Arousal responses to respiratory events during sleep: the role of pulse wave amplitude.

The study aims at assessing the changes in electroencephalography (as measured by the A-phases of cyclic alternating pattern) and autonomic activity (based on pulse wave amplitude) at the recovery of airway patency in patients with obstructive sleep apnea syndrome. Analysis of polysomnographic recordings from 20 male individuals with obstructive sleep apnea syndrome was carried out in total sleep time, non-rapid eye movement and rapid eye movement sleep. Scoring quantified the combined occurrence (time range of 4 s before and 4 s after respiratory recovery) or separate occurrence of A-phases (cortical activation), and pulse wave amplitude drops (below 30%) to apneas, hypopneas or flow limitation events. A dual response (A-phase associated with a pulse wave amplitude drop) was the most frequent response (71.8% in total sleep time) for all types of respiratory events, with a progressive reduction from apneas to hypopneas and flow limitation events. The highly significant correlation in total sleep time (r = 0.9351; P < 0.0001) between respiratory events combined with A-phases and respiratory events combined with pulse wave amplitude drops was confirmed both in non-rapid eye movement (r = 0.9622; P < 0.0001) and rapid eye movement sleep (r = 0.7162; P < 0.0006). In conclusion, a dual cortical and autonomic activation is the most common manifestation at the recovery of airway patency. The significant correlation between A-phases and relevant pulse wave amplitude drops suggests a possible role of pulse wave amplitude as a marker of cerebral response to respiratory events.

Rationale for an adjunctive therapy with fenofibrate in pharmacoresistant nocturnal frontal lobe epilepsy.

OBJECTIVE: Nocturnal frontal lobe epilepsy (NFLE) is an idiopathic partial epilepsy with a family history in about 25% of cases, with autosomal dominant inheritance (autosomal dominant NFLE [ADNFLE]). Traditional antiepileptic drugs are effective in about 55% of patients, whereas the rest remains refractory. One of the key pathogenetic mechanisms is a gain of function of neuronal nicotinic acetylcholine receptors (nAChRs) containing the mutated α4 or ß2 subunits. Fenofibrate, a common lipid-regulating drug, is an agonist at peroxisome proliferator-activated receptor alpha (PPARα) that is a ligand-activated transcription factor, which negatively modulates the function of ß2-containing nAChR. To test clinical efficacy of adjunctive therapy with fenofibrate in pharmacoresistant ADNFLE\NFLE patients, we first demonstrated the effectiveness of fenofibrate in a mutated mouse model displaying both disease genotype and phenotype. METHODS: We first tested the efficacy of fenofibrate in transgenic mice carrying the mutation in the α4-nAChR subunit (Chrna4S252F) homologous to that found in humans. Subsequently, an add-on protocol was implemented in a clinical setting and fenofibrate was administered to pharmacoresistant NFLE patients. RESULTS: Here, we show that a chronic fenofibrate diet markedly reduced the frequency of large inhibitory postsynaptic currents (IPSCs) recorded from cortical pyramidal neurons in Chrna4S252F mice, and prevented nicotine-induced increase of IPSC frequency. Moreover, fenofibrate abolished differences between genotypes in the frequency of sleep-related movements observed under basal conditions. Patients affected by NFLE, nonresponders to traditional therapy, by means of adjunctive therapy with fenofibrate displayed a reduction of seizure frequency. Furthermore, digital video-polysomnographic recordings acquired in NFLE subjects after 6 months of adjunctive fenofibrate substantiated the significant effects on control of motor-behavioral seizures. SIGNIFICANCE: Our preclinical and clinical studies suggest PPARα as a novel disease-modifying target for antiepileptic drugs due to its ability to regulate dysfunctional nAChRs.

OSA and Prolonged Oxygen Desaturation During Sleep are Strong Predictors of Poor Outcome in IPF.

