Increase In Cyclic Alternating Pattern Rate Research Articles

Non-REM Sleep Instability in Children With Primary Monosymptomatic Sleep Enuresis.

Sleep enuresis is one of the most common sleep disturbances in childhood. Parental perception of deeper sleep in children with sleep enuresis is not confirmed by objective studies. However, evidence of disturbed sleep has been demonstrated by questionnaire, actigraphy, and polysomnographic studies, but no neurophysiological correlation with low arousability has been found. The goal of this study was to analyze the sleep microstructure of children with sleep enuresis using cyclic alternating pattern (CAP) analysis. Forty-nine children were recruited, 27 with enuresis (19 males and 8 females, mean age 9.78 years, 2.52 standard deviation) and 22 normal control patients (11 males and 11 females, mean age 10.7 years, 3.43 standard deviation); all subjects underwent clinical evaluation followed by a full-night polysomnographic recording. Psychiatric, neurological, respiratory, and renal diseases were excluded. No differences in sex, age, and apnea-hypopnea index were noted in the patients with enuresis and the control patients. Sleep stage architecture in children with sleep enuresis showed a decrease in percentage of stage N3 sleep. CAP analysis showed an increase in CAP rate in stage N3 sleep and in phase A1 index during stage N3 sleep in the sleep enuresis group, but also a significant reduction of A2% and A3% and of phases A2 and A3 indexes, supporting the concept of decreased arousability in patients with sleep enuresis. The decrease of phase A2 and A3 indexes in our patients might reflect the impaired arousal threshold of children with sleep enuresis. Sleep fragmentation might result in a compensatory increase of slow wave activity (indicated by the increase of CAP rate in stage N3 sleep) and may explain the higher arousal threshold (indicated by a decrease of phase A2 and A3 indexes) linked to an increased sleep pressure. The findings of this study indicate the presence of a significant disruption of sleep microstructure (CAP) in children with sleep enuresis, supporting the hypothesis of a higher arousal threshold.

SLEEP cyclic alternating pattern (CAP) changes from school-age to adolescence in healthy subjects

Cyclic Alternating Pattern (CAP) is a well recognized process underlying sleep instability. CAP organization has been reported in several age-groups, but follow-up data in healthy children or adolescents is scarce. Objective: To assess sequential changes in CAP characteristics from school-age to adolescence in the same group of healthy subjects. We studied a sample of 45 healthy school-age children. All were participants in an ongoing cohort follow-up study since infancy. PSG recordings were performed at 10 years and repeated in adolescence. CAP was visually identified in non- REM sleep stages S1, S2 and SWS, according to international rules. The age of the subjects was 10.3 ± 0.2 and 15.6 ± 0.5 years at the time of the two assessments. CAP number, CAP rate, CAP duration but not CAP time were positively correlated between 10 and 15 years (all p < 0.05). Between-age differences were as follows: an increase in CAP time (145.8 ± 44.0 vs. 183.6 ± 53.7 min., p < 0.0001), CAP rate (41.9 ± 11.6 vs. 47.5 ± 12.0%, p < 0.01), A3 percentage (18.3 ± 9.8 vs. 27.4 ± 10.7, p < 0.0001), A3 index (9.0 ± 5.1 vs. 16.9 ± 8.1, p < 0.0001), and a decrease in A1 percentage (68.2 ± 13.3 vs. 59.7 ± 12.1, p < 0.002). We also found a lengthening of CAP cycles with a shortening of the B phase (both p < 0.03). According to sleep stages, an increase in CAP rate and A1 index was apparent in SWS, whereas A1 index was decreased in S1 and S2 (all p < 0.004). Finally, A3 index resulted higher in all non-REM sleep stages (all p < 0.004). These preliminary data show several changes in CAP parameters between 10 and 15 years. Given that the main modifications with advancing age were an increase in A3 and a reduction in A1 CAP subtypes, they provide support for a reduction in sleep stability towards adolescence in healthy subjects. Financial support: Fondecyt 1110513 and NIH HD33487 grants. (*) CONICYT PhD program fellowship.

Cyclic Alternating Patterns in Normal Sleep and Insomnia: Structure and Content Differences

This work aims to investigate new markers for the quantitative characterization of insomnia, in the context of sleep microstructure, as expressed by cyclic alternating pattern (CAP) sleep. The study group includes 11 subjects with normal sleep and 10 subjects with diagnosed primary insomnia. Differences between normal sleepers and insomniacs are investigated, in terms of dynamics and content of CAP events. The overall rate of CAP and of different phases is considered. The dynamic in the structure and alternation of CAP events is further studied in different scales by use of wavelet analysis, and calculation of energy/entropy features. The content of CAP events is studied in terms of electroencephalography (EEG) complexity analysis for the different types of events. Statistically significant differences are highlighted, both in structure and content. Besides confirming the increase in CAP rate, main findings regarding the microstructure difference in insomnia include: 1) as regards the deep sleep building phases, more irregular activation-deactivation patterns, with bigger deactivation time, i.e., distance between consecutive activation events, and appearing with higher EEG complexity in deactivation, and 2) a bigger duration of desynchronisation phases, with increased EEG complexity and more irregular patterns. This analysis extends previous findings on the relation between CAPrate increase and sleep instability mechanisms, proposing specific features of CAP that seem to play a role in insomnia (as consistently presented via classification analysis). This opens new perspectives for the understanding of the role of CAP in the quantitative characterization of sleep and its disorders.

