1,720,967 research outputs found
Modifications of cyclic alternating pattern in sleep apnea syndrome.
No full textWithin non-rapid eye movement sleep, two complementary modalities of arousal organization may be identified: (1) the cyclic alternating pattern (CAP), correlated with successive upward (phase A) and downward (phase B) fluctuations of arousal and arousal-related vegetative functions, and (2) non-CAP, corresponding to a relative stability of arousal and vegetative activities. In a 62-year-old overweight and heavily snoring man, complaining of excessive daytime sleepiness, three consecutive polysomnograms displayed a highly frequent occurrence of nocturnal apneas (apnea index: 15), mostly obstructive and mixed, limited to non-rapid eye movement sleep stages 1 and 2. The apneic episodes, that never occurred during non-CAP, exclusively appeared during the inhibitory phase B of CAP, whereas the following breathing resumption was mainly induced by an activating phase A pattern. The crucial effect of arousal instability on respiratory control is emphasized
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Morphologic and functional features of cyclic alternating pattern (CAP) sequences in normal NREM sleep.
No full textThe Cyclic Alternating Pattern (CAP) is an EEG biphasic periodic activity of normal NREM sleep, generally organized in sequences of two or more cycles and correlated to long-lasting fluctuations in the level of arousal. The remaining NREM sleep is characterized by prolonged stationary activities or non-CAP (NCAP). Criteria for the detection of morphology and reactivity of CAP and NCAP segments are defined in the sleep recordings of 10 healthy young adults. Standard sleep variables and CAP rates, referred to the ratio of CAP time to Total NREM sleep time (CAPR/NREM) and to each NREM sleep stage, were scored for statistical inferences and correlations. CAPR/NREM may be considered an additional non-redundant sleep variable which determines the measure of arousal instability during NREM sleep. The relationship between CAP and the biphasic behavior of microarousals is discussed
The Cyclic Alternating Pattern sequences in the dynamic organization of sleep.
No full textThe cyclic alternating pattern (CAP) is a physiological component of normal NREM sleep, functionally correlated with long-lasting arousal oscillations. This EEG periodic activity, organized in sequences of two or more decasecond cycles, is detectable also in coma and in other neurologic disorders, appearing as a general modality of arousal organization. Within NREM sleep, the fluctuations of CAP alternate with sustained homogeneous EEG patterns, characterized by a greater stability of arousal and called non-CAP (NCAP). In 20 sleep records of 10 healthy young adults we analysed the chronological relationship between CAP and 3 fundamental states of arousal: wakefulness, NREM sleep, REM sleep. Sleep onset and sleep recoveries after nocturnal awakenings were closely linked to CAP sequences, indicating a functional linkage between cyclic fluctuations of arousal and the beginning of any sleep behavioural state. On the basis of their temporal relationship with CAP sequences, the waking to sleep and the waking transitions appeared a symmetrical events in the organization of arousal, whereas the NREM to REM transitions and the REM to NREM transitions occurred as asymmetrical events. Moreover, almost 50\% of all NREM stage changes were accompanied by CAP sequences. The EEG and dynamic features of CAP sequences show morphological and behavioural analogies with some phasic phenomena (i.e., phase d'activation transitoire or micro-arousals) and EEG patterns reported in the literature (e.g., tracé alternant; phase transitionnelles; tracé intermittent). Our data suggest a functional correlation between the control mechanisms of CAP and the organization of sleep
Cyclic alternating pattern (CAP) in normal sleep: polysomnographic parameters in different age groups.
No full textThe present study aimed at offering a standardized database for cyclic alternating pattern (CAP) parameters across representative ages of life.CAP parameters were quantified in 40 healthy sleepers and polygraphically investigated in a partially sound-proof recording chamber under a standard laboratory setting. Four age groups were investigated (teenagers: 10-19 years; young adults: 20-39 years; middle-aged: 40-59 years; elderly: 60 years). Each group included 10 subjects (5 males and 5 females). Nocturnal recordings were accomplished after adaptation to the sleep laboratory that also served to rule out the presence of sleep-related disorders. The study indicated that CAP is a natural phenomenon of NREM sleep, with specific age-related characteristics across the life cycle.CAP rate in NREM sleep, defined as the percentage ratio of total CAP time to total NREM sleep time, showed a U-shape profile with minimum in young adults (31.9\%), maximum in the elderly group (55.3\%), and intermediate values in teenagers (43.4\%) and in middle-aged subjects (37.5\%). The longest duration of CAP cycles was found among the older subjects (31 s). The highest amounts of subtypes A1 were identified in teenagers (n = 261), while the highest amounts of A2 and A3 subtypes occurred in the elderly group (n = 183). Across the ages, the level of arousal mostly fluctuated in stages 1 and 3, whereas stage 4 emerged as the most stable NREM stage. Overall, stage 2 better reflected the CAP values referred to as total NREM sleep.The periodic arousal fluctuations reflected by CAP are a natural phenomenon of NREM sleep with specific age-related variations across the life cycle
Changes of cyclic alternating pattern (CAP) parameters in situational insomnia under brotizolam and triazolam.
