Giulia Milioli

Paradoxical insomnia: The role of CAP and arousals in sleep misperception

OBJECTIVE The relationship between CAP parameters and subjective time perception during sleep in primary insomnia was investigated. PATIENTS AND METHODS Data collected from all-night PSG recordings of 20 patients with a diagnosis of paradoxical insomnia (misperceptors) were compared with those of 20 normal gender- and age-matched subjects (controls). Besides sleep staging, scoring measures included CAP parameters and EEG arousals. RESULTS Patients and controls presented non-significant differences in the amounts of objective sleep time (464 min vs. 447 min) and objective sleep latency (9 min vs. 8 min). Compared to controls, misperceptors reported a significantly shorter time of perceived sleep (285 min vs. 461 min) and a significantly longer duration of perceived sleep latency (51 min vs. 22 min). In spite of the 11 objective awakenings, misperceptors reported only 4 subjective awakenings, while controls described 2 of the 5 objective awakenings. Arousal index (31.7/h vs. 18.6/h) and total CAP rate (58.1% vs. 35.5%) were significantly higher in misperceptors. In the sleep period between objective and subjective sleep onset, CAP rate was 64.4% in misperceptors and 45.1% in controls (p<0.002). Insomniacs showed significantly higher amounts of CAP rate in stage 1 (62.7% vs. 37.5%) and in stage 2 (53.3% vs. 33.1%), but not in slow wave sleep. CAP phase A2 subtypes were significantly increased in misperceptors (31% vs. 24%). CONCLUSIONS The study points out the topical role of enhanced activation and arousal instability not only in the first part of the night (mismatch between objective and subjective sleep onset) but also in the misperception of consecutive objective awakenings which are subjectively grouped together as a single prolonged event.

Distinctive polysomnographic traits in nocturnal frontal lobe epilepsy.

Purpose:  To describe the polysomnographic features and distribution of epileptic motor events, in relation to conventional sleep measures and cyclic alternating pattern (CAP) parameters, in 40 untreated patients with nocturnal frontal lobe epilepsy (NFLE).

Polysomnographic study of intermittent zolpidem treatment in primary sleep maintenance insomnia.

Background and Purpose: Treatment of chronic insomnia with nightly hypnotics is efficacious, but discontinuation is recommended after 1 month, less than the average disease duration. This study was undertaken to determine the efficacy of intermittent administration. Patients and Methods: A double-blind study was carried out on 8 patients (age, 32.8 ± 9 years; 3 men) with primary sleep maintenance insomnia longer than 1 month. Polysomnography of conventional sleep parameters, cyclic alternating patterns (CAPs), and arousals was performed. Perception of sleep quality was assessed on a visual analog scale. After an adaptation night, baselines were recorded followed by 6 consecutive nights of alternating treatment with zolpidem (10 mg) or placebo. Results: Significant improvements on baseline values (P < 0.0001) were observed on all 3 active treatment nights for total sleep time, sleep efficiency, CAP time, CAP rate, subtype A2, arousals, and arousal index. Deep non-rapid eye movement sleep increased with the second and third doses of active treatment (P < 0.0001). Rapid eye movement sleep increased during the last 3 polysomnographic recordings (P < 0.014). Sleep quality (visual analog scale) improved on all nights after the initial dose of active treatment (P < 0.0001). There was no evidence of rebound insomnia with placebo. Conclusions: Intermittent treatment with zolpidem in primary insomnia patients improves CAP parameters and arousals, as well as sleep duration and quality, in the absence of rebound insomnia.

Sleep and respiratory sleep disorders in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease (ILD) characterized by inflammation and progressive scarring of the lung parenchyma. IPF profoundly affects the quality of life (QoL) and fatigue is a frequently disabling symptom. The cause of fatigue is not well understood but patients with IPF often report extremely poor sleep quality and sleep-related breathing disorders (SRBD) that correlate with QoL. IPF patients present alterations in sleep architecture, including decreased sleep efficiency, slow wave sleep and rapid eye movement (REM) sleep, and increased sleep fragmentation. Moreover, sleep related hypoventilation during the vulnerable REM sleep period and obstructive sleep apnea-hypopnea syndrome (OSAHS) are frequent, but remain usually underdiagnosed. These SRBD in IPF are associated with alterations of the sleep structure, reduction of QoL and increased risk of mortality. In the absence of an effective therapy for IPF, optimizing the QoL could become the primary therapeutic goal. In this perspective the diagnosis and treatment of SRBD could significantly improve the QoL of IPF patients.

Effects of antiepileptic treatment on sleep and seizures in nocturnal frontal lobe epilepsy.

OBJECTIVE To study the effects of antiepileptic treatment on sleep parameters and video-polysomnography (VPSG) seizures in nocturnal frontal lobe epilepsy (NFLE). METHODS Twenty patients with a clinical and VPSG diagnosis of NFLE (baseline polysomnography [PSG]) underwent a clinical follow-up and performed a second VPSG after effective antiepileptic treatment lasting for at least 6 months. Conventional sleep measures, cyclic alternating pattern (CAP) parameters, and objective VPSG seizures were assessed in NFLE patients before and after treatment and were compared with the results of 20 age- and gender-matched control subjects. RESULTS Antiepileptic treatment determined a partial reduction of objective VPSG seizures of approximately 25% compared to baseline condition. Alterations of most conventional sleep measures recovered normal values, but nonrapid eye movement (NREM) sleep instability remained pathologically enhanced (CAP rate, +26% compared to controls) and was associated with persistence of daytime sleepiness. CONCLUSIONS Residual epileptic events and high levels of unstable NREM sleep can define a sort of objective resistance of both seizures and disturbed arousal system to the therapeutic purpose of the antiepileptic drugs in NFLE. This finding could determine the need for new therapeutic options in this particular form of epilepsy.

