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Biomedical subjects

William C Dement

Publications and source records attributed to William C Dement.

9 recordsLinked to original sources
PubMed2006

Armodafinil, the R-enantiomer of modafinil: wake-promoting effects and pharmacokinetic profile in the rat.

Modafinil reduces the excessive sleepiness associated with narcolepsy, obstructive sleep apnea/hypopnea syndrome, and shift work sleep disorder. In rats, modafinil promotes dose-dependent increases in wake duration. The wake-promoting activity of the R-enantiomer of modafinil (armodafinil) was evaluated in WKY rats and compared to the classical stimulant, D-methamphetamine. Electroencephalographic and electromyographic signals were assessed via a tethered cranial implant. Body temperature and locomotor activity were assessed by telemetry via intraperitoneal implant. Rats (n=60, 12 per group) were subjected to one of five parallel treatments: armodafinil at 30, 100 and 300 mg/kg i.p.; D-methamphetamine, 1 mg/kg i.p. and vehicle. Armodafinil and D-methamphetamine increased time spent awake relative to vehicle. Armodafinil-evoked increases in wake duration were dose-dependent and proportional to plasma compound exposure. Induction of wakefulness by D-methamphetamine was associated with an approximately two-fold increase in locomotor activity during the 2-h period immediately following administration relative to vehicle. D-methamphetamine also increased body temperature over the same time interval. The dose of armodafinil (100 mg/kg, i.p.) that was closest to D-methamphetamine in its wake-promoting efficacy did not produce changes in either body temperature or the intensity of locomotor activity relative to vehicle. Acute rebound hypersomnolence, characterized by increases in non-rapid eye movement sleep (NREMS) as a percentage of time and NREMS bout duration and by a decreased frequency of brief awakenings following sleep deprivation, occurred following D-methamphetamine-but not armodafinil-induced wake in this rat model which has been shown to be predictive of human drug responses.

Animals↗
PubMed2005

Sleep extension: getting as much extra sleep as possible.

Nearly all people, whether they consider themselves sleep deprived or not, can initially obtain extra sleep. However, as accumulating extra sleep reduces carryover sleep debt, a point is reached where it is no longer possible to obtain extra sleep. If there were a practical method to make a precise measurement of a person's daily sleep requirement, it may be possible to show that most individuals are carrying a very large sleep debt. Several observations and studies demonstrate that almost everyone is sleep deprived and carries some amount of sleep debt. How long such an indebtedness will persist without change if no extra sleep is obtained is not known.

Homeostasis↗
PubMed2005

History of sleep medicine.

Sleeping and dreaming always have been a fundamental part of human existence. Most early writing on these subjects was almost entirely speculation. During the twentieth century, however, scientific observation and experimentation abounded. This article emphasizes the evolution of the key concepts and research findings that characterize sleep research and sleep medicine, crucial discoveries and developments in the formative years of the field, and those principles and practices that have stood the test of time.

Brain↗
PubMed2004

The impact of extended sleep on daytime alertness, vigilance, and mood.

BACKGROUND AND PURPOSE: To measure the effects of prolonged sleep extension on daytime alertness, vigilance, and mood in healthy young adults. Little research has documented the effects of increased sleep on daytime function despite a high prevalence of daytime fatigue and sleepiness in the adult population. Past extension studies report conflicting results with regard to Multiple Sleep Latency Test (MSLT) scores, vigilance, and mood ratings. No study has challenged subjects to maximum sleep extension, defined by an MSLT score of 20. PATIENTS AND METHODS: Fifteen healthy college students reporting minimal daytime sleepiness were allowed to sleep as much as possible during a sleep extension period. MSLT scores, psychomotor vigilance task (PVT) reaction times, and profile of mood states (POMS) ratings were measured at baseline, mid-extension, and end-extension. RESULTS: There was a significant increase in both journal and actigraphy sleep totals during all extension segments (P<0.01). MSLT scores increased significantly from baseline to both mid- and end-extension (P<0.01). Five of eight tabulated PVT measures also improved significantly at mid- and end-extension with respect to baseline (P<0.05). POMS vigor and fatigue scores showed a similar improvement (P<0.01). Seven subjects achieved an MSLT score of 20. Six subjects showed substantial improvements while two subjects obtained relatively little extra sleep and showed little or no MSLT improvement. The maximum extension group displayed exceptional improvements in vigilance and POMS ratings. CONCLUSIONS: Extended sleep leads to substantial improvements in daytime alertness, reaction time, and mood.

Adolescent↗
PubMed2003

Restless legs syndrome symptoms in primary care: a prevalence study.

BACKGROUND: There are relatively few studies on the prevalence of restless legs syndrome (RLS) in the general population, even fewer that used diagnostic questions covering all 4 essential diagnostic criteria defining the RLS symptom complex, and none that have reported on the 2 RLS phenotypes for patients seen by family physicians. METHODS: To determine the prevalence of the symptom complex, diagnostic for RLS in a primary care patient population, a prospective population-based single-center study was performed. Every adult patient presenting for care in a small rural primary care practice with mostly white patients was surveyed for a 1-year period using a validated RLS diagnostic questionnaire. RESULTS: A total of 2099 patients completed the questionnaire. Analysis revealed that 24.0% of these patients were positive for all 4 of the essential symptoms used to make the diagnosis of RLS and 15.3% reported these symptoms at least weekly. In addition, the RLS symptom complex was reported significantly more often by women than men and, as a whole, patients reporting the RLS symptoms were significantly older than patients without symptoms. The prevalence of symptoms increased with age until about 60 years and then showed a steady decrease thereafter. Further, early-onset RLS was significantly more common in women than men. CONCLUSIONS: A high prevalence of RLS symptoms was observed in this primary care population. This finding supports the need for heightened awareness in both the medical community and general population regarding this disorder, which can often be effectively treated within the primary care practice.

Adult↗
PubMed2002

Technical protocol for the use of esophageal manometry in the diagnosis of sleep-related breathing disorders.

A time-tested protocol for intrathoracic pressure monitoring during sleep is described. This method of esophageal manometry uses a fluid-filled catheter to measure variations in transmitted intrathoracic pressure with respiration. Esophageal manometry is an invaluable tool for the sleep specialist in the diagnosis of sleep-related breathing disorders, especially for detecting cases of upper airway resistance syndrome and for distinguishing subtle central apneas from obstructive events. The methods for scoring esophageal pressure, the indications and contraindications for esophageal manometry, the use of esophageal manometry as the 'gold standard' for the measurement of respiratory effort, and directions for future research are also discussed.

Journal Article↗