PURPOSE: Sleep Breathing Disorders (SBD) are frequently found in idiopathic pulmonary fibrosis (IPF) and they are associated with worse quality of sleep and life and with higher mortality. The study aimed at evaluating the impact of SBD on prognosis (mortality or disease progression) in 35 patients with mild to moderate IPF. METHODS AND RESULTS: Obstructive sleep apnea (OSA) was diagnosed in 25/35 patients with IPF: 14/35 mild, 7/35 moderate, and 4/35 severe. According to the American Academy of Sleep Medicine (AASM) definition, sleep-related hypoxemia was found in 9/35 patients with IPF. According to the presence/absence of SBD, IPF patients were divided into 4 groups: NO-SBD group (Group A, 25.7%), OSA without sleep-related hypoxemia (Group B, 48.5%), OSA with sleep-related hypoxemia group (Group C, 22.8%), and only 1/35 had sleep-related hypoxemia without OSA(Group D, 2.8%). Statistical analysis was focused only on group A, B, and C. Patients with OSAS and sleep-related hypoxemia (Group C) had the worse prognosis, both in terms of mortality or clinical deterioration. SBD were the only independent risk factor (Cox Proportional Hazards Multiple Regression Analysis) for mortality (HR 7.6% IC 1.2-36.3; p = 0.029) and disease progression (HR 9.95% IC 1.8-644.9; p = 0.007). CONCLUSIONS: SBD are associated with a worse prognosis, both in terms of mortality or clinical progression. The presence of SBD should be explored in all IPF patients.

Can sleep microstructure improve diagnosis of OSAS? Integrative information from CAP parameters.

PURPOSE: The scoring of American Academy of Sleep Medicine (AASM) arousal is mandatory for the definition of respiratory event-related arousal (RERA). However there are other EEG activation phenomena, such as A phases of cyclic alternating pattern (CAP) which are associated with respiratory events in non rapid eye movements (NREM) sleep. This study aims at quantifying the additional value of CAP for the definition of respiratory events and sleep alterations in OSAS. METHODS: Analysis of polysomnographic recordings from nineteen OSAS patients was carried out. Scoring was focused on investigation of the cerebral response to flow limitation (FL) events. For this purpose we used both CAP rules and AASM arousal criteria. MAIN RESULTS: While no difference was demonstrated in the arousal index between mild and moderate-severe OSAS patients, CAP time showed a progressive enhancement from normal subjects (152.5±20.76) to mild (180.64±34.76) and moderate-severe (282.27±58.02) OSAS patients. In NREM sleep, only 41.1% of FL events met the criteria for the definition of RERA, while, 75.5% of FL events ended with a CAP A phase and most FL CAP (69.1%) terminated with a CAP phase A3 subtype. CONCLUSIONS: Our data indicate that the RERA scoring has a limited accuracy in the detection of FL events. In NREM sleep, CAP rules provided more information than AASM arousal for the definition of respiratory events and sleep alterations in OSAS.

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 brain's 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 brain's 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.

Atypical patterns in portable monitoring for sleep apnoea: features of nocturnal epilepsy?

Atypical cardiorespiratory patterns can be found during routine clinical use of portable monitoring for diagnosis of sleep-disordered breathing (SDB). Over 1,000 consecutive portable recordings were analysed to study the potential ictal nature of stereotyped cardiorespiratory and motor patterns. Snoring, airflow, thoracic effort, pulse rate, body position, oxygen saturation and activity of the anterior tibialis muscles were quantified. Recordings showing stereotyped polygraphic patterns recurring throughout the night, but without the features of sleep apnoea (apnoea/hypopnoea index <5 events·h(-1)), were selected for investigation. Once included in the study, patients underwent attended nocturnal video polysomnography. A total of 15 recordings showing repeated polygraphic patterns characterised by a sequence of microphone activation, respiratory activity atypical for sleep and wakefulness, heart rate acceleration and limb movements, followed by body position change, were selected for investigation. Once included in the study, patients underwent attended nocturnal video polysomnography that showed frontal epileptic discharges triggering periodic electroencephalographic arousals, autonomic activation and stereotyped motor patterns. A diagnosis of nocturnal frontal lobe epilepsy (NFLE) was established for all patients. NFLE should be taken into consideration in patients with stereotyped and recurrent behavioural features during portable monitoring carried out for diagnosis of SDB.

