Biomedical subjects

M Douglas Ris

Publications and source records attributed to M Douglas Ris.

4 recordsLinked to original sources

PubMed2003

The night float paradigm to decrease sleep deprivation: good solution or a new problem?

In the late 1980s physician residency training programs developed the night float rotation, characterized by a sequence of 5 - 15 days of night work without any daytime duties, thereby involving an abrupt reversal of the wake - sleep schedule. We examined the effect of the night float rotation on sleep, mood and performance of pediatric residents. Residents completed sleep diaries daily, and tests of mood (Profile of Mood States) and attention (Conner's Continuous Performance Test) three times a week during the two-week night float rotation, and during equivalent blocks of time of their daytime rotations. Results show that, despite having ample opportunity to sleep during the day, while on night float rotation residents slept less than during the nights of their normal daytime rotations, 6.3 h +/- 2.5 h and 7.2 h +/- 1.7 h, respectively, p < 0.0001. Also, during night float compared to daytime rotations residents had increased fatigue-inertia scores, 8.7 +/- 4.1 and 4.8 +/- 2.4, respectively, p < 0.0001, and decreased vigor-activity scores 10.7 +/- 5.4 and 14.8 +/- 5.3, respectively, p = 0.02. The scores for attention were not significantly different between night float and daytime rotations. The correlation coefficients of fatigue with measures of attention were not statistically significant for daytime rotations. However, for night float fatigue correlated with omission errors, r = 0.51, p = 0.001 and with attentiveness r = - 0.36, p = 0.03. Training programs that adopt the night float rotation must be aware of potential deleterious effects of the night float rotation as they may lead to serious consequences on residents' performance and patients' safety.

Adaptation, Physiological↗

PubMed2003

Causal inference in lead research: introduction to the special section on the neurobehavioral effects of environmental lead.

This Special Section on the Neurobehavioral Effects of Environmental Lead includes empirical reports from three major longitudinal prospective studies and a review of animal research modeling effects of lead on human cognition. This Introductory article addresses a fundamental controversy in lead and other epidemiologic research. It is argued that, contrary to conventional wisdom, valid causal inferences can be made from correlational research. Justification for this is to be found in contemporary frameworks drawn from the field of the philosophy of science; an essential, but often neglected perspective for such metatheoretical issues as causal inference. It is concluded that the nonexperimental methods described in the articles comprising this Special Section can, indeed, contribute to causal formulations of lead effects on human development, and that such inferences are not exclusive to experimental evidence.

Causality↗

PubMed2003

Cognitive development of lead exposed children from ages 6 to 15 years: an application of growth curve analysis.

The effect of lead exposure on cognitive growth patterns was assessed in a longitudinal study of 196 children. Performances on tests of verbal comprehension and perceptual organization (Vocabulary & Block Design, Wechsler Intelligence Scales for Children) were measured at ages 6.5, 11 and 15 years. Growth curve analyses revealed that the quadratic model best described the relationship between test scores and age. Children with higher lead levels, as measured at age 15 years, demonstrated lower verbal comprehension scores over time and greater decline in their rate of Vocabulary development at age 15 years, as compared to children with lower lead levels. Lead exposure was not significantly associated with growth in perceptual organization test scores. Socioeconomic status and maternal intelligence were statistically significantly associated with growth patterns for both test scores, independent of the effects of lead. The findings suggest that lead negatively impacts the developmental progression of specific cognitive skills from childhood through adolescence.

Adolescent↗

PubMed2002

Impact of night-float rotation on sleep, mood, and alertness: the resident's perception.

Night-float rotations were designed to alleviate the workload of residents on night call and thereby improve patient safety. However, the impact of the night float on residents is yet to be surveyed. We assessed the impact of the night-float rotation on pediatric residents using an anonymous questionnaire that covered topics, based on recall, about sleep, mood, alertness, adjustment, and others. The study was conducted in a major tertiary pediatric teaching hospital in the United States. Participants were pediatric residents who had completed one or two night-float rotations and were in active training at our teaching hospital at the time of the study. Fifty-two of 60 eligible residents (87%) responded. Sleep duration during the night-float rotation was shorter than during day-shift work in 24 residents (46%), longer in 20 (38%), and unchanged in eight (15%). A higher proportion of residents took longer to fall asleep, had more difficulty falling asleep, had more sleep interruptions, and felt less rested upon awakening. Twenty-four residents (46%) felt that their bodies never adjusted to the night shift. Also, 22 residents (43%) felt moody or depressed in contrast to seven (14%) who felt depressed during the daytime rotation (p = 0.0001). Twenty-one residents (41%) felt they were slower in their thinking during the night float than daytime rotations. The results suggest that disturbances of sleep and mood and decreased alertness, typical of night shift, are present in the night-float rotation. Residency programs should monitor closely the impact of the night-float rotation on resident well being and patient safety. The impact of night-shift work should be considered in the design of night-float schedules, and teaching should be provided for residents to learn coping strategies for night-shift work.

Affect↗