Subjective sleepiness

Figure 7 PVT reaction times prior to the first uncontrolled sleep attack during total sleep deprivation. Fourteen subjects completed 42 hr of total sleep deprivation and completed a 20-min PVT every 2 hr (represented by the closed circles) 19 subjects completed 88 hr of total sleep deprivation and completed a 10-min PVT every 2 hr (represented by the open circles). The number of test bouts (up to 30) prior to an uncontrolled sleep attack (failure to respond for 30 sec on the PVT) is represented on the bottom abscissa, with time prior to the sleep attack (up to 6 min) represented on the top abscissa. In both subject groups a progressive decline in performance on the visual PVT was evident within minutes of an uncontrolled sleep attack on console. This study also demonstrated an increase in subjective sleepiness (measured using the Stanford Sleepiness Scale) in the test bouts prior to the one in which the first sleep attack occurred. Taken together, these findings suggest that even a very sleepy subject cannot fall asleep while performing computerized tasks without some levels of awareness. (From Ref. 95.)...

Perhaps the most common type of verbal report used in sleep deprivation studies is a measure of subjective sleepiness. Subjective sleepiness is generally assessed by self-report scales (see also Chap. 1), such as the Stanford Sleepiness Scale (19), the Epworth Sleepiness Scale (20), visual analog scales (21), and the vigor and fatigue subscales on the Profile of Mood States (POMS Educational and Industrial Testing Service, San Diego, CA). These measures have been used in studies on the effects of sleep deprivation (22-25), shift work (26-28), and sleep disorders (29,30). 

A number of studies have investigated the potential of melatonin to alleviate the symptoms of jet lag. Melatonin has been found to be effective in 11 placebo-controlled studies in reducing the subjective symptoms of jet lag such as sleepiness and impaired alertness (Arendt 2005). The most severe health effects of jet lag occur following eastbound flights, since this requires a phase advancement of the biological clock. In a recent study, phase advancement after melatonin administration (using 3 mg doses just before bedtime) occurred in all 11... 

Sleepiness in narcolepsy has also been considered a subjective phenomenon associated with the instability of boundaries between behavioral states and the constant intrusion of sleep episodes into wakefulness. Under baseline conditions, 0X2R, orexin , and orexin/ataxin-3 transgenic mice have normal amounts of wakefulness and non-REM sleep during the light and dark phases and over 24 h (Chemelli et al, 1999 Hara et al, 2001 Mochizuki et al, 2004 Willie... 

Capsule given orally from B package. Subject seems to be very sleepy and tired but continues to walk around room and mumbles continuously. Incontinent of urine. Clothes changed. 

Ingestion of 5-12 g of hydroquinone has been reported to be fatal. In one nonfatal case of hydroquinone ingestion of approximately 1 g, tinnitus, dyspnea, cyanosis, and extreme sleepiness were observed. Although acute, high-dose oral ingestion produces noticeable central nervous system (CNS) effects in humans, no effects have been observed in workers exposed to lower concentrations in actual industrial situations. No signs of toxicity were found in subjects who ingested 3 00-500 mg hydroquinone daily for 3-5 months. ... 

Tranylcypromine, another MAOl, has also been shown to be effective in the treatment of social phobia. Versiani et al. [1988] implemented a 1-year, open trial of tranylcypromine in 32 subjects. Daily doses ranged from 40 to 60 mg. Twenty-nine subjects met criteria for completion of this study. Marked improvement was noted in 62% of patients [18/29], and moderate improvement was shown in 17.2% [5/29]. Six of the 29 subjects were deemed nonresponders [20.6%]. The most commonly cited side effects were orthostatic dizziness [75.5%], insomnia [44.7%], and daytime sleepiness [41.3%]. 

The initial study of clonazepam in social phobia conducted by Versiani et al. [1989] showed an overall benefit of the drug. This 8-week, open trial of 40 subjects displayed statistically significant lowering of scores on the efficacy variables, which included the Clinical Global Improvement and Severity Scales [Guy 1976], Liebowitz Social Anxiety Scale [liebowitz 1987], Hamilton Anxiety Scale [M. Hamilton 1959], and the Sheehan Disability Scale [D. V. Sheehan 1986]. The mean dose of clonazepam was 3.9 mg/day [SD 0.5 mg]. Subjects in this study reported high rates of side effects, including sleepiness [67.5%], loss of libido [67.5%], and memory problems [35%]. 

Most antipsychotic drugs cause unpleasant subjective effects in nonpsychotic individuals. The mild to severe EPS, including akathisia, sleepiness, restlessness, and autonomic effects are unlike any associated with more familiar sedatives or hypnotics. Nevertheless, low doses of some of these drugs, particularly quetiapine, are used to promote sleep onset and maintenance, although there is no approved indication for such usage. 

This process is further favored by biasing the internal expectancy set as, for example, when the subject is not only sleepy but apprehensive. Conscious efforts to maintain vigilance, even under strenuous conditions, may be unavailing because of internal expectancy (let s call it priming) if the perceptual apparatus becomes both a motive force and a shaper of false perception. 

Other dissociations are the altered states of consciousness seen in hypnosis and hysteria that have been likened to sleepwalking. The word somnambulism denotes not only sleepwalking per se, it also denotes those hypnotic trance states that impose a kind of sleepiness on susceptible subjects during waking. For Pierre Janet (and for Charcot, Freud, and the rest), this was the very essence of dissociation. The psychoanalytic model ascribed the same repressed libidinal wishes to the hypnotic somnambulist that it found to be the root cause of all dreaming. The fact of the matter is that any coordinated behavior is likely to invite the ascription of motive. If the subject is unconscious or nonconscious, then the motive must be unconscious too. 

