• Sleep Medicine and Psychophysiology
• /
• v.10 no.2
• /
• pp.100-107
• /
• 2003

Objectives: Periodic leg movements in sleep (PLMS) might be subdivided based upon whether or not they are associated with visible EEG microarousals (MA). MA is considered to be responsible for nonrestorative sleep and daytime fatigue. The American Sleep Disorders Association's (ASDA) scoring rules for MA based on visual analysis of the EEG changes suggest that MA should last more than 3 seconds. However, it has been suggested that visual analysis may not detect some changes in EEG activity. This study is aimed at measuring changes in EEG spectra during PLMS without MA in order to better understand the arousing response of PLMS. Methods: Ten drug-free patients (three men and seven women) diagnosed with PLMS by polysomnography were studied. Spectral analysis of the EEG was performed in each patient on 30 episodes of PLMS without MA, chosen randomly across the night in stage 2 non-REM sleep. We applied stricter criteria for MA compared to ASDA, by defining it as a return to alpha and theta frequency lasting at least 1 second. Results: The mean PLMS index was $16.7{\pm}10.0$. The mean PLMS duration was $1.3{\pm}0.7$ seconds. Comparison of 4-second EEG activity both before and after the onset of PLMS without MA using independent t-test showed that the movements were associated with significant increase of relative activity in the delta band (p=0.000) and significant decrease of activity in the alpha (p=0.01) and sigma (p=0.000) bands. No significant decrease in the theta (p=0.05), beta (p=0.129), or gamma (p=0.062) bands was found. Conclusion: PLMS without MA was found to be associated with EEG change characterized by increase in the delta frequency band. This finding seems to be compatible with the hypothesis of an integrative hierarchy of arousal responses of Sforza's. Considering that the subjects had lower PLMS index and shorter PLMS duration than those of the previous study, it is suggested that an even less severe form of PLMS without MA could induce neurophysiologic change, which may potentially be of clinical significance.

• Tuberculosis and Respiratory Diseases
• /
• v.45 no.1
• /
• pp.153-168
• /
• 1998

Background: The existing data indicate that obstructive sleep apnea syndrome contributes to the development of cardiovascular dysfunction such as systemic hypertension and cardiac arrhythmias, and the cardiovascular dysfunction has a major effect on high long-term mortality rate in obstructive sleep apnea syndrome patients. To a large extent the various studies have helped to clarify the pathophysiology of obstructive sleep apnea, but many basic questions still remain unanswered. Methods: In this study, the influence of obstructive sleep apnea on systemic blood pressure, cardiac rhythm and urinary catecholamines concentration was evaluated. Over-night polysomnography, 24-hour ambulatory blood pressure and ECG monitoring, and measurement of urinary catecholamines, norepinephrine (UNE) and epinephrine (UEP), during waking and sleep were undertaken in obstructive sleep apnea syndrome patients group (OSAS, n=29) and control group (Control, n=25). Results: 1) In OSAS and Control, UNE and UEP concentrations during sleep were significantly lower than during waking (P<0.01). In UNE concentrations during sleep, OSAS showed higher levels compare to Control (P<0.05). 2) In OSAS, there was a increasing tendency of the number of non-dipper of nocturnal blood pressure compare to Control (P=0.089). 3) In both group (n=54), mean systolic blood pressure during waking and sleep showed significant correlation with polysomnographic data including apnea index (AI), apnea-hypopnea index (AHI), arterial oxygen saturation nadir ($SaO_2$ nadir) and degree of oxygen desaturation (DOD). And UNE concentrations during sleep were correlated with AI, AHI, $SaO_2$ nadir, DOD and mean diastolic blood pressure during sleep. 4) In OSAS with AI>20 (n==14), there was a significant difference of heart rates before, during and after apneic events (P<0.01), and these changes of heart rates were correlated with the duration of apnea (P<0.01). The difference of heart rates between apneic and postapneic period (${\Delta}HR$) was significantly correlated with the difference of arterial oxygen saturation between before and after apneic event (${\Delta}SaO_2$) (r=0.223, P<0.001). 5) There was no significant difference in the incidence of cardiac arrhythmias between OSAS and Control In Control, the incidence of ventricular ectopy during sleep was significantly lower than during waking. But in OSAS, there was no difference between during waking and sleep. Conclusion : These results suggested that recurrent hypoxia and arousals from sleep in patients with obstructive sleep apnea syndrome may increase sympathetic nervous system activity, and recurrent hypoxia and increased sympathetic nervous system activity could contribute to the development of cardiovascular dysfunction including the changes of systemic blood pressure and cardiac function.

