias due to the collection of dream content in the early morning hours.

Haste makes waste: Decision making in patients with restless legs syndrome with and without augmentation

Objectives

To investigate decision making in patients with primary restless legs syndrome (RLS) with and without augmentation treated with dopaminergic medication.

Methods

A total of 64 non-demented RLS patients treated with dopaminergic medication with and without augmentation were included in this study. We used an information sampling task to assess how much evidence participants gather before making a decision. Performance was compared to the results of 21 healthy controls.

Results

All patients with and without augmentation gathered less information than healthy controls before making a decision (p<0.001), but there was no difference between the two patient groups (p = 1.0). Furthermore, both patient groups made more irrational decisions (e.g. decisions against the evidence they had at the time) than healthy controls (p≤0.002). In addition, RLS patients with augmentation made significantly more irrational decisions than RLS patients without augmentation (p = 0.037) and controls (p<0.001).

Conclusions

Our results show that RLS patients treated with dopaminergic drugs, regardless of having augmentation or not, jumped to conclusions and decided significantly more often against the evidence they had at the time of their decision. However, those with augmentation performed worse than all other groups and made more often irrational decisions, a phenomenon which is also common in patients with substance abuse or behavioural addictions. Thus, jumping to conclusions and deciding with a higher degree of uncertainty as well as irrational decision making is more common in RLS patients treated with dopaminergic medication particularly in those with augmentation.

Influence of a Post-Test Factor on the Results of the Multiple Sleep Latency Test

STUDY OBJECTIVES

The multiple sleep latency test (MSLT) is the standard method for the objective measurement of excessive daytime sleepiness. It is well established that preceding factors may influence the MSLT result. Aim of this study was to evaluate the potential influence of a post-test factor on the MSLT outcome.

METHODS

For this retrospective study we reviewed polysomnography (PSG) reports conducted between 2012 and 2013. PSG reports including MSLT with at least four runs were included. Patients were stratified into (1) those discharged immediately after the MSLT or (2) those discharged on the following day. For further analysis, we categorized the patients into three subgroups according to mean MSLT sleep latency: < 5, 5-9.9, and 10-19.9 minutes, corresponding to a pathological, borderline, and normal MSLT result.

RESULTS

A total of 2,749 PSG records were reviewed; 262 included MSLT and 241 met inclusion criteria for the study. Of those, 152 patients were discharged immediately after the last MSLT run, 89 on the following day. MSLT mean sleep latency, and sleep latency of the last run only, did not differ between both groups (p = 0.070 and p = 0.065). In the subgroup of patients with pathological MSLT, there was a trend towards prolonged sleep latency in the last run in patients discharged immediately after the test (p = 0.055).

CONCLUSIONS

Our findings suggest that the MSLT post-test factor of discharge timing has no major impact on the MSLT outcome.

Subjective deficits of attention, cognition and depression in patients with narcolepsy

OBJECTIVE

Patients with narcolepsy often complain about attention deficits in everyday situations. In comparison with these subjective complaints, deficits in objective testing are subtler. The present study assessed the relationships between subjective complaints, objectively measured cognitive performance, disease-related variables, and mood.

PATIENTS/METHODS

A total of 51 patients with narcolepsy and 35 healthy controls responded to questionnaires regarding subjectively perceived attention deficits, sleepiness, anxiety and depression. Moreover, they performed an extensive neuropsychological assessment tapping into attention, executive functions, and memory.

RESULTS

Patients rated their level of attention in everyday situations to be relatively poor. In an objective assessment of cognitive functioning, they showed only slight attention and executive function deficits. The subjective ratings of attention deficits significantly correlated with ratings of momentary sleepiness, anxiety, and depression, but not with objectively measured cognitive performance. Momentary sleepiness and depression predicted almost 39% of the variance in the ratings of subjectively perceived attention deficits.

CONCLUSION

The present study showed that sleepiness and depression, more than objective cognitive deficits, might play a role in the subjectively perceived attention deficits of patients with narcolepsy. The results suggested that when counselling and treating patients with narcolepsy, clinicians should pay attention to potential depression because subjective cognitive complaints may not relate to objective cognitive impairments.

Quantitative assessment of isolated rapid eye movement (REM) sleep without atonia without clinical REM sleep behavior disorder: clinical and research implications

BACKGROUND

Rapid eye movement (REM) sleep without atonia (RWA) is observed in some patients without a clinical history of REM sleep behavior disorder (RBD). It remains unknown whether these patients meet the refined quantitative electromyographic (EMG) criteria supporting a clinical RBD diagnosis. We quantitatively evaluated EMG activity and investigated its overnight distribution in patients with isolated qualitative RWA.

