Yawning and subjective sleepiness in the elderly

Yawning is related to sleep/wake transitions and time of day, probably reflecting the time course of sleepiness. As aging modifies sleep–wake and sleepiness rhythms, we suppose that yawning frequency and its time course vary as a function of age. Thirteen aged healthy subjects (77.15 ± 4.09 years) and 12 young adults (24.41 ± 3.31 years) were instructed to keep their habitual sleep schedules for three consecutive work-days, during which they were required to signal every yawning occurrence and to evaluate hourly their sleepiness level. Results showed that aged subjects yawn less frequently than young adults, particularly during morning and mid-afternoon hours. The time course of yawning was different between the two age groups: aged subjects showed earlier morning peak and evening rise compared with young adults; in addition, aged subjects showed two minor peaks in-between. Differences as a function of age in the time course of yawning were associated with differences in the time course of sleepiness. The only exception pertained to the early morning yawning peak, which was close to the awakening but it was not associated with high sleepiness in aged subjects. Our study discloses that aging modifies yawning frequency and its time course. Furthermore, as in the elderly yawning after the awakening is not associated with high sleepiness level as in young adult, we put forward that sleepiness level and the proximity of sleep/wake transitions could separately affect yawning.     

Intradialytic subjective sleepiness and oral body temperature

STUDY OBJECTIVES: Hemodialysis (HD) patients are often observed to sleep during treatment. Because of the well-described, inverse association between body temperature and sleep propensity, the purpose of this study was to describe the course of intradialytic (during HD) subjective sleepiness and examine its relationship to oral body temperature. In addition, we sought to determine if that relationship varied with dialysis treatment time of day. DESIGN: Subjective sleepiness and oral body temperature were recorded every 15 minutes through the entire course of HD. SETTING: The study was conducted at two large, inner-city dialysis units. PATIENTS OR PARTICIPANTS: The sample included 60 chronic HD patients, 20 on each of three shifts based on treatment time of day (shift 1-6:00A.M. to 10:00A.M.; shift 2-10:00A.M. to 2:00P.M.; and shift 3-2:00P.M. to 6:00P.M.. MEASUREMENTS AND RESULTS: Subjects on shift 1 were found to have a mean intradialytic sleepiness level greater than those on shift 2 (p<.04) and shift 3 (p<.003). Irrespective of shift, sleepiness increased during the first half of dialysis and decreased slightly as treatment progressed, a significant quadratic trend (p<.001). During the same period, temperature initially increased, subsequently dropped in temporal proximity to maximal sleepiness and increased again, a significant quadratic trend (p<.02). The relationship between sleepiness and temperature revealed a significant negative correlation (r=-.59, p<.03) and did not vary with treatment time of day. CONCLUSIONS: The results argue that sleep propensity increases during HD, an effect that may be related to treatment induced alterations in arousal and/or thermoregulatory processes. The effect is unrelated to treatment time of day.     

Mismatch negativity during objective and subjective sleepiness

The mismatch negativity (MMN) and P.3 of auditory event related potentials were studied during subjectively and objectively (physiologically) defined sleepiness under optimal stimulus conditions for MMN elicitation. The MMN and P3 were elicited by either small or large unattended auditory deviants presented to the left ear The participant's task was to defect either rare auditory targets presented to the right ear or rare changes in the light Hashes Eleven young adults served as participants in a nighttime experiment. The MMN declined especially at Fz and Cz bin not so markedly at the right mastoid as either subjective or objective alertness decreased The amplitude of P3 also decreased during sleepiness The attenuation of the MMN was paralleled by a decline in behavioral performance The results show that the MMN is attenuated by a decrease in alertness even before an actual sleep stale is reached.     

Determinants of subjective sleepiness in suspected obstructive sleep apnoea

Although daytime sleepiness is commonly associated with obstructive sleep apnoea (OSA), the relationship between OSA severity and subjective sleepiness has been documented elusive. This study aimed to identify clinical and polysomnographic determinants of subjective sleepiness among patients suspected of having OSA. A sleep clinic-based sample of 915 patients was interviewed with a structured questionnaire and underwent diagnostic overnight polysomnography. Subjective sleepiness was quantified by Epworth Sleepiness Scale (ESS). Excessive daytime sleepiness (defined as ESS score > 10) was present in 38.8% of patients. In multiple linear regression analysis, respiratory disturbance index [RDI; used to define (whenever RDI was >5) and quantify OSA], depression and diabetes were the most important determinants of ESS score accounting for 17%, 11% and 6% of its variability respectively. Chronic obstructive pulmonary disease (COPD), stroke, heart disease, alcohol use and body mass index were less important determinants of ESS score explaining 1-3% of its variability. In conclusion, OSA should not be considered the sole potential cause of increased subjective sleepiness in patients suspected of having OSA. Primarily depression and diabetes, but also COPD, stroke, heart disease, alcohol use and increased body mass index may contribute to increased subjective sleepiness.     

