Objective/backgroundEvaluation of hypersomnolence disorders ideally includes an assessment of vigilance using the short Sustained Attention to Response Task (SART). We evaluated whether this task... Show moreObjective/backgroundEvaluation of hypersomnolence disorders ideally includes an assessment of vigilance using the short Sustained Attention to Response Task (SART). We evaluated whether this task can differentiate between hypersomnolence disorders, whether it correlates with subjective and objective sleepiness, whether it is affected by the time of day, and symptoms of anxiety and depression.Patients/methodsWe analyzed diagnostic data of 306 individuals with hypersomnolence complaints diagnosed with narcolepsy type 1 (n=100), narcolepsy type 2 (n=20), idiopathic hypersomnia (n=49), obstructive sleep apnea (n=27) and other causes or without explanatory diagnosis (n=110). We included the Multiple Sleep Latency Test (MSLT), polysomnography, Epworth Sleepiness Scale (ESS), Hospital Anxiety and Depression Scale and SART, which were administered five times during the day (outcomes: reaction time, total, commission and omission errors).ResultsThe SART outcomes did not differ between groups when adjusted for relevant covariates. Higher ESS scores were associated with longer reaction times and more commission errors (p<.01). The main outcome, total errors, did not differ between times of the day. Reaction times and omission errors were impacted (p<.05).ConclusionsThe SART quantifies disturbed vigilance, an important dimension of disorders of hypersomnolence. Results do not suggest that depressive symptoms influence SART outcomes. A practice session is advised. Testing time should be taken into account when interpreting results. We conclude that the SART does not differentiate between central disorders of hypersomnolence. It may be a helpful addition to the standard diagnostic workup and monitoring of these disorders. Show less
This thesis covers several steps in the process of validating the Sustained Attention to Response Task as a measure of vigilance in patients with excessive daytime sleepiness. It comprises a review... Show moreThis thesis covers several steps in the process of validating the Sustained Attention to Response Task as a measure of vigilance in patients with excessive daytime sleepiness. It comprises a review of the currently circulation definitions of vigilance and a proposal for a covering definition; an extension of previous vigilance measurements in narcolepsy and other patient groups with excessive daytime sleepiness; an assessment of factors possibly influencing SART results, such as task repetition, napping, time of day, and test instruction; and the value of the SART as a treatment efficacy measure in narcolepsy and obstructive sleep apnoea. Show less
We reviewed current definitions of vigilance to propose a definition, applicable in sleep medicine. As previous definitions contained terms such as attention, alertness, and arousal, we addressed... Show moreWe reviewed current definitions of vigilance to propose a definition, applicable in sleep medicine. As previous definitions contained terms such as attention, alertness, and arousal, we addressed these concepts too. We defined alertness as a quantitative measure of the mind state governing sensitivity to stimuli. Arousal comprises a stimulus-induced upward change in alertness, irrespective of the subsequent duration of the increased level of alertness. Vigilance is defined as the capability to be sensitive to potential changes in one's environment, ie the capability to reach a level of alertness above a threshold for a certain period of time rather than the state of alertness itself. It has quantitative and temporal dimensions. Attention adds direction towards a stimulus to alertness, requiring cognitive control: it involves being prepared to process stimuli coming from an expected direction. Sustained attention corresponds to a state in which some level of attention is purposefully maintained, adding a time factor to the definition of attention. Vigilance differs from sustained attention in that the latter in addition implies a direction to which attention is cognitively directed as well as a specification of duration. Attempts to measure vigilance, however, are often in fact measurements of sustained attention. (C) 2021 The Authors. Published by Elsevier B.V. Show less
This thesis is divided into to two parts. The first part investigates the effects of the pharmaceutical gamma-hydroxybutyrate (GHB), also known as sodium oxybate (Xyrem), in various clinical... Show moreThis thesis is divided into to two parts. The first part investigates the effects of the pharmaceutical gamma-hydroxybutyrate (GHB), also known as sodium oxybate (Xyrem), in various clinical populations, including individuals with Parkinson’s disease. Most of research in part one investigates GHB in those with the condition of narcolepsy. The effects of GHB on sleep parameters, including sleep quality, is a key focus point. Other chapters explore the hormonal phenotype of narcolepsy and the impact GHB has on the hormones leptin and ghrelin in both narcolepsy and health controls. Gamma-hydroxybutyrate has a history of abuse and know abuse liability. Chapter 5 in this thesis explores the how illicit GHB and Xyrem differ in their abuse potential and incidence. Part two of the thesis focuses on how various aspects of lifestyle influence metabolism and indicators of health status. In Chapter 9, eating behavior is evaluated in response to ecologically relevant amounts of sleep loss common experienced by average people in the modern world. In Chapter 10, we explore how health young adults respond to a four-day, Paleolithic theory-themed nature trip in the German countryside. Show less
Narcolepsy is a disorder of the regulation of sleep and wakefulness, with as its major features excessive daytime sleepiness (EDS), cataplexy, hypnagogic hallucinations, sleep paralysis and... Show moreNarcolepsy is a disorder of the regulation of sleep and wakefulness, with as its major features excessive daytime sleepiness (EDS), cataplexy, hypnagogic hallucinations, sleep paralysis and disturbed nocturnal sleep. The first part of this thesis concernes an overview of the pathophysiology, symptoms and treatment of narcolepsy type 1. The second part elaborates some pathophysiological aspects, focussing on the autoimmune hypothesis of narcolepsy. The third part focuses on alterations of temperature regulation and on measuring treatment effects of symptomatic treatment on sustained attention, i.e. vigilance. Show less
The first part deals with the hypothalamic hypocretin system in disorders that are accompanied by narcolepsy-like sleep disturbances, i.e. Prader-Willi Syndrome, Parkinson__s Disease and Huntington... Show moreThe first part deals with the hypothalamic hypocretin system in disorders that are accompanied by narcolepsy-like sleep disturbances, i.e. Prader-Willi Syndrome, Parkinson__s Disease and Huntington__s Disease. To determine whether the hypocretin system is affected in these disorders, the total number of hypocretin neurons was determined using quantitative techniques in post-mortem human hypothalami. The reason why hypocretin neurons disappear in narcolepsy is still a mystery. A putative autoimmune aetiology has been hypothesized, but a screening for autoantibodies and a n=1 trial with intravenous immunoglobulins yielded no unequivocal results in favor of this hypothesis. In the second part, the consequences of hypocretin deficiency in narcoleptic patients are explored, focussing on vigilance, metabolism and the autonomic nervous system and skin temperature regulation. The ability of a specific neuropsychological test to measure vigilance as a severity indicator for narcolepsy is explored. Two possible causes for the obesity commonly seen in narcolepsy are a decreased basal metabolic rate and a changed autonomic tone. To assess the influence of hypocretin deficiency on skin temperature regulation, thermoregulatory profiles of the proximal and distal skin of narcoleptic subjects were compared to profiles of healthy controls during a daytime sleep registration. Show less