• Sleep Medicine and Psychophysiology
• /
• v.2 no.2
• /
• pp.156-164
• /
• 1995

Objectives : Patients with obstructive sleep apnea syndrome(OSAS) often complain of nocturnal enuresis. There are a few reports that OSAS patients have altered renal function, and there are some evidences that the increased release of atrial natriuretic peptide(ANP) may be involved in the pathogenesis of nocturnal urinary symptoms of OSAS patients. In this study, we measured plasma ANP concentrations during waking and sleep in OSAS patients and normal controls to investigate whether there were differences of ANP concentrations between OSAS patients and normal subjects. Methods : 27 patients with OSAS and 10 normal subjects were studied. All subjects underwent a full-night polysomnographic study. Venous blood samples were separately drawn during waking and sleep. Plasma ANP concentrations were measured using radioimmunoassay. Results : In OSAS patients, ANP concentrations during sleep($122.9\;{\pm}\;29.9pg/ml$) were significantly higher than ANP concentrations during waking($60.2\;{\pm}\;5.8pg/ml$)(p < 0.05). However, in normal subjects, there was no significant difference between ANP concentrations during waking($59.2\;{\pm}\;5.7pg/ml$) and sleep($69.6\;{\pm}\;3.0pg/ml$)(p > 0.05). There was no significant difference of ANP concentrations during waking between OSAS patients($60.2\;{\pm}\;5.8pg/ml$) and normal controls($59.2\;{\pm}\;5.7pg/ml$)(p > 0.05), and also there was no significant difference during sleep between OSAS patients($122.9\;{\pm}\;29.9pg/ml$) and normal subjects($69.6\;{\pm}\;3.0pg/ml$)(p > 0.05). Plasma ANP concentrations during sleep showed significant positive correlations with apnea index(r = 0.3846, p < 0.05) and respiratory disturbance index(r = 0.3939, p < 0.05) in OSAS patients. Conclusion : These data suggest that, in OSAS patients, plasma ANP concentrations during sleep are significantly higher than plasma ANP concentrations during waking, and there is a positive correlation between the plasma ANP concentration during sleep and the severity of sleep apnea.

• Sleep Medicine and Psychophysiology
• /
• v.2 no.1
• /
• pp.82-90
• /
• 1995

Objectives : Insomnia is significantly influenced by the pre-sleep arousal, self efficacy, sleep hygiene, depression and anxiety. The authors tried to explore how these factors are related with the clinical features of sleep. Methods : Fifty three patients diagnosed as insomnia by DSM-IV criteria were studied. They filled up the pre-sleep arousal scale(PSAS), sleep efficacy scale(SES), sleep hygiene awareness and practice scale, BDI, and state and trait anxiety scales. Results: 1) The mean values of sleep-related variables were as follows : Sleep latency,136.89 minutes ; frequences of awakening during a night, 2.28 ; minutes to get back to sleep, 42.70 ; total sleep time, 180.19 minutes ; duration of illness, 72.00 months. 2) The mean scores of scales were as follows : PSAS(cognitive), 22.40 ; PSAS(somatic), 17.32 ; SES, 20.16 ; sleep hygiene knowledge, 25.96 ; caffein knowledge, 59.78 ; sleep hygiene practice, 42.12 ; BDI. 18.2 ; state anxiety, 41.24 ; trait anxiety ; 44.50. 3) In the subjects with superimposed depression, the mean frequency of awakening during a night and the mean pre-sleep arousal scale score were higher than in those without depression. 4) Frequency of awakening were correlated positively with a PSAS(a tight tense feeling in your muscle) and sleep hygiene awareness. PSAS(cognitive) were correlated positively with a PSAS(somatic). BDI correlated positively with a PSAS item(a jittery, nervous feeling in your body)and a SES item (not allow a poor night's sleep to interfere with daily activities). Anxiety scales were correlated positively with sleep hygiene practice scale sleep, and PSAS were correlated negatively with SES. Conclusions : The mean scores of PSAS, SES, sleep hygiene awareness and practice scale, BDI, state and trait anxiety scales of insomniacs were correlated either positively or negatively in insomnia patients. These factors seem to contribute to the development and maintainence of insomnia.