Distinctive polysomnographic traits in nocturnal frontal lobe epilepsy

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). 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. 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. 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.

Effects of replacement therapy on sleep architecture in children with growth hormone deficiency

Children with GH deficiency (GHD) show a general decrease in electroencephalographic (EEG) arousability represented by a significant global decrease in Cyclic Alternating Pattern (CAP). The aim of the present study was to evaluate if sleep structure is influenced by GH substitutive therapy by analyzing the classical sleep architecture parameters and sleep microstructure by means of CAP. Laboratory polysomnographic sleep recordings were obtained from five children affected by GHD (two girls and three boys; mean age: 4.6 ± 3.1 years), at baseline and after GH therapy, and from 10 normal healthy children (four girls and six boys, mean age: 5.6 ± 2.2 years). Compared to controls, GHD subjects showed a reduced total sleep time with increased wakefulness and a consequent decrease in sleep efficiency; GH therapy was associated with an increase of the awakenings/hour and a large effect size was evident for sleep latency, sleep efficiency, and stage N3, which were decreased, and for stage W, which was increased. CAP appeared to be globally reduced and all phase A subtypes and CAP cycle showed a longer duration in GHD children vs. controls. GH substitutive treatment was followed by an increase in CAP rate (total, in N2, and in N3); additionally, A1 index was also significantly increased, especially during stage N3, with a very large effect size. On the other hand, A2 and A3 index and CAP cycle mean duration were reduced. Sleep stage architecture seems to be influenced by the GH status, but the analysis of sleep microstructure by means of CAP reveals an enhancement of EEG slow oscillations in GHD patients (demonstrated by an increase in CAP rate and A1 index during N3) after the start of GH replacement therapy. These findings deserve to be verified in a larger trial.

Sleep cyclic alternating pattern analysis in healthy children during the first year of life: A daytime polysomnographic study

We evaluated the cyclic alternating pattern (CAP) during the first year of life in order to obtain information on the maturation of arousal mechanisms during NREM sleep and to provide normative data for CAP parameters in this age range (5–16 months). Eleven healthy children (mean age 7.9 ± 3.3 months, seven boys) were studied while they slept in the morning. They underwent a 3-h video-EEG-polysomnographic recording at the Pediatric Sleep Unit of Sant’Andrea Hospital in Rome, Italy. Sleep was scored visually for sleep architecture and CAP analysis using standard criteria. Our results were complemented by CAP data from a previous sample of healthy infants (2–4 months), studied when they slept during the morning, in order to correlate CAP parameters with age. The total sample comprised 24 children. The sleep period was approximately 2 h, with a first REM latency of about 30 min, and a clear distinction between stages N1, N2, and N3. The arousal index was 12 ± 2.1 events/hour of sleep. The total CAP rate was 23.7 ± 7.6%, and it increased progressively with the deepness of sleep; the highest values were observed during stage N3 and the lowest values during stage N1. A1 phases were the most numerous (78.2%), followed by A2 (14%) and A3 (7.7%) phases. The A1 index was higher than the A2 and A3 indices, whereas the mean duration of B was higher than that of A. The correlation showed that the CAP rate, A1, A2, A3 indices, A2, A3 percentages, and the average duration of B increased with age, whereas the A1 percentage decreased. We provide the first data on CAP analysis in children aged 5–16 months, studied when they slept during the morning. Our results confirm the trend toward an increase in CAP rate during the first year of life. In addition, we observed a progressive increase in CAP rate with deepness of sleep, and with age, reflecting maturation of slow-wave activity. The decreased percentage of A1 subtypes may reflect the maturation of arousability.

NREM sleep instability changes following rapid maxillary expansion in children with obstructive apnea sleep syndrome

Objective To evaluate NREM sleep microstructure in children with obstructive sleep apnea syndrome (OSAS) before and after one year of rapid maxillary expander (RME) treatment by means of the cyclic alternating pattern (CAP). Methods Nine children with OSAS aged 4–8 years (6 males, mean age 6.4 ± 1.97 years) and age-matched normal controls were included. All subjects underwent an overnight polysomnography in the sleep laboratory after one adaptation night, as a baseline evaluation; children with OSAS were recorded again after one year of RME treatment. Results After one year of treatment the OSAS group showed a longer duration of time in bed and sleep period time, a reduction in number of stage shifts compared to baseline recordings, and the apnea–hypopnea index decreased significantly. At baseline, the OSAS group had a higher CAP rate during slow-wave sleep and an increased A2 index compared to normal controls. After one year of RME application, children with OSAS showed an increase in CAP rate associated with an increase of A1 index during slow-wave sleep. Conclusions RME treatment almost normalized sleep architecture and improved sleep respiratory disturbances; however, sleep microstructure and respiratory parameters did not completely recover. The persistence of increased CAP rate in slow-wave sleep associated with an increase of A1 index might reflect a partial failure of orthodontic treatment. On the other hand, the rebound of A1 subtypes might be an indirect sign of an attempt to normalize sleep that has been disturbed by the respiratory events.

