Faculty Bibliography

Survey and laboratory evidence suggests several factors affecting sleep-wake patterns of college students. These factors include social and academic demands, diminution of parental guidance, reduction of total sleep time, delayed bedtime, and increased nap episodes. In this study, we examined the problem of falling asleep in school as a correlate of negative moods in this population (N = 294). A multivariate analysis showed significant main effects of sleepiness on mood states based on the Profile of Mood States. Students who fell asleep in school reported higher negative mood states. Significant interactions were observed among sleepiness and age, sex, race, and duration of sleep. Specifically, younger men reported higher negative moods. No interactions were noted for alcohol and marijuana consumption; however, students who fell asleep in school consumed more alcoholic beverages and smoked more than those who did not. Perhaps falling asleep in school could be used as an index that characterizes students who manifest adaptive or psychological difficulty.

The effects of immediate-release melatonin on circadian rest-activity profiles, cognition, and mood were investigated in ten elderly individuals with self-reported sleep-wake disturbances. Melatonin (6 mg), administered 2 hr before habitual bedtime, enhanced the rest-activity rhythm and improved sleep quality as observed in a reduction in sleep onset latency and in the number of transitions from sleep to wakefulness. However, total sleep time was not significantly increased nor was wake within sleep significantly reduced. The ability to remember previously learned items improved along with a significant reduction in depressed moods. No side effects or contraindications were reported by any of our participants during the 10 day trials. These data suggest that melatonin can safely improve some aspects of sleep, memory, and mood in the elderly in short-term use.

Dementia has been associated with circadian rhythm disturbances expressed in several dimensions including body temperature, hormonal concentrations, sleep and wakefulness patterns, and rest-activity cycles. These disturbances may be the result of a dampening in the amplitude of the circadian rhythm. One of the symptoms associated with the aging process has been a decline in the amplitude of the melatonin rhythm. Here, the results of melatonin administration to two patients with Alzheimer's disease are presented. Melatonin administration enhanced and stabilized the circadian rest-activity rhythm in one of the patients along with some reduction of daytime sleepiness and an improvement in mood. The other patient, who was characterized by less cognitive impairment, showed no significant changes associated with melatonin ingestion. Interestingly, the acrophase of rest-activity was delayed for about one hour in both patients. These results suggest that melatonin may have beneficial effects in some patients with Alzheimer's disease.

The EEG photic driving response is a sensitive neurophysiological measure. It has been used to assess drug effects, forms of epilepsy, neurological status of Alzheimer's patients, and physiological arousal. Photic driving also impacts the psychological status of a person by producing increased visual imagery and decreased physiological and subjective arousal. In this study, ten volunteers underwent nocturnal polysomnography followed by six daytime testing sessions. The six sessions consisted of the alpha attenuation test, two visual analog scales for mood, the Stanford Sleepiness Scale, photic stimulation, and the multiple sleep latency test. These tests were administered 2 hours upon awakening and every 2 hours thereafter. The mean mood across the six daytime testing sessions was computed for all mood variables pre- and post-photic stimulation. Significant differences were found for the subjective moods "sleepy," "alert," and "effort." However, no significant differences were found for pre- and post-photic driving for "angry," "irritable," "hungry," "tense," "overall," "happy," "sexual," and "sad." Additionally, all participants reported increased visual imagery during photic driving, as measured by their responses to an imagery questionnaire.

The widespread use of actigraphy has led to the recognition that a number of methodological issues have to be addressed to facilitate an increased acceptability of this relatively new method. These methodological issues include actigraph placement, reliability, and sensitivity, and the phenomenon known as the "first night effect." Our findings have demonstrated that actigraphy is a reliable instrument for assessment of sleep and wakefulness. In addition, actigraph placement and reliability do not constitute a significant methodological problem as no differences were found in all of these studies. We have also observed no first-night effects associated with sleep-wake monitoring with actigraphy.

Decades of empirical observations have established the validity of actigraphy primarily in individuals without sleep disorders. Methodological problems encountered thus far coupled with the widespread use of actigraphy signal the need for concentrated efforts to establish a consensus regarding scoring procedures. Currently available scoring methods show less reliability in clinical populations. To address these issues two validation studies were conducted: one for individuals without sleep disorders and the other for patients diagnosed with insomnia. The results of these two studies using the Actigraph Data Analysis Software as the scoring method have shown that the described system is fairly precise. It can be used for actigraphs with different features and mode of operation and is applicable to individuals with insomnia. These findings corroborate previous research showing that actigraphy is a valid instrument for assessment of sleep and wakefulness.

Current evidence has shown that, overall, actigraphy is an excellent tool for unobtrusive documentation of sleep/wake activity in normal individuals. However, a number of methodological issues remain to be resolved to warrant its use in clinical research. In this paper, we report the results of a study aimed at the development of a new scoring software that can accurately identify sleep and wakefulness. Using total sleep time as an index of comparison, the software was optimized on a calibration sample and prospectively tested on a validation sample. A strong correlation coefficient (r = 0.93, p < 0.008), with an average discrepancy value of 10 minutes, was observed for the calibration sample. The application of the optimal software to the validation sample revealed an even higher correlation coefficient (r = 0.97, p < 0.0001), with an average discrepancy value of 12 minutes.