• Sleep Medicine and Psychophysiology
• /
• v.13 no.2
• /
• pp.67-74
• /
• 2006

Introduction: Excessive daytime sleepiness and cataplexy are key features of narcolepsy. Modafinil is psychostimulant used in the treatment of narcolepsy. In this study, we evaluated effects of modafinil on nocturnal sleep structure and sleep latency in multiple sleep latency test and clinical features. Methods: Twelve narcoleptic patients (7 male, age: $22.9{\pm}2.6\;yrs$) were participated in the study. All of them had done nocturnal polysomnography (nPSG), multiple sleep latency test (MSLT), clinical symptoms scales and have repeated same procedure after taking 200 mg of modafinil. We have done linear mixed model analysis to describe effects of group, medication and nap time on these measures. Results: Modafinil did not affect clinical scales except PSQI which had been reduced after medication. In this study, Modafinil reduced total sleep time, sleep efficiency and increased wake after sleep onset and percent of arousal during sleep in nocturnal polysomnography and prolonged mean sleep latency in multiple sleep latency tests in both group. Discussion: Modafinil has stimulant effect of central nervous system but its effect on night sleep is less than other psychostimulants such as methylphenidate. We ascertained that modafinil affected total sleep time, sleep efficiency and percent of wake during sleep but did not effect on sleep structure. Modafinil was effective in the management of day time sleepiness. Modafinil can enhance alertness of control group without day time sleepiness.

• Sleep Medicine and Psychophysiology
• /
• v.9 no.2
• /
• pp.115-121
• /
• 2002

Objectives: Although sleep paralysis (SP) has been known as one of the symptoms of narcolepsy, recently it has become recognized as occurring frequently in the general population. However, the prevalence of SP and its associated factors in patients with major psychiatric disorders remain unknown. This study investigated the prevalence of SP and a variety of associated experiences in those patients. Methods: The subjects were 160 psychiatric patients and 143 age- and sex-matched controls. The Korean version SP questionnaire as well as the Sleep-Wake Schedule, Epworth Sleepiness Scale and Insomnia Severity Index were administered to all the subjects. The patients were referred from Dong-A University Hospital and consisted of 74 diagnosed as schizophrenia (47.7%), 26 as bipolar disorder (16.8%) and 55 as major depression (35.5%). Results: Nearly 42% of the patient group and 39% of the control group had experienced at least one episode of SP in their lifetime, with no significant difference between the groups. However, the patient group had experienced SP more frequently than the control group. Among all subjects, no gender difference in SP incidence was found. The peak age of onset was in the range of 16-25 years for both groups. Over eight tenths of both groups reported hallucinations and over seven tenths of both groups experienced fear accompanying SP. Conclusion: This study shows that there is no difference in the lifetime prevalence of SP between psychiatric patients and the general population, whereas frequency of SP experience is higher in psychiatric patients. Terrifying hallucinations and fearful feelings frequently accompany SP in both groups.

• Science of Emotion and Sensibility
• /
• v.15 no.4
• /
• pp.453-468
• /
• 2012

This study investigated the effects of Lavandula angustifolia (L. angustifolia) aroma on the brain electrical activity evaluated by an electroencephalogram (EEG) in the male adults since many researches were performed with females and few with males. Sleep quality of 35 male adults were analyzed by Pittsburgh sleep quality index, and they were divided into two groups of good sleep quality and poor sleep quality. EEG electrodes were attached at the frontal (F3, F4), temporal (T3, T4), occipital (O1, O2), and parietal (P3, P4) regions according to the International 10-20 system. EEG was measured for 3 min per each period of before, during, and after L. angustifolia aromatherapy. Subjects with good sleep quality showed increases in the delta power at the parietal region of both cerebral hemispheres and in the theta power at the temporal region of right hemisphere (p<0.05), and a decrease in the alpha at the parietal region of both cerebral hemispheres (p<0.05). And subjects with poor sleep quality showed increases in the delta power at the frontal region of left cerebral hemisphere and in the theta power at the frontal region of both hemispheres (p<0.05). It is concluded that L. angustifolia aroma has effects on decreasing an awakening status related-brain wave and increasing the sleep status related-brain waves in the male adults with good sleep quality, and has also effects on increasing the sleep status related-brain waves in the male adults with poor sleep quality.

