Sleep-wake disturbances in sporadic Creutzfeldt-Jakob disease

BACKGROUND: The prevalence and characteristics of sleep-wake disturbances in sporadic Creutzfeldt-Jakob disease (sCJD) are poorly understood. METHODS: Seven consecutive patients with definite sCJD underwent a systematic assessment of sleep-wake disturbances, including clinical history, video-polysomnography, and actigraphy. Extent and distribution of neurodegeneration was estimated by brain autopsy in six patients. Western blot analyses enabling classification and quantification of the protease-resistant isoform of the prion protein, PrPSc, in thalamus and occipital cortex was available in four patients. RESULTS: Sleep-wake symptoms were observed in all patients, and were prominent in four of them. All patients had severe sleep EEG abnormalities with loss of sleep spindles, very low sleep efficiency, and virtual absence of REM sleep. The correlation between different methods to assess sleep-wake functions (history, polysomnography, actigraphy, videography) was generally poor. Brain autopsy revealed prominent changes in cortical areas, but only mild changes in the thalamus. No mutation of the PRNP gene was found. CONCLUSIONS: This study demonstrates in sporadic Creutzfeldt-Jakob disease, first, the existence of sleep-wake disturbances similar to those reported in fatal familial insomnia in the absence of prominent and isolated thalamic neuronal loss, and second, the need of a multimodal approach for the unambiguous assessment of sleep-wake functions in these patients.

Sleep stage II contributes to the consolidation of declarative memories

Various studies suggest that non-rapid eye movement (NREM) sleep, especially slow-wave sleep (SWS), is vital to the consolidation of declarative memories. However, sleep stage 2 (S2), which is the other NREM sleep stage besides SWS, has gained only little attention. The current study investigated whether S2 during an afternoon nap contributes to the consolidation of declarative memories. Participants learned associations between faces and cities prior to a brief nap. A cued recall test was administered before and following the nap. Spindle, delta and slow oscillation activity was recorded during S2 in the nap following learning and in a control nap. Increases in spindle activity, delta activity, and slow oscillation activity in S2 in the nap following learning compared to the control nap were associated with enhanced retention of face-city associations. Furthermore, spindles tended to occur more frequently during up-states than down-states within slow oscillations during S2 following learning versus S2 of the control nap. These findings suggest that spindles, delta waves, and slow oscillations might promote memory consolidation not only during SWS, as shown earlier, but also during S2.

Benign neonatal sleep myoclonus: a review of the literature

OBJECTIVE: Neurologically normal term infants sometimes present with repetitive, rhythmic myoclonic jerks that occur during sleep. The condition, which is traditionally resolved by 3 months of age with no sequelae, is termed benign neonatal sleep myoclonus. The goal of this review was to synthesize the published literature on benign neonatal sleep myoclonus. METHODS: The US National Library of Medicine database and the Web-based search engine Google, through June 2009, were used as data sources. All articles published after the seminal description in 1982 as full-length articles or letters were collected. Reports that were published in languages other than English, French, German, Italian, Portuguese, or Spanish were not considered. RESULTS: We included 24 reports in which 164 term-born (96%) or near-term-born (4%) infants were described. Neonatal sleep myoclonus occurred in all sleep stages, disappeared after arousal, and was induced by rocking the infant or repetitive sound stimuli. Furthermore, in affected infants, jerks stopped or even worsened by holding the limbs or on medication with antiepileptic drugs. Finally, benign neonatal sleep myoclonus did not resolve by 3 months of age in one-third of the infants. CONCLUSIONS: This review provides new insights into the clinical features and natural course of benign neonatal sleep myoclonus. The most significant limitation of the review comes from the small number of reported cases.

Sleepiness is not always perceived before falling asleep in healthy, sleep-deprived subjects

To test whether subjects spontaneously signal sleepiness before falling asleep under monotonous conditions.

Sleep quality, the neglected outcome variable in clinical studies focusing on locomotor system; a construct validation study

In addition to general health and pain, sleep is highly relevant to judging the well-being of an individual. Of these three important outcome variables, however, sleep is neglected in most outcome studies.Sleep is a very important resource for recovery from daily stresses and strains, and any alteration of sleep will likely affect mental and physical health, especially during disease. Sleep assessment therefore should be standard in all population-based or clinical studies focusing on the locomotor system. Yet current sleep assessment tools are either too long or too specific for general use.