Self-report sleep habits as predictors of subjective sleepiness

Although sleepiness is pervasive in our society, there is little agreement on how to measure sleepiness or on how well sleepiness is actually related to sleep habits. To better assess how subjective sleepiness is related to sleep, the authors used self-report measures of sleep quantity, sleep quality, and napping to predict 4 different sleepiness-related measures in a group of healthy young and middle-aged-to-older adults. A forward regression analysis indicated that sleep quality was better than sleep quantity as a predictor of participants' sleepiness. The sleep measures, furthermore, predicted sleepiness better in the older adults than in the younger adults. Finally, the 4 sleepiness measures differed in how well they were related to sleep. The findings in the study suggest that sleepiness is a complex phenomenon rather than a simple reflection of sleep quantity.     

A standard procedure enhances the correlation between subjective and objective measures of sleepiness

OBJECTIVE: The goal of this study was to assess whether instituting a standard procedure to minimize transient activation prior to the subjective rating of sleepiness can improve the predictive value of the rating process. METHODS: Thirty young adults, aged 19 to 26 years, participated in the study. Subsequent to sleeping at home with bedtime restricted to 5 hours, they came to the sleep laboratory. They were instructed to rate their level of sleepiness on the Stanford Sleepiness Scale (SSS) and visual analog scales (VAS). A "calm-down" procedure, sitting quietly with eyes closed for 1 minute, was instituted prior to sleepiness ratings for half of the subjects (experimental group) but not for the other half of the subjects (control group). A nap trial with polysomnographic recording was then conducted, followed by a vigilance test. RESULTS: For the experimental group, VAS results of "sleepiness" and "alertness" both correlated significantly with sleep-onset latency during the nap (SOL: r = -.62 and .64, respectively, P values < .05) and with reaction time (RT) on the vigilance test (r = .56 and -.54, P values < .05). The SSS ratings showed significant correlation with nap SOL (r = -.58, P < .05) but not with RT on the vigilance test (r = .19, p = .52). For the control group, none of the subjective ratings showed significant correlation with objective measures. The differences between the resultant correlations for the 2 groups were statistically significant for 2 sets of correlations: the correlation between VAS of "alertness" and nap SOL and the correlation between VAS of "sleepiness" and RT on the vigilance test. CONCLUSION: The results indicate that the subjective ratings of the sleepiness state for individuals with mild sleep restriction more faithfully reflect a physiologic tendency to fall asleep as well as cognitive attentiveness when the ratings are conducted subsequent to sitting still with eyes closed for a sufficient time to minimize transient activation.     

Prevalence and risk factors of subjective sleepiness in the general adult population

STUDY OBJECTIVES: The aim of this study was to investigate the prevalence and risk factors of self-reported excessive daytime sleepiness (EDS) in Norway. DESIGN: The Epworth Sleepiness Scale was administered by a telephone interview to a random sample of 2301 adult inhabitants of Norway. Questions of demography, symptoms of sleep disorders, and depression were included. SETTING: Norway. PARTICIPANTS: Two thousand three hundred one subjects, 18 years and older. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: The mean score of the Epworth Sleepiness Scale was 6.95 (SD = 3.8), and 17.7% had a score (> 10), indicating EDS. Univariate logistic regression analyses showed that being a man; living in southern Norway; working nights; being young; having symptoms of cataplexy, restless legs, or periodic limb movement in sleep; having breathing pauses in sleep; and having symptoms of depression were significantly related to EDS. Of these 9 predictors, only symptoms of restless legs did not maintain the significant relationship with EDS when a multiple logistic regression analysis was performed. CONCLUSIONS: The prevalence of EDS was high in this adult Norwegian population sample. EDS seems to be related to several symptoms of sleep disorders.     

