The impact of music upon sleep tendency as measured by the multiple sleep latency test and maintenance of wakefulness test

Previous work has shown that background noise or music has a small positive impact on performance during sleep deprivation. The current study examined the effect of background music on the ability to fall asleep or remain awake. Twelve normal-sleeping young adults took multiple sleep latency tests (MSLT) and maintenance of wakefulness tests (MWT) after baseline sleep and one night of total sleep deprivation either with background music or under standard (quiet) conditions. It was hypothesized that the music would help maintain wakefulness both under baseline and sleep deprivation conditions. The results of the study showed that sleep latencies were increased in both MSLT and MWT when music was presented, but that this effect occurred primarily before subjects were sleep-deprived (a significant Music by Sleep Deprivation interaction). Sleep latencies were 15 and 11 min on the MSLT (33 and 26 min on the MWT) with Music as compared to Quiet after baseline sleep. Heart rate, used as a measure of physiological arousal, was significantly elevated in MWT and MSLT trials where music was presented. These data support previous work showing that level of arousal has an impact on measured sleep tendency which is independent of that of the sleep system. On a practical level, these data indicate that music may play a small beneficial role in helping to maintain arousal.     

Scoring reliability of the multiple sleep latency test in a clinical population

STUDY OBJECTIVES: To determine intrarater and interrater scoring reliability of the multiple sleep latency test (MSLT) in a population of sleep clinic patients. DESIGN: N/A. SETTING: Urban sleep center. PATIENTS: 200 consecutive sleep center patients (diagnoses included: obstructive sleep apnea, narcolepsy, periodic-limb-movement, and individuals with no diagnosis). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: MSLTs were recorded and scored according to standard clinical procedures. One of four clinical polysomnographers and one of seven polysomnographic technologists scored each MSLT. All MSLTs were then rescored by the same polysomnographer. The intrarater reliability coefficient for mean MSLT score was .87 and interrater reliability was .90. Coefficients for the mean number of REM onsets during the MSLT were .81 for intrarater and .88 for interrater reliability. Intrarater and interrater agreement (kappa coefficients) for the presence of at least one REM onset during the MSLT was .78 and .86, respectively. For the presence of greater than one REM onset, a kappa of .78 was obtained for intrarater agreement and .91 for interrater agreement. CONCLUSIONS: The clinical MSLT displays excellent interrater and intrarater reliability estimates for both sleep latency and REM onset scores in a sleep-disordered population.     

Factors associated with maintenance of wakefulness test mean sleep latency in patients with mild to moderate obstructive sleep apnoea and normal subjects

This study investigated the possible factors related to the Maintenance of Wakefulness Test (MWT) mean sleep latency. A second analysis explored the characteristics of subjects who had discrepant Epworth Sleepiness Scale (ESS) and MWT scores. A total of 151 subjects (110 mild to moderate obstructive sleep apnoea (OSA) patients and 41 control subjects) were recruited for the study. The subjects completed an overnight Polysomnography (PSG), MWT, cognitive, performance and vigilance tasks and answered self-report questionnaires on mood and sleepiness. A forward stepwise multiple regression was performed on MWT mean sleep latency. The predictor variables age (r = 0.28), subjective sleep history for 1 week prior to MWT (sleep diary; r = 0.19) and number of >4% SaO2 Dips during the PSG (r = -0.21) best explained the MWT results, but only accounted for 12.8% of the variance in the test. It was found that 33% of subjects had discrepant ESS and MWT scores. A new variable was created to analyse these subjects (MWT/ESS discrepancy score; MED). A forward stepwise multiple regression analysis found that depression, performance errors and sleep disordered breathing explained 13.4% of the variance in MED scores. The MWT is a complex behavioural test whose scores do not seem to have a very robust relationship with potential predictors and co-correlates. Further comprehensive study is needed if the test is to be used in a diagnostically meaningful way.     