METHODS

Fifty participants with an incidental polysomnographic finding of RWA (isolated qualitative RWA) were included. Tonic, phasic, and 'any' EMG activity during REM sleep on PSG were quantified retrospectively.

RESULTS

Referring to the quantitative cut-off values for a polysomnographic diagnosis of RBD, 7/50 (14%) and 6/50 (12%) of the patients showed phasic and 'any' EMG activity in the mentalis muscle above the respective cut-off values. No patient was above the cut-off value for tonic EMG activity or phasic EMG activity in the anterior tibialis muscles. Patients with RWA above the cut-off value showed higher amounts of RWA during later REM sleep periods.

CONCLUSIONS

This is the first study showing that some subjects with incidental RWA meet the refined quantitative EMG criteria for a diagnosis of RBD. Future longitudinal studies must investigate whether this subgroup with isolated qualitative RWA is at an increased risk of developing fully expressed RBD and/or neurodegenerative disease.

Delayed diagnosis, range of severity, and multiple sleep comorbidities: a clinical and polysomnographic analysis of 100 patients of the innsbruck narcolepsy cohort

STUDY OBJECTIVES

Narcolepsy is reported to affect 26-56/100,000 in the general population. We aimed to describe clinical and polysomnographic features of a large narcolepsy cohort in order to comprehensively characterize the narcoleptic spectrum.

METHODS

We performed a chart- and polysomnographybased review of all narcolepsy patients of the Innsbruck narcolepsy cohort.

RESULTS

A total of 100 consecutive narcolepsy patients (87 with cataplexy [NC], 13 without cataplexy [N]) were included in the analysis. All subjects had either excessive daytime sleepiness or cataplexy as their initial presenting clinical feature. Age at symptom onset was 20 (6-69) years. Diagnostic delay was 6.5 (0-39) years. The complete narcolepsy tetrad was present in 36/100 patients; 28/100 patients had three cardinal symptoms; 29/100 had two; and 7/100 had only excessive daytime sleepiness. Severity varied broadly with respect to excessive daytime sleepiness (median Epworth Sleepiness Scale score: 18, range 10-24), cataplexy (8-point Likert scale: median 4.5, range 1-8), hypnagogic hallucinations (median 4.5, range 1-7), and sleep paralysis (median 3, range 1-7). Sleep comorbidity was highly prevalent and ranged from sleeprelated movement disorders (n = 55/100), parasomnias (n = 34/100), and sleeprelated breathing disorders (n = 24/100), to insomnia (n = 28/100). REM sleep without atonia or a periodic limb movement in sleep index > 5/h were present in most patients (90/100 and 75/100). A high percentage of narcoleptic patients in the present study had high frequency leg movements (35%) and excessive fragmentary myoclonus (22%). Of the narcolepsy patients with clinical features of REM sleep behavior disorder (RBD), 76.5% had EMG evidence for RBD on the multiple sleep latency test (MSLT), based on a standard cutoff of a minimum of 18% of 3-sec miniepochs.

CONCLUSION

This study is one of the largest monocentric polysomnographic studies to date of patients with narcolepsy and confirms the frequent comorbidity of narcolepsy with many other sleep disorders. Our study is the first to evaluate the percentage of patients with high frequency leg movements and excessive fragmentary myoclonus in narcolepsy and is the first to demonstrate EMG evidence of RBD in the MSLT. These findings add to the growing body of literature suggesting that motor instability is a key feature of narcolepsy.

