Understanding and predicting faculty intent to leave is important to the development of improved ... more Understanding and predicting faculty intent to leave is important to the development of improved conceptual frameworks of faculty success as well as the implementation of effective retention strategies for academic leaders and institutions that invest considerable resources in recruitment, institutional support, and compensation. This study examined the relationship between various research-based factors and faculty intent to leave by integrating components identified in the extant literature for employee turnover more generally and faculty intent to leave more specifically. The results of binary logistic regression models identified workplace stress, being in a "soft-pure" discipline, fewer years of service at the university, and higher research productivity as key predictors of faculty having considered leaving for another institution. Key predictors for faculty having considered leaving academe altogether were being in a "hard-applied" discipline, not having a spouse or partner, a perceived lack of support, a perceived lack of fit, stress of raising a family, and dissatisfaction with certain aspects of the "faculty job". The implications for research, policy, and practice are discussed.
Low and high water periods create contrasting challenges for trees inhabiting periodically floode... more Low and high water periods create contrasting challenges for trees inhabiting periodically flooded wetlands. Low to moderate flood durations and frequencies may bring nutrient subsidies, while greater hydroperiods can be energetically stressful because of oxygen deficiency. We tested the hypothesis that hydroperiod affects the growth of mangrove seedlings and saplings in a greenhouse experiment by varying flood duration while keeping salinity and soil fertility constant. We measured the growth of mangrove trees along a hydroperiod gradient over a two-year period by tracking fine-scale diameter increment. Greenhouse growth studies indicated that under a full range of annual flood durations (0-8760 h/year), hydroperiod alone exerted a significant influence on growth for one species, Laguncularia racemosa, when flooding was imposed for two growing seasons. Field evaluations, on the other hand, indicated that increased flood duration may provide nutrient subsidies for tree growth. Diameter growth was related curvilinearly to site hydroperiod, including flood duration and frequency, as well as to salinity and soil fertility. An analysis of soil physico-chemical parameters suggests that phosphorus fertility, which was also linked directly to hydroperiod, is likely to influence growth on south Florida mangrove sites. The physical removal of phosphorus by greater flood frequencies from upland sources and/or addition of phosphorus from tidal flooding balanced against increased soil aeration and reduced water deficits may be an extremely important growth determinant for south Florida mangroves.
Woody debris is abundant in hurricane-impacted forests. With a major hurricane affecting South Fl... more Woody debris is abundant in hurricane-impacted forests. With a major hurricane affecting South Florida mangroves approximately every 20 yr, carbon storage and nutrient retention may be influenced greatly by woody debris dynamics. In addition, woody debris can influence seedling regeneration in mangrove swamps by trapping propagules and enhancing seedling growth potential. Here, we report on line-intercept woody debris surveys conducted in mangrove wetlands of South Florida 9-10 yr after the passage of Hurricane Andrew. The total volume of woody debris for all sites combined was estimated at 67 m 3 /ha and varied from 13 to 181 m 3 /ha depending upon differences in forest height, proximity to the storm, and maximum estimated wind velocities. Large volumes of woody debris were found in the eyewall region of the hurricane, with a volume of 132 m 3 /ha and a projected woody debris biomass of approximately 36 t/ha. Approximately half of the woody debris biomass averaged across all sites was associated as small twigs and branches (fine woody debris), since coarse woody debris >7.5 cm felled during Hurricane Andrew was fairly well decomposed. Much of the small debris is likely to be associated with post-hurricane forest dynamics. Hurricanes are responsible for large amounts of damage to mangrove ecosystems, and components of associated downed wood may provide a relative index of disturbance for mangrove forests. Here, we suggest that a fine:coarse woody debris ratio ≤0.5 is suggestive of a recent disturbance in mangrove wetlands, although additional research is needed to corroborate such findings.