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). METHODS: We analyzed the basal polysomnographic recordings of 40 patients (20 male and 20 female; mean age: 31 ± 10 years) with a diagnosis of nocturnal frontal lobe epilepsy. Conventional sleep measures and CAP parameters were assessed. Polysomnographic recordings were subdivided in sleep cycles. The distribution of the epileptic motor events (including minor motor events, paroxysmal arousals, tonic-dystonic, or hyperkinetic seizures and epileptic nocturnal wandering) was analyzed throughout: total sleep time, non-rapid eye movement (NREM) and REM sleep, light sleep (S1 + S2), slow wave sleep (SWS), each sleep cycle, CAP or non-CAP sleep, phase A and phase B of CAP. Only clear epileptic motor events supported by video-polysomnographic evidence were taken into consideration. Polysomnographic findings of patients with NFLE were compared with those of 24 age- and gender-balanced healthy subjects without sleep complaints. KEY FINDINGS: Compared to controls, patients with NFLE showed a significant increase in wake after sleep onset, SWS duration, and REM latency, whereas REM sleep duration was significantly lower in NFLE patients. The patients with NFLE showed a significant increase of CAP time, CAP rate (72% vs. 32% in control group), CAP cycles, and mean duration of a CAP sequence. These findings were associated with a significant enhancement of all subtypes of the A phases of CAP (mainly subtype A1). A total of 139 epileptic motor events supported by video-polysomnographic evidence were counted: 98% of all seizures occurred in NREM sleep and 72% of NREM seizures emerged from SWS, the latter being particularly collected in the first sleep cycles and decreasing in frequency together with the progressive decline of deep sleep. Ninety percent of total NREM seizures occurred during a CAP sequence, and CAP-related seizures occurred in association with a phase A. SIGNIFICANCE: Significant polysomnographic alterations seem to emerge in patients with NFLE (increased REM latency, epileptic fragmentation of SWS, and increase of CAP rate). The analysis of seizure distribution showed that most epileptic events occurred in SWS, with predominance in the first sleep cycle and decreasing in frequency together with the homeostatic decline of SWS across the night. Within the NREM sleep, CAP is a manifestation of unstable sleep and represents a powerful predisposing condition for the occurrence of nocturnal motor seizures, which arise in concomitance with a phase A.

Weight Status, Adherence to the Mediterranean Diet, Physical Activity Level, and Sleep Behavior of Italian Junior High School Adolescents.

Inadequate diet, physical activity, and sleep-related behaviors are potential risk factors for overweight and obese, therefore we investigated the relations between body mass index (BMI) and behavioral factors in a sample of Italian adolescents. Four hundred nine Italian secondary school students (46% females, 12.5 ± 0.6 y.o.) were enrolled in this cross-sectional study. Anthropometric measures, adherence to the Mediterranean Diet (KIDMED), physical activity level (PAQ-C), sleep duration, daytime sleepiness (PDSS), sleep quality, and school achievement data were collected through an online questionnaire. The percentage of overweight adolescents was slightly lower (14%) compared to the regional and the national figures. Approximately 88% of the sample reported a medium/high adherence to the Mediterranean Diet and 77% a moderate/vigorous physical activity level. The average sleep duration was in line with the international sleep recommendation for adolescents and 82% had a medium/high sleep quality. No differences were found between genders except for BMI (lower in females). Unexpectedly, no differences were found among the BMI groups (normal weight vs. overweight vs. obese) for lifestyle variables; in contrast, Mediterranean Diet adherence was associated with sleep habits. Further investigation is required to better explore the associations among behavioral variables involved in adolescents' healthy development.

Sleep cardiac dysautonomia and EEG oscillations in amyotrophic lateral sclerosis.

