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As part of a larger project on the effects of benzodiazepine and caffeine on daytime sleepiness, performance and mood, this study examined the relationship among the Multiple Sleep Latency Test, lapses during a tapping task, a Visual Analog Scale, and the Stanford Sleepiness scale. Subjects were 80 male, adult nonsmokers aged 20.3 ± 2.7 years. The Multiple Sleep Latency Test, Stanford Sleepiness Scale, and the Visual Analog Scale were obtained at two-hour intervals beginning at 0700 h and ending at 1700 h. The tapping task (lapses) was administered each day at 0600 h, 1000 h, and 1400 h. A lapse was a 3-s or greater pause between taps. Correlations between the Multiple Sleep Latency Test and subjective (Visual Analog Scale and the Stanford Sleepiness Scale) measures were significant at 0600 h, but became nonsignificant as the day progressed. Correlations between lapses and the two subjective measures were generally nonsignificant. The two objective measures were significantly correlated in the total group but not in all treatment groups. The subjective measures were significantly correlated in the total sample and in each treatment group. This study reaffirms the importance of time of day when measuring sleepiness, and suggests that subjective and objective measures may measure different aspects of sleepiness. [ABSTRACT FROM AUTHOR]

Thirty-live subjects from two independent studies were awakened at EEG-defined periods during the night with 1000 Hz ascending tone series. Awakenings were made five to eight times per night during stage 2, stage 4, or REM sleep over a series of nights in good and poor sleepers. Reliability was assessed within stage, within night, between stages, and between nights. Good and poor sleepers did not differ in either depth of sleep or reliability of arousal threshold and were thus pooled in the analyses. From night to night, the most consistency was seen in stage 4 (r=.74), although REM reliability (&rmacr;1 = .49) and stage 2 reliability (&rmacr; 1 = SO and &rmacr; 1 = .69 in the two respective studies) estimates were also greater than zero. Early sleep onset and morning arousals were more variable. Reliability estimates on arousal thresholds taken within the same night for stage 2 were r= .64 and &rmacr;1 = .77 for the two studies and r=.96 for REM. The depth of sleep was not correlated with awake auditory threshold. It was concluded that five or six carefully placed arousals could give a good estimate of an individual's usual arousal threshold. [ABSTRACT FROM AUTHOR]

The response hierarchy of EEG and autonomic variables to tones of increasing intensity was studied during waking and sleep stages 2, REM, and SW (3 & 4 combined). Tones of 1000 Hz (5 sec duration, 55 sec ISI) were presented to 35 young adult male subjects. During waking, the tones began below awake auditory threshold and increased by 5 db until a motor response (button press) was made. During sleep, tones began at awake threshold and went to arousal threshold, i.e., motor response and/or an EEG change indicative of arousal. Changes in EEG, finger pulse amplitude, heart rate, skin potential, skin resistance, and respiration period were measured for each stimulus and were compared to a pseudostimulus response scored 25 sec prior to the actual stimulus. In the awake state, statistically significant responses (p < .05) were found for EEG, finger pulse, heart rate earlydeceleration, skin potential, and skin resistance to the tone at awake threshold, but not to tones at lesser db levels. During sleep, significant EEG responses were present to tones 30-25 db below arousal threshold, finger pulse 20-15 db below, and heart rate acceleration 20-5 db below. Significant skin potential, skin resistance, and motor responses were seen only at arousal threshold. Thus, in sleep, in contrast to waking, there were clear responses to stimuli below the arousal threshold, and there was definite ordering of the appearance of the various responses: EEG preceded the cardiovascular, with electrodermal and motor occurring only at arousal. This order was constant over sleep stages. Arousal thresholds were very similar across sleep stages in day sleepers (ap. proximately 35 db above awake threshold). The threshold during stage 2 for night sleepers was about 15 db lower than that for day sleepers. [ABSTRACT FROM AUTHOR]

The question is asked, can the same visceral changes occur in different states of consciousness. A survey of EEG and autonomic activity found in the awake state and during the various stages of sleep leads to the conclusion that the question must be affirmatively answered. The conclusion is reached that EEG and autonomic activity cannot be used to define states of consciousness. The state of consciousness of the subject must first be known before the physiological significance and possible behavioral meaning of the EEG and autonomic responses can be inferred. [ABSTRACT FROM AUTHOR]

During stage REM sleep, eye movements were found to be distributed in discrete bursts of rapid eye movement (REM-bursts). REM-burst time averaged approximately 10 percent of stage REM sleep and the rate within a subject was consistent from epoch-to-epoch and night-to-night. Consistent subject biases in eye movement direction were also found. Within subject correlations were obtained between REM-burst time and autonomic activity. Significant positive correlations were found for respiration rate and number of finger pulse responses. There were positive but insignificant correlations with electrodermal activity, heart rate and decreases in respiration amplitude. Autonomic variability was not significantly associated with REM-burst time. [ABSTRACT FROM AUTHOR]