Day/Night rhythm of hemostatic factors in obstructive sleep apnea

To investigate the hypothesis that day/night patterns of prothrombotic activity differ between patients with obstructive sleep apnea (OSA) and individuals with no OSA.

Sleep and biomarkers of atherosclerosis in elderly Alzheimer caregivers and controls

Perturbed sleep might contribute to cardiovascular disease by accelerating atherosclerosis. Sleep is poor in Alzheimer caregivers who are also a group at increased cardiovascular risk.

Sleep restriction attenuates amplitudes and attentional modulation of pain-related evoked potentials, but augments pain ratings in healthy volunteers

The experiment investigated the impact of sleep restriction on pain perception and related evoked potential correlates (laser-evoked potentials, LEPs). Ten healthy subjects with good sleep quality were investigated in the morning twice, once after habitual sleep and once after partial sleep restriction. Additionally, we studied the impact of attentional focussing on pain and LEPs by directing attention to (intensity discrimination) or away from the stimulus (mental arithmetic). Laser stimuli directed to the hand dorsum were rated as 30% more painful after sleep restriction (49+/-7 mm) than after a night of habitual sleep (38+/-7 mm). A significant interaction between attentional focus and sleep condition suggested that attentional focusing was less distinctive under sleep restriction. Intensity discrimination was preserved. In contrast, the amplitude of the early parasylvian N1 of LEPs was significantly smaller after a night of partial sleep restriction (-36%, p<0.05). Likewise, the amplitude of the vertex N2-P2 was significantly reduced (-34%, p<0.01); also attentional modulation of the N2-P2 was reduced. Thus, objective (LEPs) and subjective (pain ratings) parameters of nociceptive processing were differentially modulated by partial sleep restriction. We propose, that sleep reduction leads to an impairment of activation in the ascending pathway (leading to reduced LEPs). In contradistinction, pain perception was boosted, which we attribute to lack of pain control distinct from classical descending inhibition, and thus not affecting the projection pathway. Sleep-restricted subjects exhibit reduced attentional modulation of pain stimuli and may thus have difficulties to readily attend to or disengage from pain.

Selective REM sleep deprivation in narcolepsy

Narcolepsy is characterized by excessive daytime sleepiness and rapid eye movement (REM) sleep abnormalities, including cataplexy. The aim of this study was to assess REM sleep pressure and homeostasis in narcolepsy. Six patients with narcolepsy and six healthy controls underwent a REM sleep deprivation protocol, including one habituation, one baseline, two deprivation nights (D1, D2) and one recovery night. Multiple sleep latency tests (MSLTs) were performed during the day after baseline and after D2. During D1 and D2 REM sleep was prevented by awakening the subjects at the first polysomnographic signs of REM sleep for 2 min. Mean sleep latency and number of sleep-onset REM periods (SOREMs) were determined on all MSLT. More interventions were required to prevent REM sleep in narcoleptics compared with control subjects during D1 (57 ± 16 versus 24 ± 10) and D2 (87 ± 22 versus 35 ± 8, P = 0.004). Interventions increased from D1 to D2 by 46% in controls and by 53% in narcoleptics (P < 0.03). Selective REM sleep deprivation was successful in both controls (mean reduction of REM to 6% of baseline) and narcoleptics (11%). Both groups had a reduction of total sleep time during the deprivation nights (P = 0.03). Neither group had REM sleep rebound in the recovery night. Narcoleptics had, however, an increase in the number of SOREMs on MSLT (P = 0.005). There was no increase in the number of cataplexies after selective REM sleep deprivation. We conclude that: (i) REM sleep pressure is higher in narcoleptics; (ii) REM sleep homeostasis is similar in narcoleptics and controls; (iii) in narcoleptics selective REM sleep deprivation may have an effect on sleep propensity but not on cataplexy.

EEG correlation and power during maintenance of wakefulness test after sleep-deprivation

To investigate whether there are any objective EEG characteristics that change significantly between specific time periods during maintenance of wakefulness test (MWT) and whether such changes are associated with the ability to appropriately communicate sleepiness.

Assessing periodicity of periodic leg movements during sleep

Periodic leg movements (PLM) during sleep consist of involuntary periodic movements of the lower extremities. The debated functional relevance of PLM during sleep is based on correlation of clinical parameters with the PLM index (PLMI). However, periodicity in movements may not be reflected best by the PLMI. Here, an approach novel to the field of sleep research is used to reveal intrinsic periodicity in inter movement intervals (IMI) in patients with PLM.

