Article

Billiard MEEG. arousals and awakenings in relation with periodic leg movements during sleep

Sleep Disorders Unit, Cerrahpasa Medical School, University of Istanbul, Istanbul, Turkey.
Journal of Sleep Research (Impact Factor: 2.95). 10/2000; 9(3):273-7. DOI: 10.1046/j.1365-2869.2000.00202.x
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ABSTRACT It is known that periodic leg movements are frequently accompanied by full awakenings or by signs of EEG arousals. The time relationship of these EEG arousals with leg movements varies from patient to patient. They may precede or follow leg movements or occur simultaneously. It is not clear whether these arousals trigger leg movements or, alternatively, whether both EEG arousals and leg movements are separate expressions of a common pathophysiological mechanism. We investigated the temporal relationship of five EEG arousals, such as alpha activity, K-complexes, spindles, K-alpha, K-spindle activities and awakenings, with leg movements in 10 periodic leg movement patients. These EEG arousals were considered to be associated with leg movements if they occurred 10 s before/after or simultaneously with the onset of right or left tibialis muscle EMG potentials. It was found that 49.19% of EEG arousals occurred before leg movements, 30.61% occurred simultaneously and 23.18% occurred just after leg movements. The number of EEG arousals was significantly higher in the 10 s preceding leg movement than simultaneously or in the 10 s following. Alpha activity was the phenomenon associated most frequently with leg movements, irrespective of its temporal organization and was significantly higher during the 10 s preceding movement. Spindle and K-spindle activities were significantly higher before leg movement, whereas K-complex activity was significantly more frequent during leg movements. The number of awakenings was significantly higher after leg movements than simultaneously. These results indicated that leg movements are not primary, but rather are a phenomenon associated with an underlying arousal disorder.