Validation of the Innsbruck REM sleep behavior disorder inventory

A diagnosis of definite REM sleep behavior disorder requires both a positive history for REM sleep behavior disorder and polysomnographic demonstration of REM sleep without atonia. To improve and facilitate screening for REM sleep behavior disorder, there is a need for simple clinical tools with sufficient sensitivity and specificity for the identification of subjects with probable REM sleep behavior disorder. We developed a short REM sleep behavior disorder screening questionnaire with 7 REM sleep behavior disorder- and 2 non-REM sleep behavior disorder-specific control items and performed a validation study in 70 REM sleep behavior disorder subjects and 140 sleep disorder controls. Response patterns to all 7 REM sleep behavior disorder-specific items differed between REM sleep behavior disorder and non-REM sleep behavior disorder patients (all P < 0.05), whereas the 2 non-REM sleep behavior disorder-specific control items did not differentiate between REM sleep behavior disorder and non-REM sleep behavior disorder (all P > .05). In 5 of the 7 REM sleep behavior disorder-specific items, AUC was greater than 0.700. These 5 items were included in the Innsbruck REM sleep behavior disorder inventory. In this questionnaire, a cutoff of 0.25 (number of positive symptoms divided by number of answered questions) had a sensitivity of 0.914 and a specificity of 0.857 for both idiopathic and Parkinson's-related REM sleep behavior disorder (AUC, 0.886). The Innsbruck REM sleep behavior disorder inventory is a promising, easy-to-use, short screening tool for REM sleep behavior disorder with excellent sensitivity and specificity for both idiopathic and Parkinson's-related REM sleep behavior disorder.

Decision making and executive functions in REM sleep behavior disorder

STUDY OBJECTIVES

This study was designed to assess decision making and executive functions in patients with idiopathic REM sleep behavior disorder (iRBD). IRBD is often seen as an early sign of later evolving neurodegenerative disease, most importantly Parkinson disease (PD) and Lewy body dementia (DLB). It has been proposed that iRBD patients show a cognitive profile similar to patients with PD.

DESIGN

All participants performed an extensive test battery tapping executive functions as well as the IOWA gambling task, which measures decision making under ambiguity.

SETTING

University hospital sleep disorders center.

PARTICIPANTS

16 iRBD patients and 45 age- and education-matched controls.

INTERVENTION

N.A.

MEASUREMENTS AND RESULTS

Compared with controls, iRBD patients showed disadvantageous decision making under ambiguity and did not learn by feedback over the task. IRBD patients' decision pattern was characterized by the lack of a consistent strategy, as indicated by frequent shifts between the single choices. A high proportion of iRBD patients (75%) showed random performance or worse even at the end of the task. No group differences were found in tasks assessing information sampling, flexibility and categorization, problem solving, and impulsivity.

CONCLUSIONS

As suggested by the present investigation, iRBD patients may show difficulties in decision making under ambiguity in a stage when other cognitive functions are relatively well preserved. Whether this is driven by subgroups of patients prone to develop PD or DLB has to be assessed by follow-up investigations.

Narcolepsy-cataplexy: deficient prepulse inhibition of blink reflex suggests pedunculopontine involvement

Hypocretin (orexin) deficiency plays a major role in the pathophysiology of narcolepsy-cataplexy. In animal models, hypocretinergic projections to the pedunculopontine nucleus are directly involved in muscle tone regulation mediating muscle atonia - a hallmark of cataplexy. We hypothesized that pedunculopontine nucleus function, tested with prepulse inhibition of the blink reflex, is altered in human narcolepsy-cataplexy. Twenty patients with narcolepsy-cataplexy and 20 healthy controls underwent a neurophysiological study of pedunculopontine nucleus function. Blink reflex, prepulse inhibition of the blink reflex and blink reflex excitability recovery were measured. Blink reflex characteristics (R1 latency and amplitude, and R2 and R2c latency and area under the curve) did not differ between patients and controls (P > 0.05). Prepulse stimulation significantly increased R2 and R2c latencies and reduced R2 and R2c areas in patients and controls. However, the R2 and R2c area suppression was significantly less in patients than in controls (to 69.8 ± 14.4 and 74.9 ± 12.6%, respectively, versus 34.5 ± 28.6 and 43.3 ± 29.5%, respectively; each P < 0.001). Blink reflex excitability recovery, as measured by paired-pulse stimulation, which is not mediated via the pedunculopontine nucleus, did not differ between patients and controls (P > 0.05). Our data showed that prepulse inhibition is reduced in narcolepsy-cataplexy, whereas unconditioned blink reflex and its excitability recovery are normal. Because the pedunculopontine nucleus is important for prepulse inhibition, these results suggest its functional involvement in narcolepsy-cataplexy.

White and gray matter abnormalities in narcolepsy with cataplexy

STUDY OBJECTIVES

The authors applied diffusion-tensor imaging including measurements of mean diffusivity (MD), which is a parameter of brain tissue integrity, fractional anisotropy (FA), which is a parameter of neuronal fiber integrity, and voxel-based morphometry, which is a measure of gray and white matter volume, to detect brain tissue changes in patients with narcolepsy-cataplexy.

