Nicole Lovato

Bio: Nicole Lovato is an academic researcher from Flinders University. The author has contributed to research in topics: Insomnia & Circadian rhythm. The author has an hindex of 23, co-authored 69 publications receiving 1788 citations. Previous affiliations of Nicole Lovato include Cooperative Research Centre & Repatriation General Hospital.

The effects of napping on cognitive functioning

Abstract: Naps (brief sleeps) are a global and highly prevalent phenomenon, thus warranting consideration for their effects on cognitive functioning. Naps can reduce sleepiness and improve cognitive performance. The benefits of brief (5-15 min) naps are almost immediate after the nap and last a limited period (1-3h). Longer naps (> 30 min) can produce impairment from sleep inertia for a short period after waking but then produce improved cognitive performance for a longer period (up to many hours). Other factors that affect the benefits from the nap are the circadian timing of the nap with early afternoon being the most favourable time. Longer periods of prior wakefulness favour longer naps over brief naps. Those who regularly nap seem to show greater benefits than those who rarely nap. These conclusions, however, need to be accepted cautiously until more comprehensive research programmes are conducted in which all these parameters are varied. Research is also needed to test the benefits of brief naps taken more naturalistically at the time when sleepiness becomes intrusive. The significant benefits of a brief nap, containing virtually no slow wave EEG activity, are not predicted by the present theory of homeostatic sleep drive (Process S). A new biological process (Process O) suggests that sleep onset followed by only 7-10 min of sleep can result in a substantial increase of alertness because it allows the rapid dissipation of inhibition in the 'wake-active' cells associated with the 'sleep-switch' mechanism rather than the dissipation of Process S.

The impact of prolonged violent video-gaming on adolescent sleep: an experimental study.

Abstract: Video-gaming is an increasingly prevalent activity among children and adolescents that is known to influence several areas of emotional, cognitive and behavioural functioning. Currently there is insufficient experimental evidence about how extended video-game play may affect adolescents' sleep. The aim of this study was to investigate the short-term impact of adolescents' prolonged exposure to violent video-gaming on sleep. Seventeen male adolescents (mean age = 16 ± 1 years) with no current sleep difficulties played a novel, fast-paced, violent video-game (50 or 150 min) before their usual bedtime on two different testing nights in a sleep laboratory. Objective (polysomnography-measured sleep and heart rate) and subjective (single-night sleep diary) measures were obtained to assess the arousing effects of prolonged gaming. Compared with regular gaming, prolonged gaming produced decreases in objective sleep efficiency (by 7 ± 2%, falling below 85%) and total sleep time (by 27 ± 12 min) that was contributed by a near-moderate reduction in rapid eye movement sleep (Cohen's d = 0.48). Subjective sleep-onset latency significantly increased by 17 ± 8 min, and there was a moderate reduction in self-reported sleep quality after prolonged gaming (Cohen's d = 0.53). Heart rate did not differ significantly between video-gaming conditions during pre-sleep game-play or the sleep-onset phase. Results provide evidence that prolonged video-gaming may cause clinically significant disruption to adolescent sleep, even when sleep after video-gaming is initiated at normal bedtime. However, physiological arousal may not necessarily be the mechanism by which technology use affects sleep. Language: en

