The developmental feature of the sleep problems in adolescence : The approach for the application to educational stage

To clarify the actual feature of the sleep problems in adolescence from the points of view sleep loss, circadian rhythm, and development, the survey for five years was performed on 523 students in a College of Technology. The survey results were analyzed in regard to the Sleep Habits Scales and the Life Habits Scales. These scales were (1) Long sleeper-Short sleeper, (2) Good sleeper-Poor sleeper, (3) Sleep phase advanced type-Sleep phase delayed type, (4) Morningness-Eveningness, (5) Regnlar sleeper-Irregular sleeper, (6) Sleep satisfaction type-Sleep dissatisfaction type. Sleep length was shortened with advancements in grade. The irregularity and the delay of sleep phase increased with advancements in grade. Furthermore, approximately 5-10 percents of each grade student were screened as the persons who had some sleep disturbances or sleep problems. The present results suggest that the sleep problems (irregularity and phase delay) of adolescence apt to increase with advancements in grade

Changes of hypnagogic imagery and EEG stages

The aim of this study is to investigate the relationships between hypnagogic imagery and EEG stages. According to Hori, et al. (1994), the hypnagogic EEGs was classified into 9 stages, those were 1) alpha wave train, 2) alpha wave intermittent (>50%), 3) alpha wave intermittent (<50%), 4) EEG flattening, 5) ripples, 6) vertex sharp wave solitary, 7) vertex sharp wave bursts, 8) vertex sharp wave and incomplete spindles, 9) spindles. EEGs (Fz, Cz, Oz) were recorded from light off to 90 min elapsed. The subjects pressed a button when pip tones (1000Hz, 50dB, max duration : 5s, ISI : 50-70s) were presented, and reported their psychological experiences. The results showed that reaction time prolonged with progress of the hypnagogic EEG stages. The hypnagogic imageries mostly experienced when theta waves or a vertex sharp wave occurred. These imageries were almost composed of visual imageries (88%), involved 1) persons (37%), 2) static objects (21%), 3) landscapes (10%), and 4) colored patterns (8%). These imageries changed from waking daydreams to hypnagogic imageries or NREM sleep dreams as a function of progress of hypnagogic EEG stages

Psychophysiological study of arousal modulation model of music

Music is known to have both stimulatory and sedative effects. We investigated whether music modulated the arousal level. EEGs, EOG, SPR, plethysmograph, and skin temperature were recorded on 14 students (mean=22.1 yrs) during sessions of (1) baseline (pre-rest), (2) preparations of arousal (task or rest), (3) music (stimulative or calm), (4) after-effects (post-rest). Seven subjects, who were assigned to the high arousal group were preparatively increased their arousal level by the cognitive task before the music session. Other seven subjects, who were assigned to low arousal group were instructed to relax in the rest period before music session. In the high arousal group, the EEG amplitude in alpha 3 and beta bands were significantly higher in the task session than in the baseline session. In the music session the amplitude in alpha 3 and beta bands were decreased in both the stimulative and the calm music conditions. The results show that the music may induce the de-arousing effects on the subjects in the high arousal states. This tendency was clear in the calm music rather than in the stimulative music. In the low arousal group, on the contrary, the amplitude in alpha 2 band was significantly lower in the rest session than in the baseline session. In the music session the amplitude in alpha 1 band increased in both the stimulative and the calm music conditions, suggesting that the music may induce the arousing effects on the subjects in lower aroused states. This tendency was more remarkable in the stimulative music rather than in the calm music. These results support a hypothesis that the music effects on the arousal mechanisms and the different type of music induces a different effect on the arousal level

Positive effects of the presence of music on vigilance performance : The basic study of music for equipment of an educational environment

The present study explores the effects of music on the performance of vigilance task. ECG and SCL were recorded on 40 students during periods of (1) baseline, (2) pre-music, (3) music (control/musical stimulus), and (4) post-music. Twenty subjects, who were assigned to the forward replay music group, participate in the control and the music sessions. They listened to ordinary music during the music period in the music session. The other twenty subjects were assigned to reverse replay music group. They listened to the reverse playback of music, using in the forward replay group. Two types of musical stimuli increased the hit ratio in comparison with control session and maintained the hit ratio at a high level. This tendency was clear in forward replay music rather than in reverse replay music. Similar changes of performance, two types of musical stimuli increased SCL and HR. However, the positive changes of scores on mood scale (increased in vigor vs decreased in depression and fatigue) were found in only the forward replay group. These findings indicated that the music facilitated the vigilance peformace. Furthermore, it is implied that the effects on music on vigilance consisted of two functions, one of which increases vigilance level depending on quantity of musical stimuli, and the other regulates the subjects' mood in a positive direction depending on the connotative meaning of musical stimuli

Hypnagogic EEG stages and polysomnogram

The aim of this study is to show the polysomnogram of hypnagogic period. Sixteen subjects slept for two nights. Their EEGs (Fz, Cz, Pz, Oz), horizontal and vertical EOGs, submentalis EMG, thoracic and abdominal respiration were recorded. They pressed a button when pip tones (1000Hz, 50dB, max duration : 5s, ISI : 30-90s) were presented, and reported their psychological experiences, According to Hori et al. (1994), the hypnagogic EEGs just 5s before the pip tones were classified into 9 stages, as follows; 1) alpha wave train, 2) alpha wave intermittnet (%α>50), 3) alpha wave intermittent (%α<50), 4) EEG flattening, 5) ripples, 6) vertex sharp wave solitary, 7) vertex sharp wave bursts, 8) vertex sharp wave and incomplete spindles, 9) spindles. The polysomnograms of these 9 EEG stages were presented. Physiological, behavioral and subjective changes were observed as a function of hypnagogic EEG stages