BACKGROUND The effects on patient safety of eliminating extended-duration work shifts for residen... more BACKGROUND The effects on patient safety of eliminating extended-duration work shifts for resident physicians remain controversial. METHODS We conducted a multicenter, cluster-randomized, crossover trial comparing two schedules for pediatric resident physicians during their intensive care unit (ICU) rotations: extended-duration work schedules that included shifts of 24 hours or more (control schedules) and schedules that eliminated extended shifts and cycled resident physicians through day and night shifts of 16 hours or less (intervention schedules). The primary outcome was serious medical errors made by resident physicians, assessed by intensive surveillance, including direct observation and chart review. RESULTS The characteristics of ICU patients during the two work schedules were similar, but resident physician workload, described as the mean (±SD) number of ICU patients per resident physician, was higher during the intervention schedules than during the control schedules (8.8±2.8 vs. 6.7±2.2). Resident physicians made more serious errors during the intervention schedules than during the control schedules (97.1 vs. 79.0 per 1000 patient-days; relative risk, 1.53; 95% confidence interval [CI], 1.37 to 1.72; P<0.001). The number of serious errors unitwide were likewise higher during the intervention schedules (181.3 vs. 131.5 per 1000 patient-days; relative risk, 1.56; 95% CI, 1.43 to 1.71). There was wide variability among sites, however; errors were lower during intervention schedules than during control schedules at one site, rates were similar during the two schedules at two sites, and rates were higher during intervention schedules than during control schedules at three sites. In a secondary analysis that was adjusted for the number of patients per resident physician as a potential confounder, intervention schedules were no longer associated with an increase in errors. CONCLUSIONS Contrary to our hypothesis, resident physicians who were randomly assigned to schedules that eliminated extended shifts made more serious errors than resident physicians assigned to schedules with extended shifts, although the effect varied by site. The number of ICU patients cared for by each resident physician was higher during schedules that eliminated extended shifts.
The Journal of Arthroplasty, Volume 22, Issue 2, Pages 310, February 2007, Authors:John Callaghan... more The Journal of Arthroplasty, Volume 22, Issue 2, Pages 310, February 2007, Authors:John Callaghan, MD; Matthew Teusink, BA; Jonathan Donigan, MD; Lucian Warth, BS; Steve Liu, MD;Jason Sullivan, BS; Devon Goetz, MD; David Vittetoe, MD; Richard Johnston, MD. ...
Introduction Sleep deficiency and undiagnosed or untreated sleep disorders are pervasive among em... more Introduction Sleep deficiency and undiagnosed or untreated sleep disorders are pervasive among employed adults, yet are often ignored in the context of workplace health promotion. Smartphone applications (apps) are a promising, scalable approach to improving sleep among employees. We evaluated an online sleep education program followed by access to a mobile sleep training program, the dayzz app, that promotes healthy sleep, sleep disorders awareness and intervention. Methods In a sample of daytime employees affiliated with a large healthcare organization, we evaluated the intervention (sleep education at baseline plus access to the personalized app for up to 9 months) in a parallel group, randomized controlled trial. Participants were randomly assigned to either the experimental condition that received the intervention in months 1 through 9 or the control group that was assigned to receive the intervention in month 10. In a prespecified data analysis plan, the experimental and contr...
Sleep deficiency is a hidden cost of our 24-7 society, with 70% of adults in the US admitting tha... more Sleep deficiency is a hidden cost of our 24-7 society, with 70% of adults in the US admitting that they routinely obtain insufficient sleep. Further, it is estimated that 50-70 million adults in the US have a sleep disorder. Undiagnosed and untreated sleep disorders are associated with diminished health for the individual and increased costs for the employer. Research has shown that adverse impacts on employees and employers can be mitigated through sleep health education and sleep disorder screening and treatment programs. Smartphone applications (app) are increasingly commonplace and represent promising, scalable modalities for such programs. The dayzz app is a personalized sleep training program that incorporates assessment of sleep disorders and offers a personalized comprehensive sleep improvement solution. Using a sample of day workers affiliated with a large institution of higher education, we will conduct a single-site, parallel-group, randomized, waitlist control trial. Par...
We explored the predictive value of a neurobehavioral performance assessment under rested baselin... more We explored the predictive value of a neurobehavioral performance assessment under rested baseline conditions (evaluated at 8 hours awake following 8 hours of sleep) on neurobehavioral response to moderate sleep loss (evaluated at 20 hours awake two days later) in 151 healthy young participants (18–30 years). We defined each participant’s response-to-sleep-loss phenotype based on the number of attentional failures on a 10-min visual psychomotor vigilance task taken at 20 hours awake (resilient: less than 6 attentional failures, n = 26 participants; non-resilient: 6 or more attentional failures, n = 125 participants). We observed that 97% of rested participants with 2 or more attentional failures (n = 73 of 151) and 100% of rested participants with 3 or more attentional failures (n = 57 of 151) were non-resilient after moderate sleep loss. Our approach can accurately identify a significant proportion of individuals who are at high risk for neurobehavioral performance impairment from ...