Sleepiness phenomics: Modeling individual differences in subjective sleepiness profiles

The present study investigates individual differences in subjective sleepiness profiles during 36 h of sustained wakefulness in a modified constant routine protocol. Twenty-three volunteers (11 females), aged between 18 and 47 yrs (M age = 30.41, SD = 10.26) enrolled in the study. Subjective sleepiness ratings were collected every 2 h by means of visual analogue scales. Circadian rhythmicity was assessed by means of salivary cortisol. Subjective sleepiness data were analyzed using functional principal component analysis (fPCA). Our results show that approximately 80% of the variance is accounted for by three functional components. The first component explains 50.28% of the variance and is characterized by a profile of exclusively positive loadings, representing vertical shifts from the mean sleepiness profile. Scores on this component are positively related to self-reported habitual sleep times and mean slow wave activity (SWA) during wake. Positive scores on the second component (18.40% of the variance) are characterized by a higher than average peak-to-trough amplitude in subjective sleepiness profiles. Participants with higher than average scores on this component show a significantly higher amplitude in salivary cortisol profiles as opposed to participants with lower than average scores. Participants with positive scores on the third component (10.09% of the variance) show higher than average levels of subjective sleepiness during morning hours, a buildup of wake effort occurring later and more afternoon sleepiness after sleep deprivation than negative scorers. Peak levels of salivary cortisol occur significantly later in these participants. Taken together, our results suggest that component 1 represents tonic differences in sleepiness profiles primarily related to mechanisms of sleep homeostasis, component 2 to circadian amplitude differences and component 3 to diurnal preference. However, since the components are additions to a mean profile, each of the three components is likely to correspond to a mixture of multiple physiological parameters, rather than to a single process. The approach shows interesting potential for (1) revealing unidentified physiological processes, (2) testing existing assumptions about regulatory mechanisms at the basis of interindividual variability in sleepiness profiles and (3) the specification of sleepiness phenotypes on a quantitative basis.     

The risks and implications of excessive daytime sleepiness in resident physicians.

PURPOSE: To assess the levels of physiologic and subjective sleepiness in residents in three conditions: (1) during a normal (baseline) work schedule, (2) after an in-hospital 24-hour on-call period, and (3) following a period of extended sleep. METHOD: In 1996, a within-subjects, repeated-measures study was performed with a volunteer sample of 11 anesthesia residents from the Stanford University School of Medicine using three separate experimental conditions. Sixteen residents were recruited and 11 of the 16 completed the three separate experimental conditions. Daytime sleepiness was assessed using the Multiple Sleep Latency Test (MSLT). RESULTS: MSLT scores were shorter in the baseline (6.7 min) and post-call (4.9 min) conditions, compared with the extended-sleep condition (12 min, p =.0001) and there was no significant difference between the baseline and post-call conditions (p =.07). There was a significant main effect for both condition (p =.0001) and time of day (p =.0003). Subjects were inaccurate in subjectively identifying sleep onset compared with EEG measures (incorrect on 49% of EEG-determined sleep episodes). CONCLUSION: Residents' daytime sleepiness in both baseline and post-call conditions was near or below levels associated with clinical sleep disorders. Extending sleep time resulted in normal levels of daytime sleepiness. The residents were subjectively inaccurate determining EEG-defined sleep onset. Based on the findings from this and other studies, reforms of residents' work and duty hours are justified.     

Assessing subjective sleepiness during a night of sleep deprivation: examining the internal state and behavioral dimensions of sleepiness

Investigators in previous research have indicated that subjective measures of sleepiness may separate into state- and behavior-based dimensions; however, researchers have not examined this under sleep deprivation conditions. The authors' purpose in this study was to examine several measures of subjective sleepiness under sleep deprivation conditions following completion of various tasks. Fourteen students participated in a 28-hour sleep deprivation study and completed vigilance and cognitive tasks 4 times during the night. The authors administered subjective measures of sleepiness after each task. Factor analyses indicated that when individuals were not excessively sleepy, subjective sleepiness measures separated into 2 dimensions: state and behavioral sleepiness. However, when individuals were more fatigued, there was no distinction between the state and behavior dimensions of sleepiness. The current results suggest that using measures that assess state and behavioral sleepiness separately could be useful in clinical and research settings when extreme levels of sleepiness are not expected.     