Generator sources of 14Hz/12Hz sleep spindles during stage 2 sleep

The present study investigated the equivalent dipole sources of two types of human sleep spindles (14 and 12Hz) during stage 2 sleep. Dipole analysis of the 21 scalp EEGs (Fp1,Fp2,F3,F4,C3,C4,P3,P4,O1,O2,F7,F8,T3,T4,T5,T6,Fpz, Fz, Cz, Pz and Oz) was carried out on ten male subjects (20-26yr). This study showed that sleep spindle can be represented by single equivalent dipole. For both 14 and 12Hz sleep spindles, the equivalent dipole sources appeared in center of the brain. The orientation of the equivalent dipole of 14Hz sleep spindle was in the centro-parietal direction, while that of 12Hz sleep spindle was in the frontal direction. These results suggest that both types of sleep spindle activities are generated in the thalamus, and the thalamo-cortical pathway are different for the two types of sleep spindles

Attitude toward Daytime Nap in the Aged

This study investigated attitudes toward daytime nap on the 470 aged people (M=73.7 years old) by two measures. One measure was 13 items-scale on an attitude toward positive effects of daytime nap (AE). Another measure was 15 items-scale on an attitude toward napping person (AP). A factor analysis confirmed that AE consists of 3 dimensions of effects of daytime nap : effects on work, physical effects, and psychological effects, and that AP consists of 2 dimensions of beliefs about napping person : belief about taboo and belief about rest. The survey results clearly show that most of the aged people have positive attitudes toward daytime nap. So far, it has been proposed that there are social pressures which inhibit daytime nap in Japanese country and that daytime nap in the aged people is harmful to their health. The results of present study were, however, inconsistency with these previous issues

Effects of ultradian variation on smoking behavior

The purpose of this study is to examine the enhancement model of smoking maintenance, which has been proposed by Mangan & Golding (1978). We studied the relationships of the ultradian variations among the smoking behavior and sleepiness. The results were as follows. (1) The results of the time series analysis revealed that several spectral peaks were obtained in day time fluctuations of smoking behavior, sleepiness, mood and task performance. The average peak frequency for each parameter distributed in the range of 10 to 14 cycle/day (c/d : See Fig. 3-6). (2) The significant correlations were obtained between the parameters of the smoking behavior (frequency of puffing and VAS score of need for smoking) and the daytime sleepiness (VAS score). The significant average correlation coefficients between smoking need and sleepiness were observed (See Table 2). In general, present results agree with the enhancement model of smoking maintenance

Effects of self-awakening on sleep structure and sleep inertia during or after the short nap

本研究の目的は, 短時期仮眠における自己覚醒の企図が, 睡眠構造および睡眠慣性に及ぼす影響を検討することである。実験は, 自分で目覚める自己覚醒条件と,実験者が強制的に覚醒させる強制覚醒条件の参加者内比較計画で行った。覚醒水準の評価には, 聴覚オドボール課題により算出された事象関連電位のP300と課題正反応時間,Visual Analog Scale (Vas)による主観的覚醒水準評定値を用いた。睡民構造の詳細な検討のために,Hori et al. (1994)の脳波段階判定(9段階)を用いた。実験参加者は,大学生・大学院生14名であった。実験参加者は,4minの聴覚オドボール課題と1minのVAS評定からなる計5分間の課題を2セッション(計10分間)行った。その後,約20分間の仮眠をとり,覚醒後に同様の課題を6セッション(計30分間)行った。本研究の結果,自己覚醒を用いて出眠した場合には,強制覚醒の場合と比べて,P300振幅は大きくなり,主観的眠気は低減していた。また,自己覚醒を意図した場合には,睡眠構造が浅くなる傾向があった。これらの結果から,強制覚醒よりも自己覚醒をもちいた仮眠が,午後の眠気を抑える方法として有効であることが示された。(518語)The aim of this study was the investigation of the effects of self-awakening on sleep inertia and sleep structure at the short nap. The participants were take part in the self-awakening and forced-awakening condition. In the self-awakening condition, participant woke up by themselves. However, experimenter in the forced-awakening condition waked participants up. The physiological arousal level and subjective sleepiness were evaluated by P300 of the event related potential (ERP) and visual analog scale (VAS). For evaluating the sleep structure elaborately, we used the Hori's EEG stages. Participants were 14 healthy college students. They participated the task consist of auditory oddball task (4 min) and VAS rating (1 min). Participant carried out two sessions (10 min) before the nap. Thereafter, they took a short nap around 20 min. After the nap, they carried out six sessions (30 min) again. P300 amplitude was lower after forced -awakening than self-awakening. On the other hand, subjective sleepiness was greater after the forced-awakening than self-awakening. And sleep structure was deeper during the forced-awakening than self-awakening. Those results suggest that a short nap with self-awakening was more useful than with forced-awakening

Relationship of daytime activity and nocturnal sleep in the elderly

This study investigated the relationship between the level of daytime activities and nocturnal sleep in the elderly using the wrist actigraph and ambulatory polysomnograph (PSG) system. Ten male and ten female subjects (mean age ± SE=73.2 ± 1.62 years; range 65-81 years) participated in this study. The level of daytime activity was positively correlated with the sleep efficiency of the subsequent night. Based on the amount of daytime activity level on the PSG recording night, 6 participants were selected as the high activity group, and other 6 participants selected as the low activity group. The duration of slow wave sleep (SWS) was significantly longer for high activity group than those for low activity group. Moreover, the duration of wake after sleep onset was longer for low activity group than those for high activity group. The results imply that increment the time of physical activities may improve the quality of nocturnal sleep for the elderly subjects