STUDY OBJECTIVES: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease due to loss of motor neurons. However, the autonomic nervous system (ANS) can also be involved. The aim of this research was to assess the sleep macro- and microstructure, the cardiac ANS during sleep, and the relationships between sleep, autonomic features, and clinical parameters in a cohort of ALS patients. METHODS: Forty-two consecutive ALS patients underwent clinical evaluation and full-night video-polysomnography. Only 31 patients met inclusion criteria (absence of comorbidities, intake of cardioactive drugs, or recording artifacts) and were selected for assessment of sleep parameters, including cyclic alternating pattern (CAP) and heart rate variability (HRV). Subjective sleep quality and daytime vigilance were also assessed using specific questionnaires. RESULTS: Although sleep was subjectively perceived as satisfactory, compared with age- and sex-matched healthy controls, ALS patients showed significant sleep alteration: decreased total sleep time and sleep efficiency, increased nocturnal awakenings, inverted stage 1 (N1)/stage 3 (N3) ratio, reduced REM sleep, and decreased CAP rate, the latter supported by lower amounts of A phases with an inverted A1/A3 ratio. Moreover, a significant reduction in HRV parameters was observed during all sleep stages, indicative of impaired autonomic oscillations. CONCLUSION: Our results indicate that sleep is significantly disrupted in ALS patients despite its subjective perception. Moreover, electroencephalogram activity and autonomic functions are less reactive, as shown by a decreased CAP rate and a reduction in HRV features, reflecting an unbalanced autonomic modulation.

Quality of life in idiopathic pulmonary fibrosis: The impact of sleep disordered breathing.

PURPOSE: the study aims at describing the role of sleep disordered breathing (SDB) on daytime symptoms, quality of sleep and quality of life (QoL) in patients with moderate-severe IPF. METHODS: we enrolled 34 consecutive room air breathing IPF outpatients who received a full-night polysomnography. The following questionnaires were administered: Epworth Sleepiness Score (ESS), Pittsburg Sleep Quality Index (PSQI), StGeorge's Questionnaire (StGQ). RESULTS: patients were classified in 3 groups:Group A (NO-SDB, 9 patients), Group B(OSAS without sleep-related hypoxemia, 17 patients), Group C(OSAS with sleep-related hypoxemia, 8 patients). Although sleep parameters showed no significant differences among the 3 groups, worse measures were found in group C. 50% of patients (17/34) reported a StGQ score indicating a reduced QoL and the StGQ score was significantly higher in group C patients compared to group A (p < 0.05). In the stepwise multiple regression analysis, 75% of StGQ score variability was significantly predicted by FVC(Forced Vital Capacity) %, DLco (diffusion lung capacity for carbon monoxide)%, PSQI and ESS. CONCLUSIONS: in patients with IPF both subjective and polysomnographic poor sleep quality are extremely common features, they are predicted by variables associated with SBD severity and are linked to low QoL. IPF with more severe SDB present poor sleep quality and a worse QoL compared to SDB-free or OSAS-only.

EEG Spectral Coherence Analysis in Nocturnal Epilepsy.

OBJECTIVE: Electroencephalography (EEG) is widely employed in the study of sleep disorders. This paper exploits the identification of cyclic alternating patterns (CAPs), a periodic ubiquitous phenomenon nested in the sleep stages, to analyze the EEG spectral coherence in subjects affected by nocturnal frontal lobe epilepsy (NFLE) and healthy controls. METHODS: For each EEG recording, we extracted several CAP A1 subtype 4 s time series. We analyze the coherence between each pair of electrodes for each individual to obtain its distribution for each frequency range of interest to investigate differences between cases and controls. In addition, the imaginary and real parts of the spectral coherence were calculated and plotted to assess their likelihood of segregation into different classes and anatomical regions. RESULTS: The results of this study suggest a relevant frontal-temporal neural circuitry difference between individuals affected by epilepsy and controls. CONCLUSION: This supports the observation that, though highly variable, a broad range of executive, cognitive and attentional deficit observed in subjects affected by NFLE might depend on frontal-temporal altered networking. SIGNIFICANCE: The investigation of EEG activity in the domain of the complex sleep architecture represents a challenging topic in neurophysiology and needs new methods to explore the manifold aspects of sleep. This work aims to provide a simple method to distinguish NFLE from healthy subjects from a functional connectivity point of view and to explore the possibility of using a smaller EEG channel set to support diagnosis.