Despite sleep disturbance being a common complaint in individuals with autism, specific sleep phe... more Despite sleep disturbance being a common complaint in individuals with autism, specific sleep phenotypes and their relationship to adaptive functioning have yet to be identified. This study used cluster analysis to find distinct sleep patterns and relate them to independent measures of adaptive functioning in individuals with autism. Approximately 50,000 nights of care-giver sleep/wake logs were collected on school-days for 106 individuals with low functioning autism (87 boys, 14.77 ± 3.11 years) for 0.5-6 years (2.2 ± 1.5 years) from two residential schools. Using hierarchical cluster analysis, performed on summary statistics of each individual across their recording duration, two clusters of individuals with clearly distinguishable sleep phenotypes were found. The groups were summarized as 'unstable' sleepers (cluster 1, n = 41) and 'stable' sleepers (cluster 2, n = 65), with the former exhibiting reduced sleep duration, earlier sleep offset, and less stability in ...
Firefighters' schedules include extended shifts and long work weeks which cause sleep deficie... more Firefighters' schedules include extended shifts and long work weeks which cause sleep deficiency and circadian rhythm disruption. Many firefighters also suffer from undiagnosed sleep disorders, exacerbating fatigue. We tested the hypothesis that a workplace-based Sleep Health Program (SHP) incorporating sleep health education and sleep disorders screening would improve firefighter health and safety compared to standard practice. Prospective station-level randomized, field-based intervention. US fire department. 1189 firefighters. Sleep health education, questionnaire-based sleep disorders screening, and sleep clinic referrals for respondents who screened positive for a sleep disorder. Firefighters were randomized by station. Using departmental records, in an intention-to-treat analysis, firefighters assigned to intervention stations which participated in education sessions and had the opportunity to complete sleep disorders screening reported 46% fewer disability days than those...
Sleep deficiency and the use of sleep-promoting medication are prevalent during spaceflight. Oper... more Sleep deficiency and the use of sleep-promoting medication are prevalent during spaceflight. Operations frequently dictate work during the biological night and sleep during the biological day, which contribute to circadian misalignment. We investigated whether circadian misalignment was associated with adverse sleep outcomes before (preflight) and during spaceflight missions aboard the International Space Station (ISS). Actigraphy and photometry data for 21 astronauts were collected over 3,248 days of long-duration spaceflight on the ISS and 11 days prior to launch (n = 231 days). Sleep logs, collected one out of every 3 weeks in flight and daily on Earth, were used to determine medication use and subjective ratings of sleep quality. Actigraphy and photometry data were processed using Circadian Performance Simulation Software to calculate the estimated endogenous circadian temperature minimum. Sleep episodes were classified as aligned or misaligned relative to the estimated endogenous circadian temperature minimum. Mixed-effects regression models accounting for repeated measures were computed by data collection interval (preflight, flight) and circadian alignment status. The estimated endogenous circadian temperature minimum occurred outside sleep episodes on 13% of sleep episodes during preflight and on 19% of sleep episodes during spaceflight. The mean sleep duration in low-Earth orbit on the ISS was 6.4 ± 1.2 h during aligned and 5.4 ± 1.4 h (P o 0.01) during misaligned sleep episodes. During aligned sleep episodes, astronauts rated their sleep quality as significantly better than during misaligned sleep episodes (66.8 ± 17.7 vs. 60.2 ± 21.0, P o0.01). Sleep-promoting medication use was significantly higher during misaligned (24%) compared with aligned (11%) sleep episodes (Po 0.01). Use of any medication was significantly higher on days when sleep episodes were misaligned (63%) compared with when sleep episodes were aligned (49%; P o 0.01). Circadian misalignment is associated with sleep deficiency and increased medication use during spaceflight. These findings suggest that there is an immediate need to deploy and assess effective countermeasures to minimize circadian misalignment and consequent adverse sleep outcomes both before and during spaceflight.
Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, Jan 12, 2015
Heart attacks and motor vehicle crashes (MVC) are the leading causes of death in US firefighters.... more Heart attacks and motor vehicle crashes (MVC) are the leading causes of death in US firefighters. Given that sleep disorders are an independent risk factor for both of these, we examined the prevalence of common sleep disorders in a national sample of firefighters and their association with adverse health and safety outcomes. Firefighters (n = 6,933) from 66 US fire departments were assessed for common sleep disorders using validated screening tools, as available. Firefighters were also surveyed about health and safety, and documentation was collected for reported MVCs. A total of 37.2% of firefighters screened positive for any sleep disorder including obstructive sleep apnea (OSA), 28.4%; insomnia, 6.0%; shift work disorder, 9.1%; and restless legs syndrome, 3.4%. Compared with those who did not screen positive, firefighters who screened positive for a sleep disorder were more likely to report an MVC (adjusted odds ratio 2.00, 95% CI 1.29-3.12, p = 0.0021) and were more likely to s...
Numerous measures shown to depict reliably the developing drowsy state include changes in human e... more Numerous measures shown to depict reliably the developing drowsy state include changes in human electroencephalographic (EEG) output, 10,11 electrooculography (EOG) or other oculographic measurements, 7,12,13 heart rate variability, 14-16 and neurobehavioral measures of attention and vigilance (i.e., psychomotor vigilance task). 6,17,18 While these measurements are sensitive to drowsiness, they can present numerous problems: (1) most measures require substantial off-line processing, especially EEG/EOG; (2) performance measures present a snapshot Study Objectives: Numerous ocular parameters have been proposed as reliable physiological markers of drowsiness. A device that measures many of these parameters and then combines them into a single metric (the Johns Drowsiness Scale [JDS]) is being used commercially to assess drowsiness in professional drivers. Here, we examine how these parameters refl ect changes in drowsiness, and how they relate to objective and subjective indices of the drowsy state in a controlled laboratory setting. Design: A within subject prospective study. Participants: 29 healthy adults (18 males; mean age 23.3 ± 4.6 years; range 18-34 years) Interventions: N/A. Measurements and Results: Over the course of a 30-h extended wake vigil under constant routine (CR) conditions, participants were monitored using infrared refl ectance oculography (Optalert) and completed bi-hourly neurobehavioral tests, including the Karolinska Sleepiness Scale (KSS) and Psychomotor Vigilance Task (PVT). Ocular-defi ned increases in drowsiness were evident with extended time awake and during the biological night for all ocular parameters; JDS being the most sensitive marker of drowsiness induced by sleep regulatory processes (p < 0.0001). In addition, the associations between JDS in the preceding 10-min period and subsequent PVT lapses and KSS were stronger (AUC 0.74/0.80, respectively) than any other ocular metric, such that PVT lapses, mean response time (RT), and KSS increased in a dose-response manner as a function of prior JDS score (p < 0.0001). Conclusions: Ocular parameters captured by infrared refl ectance oculography detected fl uctuations in drowsiness due to time awake and during the biological night. The JDS outcome was the strongest predictor of drowsiness among those tested, and showed a clear association to objective and subjective measures of drowsiness. Our fi ndings indicate this real-time objective drowsiness monitoring system is an effective tool for monitoring changes in alertness and performance along the alert-drowsy continuum in a controlled laboratory setting.
Phoenix Mars Lander-Barger et al INTRODUCTION Space exploration presents physiological challenges... more Phoenix Mars Lander-Barger et al INTRODUCTION Space exploration presents physiological challenges for engineers, scientists and mission controllers. The Phoenix Mars Lander (PML) mission aimed to investigate the Martian arctic soils for history of water and potential for habitability. 1 In order to maximize personnel and communication efficiency as well as science output, mission control personnel were required to communicate with the solar powered Lander based on a Mars, rather than an Earth, day that lasts 24.65 h, almost 40 min longer per day than on Earth. Unfortunately for this mission, the human circadian system, which governs the daily timing of sleep, performance, and alertness, among many other functions, has evolved to synchronize strictly to a 24-h Earth day. Although early reports stated that the period of the human circadian pacemaker was close to 25 h (and therefore close to a Mars day), 2 more careful assessment of the circadian pacemaker in humans shows that the intrinsic circadian period is much closer to 24 h (24.2 h on average). 3,4 Synchronizing the circadian system to
Understanding and predicting faculty intent to leave is important to the development of improved ... more Understanding and predicting faculty intent to leave is important to the development of improved conceptual frameworks of faculty success as well as the implementation of effective retention strategies for academic leaders and institutions that invest considerable resources in recruitment, institutional support, and compensation. This study examined the relationship between various research-based factors and faculty intent to leave by integrating components identified in the extant literature for employee turnover more generally and faculty intent to leave more specifically. The results of binary logistic regression models identified workplace stress, being in a "soft-pure" discipline, fewer years of service at the university, and higher research productivity as key predictors of faculty having considered leaving for another institution. Key predictors for faculty having considered leaving academe altogether were being in a "hard-applied" discipline, not having a spouse or partner, a perceived lack of support, a perceived lack of fit, stress of raising a family, and dissatisfaction with certain aspects of the "faculty job". The implications for research, policy, and practice are discussed.