No full textThe standardized scoring criteria of sleep can serve as a rough tool for monitoring the effects of psychoactive compounds, both in normal sleepers and in insomniac patients. More sensitive information on the impact of perturbing factors and drugs during sleep is supplied by the cyclic alternating pattern (CAP) parameters. In particular, CAP rate, which measures the amount of arousal instability during NREM sleep, has been proved of high reliability in a variety of clinical and pharmacological settings. The present study aimed at evaluating the activity of brotizolam (Br) 0.25 mg and triazolam (Tr) 0.25 mg on both conventional and CAP parameters in a model of situational insomnia of intermediate severity. Six middle-aged healthy subjects (three males and three females, aged 40-55 years) with no complaints about sleep, underwent a polysomnographic investigation according to a double-blind crossover design: placebo without noise (night 1), placebo with noise (night 2), brotizolam or triazolam without noise (nights 3 and 5), brotizolam or triazolam with noise (nights 4 and 6). The unperturbed nights consisted of standard recording conditions in a sound-protected sleep laboratory, whereas situational insomnia was accomplished by means of continuous white noise at 55 dBA delivered throughout the night. Subjects received medication orally at bedtime. An interval of at least 48 h was secured between consecutive recordings in the same individual. Compared to baseline conditions, situational insomnia was characterized by a shorter amount of total sleep (-40 min) and by an extension of intrasleep awakenings (+62 min).(ABSTRACT TRUNCATED AT 250 WORDS
Cyclic alternating pattern as a provocative factor in nocturnal paroxysmal dystonia.
No full textWe made a polygraphic study of 6 patients with nocturnal paroxysmal dystonia (NPD) in which the cyclic alternating pattern (CAP) parameters were compared with those of a group of age- and sex-matched controls.All patients met the requirements for NPD diagnosis, characterized by generalized stereotyped movements (dystonic-dyskinetic), with a 1-min centered duration but with no clear evidence of epileptic abnormalities in the waking EEG and during nocturnal recordings.Besides the major events, the NPD polysomnograms also showed shorter, repeated episodes of shorter duration (generally <20 s) consisting of abrupt movements involving one or more body segments. Overall, the motor events in patients with NPD were closely related to periods of unstable non-REM (NREM) sleep, as evidenced by the sequences of CAP, and began during an A phase. According to the conventional scoring parameters, NPD and controls differed only in sleep latency (+14 min in the NPD patients: p < 0.04). However, the architecture of sleep in the group with NPD was characterized by prolonged and irregular NREM/REM cycles. In addition, the NPD recordings showed significantly higher values of CAP rate (p < 0.0001). When major motor attacks were suppressed by medication, sleep was characterized by a decrease in the excessive amounts of CAP rate and by a more regular architecture.The modulatory role of CAP on nocturnal motor events is reported
Clinical and polysomnographic effects of trazodone CR in chronic insomnia associated with dysthymia.
No full textSix middle aged subjects complaining of chronic insomnia associated with dysthymia were investigated in a 2-month single blind study: a 7-day placebo treatment period, followed by a 6-week phase with increasing doses of trazodone controlled release (CR) formulation (50 mg through days 8-10; 75 mg through days 11-13; 150 mg through days 14-49) and then a final 7-day withdrawal period under placebo. Medication was always administered at bedtime. Five polysomnographic recordings were accomplished by each subject (sleep 1: under baseline placebo; sleep 2-3-4; under active treatment; sleep 5: after drug discontinuation). A "blind" EEG reader analysed the traditional polysomnographic variables (macrostructure of sleep) and the amount and percentage ratio (CAP rate) of cyclic alternating pattern (CAP), the microstructural parameter that measures the instability of arousal during sleep. Visual analogue scales (VAS) for the evaluation of subjective sleep quality and the Hamilton rating scale for depression (HAM-D) were regularly assessed across the study. Statistical analysis was based on an ANOVA test with repeated measures completed by means of Bonferroni adjusted probabilities. No significant differences emerged from the macrostructural parameters referred to sleep initiation and maintenance, while significant overall modifications emerged from stage 2 (P < 0.0005), slow wave sleep (P < 0.0001), total CAP time (P < 0.0001) and CAP rate (P < 0.0001). Compared to the placebo baseline night, a significant increase of slow wave sleep (+40 min) and significant reductions of stage 2 (-67 min), CAP time (-90 min) and CAP rate (-23\%) were already found on day 4 of treatment (sleep 2).(ABSTRACT TRUNCATED AT 250 WORDS
Variations of cyclic alternating pattern rate and homeostasis of sleep organization: a controlled study on the effects of white noise and zolpidem.
No full textThe Cyclic Alternating Pattern (CAP) is a physiologic structure of normal non-REM (NREM) sleep, functionally correlated to long-lasting arousal instability. In 12 healthy volunteers, a continuous 45 dB (A) white noise induced no remarkable changes on the standard sleep parameters. However, compared to the baseline conditions, the acoustic perturbation determined a significant increase of the Cyclic Alternating Pattern Rate (CAPR), that measures the amount of CAP during sleep. Ten mg of zolpidem, a novel imidazopyridine hypnotic compound, did not modify the structure of unperturbed sleep, but induced a highly significant reduction of the increased values of CAP Rate due to white noise. The homeostatic function of CAP is stressed. CAPR appears to be a highly sensitive indicator of environmental modification during sleep
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