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.

Electrophysiological and microstructural features of sleep in children at high risk for depression: a preliminary study.

OBJECTIVE: This preliminary study investigated electrophysiological and microstructural features of sleep in children and adolescents 4-18 years of age who were born to depressed mothers. METHODS: A total of 31 healthy subjects (15 male and 16 female) participated in the study. In this sample, 20 children born to mothers diagnosed with Major Depressive Disorder (MDD) were designated as "high-risk"; 11 children born to mothers without a personal history of depression were designated as "low-risk." Polysomnography including three-channel electroencephalography (EEG) was recorded for one night at the Pediatric Sleep Unit of the University Hospital of Lyon, France. Clinical and demographic data were collected. Sleep architectural parameters were analyzed. Sleep microstructure was assessed with the scoring of cyclic alternating pattern (CAP) and CAP measures were calculated. Spectral analysis was performed, and mean EEG band power was computed for each sleep stage. Sleep electrophysiological features (slow waves and sleep spindles) were detected, and related parameters were analyzed. Data were compared between high- and low-risk groups using Student t tests. RESULTS: A reduction in low-frequency spindle activity and slow spindles spatio-temporal characteristics over frontal and central derivations, and an altered distribution of CAP phase A subtypes (reduction of A1 over A2-3 ratio) were observed in the high-risk group relative to the low-risk group. CONCLUSION: Limited spindles generation and increased non-rapid eye movement sleep instability, observed in children born to depressed mothers, might reflect functional anomalies in cortical plasticity that could represent a pathogenic factor or an epiphenomenon for MDD.

F-Wave Duration as a Specific and Sensitive Tool for the Diagnosis of Restless Legs Syndrome/Willis-Ekbom Disease.

STUDY OBJECTIVES: Restless legs syndrome, also known as Willis-Ekbom disease (RLS/WED), is a frequent condition, though its pathophysiology is not completely understood. The diagnosis of RLS/WED relies on clinical criteria, and the only instrumental tool, the suggested immobilization test, may lead to equivocal results. Recently, neurophysiological parameters related to F-wave duration have been proposed as a diagnostic aid. The aim of this study is to assess and compare the diagnostic values of these parameters in diagnosis of RLS/WED. METHODS: Fifteen women affected by primary RLS/WED and 17 age- and sex- matched healthy subjects. A complete electroneurographic evaluation, including nerve conduction studies (NCS), cutaneous silent period (CSP), and F-wave parameters, namely amplitude, F-wave duration (FWD), and the ratio between FWD and duration of the corresponding compound muscle action potential (FWD/CMAPD). RESULTS: No subject showed alterations of the NCS. However, FWD and FWD/CMAPD of both upper and lower limbs were significantly longer in patients than controls. Tibial FWD/CMAPD best discriminated RLS/WED patients from controls. A cutoff of 2.06 yielded a sensitivity of 69.2%, a specificity of 94.1%, a positive predictive power of 90%, and a negative predictive power of 80% (area under the curve = 0.817; 95% confidence interval = 0.674-0.959). The combination of ulnar or tibial FWD/CMAPD increases the sensitivity (85.7%) while slightly decreasing the specificity (87.5%, positive predictive value: 85.7%, negative predictive value: 87.5%). CONCLUSIONS: Lower limb FWD/CMAPD ratio may represent a supportive diagnostic tool, especially in cases of evening lower leg discomfort of unclear interpretation.

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.

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.

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.

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.