The relationship between focal seizures and sleep: An analysis of the cyclic alternating pattern

Purpose The aim of this study was to examine the relationship between focal epileptic seizures and sleep through analysis of the cyclic alternating pattern (CAP). Methods We analyzed the recordings of a total of 56 nocturnal partial seizures (13 occurring as isolated events and 43 “in clusters” during a full-night ambulatory polysomnography) in 12 adult patients affected by localization-related focal epilepsy (7 males, 5 females; mean age 35 + 12.8 years; range 25–71). Results On exact binomial distribution analysis, seizures were more frequent in CAP than in non-CAP sleep, and in CAP phase A than in CAP phase B ( p < 0.001). Seizures occurring in clusters were more frequently associated with CAP sleep ( p < 0.05) than isolated seizures and first seizures of seizure clusters. Increase of CAP rate during the 30-min of sleep period after the occurrence of a seizure was documented in both cluster and isolated seizures. Conclusions Our data indicate that an intra-sleep condition of highly fluctuating vigilance constitutes the real substrate for the occurrence of epileptic seizures regardless of the NREM stage in which they occur. The occurrence of partial seizures during sleep appears to induce sleep instability, which may in turn result in the facilitation of clusters of seizures. Together, these data highlight the potential of sleep fragmentation to modulate intra-sleep seizure occurrence.

Sleep Cyclic Alternating Pattern in Normal Preschool-Aged Children

To evaluate the characteristics of the cyclic alternating pattern (CAP) in the sleep of preschool-aged children in order to obtain normative parameters in this age range. Prospective study. University sleep laboratory. Ten normal healthy subjects (6 girls and 4 boys, mean age 4.6 years; range 3-6 years) underwent polysomnography recordings for 2 consecutive nights in a standard laboratory setting. Sleep data were stored on a computer using a polysomnography digital system (Embla N7000, Medcare, Iceland). Sleep structure was visually scored according to the Rechtschaffen and Kales criteria. The cyclic alternating pattern was visually scored following the criteria by Terzano et al. These criteria were modified for the purposes of this study because it was noticed that, at the age of the group under analysis, most electroencephalogram arousals, often accompanied by electromyogram activation, are expressed at the level of the electroencephalogram by theta frequencies and not alpha or higher frequencies. The CAP rate in preschool-aged children (25.93%) showed a progressive increase with the deepness of sleep, with highest values during non-rapid eye movement (NREM) stage 3 (44.0%) and 4 sleep (46.08%) and lowest values in NREM stage 2 (17.26%). The CAP time showed its longest duration during stage 2 sleep, followed by stage 4, stage 3, and NREM stage 1. The CAP cycle duration showed no differences across NREM stages. The cyclic alternating pattern phase A was longer and phase B was shorter during stage 1 than during stages 2, 3, and 4. A1 phases were the most numerous (63.2%), followed by A2 (21.5%) and by A3 (15.3%). The distribution of A-phase subtypes across NREM sleep stages (A index) showed significant differences for the A1 subtypes that occurred more frequently during stage 3 and 4 sleep than during stages 1 and 2. The A2 index showed no significant differences across NREM sleep stages, while the A3 index was significantly higher during stage 1 sleep than during stages 2, 3, and 4. The analysis of the A1 interval distribution showed a log-normal-like distribution with a peak around 25 seconds for the A1 phases and no clear peak for A2-A3 phases. The analysis of CAP in preschool-aged children is characterized by an increase of CAP rate during slow-wave sleep and a high percentage of A1 phases and A2 phases. However, the lower percentage of A1 paralleled by an increase of A2 could represent a signal of higher sleep instability in this age group as compared with prepubertal school-aged children.

Microstructure of sleep in depressed patients according to the cyclic alternating pattern

Background: The aim of this study was to evaluate the microstructure of the EEG sleep of depressed subjects by cyclic alternating pattern (CAP) analysis. Methods: 78 patients affected by major depression and 18 control subjects matched for age and sex underwent a full night polysomnographic study. Results: A significant increase in CAP rate (60 versus 35%) was found in the patients group compared to controls while no significant difference was found with the traditional analysis. Conclusion: In depressed subjects CAP analysis is able to show a microstructural sleep impairment, which is not evident at the macrostructural level, providing an objective measure of sleep disturbance in those patients.