Sensitivity and specificity of the multiple sleep latency test (MSLT), the maintenance of wakefulness test and the epworth sleepiness scale: failure of the MSLT as a gold standard

Excessive daytime sleepiness (EDS) is an important symptom that needs to be quantified, but there is confusion over the best way to do this. Three of the most commonly used tests: the multiple sleep latency test (MSLT), the maintenance of wakefulness test (MWT) and the Epworth sleepiness scale (ESS) give results that are significantly correlated in a statistical sense, but are not closely related. The purpose of this investigation was to help clarify this problem. Previously published data from several investigations were used to calculate the reference range of normal values for each test, defined by the mean+/-2 SD or by the 2.5 and 97.5 percentiles. The 'rule of thumb' that many people rely on to interpret MSLT results is shown here to be misleading. Previously published results from each test were also available for narcoleptic patients who were drug-free at the time and who by definition had EDS. This enabled the sensitivity and specificity of the three tests to be compared for the first time, in their ability to distinguish the EDS of narcolepsy from the daytime sleepiness of normal subjects. The receiver operator characteristic curves clearly showed that the ESS is the most discriminating test, the MWT is next best and the MSLT the least discriminating test of daytime sleepiness. The MSLT can no longer be considered the gold standard for such tests.     

短半衰期催眠药对失眠症患者白天多次睡眠潜伏期测定的影响

目的 :探讨两种短半衰期催眠药佐匹克隆和三唑仑对失眠患者白天多次睡眠潜伏期测定 (MSLT)的影响。方法 :按照ICD 10的诊断标准收集 2 2例非器质性失眠症患者 ,随机分为两组 ,在服用 0 5mg三唑仑或 15mg佐匹克隆前后 ,分别进行MSLT检测。结果 :两药均可使白天MSLT的平均睡眠潜伏期和前两次测定的睡眠潜伏期明显缩短 ,使REM睡眠增加。两药对MSLT的影响特点相似。结论 :催眠药物可使失眠患者白天的困倦程度明显增高 ,这可能与药物的受体后效应有关 ,与药物种类的关系不大。     

发作性睡病的临床特征及多次小睡潜伏期试验

目的：探讨发作性睡病的临床特征及多次小睡潜伏期试验(MSLT)在诊断发作性睡病中的作用。方法：对6例发作性睡病的诊断过程进行回顾性分析。结果：6例患者均有白天过度嗜睡．其中4例伴猝倒。首发症状为白天过度嗜睡5例。猝倒1例。以白天过度嗜睡就诊者3例，以猝倒就诊者3例。6例患者进行MSLT检查，所有患者平均睡眠潜伏期都小于5min．其中5例出现≥2次的睡眠始发REM睡眠(SOREMS)。结论：充分认识发作性睡病的临床特征是诊断的关键。对于临床表现不典型的病例，MSLT将有助于诊断。     

Assessing the efficacy to conduct the multiple sleep latency test with actigraphy

This study explored the efficacy of 1 actigraphy (ACT) brand, at different analytic settings, for use to administer the Multiple Sleep Latency Test (MSLT). Forty-one first-time postpartum mother and father participants were administered the MSLT with concurrent ACT. To identify ACT sleep onset latency (SOL), ACT signals were interpreted with iterations of different "wake threshold value" (WTV) and "immobile minutes for sleep onset" value (IMV) settings. The different iterations of ACT-SOL values were compared to MSLT-SOL values. The WTV settings did not affect ACT-SOL, but the ACT-SOL and MSLT-SOL significantly differed at each ACT-IMV setting. ACT consistently identified SOL too soon; however, future research, along with technological innovation, may identify a viable methodology to conduct an ambulatory MSLT.     