DESIGN

N/A.

PATIENTS

Patients with narcolepsy-cataplexy (n = 16) and age-matched healthy control subjects (n = 12) were studied.

INTERVENTIONS

Whole cerebral MD, FA measures, and the volumes of the gray and white matter compartments were analyzed using statistical parametric mapping.

MEASUREMENT AND RESULTS

Significant MD increases and concomitant FA decreases were localized in the fronto-orbital cortex (P < 0.001) and the anterior cingulate (FA, P < 0.001; MD, P = 0.03) in narcolepsy-cataplexy. Additional MD increases without FA changes were detected in the ventral tegmental area, the dorsal raphe nuclei (P < 0.001), and the hypothalamus (P < 0.01). FA signal decreases were observed in the white matter tracts of the inferior frontal and inferior temporal cortices of narcolepsy-cataplexy patients (P < 0.001). Brain volume loss was evident in focal areas of the inferior and superior temporal cortices (P < 0.001) and the cingulate (P = 0.038).

CONCLUSIONS

Areas of increased diffusivity in the hypothalamus appear consistent with hypocretinergic cell loss reported in narcolepsy-cataplexy. Signal abnormalities in the ventral tegmental area and the dorsal raphe nuclei correspond to major synaptic targets of hypocretin neurons that were associated with the regulation of the sleep-wake cycle. Brain tissue alterations identified in the frontal cortex and cingulate are crucial in the maintenance of attention and reward-dependent decision making, both known to be impaired in narcolepsy-cataplexy.

A descriptive analysis of neck myoclonus during routine polysomnography

STUDY OBJECTIVES

Although episodes of neck myoclonus (head jerks) in REM sleep have a characteristic appearance, they have so far not been described systematically in video-polysomnography. This study assesses the occurrence, frequency, and characteristics of neck myoclonus in REM sleep in a prospective sleep disorder cohort, and investigates clinical correlates and associations with medication.

SETTING

University hospital sleep disorders center.

PARTICIPANTS

Two-hundred twenty-eight mixed sleep disorder patients.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND RESULTS

REM sleep was screened visually for short "stripe-shaped" movement-induced artifacts visible vertically over the EEG leads in polysomnographic registration. If such artifact was present, the synchronized video was inspected for the presence of neck myoclonus. Out of 205 patients, 54.6% (n = 112) had neck myoclonus during REM sleep. The mean neck myoclonus index was 1.0 +/- 2.7/h REM sleep. Younger patients had a higher neck myoclonus index than older patients (< 45 years versus 45-60 years versus > 60 years: 1.8 +/- 4.2 versus 0.6 +/- 1.1 versus 0.5 +/- 1.1; P = 0.004). Ninety-five percent of subjects < 45 years had a neck myoclonus index between 0 and 9.4/h; 95% of subjects > 45 years had a neck myoclonus index between 0 and 2.7/h. Patients on benzodiazepine treatment had no neck myoclonus (0/112 vs. 13/93; P < 0.001). In 23 patients, additional surface neck EMG was performed. EMG activation associated with neck myoclonus had a mean duration of 0.6 +/- 0.4 sec. Correlation between duration of neck EMG activation and movement-induced EEG artifact duration was very high (rho = 0.96; P < 0.001).

CONCLUSIONS

Neck myoclonus is common during REM sleep and more frequent in younger individuals. This could indicate that neck myoclonus during REM sleep is a physiological phenomenon. If there is a cut-off distinguishing normal from excessive has to be investigated in further studies.

REM sleep behavior disorder in 703 sleep-disorder patients: the importance of eliciting a comprehensive sleep history

OBJECTIVES

The aim of our study was to evaluate the frequency of REM sleep behavior disorder (RBD) in a mixed sleep laboratory population and to assess potential associations. Moreover, we investigated referral diagnoses of patients subsequently diagnosed with RBD and assessed the frequency of incidental RBD.

METHODS

Charts and polysomnographic reports of 703 consecutive patients comprising the full spectrum of ICSD-2 sleep disorders [501 males, 202 females; mean age, 51.0+/-14.1 years (range: 10-82 years)] were carefully reviewed. The vast majority of patients were adults (98.7%). Patients were categorized into those with and without RBD. For associations, all concomitant sleep and neurological diagnoses and medications were evaluated.