No depth. Five hypnotic subjects and the simulator completed this condition. All found it unpleasant, and the outside evaluator raised the question of schizophrenia in each instance. One showed disturbances of gait, posture, and movement, similar to that seen in catatonia a second felt that the people around him were inhuman robots, plotting against him one subject showed marked withdrawal and sleepiness, and two showed inappropriate emotional behavior along with regression. The simulator also became withdrawn and hostile. 

EDS, of any cause, is common. The exact prevalence is difficult to determine, since sleepiness is not an all-or-none phenomenon, but it can be estimated. Using a subjective scale, the Epworth Sleepiness Scale (ESS), about 26% of normal subjects score >10 and about 2.5% score >15 (1). Using an objective method, the MSLT, about 32% of subjects score in the severely sleepy range (2). In addi-... 

A visual analog scale can be used for sleepiness, and is similar to what is commonly used in the assessment of pain. It typically uses a horizontal line (e.g., 10 cm), on which subjects can draw a vertical mark indicating their degree of alertness or sleepiness. In theory this provides a continuous measure, rather than a discrete integer. This is probably overly simplistic to measure a multidimensional and complex phenomenon like sleepiness. It does not add much to simple history taking, and is overall rarely used (3,4). 

The Stanford Sleepiness Scale (SSS) (5) was the most commonly used scale for sleepiness prior to the ESS. It seems to reliably quantify sleepiness in healthy persons (5,6), but its usefulness in sleep disorders is less certain. The SSS consists of seven descriptive phrases that describe the subject s state (see Fig. 1), of which subjects must choose the one that best describes how they feel at the time. Thus,... 

The Karolinska Sleepiness Scale (8) is comparable to the SSS. The choice here is among nine descriptive statements (phrases that describe the subject s state). Here the statements specifically refer to how the patient felt in the previous 10 min. 

Other (less specific) scales have also been used as part of the evaluation of EDS. The basic Nordic Sleep Questionnaire (24) is a quantitative measure of subjective sleep complaints not limited to sleepiness. It focuses on events that happen (during sleep or wakefulness), and grades them on a five-point scale from 1 (never) to 5 (almost every day/night). Thus it is best suited for events but not for sleepiness as such. The Sleep Disorders Questionnaire (SDQ) (25) was extracted from another comprehensive questionnaire, the Sleep Questionnaire and Assessment of Wakefulness (SQAW) of Stanford, but is more geared for the diagnosis of specific sleep disorders (e.g., sleep apnea, narcolepsy) than for the evaluation and quantification of EDS. 

It is important for clinicians and researchers alike to know whether they should rely on objective or subjective measures of sleepiness, or both, and how the two types of measures relate to each other. Since sleep latency on the MSLT is considered the gold standard for objective measure and grading of sleepiness, studies have used this as the objective gold standard. However, not all subjective scales have been studied. Several investigators have reported weak or no association between sleep latency and subjective scales such as the Stanford Sleepiness Scale (26-29). The SWAI, or more specifically its EDS subscale, appears to reli-... 

The lack of association, or weak correlation, between subjective scales and objective measures suggests that subjective and objective measures evaluate different aspects of sleepiness. This is the prevailing view (15,30,31,35,36), and it is supported by the association between the ESS, nocturnal sleep latency (on polysomnogram), and respiratory disturbance index (12). 

Akerstedt T, Gillberg M. Subjective and objective sleepiness in the active individual. Int J Neurosci 1990 52 29-37. 

Hamish MJ, Chard SR, Qrr WC. Relationship between measures of objective and subjective sleepiness. Sleep Res 1996 25 492. 

Sangal RB, Mitler MM, Sangal JM. Subjective sleepiness ratings (Epworth Sleepiness Scale) do not reflect the same parameter of sleepiness as objective sleepiness (maintenance of wakefulness test) in patients with narcolepsy. Clin Neurophysiol 1999 110 2131-2135. 

The technique most commonly used for objective evaluation of daytime sleepiness is the Multiple Sleep Latency Test (MSLT). It is composed of a series of naps during which subjects are asked not to resist sleep. The speed of falling asleep on tests across time is the chief outcome of the MSLT, which has achieved widespread acceptance because of its simple, intuitive approach to sleepiness. Hence, the greater levels of sleepiness are indicated by more rapid sleep onsets. Furthermore, the MSLT provides several opportunities to test for sleep-onset rapid-eye-movement (REM) episodes, the primary diagnostic sign of narcolepsy. 

The underlying assumption of the MSLT is that lower scores indicate greater sleepiness and vice versa. A common rubric holds that a daily average score of less than 5 min indicates a pathological level of daytime sleepiness. This level is associated with impaired performance in patients and in sleep-deprived normal subjects (26). Scores of adult normal controls usually range from 10 to 20 min (27). Scores between 5 and 10 min indicate moderate sleepiness, and may or may not be associated with pathological conditions (23). 

The MSLT has been utilized in many studies to examine the effects of sleep deprivation on daytime sleepiness. As described earlier, Carskadon and Dement (11) performed the first MSLT study to test the effects of two nights of sleep loss in six young subjects. The scores fell to about 1 min at 0600 on the first night of sleep loss and remained at similarly low values throughout the sleep loss period. After one night of recovery sleep the scores remained significantly below baseline levels, which were not achieved until after the second recovery night. 

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