Spontaneous electrodermal activity (EDA) (galvanic skin response [GSRI and skin potential response [SPR]) was recorded during daytime sleep and nighttime sleep. During all sleep, spontaneous EDA occurred most frequently during stages 3 and 4 (slow wave sleep) and least frequently during stage 1 (rapid eye movement [REM] and non-REM). This pattern was consistent over 3 nights of sleep. There was no relation between waking and sleeping spontaneous EDA. The spontaneous EDA during slow wave sleep significantly exceeded that during waking. During sleep, spontaneous SPRs often occurred without spontaneous GSRs. [ABSTRACT FROM AUTHOR]

Active eccrine sweat gland activity was measured in 30 Negro and 29 Caucasian male subjects to determine whether sweat gland activity was a possible factor in racial differences in skin conductance. Basal skin conductance, heart rate, respiratory rate, finger skin temperature and blood pressure were also obtained. Negro Ss had significantly lower skin conductance but no other significant physiological differences were found. While there was no significant difference in number of active sweat glands between the races, the intragroup relationship between sweat gland count and skin conductance was significantly higher for the Negro Ss. The two groups did not differ in number of nonspecific galvanic skin responses (GSRs) but the Caucasian Ss showed greater change in skin conductance to an initial tone stimulus. When differences in prestimulus levels were taken into account, the group differences in response to stimuli were no longer significant. [ABSTRACT FROM AUTHOR]

Lockhart and Grings (1963) have suggested that a previous analysis of galvanic skin response (GSR) conditioning by Stewart, Stern, Winokur, and Fredman (1961) failed to establish its major point since it neglected to include a pseudoconditioning control for sensitization effects. In the present paper an experiment is reported in which this control was included, and it was found that the initial report of Stewart et al. was supported. That is, then was significant evidence of a conditional anticipatory GSR which was not due to sensitization effects. [ABSTRACT FROM AUTHOR]

In three independent studies using 105 subjects, regression analysis was used to determine which autonomic variables are most affected by the "law of initial value" and whether the "law" always acts in the same way, i.e. are large respouses always associated with low prestimulus levels of activity and conversely. For GSR, heart rate, respiration rate, and skin temperature it was found that the slope of the regression of stimulus level on prestimulus level (b[yxsub]) distinguishes these four ANS variables. The conclusion is that the LIV operates as one would predict for heart rate and respiration rate responses, with values of b[yxsub] less than one; but that the law does not operate for skin (finger) temperature responses, since b[yxsub] is consistently very close to one. For GSR responses expressed in terms of conductance, the converse of the LIV seems to hold, with b[yxsub] consistently greater than one. [ABSTRACT FROM AUTHOR]

Alert and drowsy subjects (by EEG criterion) were compared in two experiments for psychophysiological habituation of the orienting response. Subjects in Experiment I (N = 30) received 10 presentations of a doorbell-type buzzer, and in Experiment H (N = 69) they received 10 presentations of a 500-cps tone. Comparisons were made of: (1) galvanic skin response (GSR); (2) spontaneous GSRs between trials; (3) heart rate (HR) responses; (4) finger vasoconstriction responses; (5) finger temperature responses; and (6) respiration. Results showed that there were no differences between groups in GSR; however, the drowsy group showed consistently fewer spontaneous GSRs. Cardiovascular response measures of the drowsy groups showed consistently and significantly greater responses on the later trials and, therefore, no habituation of these responses. This finding was more consistent for HR than vasomotor response. In the discussion of these results, the authors were able to rule out several possible explanations, hence the reasons for this differential autonomic response are as yet unknown. [ABSTRACT FROM AUTHOR]

Heart rate responses evoked by a 3-sec auditory stimulus were averaged within stages of sleep for five subjects. Although there were some individual differences, the evoked HR response is generally diphasic, with the peak of the acceleratory component occurring on the fourth post-stimulus beat and the trough of the de- celeratory component occurring on the 10th post-stimulus beat. Unlike other variables, which are depressed during the rapid eye movement (REM) stage, the HR response tends to be larger during the REM stage than during other stages of sleep. The size of the response is not appreciably affected by time of night, since HR Is non-habituating during sleep, but is affected by the respiratory cycle phase, being largest when the stimulus occurs during inspiration or the period imme- diately prior to inspiration, and smallest when the stimulus occurs during the expiratory phase. [ABSTRACT FROM AUTHOR]

Thirty young male volunteers participated in a study of sustained continuous performance using a variety of computer-based tasks. After 6 hrs of recorded sleep, 10 subjects were assigned to perform. continuously for 42 hrs without break. Three of these subjects were unable to complete the 42-hr assignment, and 8 of the 10 suffered psychological events such as hallucinations and disorientation. Ten subjects permitted six 1-hr naps over the 42 hrs performed more successfully than those allowed no sleep. Ten subjects permitted one 6-hr rest period performed best of all. Fatigue effects appeared after 6 hrs. Time-of-day (circadian) effects were at times stronger than fatigue. [ABSTRACT FROM AUTHOR]