REM sleep episodes during the maintenance of wakefulness test in patients with sleep apnea syndrome and patients with narcolepsy

Twelve patients with sleep apnea, 12 narcoleptic patients, and 10 controls were given 20-min opportunities to remain awake while sitting comfortably. Test sessions were administered at 10:00, 12:00, 14:00, 16:00, and 18:00. Apneic and narcoleptic subjects were less capable of maintaining wakefulness than controls. Patients with sleep apnea had an average of 1.4 daytime rapid eye movement (REM) episodes with the peak incidence at 14:00. Narcoleptics also had sleep onset REM periods (mean of 2.7), whereas none of the controls had REM episodes during the daytime testing. Narcoleptic and control groups differed in the probability of REM occurring at each session. There were time-of-day differences in the probability of REM occurring between patient groups. The amount of stage REM the night preceding testing was unrelated to the occurrence of REM episodes during the day in either patient group. In addition, there were notable differences in the frequency of sleep onset REM periods when patients were sitting as opposed to being supine during nap studies. Sleep latency and frequency of REM episodes on the maintenance of wakefulness test were independent of the subject's age. The maintenance of wakefulness test proved unsatisfactory as a diagnostic procedure, but appeared useful as an adjunct procedure in the evaluation of treatment efficacy of hypersomnia.     

The clinical predictors of sleepiness correlated with the multiple sleep latency test in an Asian Singapore population

STUDY OBJECTIVES: To explore the clinical predictors of sleepiness as objectively determined by the Multiple Sleep Latency Test with the Epworth Sleepiness Scale, age, body mass index, and overnight polysomnographic parameters at a tertiary referral center Sleep Disorders Unit. DESIGN: Retrospective, consecutive case series review. SETTING: A multidisciplinary sleep disorders unit in Singapore General Hospital, a tertiary-care university-affiliated hospital. PATIENTS: 72 consecutive patients evaluated for sleep disorders with overnight polysomnograms and Multiple Sleep Latency Tests between March 2002 and September 2002. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Mean sleep latency on the Multiple Sleep Latency Test was 9.0 +/- 4.4 minutes, and mean Epworth Sleepiness Scale score was 10.8 +/- 5.8. On univariate analysis, mean sleep latency on the Multiple Sleep Latency Test showed a significant negative correlation with the Epworth Sleepiness Scale score, apnea-hypopnea index, body mass index, arousal index, and time spent below 90% oxygen saturation during overnight polysomnography. After performing multiple linear regression, only Epworth Sleepiness Scale score and apnea-hypopnea index remained significantly correlated (P = .039 and P = .008, respectively). An Epworth Sleepiness Scale score of 8 or above predicted a mean sleep latency on the Multiple Sleep Latency Test of less than 10 minutes with a sensitivity of 73.9% and specificity of 50.0%. CONCLUSIONS: The Epworth Sleepiness Scale and apnea-hypopnea index are useful predictors of sleepiness in our Asian Singapore population.     

Sleep perception and the multiple sleep latency test in patients with primary insomnia

The purpose of this study was to examine the relationship between overnight sleep perception and the daytime multiple sleep latency test (MSLT) among individuals who were primary insomnia patients (PIPs) or good sleeper controls (GSCs). We collected overnight sleep data via polysomnography (PSG), subjective sleep data via a morning questionnaire (self‐evaluated) and MSLT data via four 20‐min naps over 8 h. Subjects included 122 PIPs and 48 GSCs. Sleep perception was calculated as subjective sleep time/objective sleep time × 100%. PIPs showed a significant difference (P < 0.001) between sleep time, as determined by PSG (387.8 ± 100 min) and self‐report (226.3 ± 160 min), but no difference was obtained for GSCs (440.6 ± 53 versus 435.4 ± 65 min). The means for sleep perception were 56.4 ± 38.8% for the PIPs and 99.3 ± 13.6% for the GSCs (P < 0.001). In the PIPs group, weak but statistically significant negative correlations (r: ?0.20 to ?0.25) were found for MSLT versus sleep perception and versus self‐ and PSG‐evaluated sleep time. Compared to PIPs with low scores on the MSLT, those with high scores had less sleep perception (%), less self‐ and PSG‐evaluated sleep time and greater sleep misperception time. GSCs did not show significant correlations between MSLT and sleep measures or differences in comparisons between individuals with high and low scores on the MSLT. These results add novel data to the literature by suggesting that 24‐h hyperarousal potentially plays a key role in the pathophysiological issues of insomnia.     