• Journal of Life Science
• /
• v.22 no.8
• /
• pp.1077-1084
• /
• 2012

This study investigated the effects of Origanum majorana essential aroma therapy on electrical activity in the brain as evaluated by an electroencephalogram (EEG). The subjects were 29 healthy female young adults, and their sleep quality was assessed by using the Pittsburgh Sleep Quality Index. EEG electrodes were attached at the frontal, temporal, occipital, and parietal lobes according to the international 10-20 system. Subjects were exposed to organic Origanum majorana essential aroma (50 ${\mu}l$) for a period of 3 minutes each before, during, and after aromatherapy. Subjects with good sleep quality showed that Origanum majorana essential aroma increased the theta power at the frontal and temporal lobes of both cerebral hemispheres, the left parietal lobe, and the right occipital lobe. Furthermore, Origanum majorana essential aroma decreased the alpha power at the left occipital lobe and the beta power at the right temporal lobe. On the other hand, subjects with poor sleep quality showed an increase in the theta power at the temporal lobe of both cerebral hemispheres and a decrease in the alpha power at the left parietal lobe by Origanum majorana essential aroma therapy. It is concluded that Origanum majorana essential aroma therapy diminishes the state of wakefulness in the brain; alpha and beta powers were both decreased in the subjects with good sleep quality, but only alpha power was decreased in the subjects with poor sleep quality. Moreover, Origanum majorana essential aroma therapy has a sleep-inducing effect in both subjects with good sleep quality and poor sleep quality.

• Sleep Medicine and Psychophysiology
• /
• v.5 no.1
• /
• pp.45-53
• /
• 1998

Objectives : The change of sleep patterns commonly occurs in association with the pregnancy. This study was to investigate sleep habits during the course of normal pregnancy. Methods : Sleep habits questionnaire was administered to healthy women in their first trimester(TR1) of pregnancy and then the same questionnaire was repeatedly administered during their second(TR2) and third(TR3) trimesters. The following aspects were assessed : patterns of night sleep, daytime status, sleep posture, reasons for sleep alteration, and the experience of any particular parasomnias, as well as sleep problem-related treatment or medication. Data analysis was based on 26 women who maintaind good health throughout their pregnancy and completed the questionnaire three times. Results : In comparisons between each trimester and non-pregnant state, total night sleep time, daytime tiredness, and sleepiness were significantly increased in all trimesters. Sleep latency was significantly decreased in TR1 and TR2, but not in TR3. In addition, refreshed feeling on waking the following day was significantly decreased and the number of awakenings during night sleep was significantly increased in TR3, but not in TR1 and TR2. In comparisons between trimesters, there was a significant increase in sleep latency, daytime sleepiness and the number of awakenings during night sleep and a significant decrease in refreshed feeling on waking the following day in TR3 compared to TR1 and TR2. Over the course of pregnancy, the rate of lateral position during sleep was gradually increased and all the pregnant women took the lateral sleeping posture in TR3. The major reasons for sleep pattern alteration were nausea, vomiting and heartburn in TR1, urinary frequency, fetal movement and ache in hips in TR2, and urinary frequency, fetal movement, cramp in legs and backache in TR3. Conclusion : These findings are expected to be useful for educating pregnant women about sleep hygiene. In future studies, the underlying factors and mechanisms regarding sleep patterns during pregnancy will need to be clarified.

• Sleep Medicine and Psychophysiology
• /
• v.25 no.2
• /
• pp.82-91
• /
• 2018

Objectives: Synchronous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has been used to explore sleep stage dependent functional brain networks. Despite a growing number of sleep studies using EEG-fMRI, few studies have conducted network analysis on whole night sleep due to difficulty in data acquisition, artifacts, and sleep management within the MRI scanner. Methods: In order to perform network analysis for whole night sleep, we proposed experimental procedures and data processing techniques for EEG-fMRI. We acquired 6-7 hours of EEG-fMRI data per participant and conducted signal processing to reduce artifacts in both EEG and fMRI. We then generated a functional brain atlas with 68 brain regions using independent component analysis of sleep fMRI data. Using this functional atlas, we constructed sleep level dependent functional brain networks. Results: When we evaluated functional connectivity distribution, sleep showed significantly reduced functional connectivity for the whole brain compared to that during wakefulness. REM sleep showed statistically different connectivity patterns compared to non-REM sleep in sleep-related subcortical brain circuits. Conclusion: This study suggests the feasibility of exploring functional brain networks using sleep EEG-fMRI for whole night sleep via appropriate experimental procedures and signal processing techniques for fMRI and EEG.