Low and high water periods create contrasting challenges for trees inhabiting periodically floode... more Low and high water periods create contrasting challenges for trees inhabiting periodically flooded wetlands. Low to moderate flood durations and frequencies may bring nutrient subsidies, while greater hydroperiods can be energetically stressful because of oxygen deficiency. We tested the hypothesis that hydroperiod affects the growth of mangrove seedlings and saplings in a greenhouse experiment by varying flood duration while keeping salinity and soil fertility constant. We measured the growth of mangrove trees along a hydroperiod gradient over a two-year period by tracking fine-scale diameter increment. Greenhouse growth studies indicated that under a full range of annual flood durations (0-8760 h/year), hydroperiod alone exerted a significant influence on growth for one species, Laguncularia racemosa, when flooding was imposed for two growing seasons. Field evaluations, on the other hand, indicated that increased flood duration may provide nutrient subsidies for tree growth. Diameter growth was related curvilinearly to site hydroperiod, including flood duration and frequency, as well as to salinity and soil fertility. An analysis of soil physico-chemical parameters suggests that phosphorus fertility, which was also linked directly to hydroperiod, is likely to influence growth on south Florida mangrove sites. The physical removal of phosphorus by greater flood frequencies from upland sources and/or addition of phosphorus from tidal flooding balanced against increased soil aeration and reduced water deficits may be an extremely important growth determinant for south Florida mangroves.
Woody debris is abundant in hurricane-impacted forests. With a major hurricane affecting South Fl... more Woody debris is abundant in hurricane-impacted forests. With a major hurricane affecting South Florida mangroves approximately every 20 yr, carbon storage and nutrient retention may be influenced greatly by woody debris dynamics. In addition, woody debris can influence seedling regeneration in mangrove swamps by trapping propagules and enhancing seedling growth potential. Here, we report on line-intercept woody debris surveys conducted in mangrove wetlands of South Florida 9-10 yr after the passage of Hurricane Andrew. The total volume of woody debris for all sites combined was estimated at 67 m 3 /ha and varied from 13 to 181 m 3 /ha depending upon differences in forest height, proximity to the storm, and maximum estimated wind velocities. Large volumes of woody debris were found in the eyewall region of the hurricane, with a volume of 132 m 3 /ha and a projected woody debris biomass of approximately 36 t/ha. Approximately half of the woody debris biomass averaged across all sites was associated as small twigs and branches (fine woody debris), since coarse woody debris >7.5 cm felled during Hurricane Andrew was fairly well decomposed. Much of the small debris is likely to be associated with post-hurricane forest dynamics. Hurricanes are responsible for large amounts of damage to mangrove ecosystems, and components of associated downed wood may provide a relative index of disturbance for mangrove forests. Here, we suggest that a fine:coarse woody debris ratio ≤0.5 is suggestive of a recent disturbance in mangrove wetlands, although additional research is needed to corroborate such findings.