Oculomotor changes are associated to daytime sleepiness in the multiple sleep latency test

Sleep onsets in the diurnal multiple sleep latency test (MSLT), following different sleep lengths of the preceding night sleep (8, 5, 4, 3, 2, 1 h) and following the corresponding recovery nights, were considered for a study on changes of oculomotor activity during sleep onset. The study aimed to assess the individual time course in spontaneous blinks (SBs) and slow eye movements (SEMs) during the sleep onset period and also the relationship with sleep latencies in the MSLT. Group analyses compared oculomotor changes between conditions characterized by a different level of daytime sleepiness. The results show a clear inverse relation between the two oculomotor measures, with a linear SB decrease and quadratic SEM increase across the wake-sleep transition. A 150 s sample of SB and SEM activity at the start of MSLT trials correlates with individual subsequent sleep latency. Finally, mean changes in daytime sleepiness as measured by the MSLT are paralleled by coherent oculomotor changes, with a significant linear decrease of SB as sleepiness increases as a consequence of previous sleep reduction. Both individual and group results show that endogenous blinking is associated with moderate changes in daytime sleepiness.     

Diagnosis of narcolepsy using the multiple sleep latency test: analysis of current laboratory criteria

Multiple sleep latency tests (MSLT) performed on 144 patients with excessive daytime somnolence were examined for the diagnostic reliability of a short sleep latency (SL less than 5 min) and the presence of sleep-onset REM periods (SOREMPs). Based on clinical criteria, 61 patients (42%) were diagnosed as having narcolepsy. Thirty-five narcoleptic patients and five nonnarcoleptic patients exhibited a mean SL less than 5 min, yielding a sensitivity of 57% and a specificity of 94% for this criterion for pathological drowsiness. The occurrence of two or more SOREMPs was found in 52 narcoleptic patients but in only one nonnarcoleptic patient (sensitivity of 84% and specificity of 99%). Those narcoleptic patients with cataplexy demonstrated a shorter SL and more frequent SOREMPs than their noncataplectic counterparts. It was concluded that the MSLT is a highly reliable laboratory tool for the confirmation of the diagnosis of narcolepsy based on the SOREMP criterion. The criterion value for SL in pathological drowsiness may depend on laboratory conditions as well as the patient population selected.     

The maintenance of wakefulness test in normal healthy subjects

STUDY OBJECTIVES: The Maintenance of Wakefulness Test (MWT) examines an individual's ability to stay awake in an environment of decreased sensory stimulation. Only 1 previous study has systematically examined the MWT in normal healthy subjects. SETTING: Sleep disorders unit laboratory PARTICIPANTS AND DESIGN: 31 subjects (mean age 48.5 years, SD 9.6; 8 women) were randomly selected via the telephone directory within a 30-km radius of the test centers. They answered a general screen for health complaints (respiratory, cardiovascular, and psychiatric disorders) and sleep difficulties (snoring). INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Overnight polysomnography and a 40-minute MWT the following day were performed on all subjects. Mean sleep latency to the first epoch of unequivocal sleep during the 40-minute trial MWT was 36.9 +/- 5.4 (SD) minutes. The lower normal limit, defined as 2 SD below the mean, was therefore 26.1 minutes. Mean sleep latency for the first 20 minutes of the trial (with sleep latency defined as time to the first appearance of 1 epoch of stage 1 sleep or a 10-second microsleep) was 18.6 +/- 2.3 minutes, with a lower normal limit of 14.0 minutes. CONCLUSIONS: The mean results are consistent with previously published normative data. However, the SDs found in this study are smaller, and, thus, the lower normal limit suggested here is 4 to 6 minutes longer. The subjects in this study were randomly selected from the general population and may, therefore, be a truer representation of the normal population than in the previous study in which subjects were recruited via hospital advertisements and word of mouth.     