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    • "PLMS are frequently associated with cortical activation (Iriarte et al. 2004). However, the notion that PLMS cause arousal is not accurate, as arousals may occur prior to the leg movement (Ferri et al. 2007; Karadeniz et al. 2000). Interestingly, the facts that experimentally induced arousals (i.e., sleep fragmentation) during sleep do not elicit PLMS in normal subjects (Ferri et al. 2013), and that arousals and PLMS can be dissociated Fig. 1 Mean R–R interval, standard deviation of the NN interval (SDNN), low-frequency components (LF), and high frequency components (HF) during different sleep stages (N1-N2, N3, REM) as well as during wakefulness before (W-pre) and after (W-post) sleep in PLMS patients, and control subjects. "
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    ABSTRACT: The relationship between the autonomic nervous system and periodic leg movements during sleep (PLMS) is not completely understood. We aimed to determine whether patients with PLMS exhibit any changes in their basal heart rate variability (HRV), excluding episodes of leg movements and arousals. To investigate this, we conducted a cross-sectional study including 13 patients with PLMS (PLMS ≥ 20) and 13 matched controls, free of cardiovascular diseases and medications. Time-and frequency-domain HRV measures [mean R-R interval, low frequency (LF), high frequency (HF), LF/HF] were calculated across all sleep stages as well during wakefulness just before and after sleep during one-night polysomnography. We only took ECG segments of sleep without arousals and excluded periods of 30 s before and after the leg movements. No statistical differences between PLMS and control subjects were found in any of the time- or frequency-domain HRV measures across sleep stages. Basal cardiac autonomic modulation in patients with PLMS is similar to that of control subjects. Our results argue against a role for a basal disturbance of the cardiac autonomic nervous system in the pathogenesis of PLMS.
    Journal of Neural Transmission 11/2013; 121(4). DOI:10.1007/s00702-013-1116-8 · 2.87 Impact Factor
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    • "MA detection criteria for REM sleep included an increase in submental EMG amplitude, in addition to a shift in EEG activity. The PLMS was scored as associated with MA if the latter occurred simultaneously or within 1 s before or after the onset of tibialis muscle EMG activity (Karadeniz et al., 2000; Mendelson, 1996). To optimize the detection of the PLM onset, any increase in the amplitude of the EMG signal (even when the amplitude was less than 20%) was considered as the beginning of the motor phenomenon. "
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    ABSTRACT: Typical changes in spectral electroencephalographic (EEG) activity and heart rate (HR) have been described in periodic leg movements (PLM) associated with or without microarousals (MA). We aimed to determine the effects of sleep stage and wakefulness on these responses to ascertain whether a common pattern of EEG and HR activation takes place. The time course of EEG spectral activity and HR variability associated with PLM was analysed in 13 patients during light NREM sleep, rapid-eye-movement (REM) sleep and wakefulness. The same analysis was also conducted for PLM without MA occurring in stage 2. A significant EEG and electrocardiogram (ECG) activation was found associated with PLM during sleep, but not during wakefulness. While in light NREM sleep, an increase in delta and theta bands was detected before the PLM onset, in REM sleep the EEG activation occurred simultaneously with the PLM onset. Moreover, during stage 1 and REM sleep, alpha and fast frequencies tended to remain sustained after the PLM onset. In contrast, during wakefulness, a small and not significant increase in cerebral activity was present, starting at the PLM onset and persisting in the post-movement period. A typical pattern of cardiac response was present during NREM and REM sleep, the autonomic activation being lesser and prolonged during wakefulness. We conclude that the EEG and HR responses to PLM differ between sleep stages and wakefulness with lesser changes found during wakefulness. These findings suggest that specific sleep state-dependent mechanisms may underlie the occurrence of PLM.
    Clinical Neurophysiology 11/2004; 115(10):2236-46. DOI:10.1016/j.clinph.2004.04.024 · 2.98 Impact Factor
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    • "The temporal overlap between cortical , somato - motor and vegetative events within the same arousal episode does not necessarily imply synchrony and the order of activation of the single compartments can vary in the different physiologic or pathologic circumstances ( Karadeniz et al . 2000 ) . In arousal phenomena during sleep there is no mandatory chronologic and etiologic subordination . The phenomenon takes place within interactive loops in which the cerebral cortex can be the starting or the ending point but anyway a source of control ."
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    ABSTRACT: The role of arousals in sleep is gaining interest among both basic researchers and clinicians. In the last 20 years increasing evidence shows that arousals are deeply involved in the pathophysiology of sleep disorders. The nature of arousals in sleep is still a matter of debate. According to the conceptual framework of the American Sleep Disorders Association criteria, arousals are a marker of sleep disruption representing a detrimental and harmful feature for sleep. In contrast, our view indicates arousals as elements weaved into the texture of sleep taking part in the regulation of the sleep process. In addition, the concept of micro-arousal (MA) has been extended, incorporating, besides the classical low-voltage fast-rhythm electroencephalographic (EEG) arousals, high-amplitude EEG bursts, be they like delta-like or K-complexes, which reflects a special kind of arousal process, mobilizing parallely antiarousal swings. In physiologic conditions, the slow and fast MA are not randomly scattered but appear structurally distributed within sleep representing state-specific arousal responses. MA preceded by slow waves occurs more frequently across the descending part of sleep cycles and in the first cycles, while the traditional fast type of arousals across the ascending slope of cycles prevails during the last third of sleep. The uniform arousal characteristics of these two types of MAs is supported by the finding that different MAs are associated with an increasing magnitude of vegetative activation ranging hierarchically from the weaker slow EEG types (coupled with mild autonomic activation) to the stronger rapid EEG types (coupled with a vigorous autonomic activation). Finally, it has been ascertained that MA are not isolated events but are basically endowed with a periodic nature expressed in non-rapid eye movement (NREM) sleep by the cyclic alternating pattern (CAP). Understanding the role of arousals and CAP and the relationship between physiologic and pathologic MA can shed light on the adaptive properties of the sleeping brain and provide insight into the pathomechanisms of sleep disturbances. Functional significance of arousal in sleep, and particularly in NREM sleep, is to ensure the reversibility of sleep, without which it would be identical to coma. Arousals may connect the sleeper with the surrounding world maintaining the selection of relevant incoming information and adapting the organism to the dangers and demands of the outer world. In this dynamic perspective, ongoing phasic events carry on the one hand arousal influences and on the other elements of information processing. The other function of arousals is tailoring the more or less stereotyped endogenously determined sleep process driven by chemical influences according to internal and external demands. In this perspective, arousals shape the individual course of night sleep as a variation of the sleep program.
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