EEG spectral power and sleepiness during 24 h of sustained wakefulness in patients with obstructive sleep apnea syndrome.
ABSTRACT This study investigated if obstructive sleep apnea syndrome (OSAS) may be associated with higher activity in different frequency bands of the EEG during a sustained wakefulness paradigm.
Twelve OSA patients and 8 healthy controls were studied with the Karolinska Drowsiness Test (KDT) and subjective ratings of sleepiness (VAS and KSS) conducted every hour during 24 h of sustained wakefulness.
The waking EEG activity, mainly in the low (0.5-7.8 Hz) and fast (12.7-29.2 Hz) frequency band, increased as time awake progressed in both groups but more obviously in OSA patients. A similar pattern was observed for rated sleepiness in both groups. Moreover, VAS ratings of alertness were closely related to the awake theta, fast alpha and beta bands in controls but not in OSA patients.
OSAS was associated with a wake-dependent increase in low (0.5-7.8 Hz) and fast (12.7-29.2 Hz) frequency range activity. Variations in behavioural sleepiness measured by VAS ratings closely reflect most of the waking EEG parameters in controls but not in OSA patients.
In a sustained wakefulness paradigm, higher activity in delta, theta and beta bands associated with OSAS indicates that OSA patients show marked signs of higher sleepiness and stronger efforts than controls to stay awake, even though they tend to underestimate their sleepiness.
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ABSTRACT: Infantile spasms (ISs) were thought to be a kind of intractable seizure, and diagnosed with one or many of the following: nodding spasm clusters, mental retardation, or showing up as interictal hypsarrhythmia on electroencephalograms. While these spasms represent a major therapeutic challenge, limited parameters are available to evaluate their status before and after treatment. The American Academy of Neurology/Child Neurology Society recommends that administration of adrenocorticotropic hormone (ACTH) is effective for short-term treatment of children with IS. To determine whether there were differences in EEG manifestations, we performed a power spectral analysis of the EEG of hypsarrhythmia to determine the effects of ACTH, before and after its administration.Methods After obtaining informed consents from guardians, we recruited children younger than 3 years of age, who fulfilled both the definition of IS and were receiving other antiantiepileptic drugs (valproic acid, vigabatrin, lamotrigine, etc.) in Taipei Medical University-affiliated hospitals from November 2009 to June 2012. Patients with IS were administered synthetic ACTH subcutaneously for 2 weeks following a 6-week tapering-off period. The data were later analyzed by fast Fourier transformation (FFT) analysis.ResultsThe average EEG voltage of five patients before ACTH treatment for all the brain regions ranged from 92.21 to 153.02 μV (mean: 106.64 ± 12.36 μV; n = 5). We found that the frequency corresponding to the theta wave power (7.8 Hz) showed a prominent elevation in all of the five IS patients with hypsarrhythmia. Before commencing ACTH treatment, the theta wave power was in the range of 14.77–27.52 μV (mean: 21.05 ± 2.15 μV; n = 5). Two weeks after ACTH treatment, the theta wave power decreased to a range of 1.81–6.01 μV (mean 3.81 ± 0.67; n = 5). Thus, we conclude that administration of ACTH induced a significant decrease in the theta wave power (mean decrease: −80.95 ± 3.42%; p < 0.05; n = 5).Conclusion Performing an FFT spectrum analysis of an EEG such as EEG of the hypsarrhythmia can serve as an objective tool to understand specific signal processing in children with IS. This is the first finding to discover the inhibitory effect of ACTH on the theta wave power. The inter-relationship between ACTH and theta power needs to be elucidated in the future studies.Journal of Experimental and Clinical Medicine 12/2012; 4(6):330-333. DOI:10.1016/j.jecm.2012.10.009
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ABSTRACT: Pathophysiological models of insomnia invoke the concept of 24-hour hyperarousal, which could lead to symptoms and physiological findings during waking and sleep. We hypothesized that this arousal could be seen in the waking electroencephalogram (EEG) of individuals with primary insomnia (PI), and that waking EEG power would correlate with non-REM (NREM) EEG. Subjects included 50 PI and 32 good sleeper controls (GSC). Five minutes of eyes closed waking EEG were collected at subjects' usual bedtimes, followed by polysomnography (PSG) at habitual sleep times. An automated algorithm and visual editing were used to remove artifacts from waking and sleep EEGs, followed by power spectral analysis to estimate power from 0.5-32 Hz. We did not find significant differences in waking or NREM EEG spectral power of PI and GSC. Significant correlations between waking and NREM sleep power were observed across all frequency bands in the PI group and in most frequency bands in the GSC group. The absence of significant differences between groups in waking or NREM EEG power suggests that our sample was not characterized by a high degree of cortical arousal. The consistent correlations between waking and NREM EEG power suggest that, in samples with elevated NREM EEG beta activity, waking EEG power may show a similar pattern. Wu YM; Pietrone R; Cashmere JD; Begley A; Miewald JM; Germain A; Buysse DJ. EEG power during waking and NREM sleep in primary insomnia. J Clin Sleep Med 2013;9(10):1031-1037.Journal of clinical sleep medicine: JCSM: official publication of the American Academy of Sleep Medicine 01/2013; 9(10):1031-1037. DOI:10.5664/jcsm.3076 · 2.83 Impact Factor
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ABSTRACT: The main consequence of insufficient sleep is sleepiness. While measures of sleep latency, continuous encephalographical/electro-oculographical (EEG/EOG) recording and performance tests are useful indicators of sleepiness in the laboratory and clinic, they are not easily implemented in large, real-life field studies. Subjective ratings of sleepiness, which are easily applied and unobtrusive, are an alternative, but whether they measure sleepiness sensitively, reliably and validly remains uncertain. This review brings together research relevant to these issues. It is focused on the Karolinska Sleepiness Scale (KSS), which is a nine-point Likert-type scale. The diurnal pattern of sleepiness is U-shaped, with high KSS values in the morning and late evening, and with great stability across years. KSS values increase sensitively during acute total and repeated partial sleep deprivation and night work, including night driving. The effect sizes range between 1.5 and 3. The relation to driving performance or EEG/EOG indicators of sleepiness is highly significant, strongly curvilinear and consistent across individuals. High (>6) KSS values are associated particularly with impaired driving performance and sleep intrusions in the EEG. KSS values are also increased in many clinical conditions such as sleep apnea, depression and burnout. The context has a strong influence on KSS ratings. Thus, physical activity, social interaction and light exposure will reduce KSS values by 1–2 units. In contrast, time-on-task in a monotonous context will increase KSS values by 1–2 units. In summary, subjective ratings of sleepiness as described here is as sensitive and valid an indicator of sleepiness as objective measures, and particularly suitable for field studies.Journal of Sleep Research 04/2014; 23(3). DOI:10.1111/jsr.12158 · 2.95 Impact Factor