BACKGROUND The effects on patient safety of eliminating extended-duration work shifts for residen... more BACKGROUND The effects on patient safety of eliminating extended-duration work shifts for resident physicians remain controversial. METHODS We conducted a multicenter, cluster-randomized, crossover trial comparing two schedules for pediatric resident physicians during their intensive care unit (ICU) rotations: extended-duration work schedules that included shifts of 24 hours or more (control schedules) and schedules that eliminated extended shifts and cycled resident physicians through day and night shifts of 16 hours or less (intervention schedules). The primary outcome was serious medical errors made by resident physicians, assessed by intensive surveillance, including direct observation and chart review. RESULTS The characteristics of ICU patients during the two work schedules were similar, but resident physician workload, described as the mean (±SD) number of ICU patients per resident physician, was higher during the intervention schedules than during the control schedules (8.8±2.8 vs. 6.7±2.2). Resident physicians made more serious errors during the intervention schedules than during the control schedules (97.1 vs. 79.0 per 1000 patient-days; relative risk, 1.53; 95% confidence interval [CI], 1.37 to 1.72; P<0.001). The number of serious errors unitwide were likewise higher during the intervention schedules (181.3 vs. 131.5 per 1000 patient-days; relative risk, 1.56; 95% CI, 1.43 to 1.71). There was wide variability among sites, however; errors were lower during intervention schedules than during control schedules at one site, rates were similar during the two schedules at two sites, and rates were higher during intervention schedules than during control schedules at three sites. In a secondary analysis that was adjusted for the number of patients per resident physician as a potential confounder, intervention schedules were no longer associated with an increase in errors. CONCLUSIONS Contrary to our hypothesis, resident physicians who were randomly assigned to schedules that eliminated extended shifts made more serious errors than resident physicians assigned to schedules with extended shifts, although the effect varied by site. The number of ICU patients cared for by each resident physician was higher during schedules that eliminated extended shifts.
The Journal of Arthroplasty, Volume 22, Issue 2, Pages 310, February 2007, Authors:John Callaghan... more The Journal of Arthroplasty, Volume 22, Issue 2, Pages 310, February 2007, Authors:John Callaghan, MD; Matthew Teusink, BA; Jonathan Donigan, MD; Lucian Warth, BS; Steve Liu, MD;Jason Sullivan, BS; Devon Goetz, MD; David Vittetoe, MD; Richard Johnston, MD. ...
Introduction Sleep deficiency and undiagnosed or untreated sleep disorders are pervasive among em... more Introduction Sleep deficiency and undiagnosed or untreated sleep disorders are pervasive among employed adults, yet are often ignored in the context of workplace health promotion. Smartphone applications (apps) are a promising, scalable approach to improving sleep among employees. We evaluated an online sleep education program followed by access to a mobile sleep training program, the dayzz app, that promotes healthy sleep, sleep disorders awareness and intervention. Methods In a sample of daytime employees affiliated with a large healthcare organization, we evaluated the intervention (sleep education at baseline plus access to the personalized app for up to 9 months) in a parallel group, randomized controlled trial. Participants were randomly assigned to either the experimental condition that received the intervention in months 1 through 9 or the control group that was assigned to receive the intervention in month 10. In a prespecified data analysis plan, the experimental and contr...
Sleep deficiency is a hidden cost of our 24-7 society, with 70% of adults in the US admitting tha... more Sleep deficiency is a hidden cost of our 24-7 society, with 70% of adults in the US admitting that they routinely obtain insufficient sleep. Further, it is estimated that 50-70 million adults in the US have a sleep disorder. Undiagnosed and untreated sleep disorders are associated with diminished health for the individual and increased costs for the employer. Research has shown that adverse impacts on employees and employers can be mitigated through sleep health education and sleep disorder screening and treatment programs. Smartphone applications (app) are increasingly commonplace and represent promising, scalable modalities for such programs. The dayzz app is a personalized sleep training program that incorporates assessment of sleep disorders and offers a personalized comprehensive sleep improvement solution. Using a sample of day workers affiliated with a large institution of higher education, we will conduct a single-site, parallel-group, randomized, waitlist control trial. Par...
We explored the predictive value of a neurobehavioral performance assessment under rested baselin... more We explored the predictive value of a neurobehavioral performance assessment under rested baseline conditions (evaluated at 8 hours awake following 8 hours of sleep) on neurobehavioral response to moderate sleep loss (evaluated at 20 hours awake two days later) in 151 healthy young participants (18–30 years). We defined each participant’s response-to-sleep-loss phenotype based on the number of attentional failures on a 10-min visual psychomotor vigilance task taken at 20 hours awake (resilient: less than 6 attentional failures, n = 26 participants; non-resilient: 6 or more attentional failures, n = 125 participants). We observed that 97% of rested participants with 2 or more attentional failures (n = 73 of 151) and 100% of rested participants with 3 or more attentional failures (n = 57 of 151) were non-resilient after moderate sleep loss. Our approach can accurately identify a significant proportion of individuals who are at high risk for neurobehavioral performance impairment from ...
