Daytime Exposure to Short- and Medium-Wavelength Light Did Not Improve Alertness and Neurobehavioral Performance.

While previous studies have demonstrated short-wavelength sensitivity to the acute alerting effects of light during the biological night, fewer studies have assessed the alerting effect of light during the daytime. This study assessed the wavelength-dependent sensitivity of the acute alerting effects of daytime light exposure following chronic sleep restriction in 60 young adults (29 men, 31 women; 22.5 ± 3.1 mean ± SD years). Participants were restricted to 5 h time in bed the night before laboratory admission and 3 h time in bed in the laboratory, aligned by wake time. Participants were randomized for exposure to 3 h total of either narrowband blue (λmax 458-480 nm, n = 23) or green light (λmax 551-555 nm, n = 25) of equal photon densities (2.8-8.4 × 10(13) photons/cm(2)/sec), beginning 3.25 h after waking, and compared with a darkness control (0 lux, n = 12). Subjective sleepiness (Karolinska Sleepiness Scale), sustained attention (auditory Psychomotor Vigilance Task), mood (Profile of Mood States Bi-Polar form), working memory (2-back task), selective attention (Stroop task), and polysomnographic and ocular sleepiness measures (Optalert) were assessed prior to, during, and after light exposure. We found no significant effect of light wavelength on these measures, with the exception of a single mood subscale. Further research is needed to optimize the characteristics of lighting systems to induce alerting effects during the daytime, taking into account potential interactions between homeostatic sleep pressure, circadian phase, and light responsiveness.

Infant gastro-oesophageal reflux disease (GORD): Australian GP attitudes and practices.

AIM: The aim of this study was to evaluate the attitudes and practices of Australian general practitioners (GPs) regarding infant gastro-oesophageal reflux disease (GORD) diagnosis and management. METHODS: A national cross-sectional survey, involving a random sample of currently practising Australian GPs (n = 2319) was undertaken between July and September 2011. GPs attitudes and management of infant GORD were surveyed via an online and paper-based 41-item questionnaire. RESULTS: In total, 400 responses were analysed (17.24% response rate). The majority of GPs employed empirical trials of acid-suppression medication and/or lifestyle modifications to diagnose infant GORD. GPs frequently recommended dietary modification despite the belief that they were only moderately effective at best. In addition, GPs frequently prescribed acid-suppression medication, despite concerns regarding their safety in the infant population. Other GP concerns included the lack of clinical guidelines and education for GPs about infant GORD, as well as the level of evidence available for the safety and efficacy of diagnostic tests and treatments. CONCLUSION: Despite the important role Australian GPs play in the diagnosis and management of infant GORD, high-level evidence-based guidelines for GPs are lacking. Consequently, GPs engage in diagnostic and management practices despite their concerns regarding the safety and effectiveness.

Inter-Individual Differences in Neurobehavioural Impairment following Sleep Restriction Are Associated with Circadian Rhythm Phase.

Although sleep restriction is associated with decrements in daytime alertness and neurobehavioural performance, there are considerable inter-individual differences in the degree of impairment. This study examined the effects of short-term sleep restriction on neurobehavioural performance and sleepiness, and the associations between individual differences in impairments and circadian rhythm phase. Healthy adults (n = 43; 22 M) aged 22.5 ± 3.1 (mean ± SD) years maintained a regular 8:16 h sleep:wake routine for at least three weeks prior to laboratory admission. Sleep opportunity was restricted to 5 hours time-in-bed at home the night before admission and 3 hours time-in-bed in the laboratory, aligned by wake time. Hourly saliva samples were collected from 5.5 h before until 5 h after the pre-laboratory scheduled bedtime to assess dim light melatonin onset (DLMO) as a marker of circadian phase. Participants completed a 10-min auditory Psychomotor Vigilance Task (PVT), the Karolinska Sleepiness Scale (KSS) and had slow eye movements (SEM) measured by electrooculography two hours after waking. We observed substantial inter-individual variability in neurobehavioural performance, particularly in the number of PVT lapses. Increased PVT lapses (r = -0.468, p < 0.01), greater sleepiness (r = 0.510, p < 0.0001), and more slow eye movements (r = 0.375, p = 0.022) were significantly associated with later DLMO, consistent with participants waking at an earlier circadian phase. When the difference between DLMO and sleep onset was less than 2 hours, individuals were significantly more likely to have at least three attentional lapses the following morning. This study demonstrates that the phase of an individual's circadian system is an important variable in predicting the degree of neurobehavioural performance impairment in the hours after waking following sleep restriction, and confirms that other factors influencing performance decrements require further investigation.