Practice parameters for the use of actigraphy in the assessment of sleep and sleep disorders: an update for 2007

BACKGROUND: Actigraphy is increasingly used in sleep research and the clinical care of patients with sleep and circadian rhythm abnormalities. The following practice parameters update the previous practice parameters published in 2003 for the use of actigraphy in the study of sleep and circadian rhythms. METHODS: Based upon a systematic grading of evidence, members of the Standards of Practice Committee, including those with expertise in the use of actigraphy, developed these practice parameters as a guide to the appropriate use of actigraphy, both as a diagnostic tool in the evaluation of sleep disorders and as an outcome measure of treatment efficacy in clinical settings with appropriate patient populations. RECOMMENDATIONS: Actigraphy provides an acceptably accurate estimate of sleep patterns in normal, healthy adult populations and inpatients suspected of certain sleep disorders. More specifically, actigraphy is indicated to assist in the evaluation of patients with advanced sleep phase syndrome (ASPS), delayed sleep phase syndrome (DSPS), and shift work disorder. Additionally, there is some evidence to support the use of actigraphy in the evaluation of patients suspected of jet lag disorder and non-24hr sleep/wake syndrome (including that associated with blindness). When polysomnography is not available, actigraphy is indicated to estimate total sleep time in patients with obstructive sleep apnea. In patients with insomnia and hypersomnia, there is evidence to support the use of actigraphy in the characterization of circadian rhythms and sleep patterns/disturbances. In assessing response to therapy, actigraphy has proven useful as an outcome measure in patients with circadian rhythm disorders and insomnia. In older adults (including older nursing home residents), in whom traditional sleep monitoring can be difficult, actigraphy is indicated for characterizing sleep and circadian patterns and to document treatment responses. Similarly, in normal infants and children, as well as special pediatric populations, actigraphy has proven useful for delineating sleep patterns and documenting treatment responses. CONCLUSIONS: Recent research utilizing actigraphy in the assessment and management of sleep disorders has allowed the development of evidence-based recommendations for the use of actigraphy in the clinical setting. Additional research is warranted to further refine and broaden its clinical value.     

Control of sleep and wakefulness

This review summarizes the brain mechanisms controlling sleep and wakefulness. Wakefulness promoting systems cause low-voltage, fast activity in the electroencephalogram (EEG). Multiple interacting neurotransmitter systems in the brain stem, hypothalamus, and basal forebrain converge onto common effector systems in the thalamus and cortex. Sleep results from the inhibition of wake-promoting systems by homeostatic sleep factors such as adenosine and nitric oxide and GABAergic neurons in the preoptic area of the hypothalamus, resulting in large-amplitude, slow EEG oscillations. Local, activity-dependent factors modulate the amplitude and frequency of cortical slow oscillations. Non-rapid-eye-movement (NREM) sleep results in conservation of brain energy and facilitates memory consolidation through the modulation of synaptic weights. Rapid-eye-movement (REM) sleep results from the interaction of brain stem cholinergic, aminergic, and GABAergic neurons which control the activity of glutamatergic reticular formation neurons leading to REM sleep phenomena such as muscle atonia, REMs, dreaming, and cortical activation. Strong activation of limbic regions during REM sleep suggests a role in regulation of emotion. Genetic studies suggest that brain mechanisms controlling waking and NREM sleep are strongly conserved throughout evolution, underscoring their enormous importance for brain function. Sleep disruption interferes with the normal restorative functions of NREM and REM sleep, resulting in disruptions of breathing and cardiovascular function, changes in emotional reactivity, and cognitive impairments in attention, memory, and decision making.     

A negative expiratory pressure test during wakefulness for evaluating the risk of obstructive sleep apnea in patients referred for sleep studies

OBJECTIVE:

Obstructive sleep apnea is characterized by increased upper airway collapsibility during sleep. The present study investigated the use of the negative expiratory pressure test as a method to rule out obstructive sleep apnea.