Performance and cardiovascular measures in normal adults with extreme MSLT scores and subjective sleepiness levels

STUDY OBJECTIVES: The purpose of this study was to determine the relationship of subjective and objective sleepiness across several nights. Extreme groups were chosen based upon both Multiple Sleep Latency Test (MSLT) findings and report of characteristic subjective sleepiness, and groups were compared across sleep, demographic, performance, and physiologic variables. DESIGN AND SETTING: Subjects spent 3 baseline nights and the following days in the laboratory. Standard polysomnographic recordings were made on each night. On each day, subjects had an MSLT, performance testing, and metabolic and heart rate observation periods. PARTICIPANTS: Participants were 50 adult normal sleepers. INTERVENTIONS: None. MEASUREMENT AND RESULTS: Those subjects with sleep latencies on the MSLT of more than 10 minutes following the adaptation night (Alert) were compared with 2 groups of subjects with sleep latencies on the MSLT of less than 7 minutes following the adaptation night. Subjects with MSLT < 7 were divided into those who reported subjective sleepiness during the day (subjective sleepiness > 1 SD above the mean for the entire group-Sleepy-Sleepy) and those who did not report subjective sleepiness (subjective sleepiness < 1 SD above the mean for the entire group--Sleepy-Alert). The Alert group maintained longer sleep latencies than the other groups and had improved performance on vigilance compared to the Sleepy-Sleepy group on all days and on some days compared to the Sleepy-Alert group. Vigilance was improved in the Sleepy-Alert group compared with the Sleepy-Sleepy group on all days. The Alert group had higher heart rate and increased low/high spectral heart rate power compared to both sleepy groups, and the Sleepy-Alert group had higher heart rate and increased low/high spectral heart rate power compared to the Sleepy-Sleepy group at some points. CONCLUSIONS: It was concluded that normal adults with short MSLT latencies differ from those with longer latencies on both cardiac and performance variables. Also, those individuals with short latencies can be divided into subgroups claiming subjective sleepiness or denying sleepiness. Those denying sleepiness have improved vigilance performance and greater heart rate and low/high spectral heart rate power compared to those with subjective sleepiness. Both the MSLT group differences and the subjective group differences imply that ability to maintain wakefulness and performance in sedentary situations may be related to innate ability to maintain physiologic arousal.     

A survey of elderly diabetic patients attending a community clinic in Hong Kong

A cross-sectional survey was conducted on Chinese diabetic patients attending a community clinic in Hong Kong. A questionnaire, physical examination and blood tests were administered. Of 155 adults with diabetes mellitus recruited, the mean age was 63 years (SD 10.3), 77.4% were female and 41.9% illiterate. Half the patients achieved adequate knowledge scores. Knowledge was found to be associated with education level (OR 4.3, 95% CI 1.8, 10.0), longer disease duration (OR 3.2, 95% CI 1.4, 7.4) and complications (OR 0.3, 95% CI 0.1, 0.8). No correlation was found between knowledge and attitude or practice. Attitude was found to be associated with practice (OR 1.2, 95% CI 1.0, 1.3) and male gender (OR 2.9, 95% CI 1.1, 7.5); practice was associated with hypertension (0.5, 95% CI 0.2, 0.9). Older less educated Chinese diabetic patients can be educated about diabetes management, but knowledge does not always translate into practice.     

Stress vulnerability and the effects of moderate daily stress on sleep polysomnography and subjective sleepiness

The purpose of this study was to investigate if and how sleep physiology is affected by naturally occurring high work stress and identify individual differences in the response of sleep to stress. Probable upcoming stress levels were estimated through weekly web questionnaire ratings. Based on the modified FIRST‐scale (Ford insomnia response to stress) participants were grouped into high (n = 9) or low (n = 19) sensitivity to stress related sleep disturbances (Drake et al., 2004). Sleep was recorded in 28 teachers with polysomnography, sleep diaries and actigraphs during one high stress and one low stress condition in the participants home. EEG showed a decrease in sleep efficiency during the high stress condition. Significant interactions between group and condition were seen for REM sleep, arousals and stage transitions. The sensitive group had an increase in arousals and stage transitions during the high stress condition and a decrease in REM, whereas the opposite was seen in the resilient group. Diary ratings during the high stress condition showed higher bedtime stress and lower ratings on the awakening index (insufficient sleep and difficulties awakening). Ratings also showed lower cognitive function and preoccupation with work thoughts in the evening. KSS ratings of sleepiness increased during stress for the sensitive group. Saliva samples of cortisol showed no effect of stress. It was concluded that moderate daily stress is associated with a moderate negative effect on sleep sleep efficiency and fragmentation. A slightly stronger effect was seen in the sensitive group.     