EEG segmentation for improving automatic CAP detection

OBJECTIVE The aim of this study is to provide an improved method for the automatic classification of the Cyclic Alternating Pattern (CAP) sleep by applying a segmentation technique to the computation of descriptors from the EEG. METHODS A dataset of 16 polysomnographic recordings from healthy subjects was employed, and the EEG traces underwent first an automatic isolation of NREM sleep portions by means of an Artificial Neural Network and then a segmentation process based on the Spectral Error Measure. The information content of the descriptors was evaluated by means of ROC curves and compared with that of descriptors obtained without the use of segmentation. Finally, the descriptors were used to train a discriminant function for the automatic classification of CAP phases A. RESULTS A significant improvement with respect to previous scoring methods in terms of both information content carried by the descriptors and accuracy of the classification was obtained. CONCLUSIONS EEG segmentation proves to be a useful step in the computation of descriptors for CAP scoring. SIGNIFICANCE This study provides a complete method for CAP analysis, which is entirely automatic and allows the recognition of A phases with a high accuracy thanks to EEG segmentation.

Acute shift of a case of moderate obstructive sleep apnea syndrome towards one of severe central sleep apnea syndrome after an ischemic stroke.

Article history: Received 21 December 2011 Received in revised form 12 January 2012 Accepted 27 January 2012 Available online 22 March 2012

Cyclic alternating pattern in polysomnography: what is it and what does it mean?

Purpose of review The relevance of sleep instability is poorly appreciated among the metrics of sleep physiology. The cyclic alternating pattern (CAP) is a periodic electroencephalogram activity of non-REM sleep, characterized by sequences of transient electrocortical events that are distinct from the tonic background and recur at up to 1-min intervals. In the dynamic organization of sleep, CAP expresses a condition of instability that reflects the brains effort in preserving and regulating the physiological structure of sleep. Recent findings CAP quantification is a topical feature in the evaluation of sleep quality. In addition to duration, depth, and continuity, sleep restorative properties depend on the brains capacity to determine the periods of sustained stable sleep. This issue is not confined only to the electroencephalogram activities but reverberates upon the ongoing autonomic and behavioral functions, which are mutually entrained in a synchronized oscillation. As a master clock involved in the dynamic organization of sleep, CAP plays a crucial role in numerous sleep disorders and is powerfully influenced by medication and appropriate treatment. Summary This article reviews the scoring, significance, and clinical applications of CAP.

Weight Status Is Related with Gender and Sleep Duration but Not with Dietary Habits and Physical Activity in Primary School Italian Children

The prevalence of overweight and obesity in children has risen greatly worldwide. Diet and poor physical activity are the two risk factors usually examined, but epidemiological evidence exists suggesting a link between sleep duration and overweight/obesity in children. The aim of this study was to describe the relationship among body mass index (BMI), diet quality, physical activity level, and sleep duration in 690 children attending the 5th grade in primary schools (9–11 years old) in the city of Parma (Italy) involved in the Giocampus educational program. This was achieved through (i) measuring anthropometric data to compute body mass index; (ii) administering a food questionnaire to evaluate adherence to the Mediterranean Diet (KIDMED score); and (iii) administering a lifestyle questionnaire to classify children physical activity level (PAL), sleep duration, and school achievement. A highly significant negative association was found between BMI and sleep hours. Moreover, there was a significant positive association between PAL and KIDMED scores. No evidence was found of association between BMI and PAL, nor between BMI and KIDMED score. Data from this study established that BMI is correlated to gender and sleep duration, defining sleep habits as one of the factors linked to overweight and obesity.

Complex sleep apnea syndrome in stroke patients

Fig. 1. A profile of Tiberius Claudius Germanicus appears on the obverse of this silver denarius struck during the Imperial Roman Era (ca. first century CE; photo provided courtesy of A Pangerl of www.romancoins.info). To the Editor We would like to thank Dr. Sacchetti and co-workers for their interest in our article [1]. Sacchetti et al. raise the question whether a stroke may transform, in selected patients, an obstructive sleep apnea syndrome (OSAHS) into a complex-sleep apnea syndrome (Comp-SAS) and postulate that the appearance of central respiratory events may represent a stable consequence of stroke, and may complicate the treatment approach to sleep apnea. This hypothesis is supported by their preliminary data showing mixed (obstructive and central) apneas four months after the stroke. This high prevalence of central and mixed respiratory events in stable phase after stroke is higher than that found in other studies, about the time course of sleep breathing disorders and central periodic breathing in stroke patients [2,3]. These data also contradict in part the attenuation of central respiratory events within week or a few months after the stroke described by the same authors or in OSAHS patients with CompSAS [4]. In OSAHS patients some predictive factors for appearance of CompSAS during CPAP treatment have been proposed [5], which include atrial fibrillation, use of opioids, sleep disruption and features of initial sleep apnea syndrome (in term of severity of obstructive apneas and presence of relevant mixed/central events). The last two factors are probably strictly related to the fluctuations of ventilatory control system and CO2 levels, that we documented in our paper [1], as well as, the fluctuations of arousal system in NREM sleep that have been described as possible distinctive patterns of some patients with OSAHS [6]. Finally, in our opinion, the question is to clarify if these or other factors can tell us whether initial ‘‘complex’’ cases of OSAHS are more prone to develop a clear CompSAS after a stroke and, whether as suggestedbySacchetti andco-workers, tomerge this ‘‘pre-stroke’’ profile of sleep disordered breathing with ‘‘post-stroke’’ features. Thismay enable us to findout possible factors able to distinguish patientswith a transient CompSAS frompatientswith a persistent one.