METHODS:

Flow limitation was evaluated in 155 subjects. All subjects underwent a diurnal negative expiratory pressure test and a nocturnal sleep study. The severity of sleep apnea was determined based on the apnea-hypopnea index. Flow limitation was assessed by computing the exhaled volume at 0.2, 0.5, and 1.0 s (V_0.2, V_0.5, and V_1.0, respectively) during the application of a negative expiratory pressure and expressed as a percentage of the previous exhaled volume. Receiver-operating characteristic curves were constructed to identify the optimal threshold volume at 0.2, 0.5, and 1.0 s for obstructive sleep apnea detection.

RESULTS:

Mean expiratory volumes at 0.2 and 0.5 s were statistically higher (p<0.01) in healthy subjects than in all obstructive sleep apneic groups. Increasing disease severity was associated with lower expiratory volumes. The V_0.2 (%) predictive parameters for the detection of sleep apnea were sensitivity (81.1%), specificity (93.1%), PPV (98.1%), and NPV (52.9%). Sensitivity and NPV were 96.9% and 93.2%, respectively, for moderate-to-severe obstructive sleep apnea, and both were 100% for severe obstructive sleep apnea.

CONCLUSION:

Flow limitation measurement by V_0.2 (%) during wakefulness may be a very reliable method to identify obstructive sleep apnea when the test is positive and could reliably exclude moderate and severe obstructive sleep apnea when the test is negative. The negative expiratory pressure test appears to be a useful screening test for suspected obstructive sleep apnea.     

Practice parameters for the medical therapy of obstructive sleep apnea

Therapies for obstructive sleep apnea other than positive airway pressure, oral appliances, and surgical modifications of the upper airway are reviewed in this practice parameter. Several of these therapies such as weight loss and positional therapy hold some promise. Others, such as serotonergic agents, may gain credibility in the future but lack well-designed clinical trials. No practice parameters could be developed for a number of possible therapeutic modalities that had little or no evidence-based data on which to form a conclusion. The role of an organized, targeted weight-loss program either as a single therapy or as a supplement to PAP needs to be clarified. Although bariatric surgery is increasingly performed for refractory medically complicated obesity, its long-term effectiveness in treatment of obstructive sleep apnea in morbidly obese patients is not yet demonstrated. Positional therapy, or methods for preventing sleep in the supine position, has probably been underutilized due to lack of easily measured predictive factors and randomized controlled trials.     

Humoral transmission of sleep and wakefulness

Extracorporal hemodialysis was used as a method for extracting psychotropic humors from the cerebral blood. For such experiments the dialyser of Kuhn and co-workers was adopted, since it operates with a small volume of blood (5 ml) and dialysing fluid (30 ml). Venous blood from the brain flows from the confluens sinuum through a metal canula to the dialyser and returns through a polyvinyl catheter into the femoral vein.After an adaptation period of 40 min, hemodialysis is prolonged during 80 min. The dialysate is then injected into another intact animal, in order to test the physiological properties of the dialysed humor.

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Zusammenfassung Die extracorporelle Hämodialyse wurde als Methode zur Extrahierung von psychotropen Faktoren aus dem Hirnblut von Kaninchen verwendet. Als Dialysiergerät diente die von Kuhn et al. konstruierte künstliche Niere, welche ein Blutfüllvolumen von ca. 5 ml und eine minimale Dialysierflüssigkeitsmenge von 30 ml erfordert. Das Hirnblut wurde aus dem Confluens sinuum mit einer Metallkanüle entnommen und dem Tier über einen in die V. femoralis eingelegten Polyvinylkatheter wieder zugeleitet.Die Wirkung des Dialysats prüften wir durch i.v. Injektion an einem zweiten, freibeweglichen Receptortier, bei welchem wir gleichzeitig das Verhalten beobachteten und die elektrische Hirnaktivität registrierten.

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With 1 Figure in the Text

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This paper is dedicated to the memory of Prof. W. Kuhn, who put the hemodialyser at our disposal a few months before his death.