Synchronous communication facilitates interruptive workflow for attending physicians and nurses in clinical settings

Study objective

Inter-clinician communication accounts for more than half of all information exchanges within the health care system. A non-participatory, qualitative time-and-motion observational study was conducted in order to gain a better understanding of inter-clinician communication behaviors, routine workflow patterns, and the use of information communication technologies (ICTs) within the clinical workspace.

Method

Over a 5-day period, seven attending physicians and two nurses were shadowed for 2-4 h at a time. Inter-clinician communication events were tracked in real-time using synchronized digital stopwatches. Observations were recorded on a paper-based, semi-structured observation tool and later coded for analysis.

Results

Nine hundred and eighty-seven communication events were observed over 2024.67 min. Clinicians were observed to spend the majority of their time on patient care (85.4% in this study) with about three-fourths of that time spent on indirect patient care (e.g. charting). Clinicians were observed to prefer using synchronous communication modes, which led to multitasking and created a highly interrupted workflow. Forty-two percent (n = 415) of communication events were coded as interruptions and study participants were seen multitasking 14.8% of the time. Though each interruption was short-lived (on average 0.98 ± 2.24 min for attending physicians), they occurred frequently. Both attending physicians and nurses were the recipients of more interruptions than they initiated.

Conclusion

This study demonstrated that the clinical workspace is a highly interruptive environment. Multiple interruptions in the communication processes between clinicians consume time and have the potential to increase the risk of error. This workflow analysis may inform the development of communication devices to enhance inter-clinician communication by reducing interruptions or deferring interruptions to more appropriate times.     

Slow eye movements and subjective estimates of sleepiness predict EEG power changes during sleep deprivation

RATIONALE: The aim of the present study was to assess, intraindividually, the relationship among slow eye movements, electroencephalogram (EEG) power, and subjective measures of sleepiness during a 40-hour sleep deprivation comparing 2 experimental conditions: eyes-open and eyes-closed. METHODS: Nineteen normal subjects participated in a sleep-deprivation protocol with recordings of the waking Cz-A1-2 EEG in 36 sessions at 1-hour intervals starting at 10:00 AM. Each session consisted of a 2-minute eyes-closed period, followed by a 4-minute eyes-open period. Electrooculogram, self-ratings (Karolinska Sleepiness Scale and Visual Analog Scale for Global Vigor), and tympanic temperature were also recorded. RESULTS: Changes in sleepiness and alertness are paralleled by increases in slow eye movements and theta and delta EEG power. The beginning of the rise of delta, theta, and slow eye movement activity corresponded to the nadir of temperature, peaking at 7:00AM. Cross-correlational analyses showed that changes in slow eye movements were strictly phase locked to those in slow-frequency EEG bands and in subjective measures. The comparison of time intervals that were equivalent with respect to circadian phase confirms the effects of the increased sleepiness on slow eye movement activity and on the other measures. The temporal concordance of the different physiologic and subjective measures is also reflected in the individual time courses. Individual and group analyses converged in indicating that slow eye movements can be considered reliable indexes of sleepiness but only in the eyes-closed condition. CONCLUSIONS: Results suggest that subjective and EEG changes associated with higher sleepiness are paralleled by an increase in slow eye movement activity, but this relationship exists almost exclusively with the eyes closed. Hence, its use in practical and operational contexts seems limited.     

北京协和医院临床住院医师对超声检查认识情况的调查分析

目的调查临床科室住院医师对超声检查的了解及认识情况,为今后的超声工作及教学培训提供依据。方法2014年12月对北京协和医院4个临床学系105名住院医师发放调查问卷,调查其对超声检查的理解程度、与超声医师沟通情况及超声检查在临床中作用的认识等。结果共获得100份有效问卷。81%的临床住院医师对于超声检查指征略微或中等了解,而对检查结果为中等或相等接受程度者占91%;70%对床旁超声的检查指征略微或中等了解;住院医师与超声医师的沟通较少,90%认为超声检查在临床工作中是相当及非常重要的,而对于完整地为患者解释超声报告自信心中等者占59%。结论了解临床需求并进行针对性培训有助于超声在临床工作中发挥作用。