RESULTS

Thirty-four patients (4.8%) were diagnosed with RBD (27 men; 7 women, mean age, 57.7+/-12.3 years). RBD was idiopathic in 11 patients (1.6%; 9 men) and symptomatic in 23 patients (3.3%; 18 men) secondary to Parkinsonian syndromes (n=11), use of antidepressants (n=7), narcolepsy with cataplexy (n=4), and pontine infarction (n=1). Six out of 34 patients were referred for suspected RBD, 20 reported RBD symptoms only on specific questioning, and 8 patients had no history of RBD but showed typical RBD behavioral manifestations in the video-polysomnography. Logistic regression analysis revealed significant associations between RBD and the presence of Parkinsonian syndromes (odds ratio [OR] 16.8, 95%CI: 6.4-44.1; P<0.001), narcolepsy with cataplexy (OR 10.7, 95%CI: 2.9-40.2; P<0.001), SSRI use (OR 3.9, 95%CI: 1.6-9.8; P=0.003), and age (OR 1.5/10-year increase, 95%CI: 1.0-2.0; P=0.039).

CONCLUSION

In this population of 703 consecutive sleep-disorder patients, RBD was uncommon. Its etiology was predominantly symptomatic. The majority of RBD patients reported RBD symptoms on specific questioning only, underlining the importance of eliciting a comprehensive sleep history for the diagnosis of RBD.

[Outlines of interdisciplinary addiction research given by the example of medical imaging with PET, SPECT and fMRI regarding effects of psychotropic substances]

The addiction phenomenon provides a fertile ground for the application of the tools of medical imaging which contribute to the development of scientific conceptualization of the effect of psychotropic substances. Medical imaging as for instance PET (Positron Emission Tomography), SPECT (Single Photon Emission Tomography) or functional Magnetic Resonance Imaging (fMRI) are well established for the examination of functional activity in the living brain. Medical imaging permits the development of functional activation maps during perceptual, cognitive or emotional efforts with a high temporal and spatial resolution. Medical imaging devices have therefore also been used to help our understanding of many aspects of the pharmacokinetics and pharmacodynamics of abused drugs. Because Delta-9-Tetrahydrocannabinol and cocaine continue to be the most commonly used illicit drugs, their effects on the brain function are of major interest. The cannabinoid CB(1) receptor agonist Delta(9)-THC as for instance has also been suggested for treatment of Tourette syndrome (TS). This article provides an overview of present applications of medical imaging with PET, SPECT, and fMRI and its results regarding addiction-related research on Delta-9-Tetrahydrocannabinol and cocaine.

The severity range of restless legs syndrome (RLS) and augmentation in a prospective patient cohort: association with ferritin levels

OBJECTIVES

The aim of the study was to prospectively examine all patients with a diagnosis of RLS consulting a sleep disorders clinic and to assess RLS severity and augmentation and their associations, including ferritin levels.

METHODS

Patients were stratified into patients with RLS as ancillary diagnosis, RLS sufferers without current augmentation and RLS sufferers with current augmentation. Work-up included RLS severity scales and blood biochemical variables including indices of iron metabolism.

RESULTS

In an 18-month period, 302 patients with RLS (183 women, 119 men; mean age, 59.1+/-13.7 years) were recruited. RLS was considered idiopathic in 291 patients (96.4%). Most patients (240, 79.5%) were RLS sufferers, whereas the remaining 62 (20.5%) had RLS as ancillary diagnosis. Nineteen out of 162 patients treated with dopaminergic agents (11.7%) had current augmentation. Almost one-third of all patients (31.1%) had ferritin levels <50microg/l. Patients with an ancillary diagnosis of RLS had higher ferritin levels than RLS sufferers without current augmentation. The lowest ferritin levels were present in RLS sufferers with current augmentation 132.8+/-98.0microg/l vs. 100.6+/-84.5microg/l vs. 55.8+/-43.6microg/l; p=0.002). Patients with augmentation did not differ from non-augmented patients regarding age, gender, RLS etiology, presence of previous augmentation, or any other documented comorbidity (p>0.05).

CONCLUSION

The severity spectrum of RLS in this clinical cohort ranged from the ancillary diagnosis of RLS to augmented RLS. There was an inverse correlation between RLS severity and ferritin levels. Patients with current augmentation had the lowest ferritin levels. Our data further strengthen a putative role of low iron stores as a potential aggravator of idiopathic RLS. Moreover, low ferritin might represent a potential biomarker of RLS augmentation under dopaminergic therapy.