Identification of problems in functioning of people with sleep disorders in a clinical setting using the International Classification of Functioning Disability and Health (ICF) Checklist

We conducted an explorative, cross-sectional, multi-centre study in order to identify the most common problems of people with any kind of (primary) sleep disorder in a clinical setting using the International Classification of Functioning, Disability and Health (ICF) as a frame of reference. Data were collected from patients using a structured face-to-face interview of 45-60 min duration. A case record form for health professionals containing the extended ICF Checklist, sociodemographic variables and disease-specific variables was used. The study centres collected data of 99 individuals with sleep disorders. The identified categories include 48 (32%) for body functions, 13 (9%) body structures, 55 (37%) activities and participation and 32 (22%) for environmental factors. 'Sleep functions' (100%) and 'energy and drive functions', respectively, (85%) were the most severely impaired second-level categories of body functions followed by 'attention functions' (78%) and 'temperament and personality functions' (77%). With regard to the component activities and participation, patients felt most restricted in the categories of 'watching' (e.g. TV) (82%), 'recreation and leisure' (75%) and 'carrying out daily routine' (74%). Within the component environmental factors the categories 'support of immediate family', 'health services, systems and policies' and 'products or substances for personal consumption [medication]' were the most important facilitators; 'time-related changes', 'light' and 'climate' were the most important barriers. The study identified a large variety of functional problems reflecting the complexity of sleep disorders. The ICF has the potential to provide a comprehensive framework for the description of functional health in individuals with sleep disorders in a clinical setting.

Excitability and recruitment patterns of spinal motoneurons in human sleep as assessed by F-wave recordings

This study examines the excitability and recruitment of spinal motoneurons in human sleep. The main objective was to assess whether supraspinal inhibition affects the different subpopulations of the compound spinal motoneuron pool in the same way or rather in a selective fashion in the various sleep stages. To this end, we studied F-conduction velocities (FCV) and F-tacheodispersion alongside F-amplitudes and F-persistence in 22 healthy subjects in sleep stages N2, N3 (slow-wave sleep), REM and in wakefulness. Stimuli were delivered on the ulnar nerve, and F-waves were recorded from the first dorsal interosseus muscle. Repeated sets of stimuli were stored to obtain at least 15 F-waves for each state of vigilance. F-tacheodispersion was calculated based on FCVs using the modified Kimura formula. Confirming the only previous study, excitability of spinal motoneurons was generally decreased in all sleep stages compared with wakefulness as indicated by significantly reduced F-persistence and F-amplitudes. More importantly, F-tacheodispersion showed a narrowed range of FCV in all sleep stages, most prominently in REM. In non-REM, this narrowed range was associated with a shift towards significantly decreased maximal FCV and mean FCV as well as with a trend towards lower minimal FCV. In REM, the lowering of mean FCV was even more pronounced, but contrary to non-REM sleep without a shift of minimal and maximal FCV. Variations in F-tacheodispersion between sleep stages suggest that different supraspinal inhibitory neuronal circuits acting on the spinal motoneuron pool may contribute to muscle hypotonia in human non-REM sleep and to atonia in REM sleep.

Paediatric traffic accident and obstructive sleep apnoea by antrochoanal polyps: case report and literature review

Antrochoanal polyps are hyperplasias of the nasal mucosa, which have their origin in the maxillary sinus and extend through the nasal cavity and the choanae into the naso- and oropharynx. In children antrochoanal polyps represent one of the more frequent manifestations of paediatric nasal polyposis. Most studies on antrochoanal polyps in children report only on nasal obstruction, hyponasal speech and snoring, which are also encountered in the most common cause of obstructive sleep apnoea syndrome; i.e. adenoid or tonsillar hyperplasia. Only very few studies report on additional health hazards by antrochoanal polyps ranging from obstructive sleep apnoea syndrome to swallowing disorders and cachexia. We present the case of an 8 year old girl with a bicycle accident caused by excessive daytime sleepiness and obstructive sleep apnoea syndrome due to an extensive antrochoanal polyp. After a transnasal polypectomy and meatotomy type II the obstructive sleep apnoea and day time sleepiness resolved completely. Awareness of this additional health hazard is important and correct evaluation and timely diagnosis of a potential antrochoanal polyp is mandatory because minimally invasive rhinosurgery is highly curative in preventing further impending problems.