The Stanford Sleepiness Scale (SSS) is a self-rating scale which is used to quantify progressive steps in sleepiness. The present study investigated whether the SSS cross-validates with performance on mental tasks and whether the SSS demonstrates changes in sleepiness with sleep loss. Five college student Ss were given a brief test of memory and the Wilkinson Addition Test in 2 test sessions and The Wilkinson Vigilance Test in 2 other sessions spaced throughout a 16-hr day for 6 days. Ss made SSS ratings every 15 min during their waking activities. On night 4, Ss underwent all night sleep deprivation. On all other nights, Ss were allowed only 8 hrs in bed. Mean SSS ratings correlated r= .68 with performance on the Wilkinson Tests. Discrete SSS ratings correlated r= .47 with performance on the memory test. Moreover, mean baseline SSS ratings were found to be significantly lower than corresponding ratings of the deprivation period.

Quantification of sleepiness: a new approach.

The hyperarousal model of insomnia: A review of the concept and its evidence

Sleep deprivation: Effect on sleep stages and EEG power density in man

Nearly 200 studies have examined the impact that either acute or long-term exercise has upon cognition. Subsets of these studies have been reviewed using the traditional narrative method, and the common conclusion has been that the results are mixed. Therefore, a more comprehensive review is needed that includes all available studies and that provides a more objective and reproducible review process. Thus, a meta-analytic review was conducted that included all relevant studies with sufficient information for the calculation of effect size (N = 134). The overall effect size was 0.25, suggesting that exercise has a small positive effect on cognition. Examination of the moderator variables indicated that characteristics related to the exercise paradigm, the participants, the cognitive tests, and the quality of the study influence effect size. However, the most important finding was that as experimental rigor decreased, effect size increased. Therefore, more studies need to be conducted that emphasize experimental rigor.

/pdf/the-influence-of-physical-fitness-and-exercise-upon-11zj3fe3mn.pdf

The Influence of Physical Fitness and Exercise upon Cognitive Functioning: A Meta-Analysis

Converging evidence and new research methodologies from across the neurosciences permit the neuroscientific study of the role of sleep in off-line memory reprocessing, as well as the nature and function of dreaming. Evidence supports a role for sleep in the consolidation of an array of learning and memory tasks. In addition, new methodologies allow the experimental manipulation of dream content at sleep onset, permitting an objective and scientific study of this dream formation and a renewed search for the possible functions of dreaming and the biological processes subserving it.

https://www.cogsci.ucsd.edu/~pineda/COGS175/readings/Stickgold.pdf

Sleep, learning, and dreams: off-line memory reprocessing

: Young male Naval volunteers were denied normal nocturnal sleep and maintained on a 60-min treatment-160-min testing schedule for 40 consecutive hours Ten subjects bicycled, 20 subjects controlled EEG activity during bedrest, and 10 subjects napped Eight measures of addition, auditory vigilance, mood, and oral temperature were obtained The Bedrest group showed significant impairment on all eight measures, and thus, gave no support to the forced rest theory of sleep function The exercise group was worse than the Nap and Bedrest groups for all measures In spite of fragmented, reduced sleep (about 37 hours per 24 hours), the Nap group had no impairment on six of the measures The results suggest that exercise increases the impairment due to sleep loss, and naps reduce or remove this impairment

Effects of Exercise, Bedrest and Napping on Performance Decrement During 40 Hours

Spectral analysis of the EEG of dominant and non-dominant alpha subjects during waking and sleeping

Immediate recall of word lists showed significant impairment after one night of sleep loss. Since S was required to write down each word immediately after its presentation, the deficit was not due to failure of sensory registration. With 24-hr. delayed testing, a picture-recognition test did not show significant deficit after one night of sleep loss. Performance on this test was impaired, however, after a night of recovery sleep. These results imply that moderate sleep loss causes deficit in formation of the memory trace rather than in storage or retrieval functions and that this effect is probably independent of the physiological lapses (brief periods of sleep) which affect vigilance and sensory registration.

Some effects of sleep loss on memory.

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 responses 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 (Byx) 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 Byx less than one; but that the law does not operate for skin (finger) temperature responses, since Byx is consistently very close to one. For GSR responses expressed in terms of conductance, the converse of the LIV seems to hold, with Byx consistently greater than one. Law of initial value (LIV), Autonomic nervous system. (ANS)

Differential effect of the law of initial value (liv) on autonomic variables.

Twelve young (17–21 yrs) male Navy recruits volunteered for a sleep loss study. After 4 baseline days, the Ss were completely deprived of sleep for 2 days and nights. Next followed an experimental phase of 2 days and nights after which all Ss received 2 nights of uninterrupted sleep.



During the experimental phase, the 4 Ss in the REM-deprived group were aroused whenever they showed signs of REM sleep. The 4 Ss of the stage 4-deprived group were aroused whenever they showed signs of entering stage 4 sleep, and the 4 Ss of the Control group had uninterrupted sleep.



All tests (speed and accuracy of addition, speed and accuracy of self-paced vigilance, errors of omission in experimenter paced vigilance, immediate recall of word lists, and mood) showed significant impairment after the first night of complete sleep loss. But during the experimental (sleep-stage-deprivation) and recovery phases, all three groups showed equal rates of recovery.



Depriving the S of stage REM or stage 4 during recovery sleep does not affect the recuperation rate. Frequent arousals (50–100 per night) also do not impair recovery. The amount of sleep is probably more important than the kind of sleep.

Ardie Lubin

Papers

Effects of Exercise, Bedrest and Napping on Performance Decrement During 40 Hours

Spectral analysis of the EEG of dominant and non-dominant alpha subjects during waking and sleeping

Some effects of sleep loss on memory.

Differential effect of the law of initial value (liv) on autonomic variables.

The Recuperative Effects of REM Sleep and Stage 4 Sleep on Human Performance After Complete Sleep Loss: Experiment 1