The Effect of Presleep Video-Game Playing on Adolescent Sleep

Abstract: The 24-hour circadian rhythm becomes increasingly delayed throughout puberty, making adolescents more prone to becoming “evening types.”1,2 During adolescence, increased alertness occurs later in the evening, making it difficult to initiate sleep at a reasonable hour.1 As a result, the adolescent has “time to fill” late at night. This time is spent performing homework, casual work, or socializing,3 as well as reading or using electronic media such as computer games, television, mobile phones, or the Internet.4 Unfortunately, some of these activities are stimulating and can themselves promote late-night alertness. Emerging evidence suggests that playing video games before bedtime may be a particularly disruptive presleep activity for adolescents.4 BRIEF SUMMARY Current Knowledge/Study Rationale: Cross-sectional evidence indicates adolescents playing video games prior to sleep results in sleep disturbance. The present study sought to confirm these findings using an experimental paradigm. Study Impact: The magnitude of the effect of pre-sleep videogaming for adolescents may be more modest than previously thought. However, further experimental studies are needed to ascertain whether there is a cumulative effect of playing video games, and whether particular individuals (e.g., poor sleepers) are more susceptible to the ill effects of pre-sleep videogaming. Cross-sectional research has linked stimulating, nighttime video-game playing by adolescents to later bedtimes, insufficient sleep, and increased daytime tiredness.4,5 However, sleep latency was not measured, providing little insight into the stimulation from video gaming on nocturnal sleep. Two experimental studies have investigated the effect on sleep latency, though their findings are inconsistent. In a study of 11 young adolescents (mean age = 13.5 years), Dworak et al.6 found that playing video games for 60 minutes between 18:00 and 19:00 led to a mean 21.7-minute increase in sleep onset latency (SOL) relative to a control condition. In their study of 7 young adults (mean age = 24.7 years), Higuchi et al.7 found that the participants' mean SOL was just 2.3 minutes longer after playing a video game for 2 hours and 45 minutes, relative to a control condition. This SOL extension7 is considered to be too short to have any detrimental effects on adolescent sleep. Interestingly, SOL was short (< 7 minutes) in all conditions, most likely a reflection of increased homeostatic sleep pressure because lights out occurred at 02:00 (1 hour later than participants' typical lights-out time).7 The present study seeks to address this limitation by verifying the extent to which presleep video-game playing can increase SOL for adolescents (aged 14-18 years) when sleep is attempted at their normal “lights-out” time. The most logical explanation as to how video-game playing can reduce sleepiness relates to the stimulating nature of the activity. The active participation of video-game playing has been consistently shown to increase physiologic arousal,8,9 with heart rate the most common index used. Modern video games may evoke arousal through their interactive nature, particularly the “survival” of the player dependent on responding to stimuli rapidly and effectively8 in a virtual world that graphically depicts realistic and violent subject matter.10 However, physiologic arousal responses to videogaming have been mixed,7,11 suggesting that multiple indicators of arousal should be employed. Cognitive alertness is another potential mechanism to impair efforts to initiate sleep,12 and can be objectively measured by calculating electroencephalogram (EEG) alpha or beta activity, or by analyzing neuronal activity.13 Only 1 study has examined the capacity of video-game playing to increase cognitive alertness.13 Using functional magnetic resonance imaging (fMRI), Mathiak and Weber found video-game playing to heighten cognitive alertness, especially during violent scenes.13 This is extremely relevant considering that more than half of video games (including the one used in the present study) depict violent scenes.14 Therefore, physiologic arousal and cognitive alertness may be partially responsible for the previously reported effect of video-game playing on sleepiness. We propose that videogaming, compared with an opposing, presleep activity requiring passive observation, will result in participants' greater arousal that subsequently affects the sleep initiation process. Research has also suggested that presleep video-game playing may influence sleep architecture, although again, findings have been inconsistent, with 1 study finding a reduction of 4.7 minutes of slow wave sleep (SWS) in young adolescents,6 whereas, in another study, young adults experienced 15.8 minutes less rapid eye movement (REM) sleep.7 Given that research has indicated that insufficient REM sleep and SWS may impair memory processes,15,16 clarifying the impact that videogaming may have on sleep architecture for adolescents is important. Much ambiguity remains regarding the potential for presleep video-game playing to directly affect adolescent sleep, an unfortunate situation considering the activity's widespread popularity.17 With this in mind, we predict that presleep video-game playing will increase alertness (i.e., increased SOL and decreased subjective sleepiness), relative to control, and that this will be influenced by increased physiologic arousal and cognitive alertness. A more exploratory approach regarding the effect of presleep video-game playing on sleep architecture will be taken, due to the conflicting nature of previous findings.

Chronotype differences in circadian rhythms of temperature, melatonin, and sleepiness as measured in a modified constant routine protocol.

Abstract: Evening chronotypes typically have sleep patterns timed 2-3 hours later than morning chronotypes. Ambulatory studies have suggested that differences in the timing of underlying circadian rhythms as a cause of the sleep period differences. However, differences in endogenous circadian rhythms are best explored in laboratory protocols such as the constant routine. We used a 27-hour modified constant routine to measure the endogenous core temperature and melatonin circadian rhythms as well as subjective and objective sleepiness from hourly 15-minute sleep opportunities. Ten (8f) morning type individuals were compared with 12 (8f) evening types. All were young, healthy, good sleepers. The typical sleep onset, arising times, circadian phase markers for temperature and melatonin and objective sleepiness were all 2-3 hours later for the evening types than morning types. However, consistent with past studies the differences for the subjective sleepiness rhythms were much greater (5-9 hours). Therefore, the present study supports the important role of subjective alertness/sleepiness in determining the sleep period differences between morning and evening types and the possible vulnerability of evening types to delayed sleep phase disorder.

Using Multivariate Statistics

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Light-emitting diodes

Abstract: Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

Management of Chronic Insomnia Disorder in Adults: A Clinical Practice Guideline From the American College of Physicians

Abstract: These new guideline recommendations from the American College of Physicians provide evidence-based advice for the management of chronic insomnia disorder in adults. Implementation of these guidelin...