Despite sleep disturbance being a common complaint in individuals with autism, specific sleep phe... more Despite sleep disturbance being a common complaint in individuals with autism, specific sleep phenotypes and their relationship to adaptive functioning have yet to be identified. This study used cluster analysis to find distinct sleep patterns and relate them to independent measures of adaptive functioning in individuals with autism. Approximately 50,000 nights of care-giver sleep/wake logs were collected on school-days for 106 individuals with low functioning autism (87 boys, 14.77 ± 3.11 years) for 0.5-6 years (2.2 ± 1.5 years) from two residential schools. Using hierarchical cluster analysis, performed on summary statistics of each individual across their recording duration, two clusters of individuals with clearly distinguishable sleep phenotypes were found. The groups were summarized as 'unstable' sleepers (cluster 1, n = 41) and 'stable' sleepers (cluster 2, n = 65), with the former exhibiting reduced sleep duration, earlier sleep offset, and less stability in ...
Firefighters' schedules include extended shifts and long work weeks which cause sleep deficie... more Firefighters' schedules include extended shifts and long work weeks which cause sleep deficiency and circadian rhythm disruption. Many firefighters also suffer from undiagnosed sleep disorders, exacerbating fatigue. We tested the hypothesis that a workplace-based Sleep Health Program (SHP) incorporating sleep health education and sleep disorders screening would improve firefighter health and safety compared to standard practice. Prospective station-level randomized, field-based intervention. US fire department. 1189 firefighters. Sleep health education, questionnaire-based sleep disorders screening, and sleep clinic referrals for respondents who screened positive for a sleep disorder. Firefighters were randomized by station. Using departmental records, in an intention-to-treat analysis, firefighters assigned to intervention stations which participated in education sessions and had the opportunity to complete sleep disorders screening reported 46% fewer disability days than those...
Sleep deficiency and the use of sleep-promoting medication are prevalent during spaceflight. Oper... more Sleep deficiency and the use of sleep-promoting medication are prevalent during spaceflight. Operations frequently dictate work during the biological night and sleep during the biological day, which contribute to circadian misalignment. We investigated whether circadian misalignment was associated with adverse sleep outcomes before (preflight) and during spaceflight missions aboard the International Space Station (ISS). Actigraphy and photometry data for 21 astronauts were collected over 3,248 days of long-duration spaceflight on the ISS and 11 days prior to launch (n = 231 days). Sleep logs, collected one out of every 3 weeks in flight and daily on Earth, were used to determine medication use and subjective ratings of sleep quality. Actigraphy and photometry data were processed using Circadian Performance Simulation Software to calculate the estimated endogenous circadian temperature minimum. Sleep episodes were classified as aligned or misaligned relative to the estimated endogenous circadian temperature minimum. Mixed-effects regression models accounting for repeated measures were computed by data collection interval (preflight, flight) and circadian alignment status. The estimated endogenous circadian temperature minimum occurred outside sleep episodes on 13% of sleep episodes during preflight and on 19% of sleep episodes during spaceflight. The mean sleep duration in low-Earth orbit on the ISS was 6.4 ± 1.2 h during aligned and 5.4 ± 1.4 h (P o 0.01) during misaligned sleep episodes. During aligned sleep episodes, astronauts rated their sleep quality as significantly better than during misaligned sleep episodes (66.8 ± 17.7 vs. 60.2 ± 21.0, P o0.01). Sleep-promoting medication use was significantly higher during misaligned (24%) compared with aligned (11%) sleep episodes (Po 0.01). Use of any medication was significantly higher on days when sleep episodes were misaligned (63%) compared with when sleep episodes were aligned (49%; P o 0.01). Circadian misalignment is associated with sleep deficiency and increased medication use during spaceflight. These findings suggest that there is an immediate need to deploy and assess effective countermeasures to minimize circadian misalignment and consequent adverse sleep outcomes both before and during spaceflight.
Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine, Jan 12, 2015
Heart attacks and motor vehicle crashes (MVC) are the leading causes of death in US firefighters.... more Heart attacks and motor vehicle crashes (MVC) are the leading causes of death in US firefighters. Given that sleep disorders are an independent risk factor for both of these, we examined the prevalence of common sleep disorders in a national sample of firefighters and their association with adverse health and safety outcomes. Firefighters (n = 6,933) from 66 US fire departments were assessed for common sleep disorders using validated screening tools, as available. Firefighters were also surveyed about health and safety, and documentation was collected for reported MVCs. A total of 37.2% of firefighters screened positive for any sleep disorder including obstructive sleep apnea (OSA), 28.4%; insomnia, 6.0%; shift work disorder, 9.1%; and restless legs syndrome, 3.4%. Compared with those who did not screen positive, firefighters who screened positive for a sleep disorder were more likely to report an MVC (adjusted odds ratio 2.00, 95% CI 1.29-3.12, p = 0.0021) and were more likely to s...
Numerous measures shown to depict reliably the developing drowsy state include changes in human e... more Numerous measures shown to depict reliably the developing drowsy state include changes in human electroencephalographic (EEG) output, 10,11 electrooculography (EOG) or other oculographic measurements, 7,12,13 heart rate variability, 14-16 and neurobehavioral measures of attention and vigilance (i.e., psychomotor vigilance task). 6,17,18 While these measurements are sensitive to drowsiness, they can present numerous problems: (1) most measures require substantial off-line processing, especially EEG/EOG; (2) performance measures present a snapshot Study Objectives: Numerous ocular parameters have been proposed as reliable physiological markers of drowsiness. A device that measures many of these parameters and then combines them into a single metric (the Johns Drowsiness Scale [JDS]) is being used commercially to assess drowsiness in professional drivers. Here, we examine how these parameters refl ect changes in drowsiness, and how they relate to objective and subjective indices of the drowsy state in a controlled laboratory setting. Design: A within subject prospective study. Participants: 29 healthy adults (18 males; mean age 23.3 ± 4.6 years; range 18-34 years) Interventions: N/A. Measurements and Results: Over the course of a 30-h extended wake vigil under constant routine (CR) conditions, participants were monitored using infrared refl ectance oculography (Optalert) and completed bi-hourly neurobehavioral tests, including the Karolinska Sleepiness Scale (KSS) and Psychomotor Vigilance Task (PVT). Ocular-defi ned increases in drowsiness were evident with extended time awake and during the biological night for all ocular parameters; JDS being the most sensitive marker of drowsiness induced by sleep regulatory processes (p < 0.0001). In addition, the associations between JDS in the preceding 10-min period and subsequent PVT lapses and KSS were stronger (AUC 0.74/0.80, respectively) than any other ocular metric, such that PVT lapses, mean response time (RT), and KSS increased in a dose-response manner as a function of prior JDS score (p < 0.0001). Conclusions: Ocular parameters captured by infrared refl ectance oculography detected fl uctuations in drowsiness due to time awake and during the biological night. The JDS outcome was the strongest predictor of drowsiness among those tested, and showed a clear association to objective and subjective measures of drowsiness. Our fi ndings indicate this real-time objective drowsiness monitoring system is an effective tool for monitoring changes in alertness and performance along the alert-drowsy continuum in a controlled laboratory setting.
Phoenix Mars Lander-Barger et al INTRODUCTION Space exploration presents physiological challenges... more Phoenix Mars Lander-Barger et al INTRODUCTION Space exploration presents physiological challenges for engineers, scientists and mission controllers. The Phoenix Mars Lander (PML) mission aimed to investigate the Martian arctic soils for history of water and potential for habitability. 1 In order to maximize personnel and communication efficiency as well as science output, mission control personnel were required to communicate with the solar powered Lander based on a Mars, rather than an Earth, day that lasts 24.65 h, almost 40 min longer per day than on Earth. Unfortunately for this mission, the human circadian system, which governs the daily timing of sleep, performance, and alertness, among many other functions, has evolved to synchronize strictly to a 24-h Earth day. Although early reports stated that the period of the human circadian pacemaker was close to 25 h (and therefore close to a Mars day), 2 more careful assessment of the circadian pacemaker in humans shows that the intrinsic circadian period is much closer to 24 h (24.2 h on average). 3,4 Synchronizing the circadian system to
Uploads
Papers by Jason Sullivan