STEM with Scientific and Technical Writing encompasses both scientific research and engineering. The first half of the year focuses on student independent research projects, which involve brainstorming, literature review, and experimentation. The latter half transitions to a group project, in which students develop an assistive technology product. Students practice communicating their process with scientific writing assignments.
This project used a sunrise alarm which simulated dawn to decrease the effects of sleep inertia. Sleep quality and overall daytime sleepiness were also looked at.
Sleep inertia is the period of impaired performance that occurs immediately after waking, lasting up to two hours. Sleep inertia causes a myriad of detrimental effects, including increased reaction time, drowsiness, and risk of vehicle crashes. To ease the effects of sleep inertia, a sunrise alarm which simulates the sunrise by gradually increasing light was created. Test subjects used their standard sound alarm for a week, recording subjective sleepiness and sleep quality. The process was then repeated with sunrise alarms. Results showed that sleepiness decreased over the first thirty minutes after waking in both controls. There was no significant difference in sleep quality, daytime sleepiness, or sleepiness right after waking, but there was a difference 30 minutes after waking. Further research is needed to determine what the optimal light level is to induce wakefulness, as well as the light increase rate.
People experience drowsiness right after waking, which is detrimental to their cognitive performance.
The overall aim of this project is to develop an alarm system that utilizes LED light as a mechanism to wake people up. As a result of using the light alarm, sleepiness should decrease, and sleep quality could possibly improve as well.
Sleep inertia is defined to be the period of impaired performance and increased drowsiness after awakening (Lubin et al., 1976). Sleepiness negatively affects decision making, behavioral alertness, attention, reaction time, and psychomotor vigilance (Banks & Dinges, 2007; Bartlett et al., 2022; Jackson et al., 2013). Reaction time and psychomotor vigilance in particular are associated with driving; one study showed that sleep loss resulted in decreased driving performance in a simulation (Jackson et al., 2013). 2.5% of fatal crashes involve drowsy driving, and in the years 2005-2009, there were at least 30,000 crashes each year involving drowsy driving (Traffic Safety Facts Crash Stats: Drowsy Driving, 2011).
Previous studies have examined multiple countermeasures to sleep inertia, including caffeine, light, and sound (Hilditch et al., 2016). Previous studies show that caffeine improves subjective alertness and objective performance during sleep inertia (Hayashi et al., 2003; Newman et al. 2013). While Hayashi showed that caffeine in the form of coffee worked better than light, ingesting caffeine can cause diarrhea and increased blood pressure (“The Effects of Caffeine on Your Body”). Additionally, some people may avoid the use of coffee, leaving them without that option to decrease sleepiness.
In the case of light, subjective sleepiness and fatigue was lowered after exposure to a bright light for one minute after an afternoon nap (Hayashi et al., 2003). Furthermore, dawn simulation has been shown to improve subjective alertness and objective performance after waking (Thompson et al., 2014) and improve mood in people with winter depression (Norden and Avery, 1993).
The testing consisted of two phases: the normal alarm phase and the sunrise alarm phase. During the normal alarm phase, the participants used their normal alarm on weekdays. During the sunrise alarm phase, they used the sunrise alarm on weekdays. Each phase lasted for one week, consisting of five weekdays and two weekends. At five and thirty minutes post-wake on each weekday, the participants rated their subjective sleepiness. At the end of each phase, they completed the Pittsburgh Sleep Quality Index and the Epworth Sleepiness Scale.
To measure subjective sleepiness at a certain point in team,
we created a simple 1-10 scale called the Instantaneous
Sleepiness Scale (ISS). A score of 1 indicates full
alertness, while a score of 10 means extremely sleepy.
The Pittsburgh Sleep Quality Index (PSQI) is a self-reported
questionnaire to quantify sleep quality (Buysse et al.,
1988). The score range is 0-21. A score <=5 indicates
good sleep quality and a score >5 indicates poor sleep
quality. The Epworth Sleepiness Scale (ESS) is a
questionnaire which measures general level of daytime
sleepiness over a period of time, rather than a specific
moment in time (Johns, 1991). It is scored from 0 to 24. A
score of 16 or more indicates excessive daytime sleepiness
and a normal score is in the range 0-9. 10-15 could mean
excessive daytime sleepiness depending on the situation.
Statistical test
Ideally, 4 matched pairs tests would have been used for the phase 1 and phase 2 values of 5 minutes ISS, 30 minutes ISS, ESS, and PSQI. Due to a small sample size (n = 5 for ESS and PSQI, n = 25 for ISS) and non-normal data, the Wilcoxon signed-rank test was used to evaluate the differences between each of the scales. Additionally, it was also used to evaluate the difference between 5 minute ISS and 30 minute ISS of both phases.
Instantaneous Sleepiness ScaleSubjective sleepiness significantly decreased between 5 minutes and 30 minutes after waking (⍺ = 0.01). This agrees with the findings from Jewett in 2014, that sleep inertia dissipates with time. The difference of 5 minutes ISS between phase 1 and phase 2 was not significant, but 30 minutes was. This was a surprising result, because it was expected that if there was to be an effect, it would be right after waking up. Then, the difference between normal alarm sleepiness and sunrise alarm sleepiness would decrease as time passed. However, the result was the opposite. Initially, the subject feels just as tired, then the dissipation of sleep inertia is accelerated.
Epworth Sleepiness Scale and Pittsburgh Sleep Quality IndexNeither the ESS nor the PSQI had a significant difference between the normal alarm phase and sunrise alarm phase (⍺ = 0.05). Furthermore, performing a linear regression on the graph of PSQI scores vs. ESS scores revealed no correlation between sleep quality and daytime sleepiness.
The objective of this study was to construct an alarm that emitted light to reduce the effects of sleep inertia. Testing included a normal alarm phase and a sunrise alarm phase, in which subjective sleepiness, daytime sleepiness, and sleep quality were assessed. Subjective sleepiness at 30 minutes after waking showed a significant decrease when using the sunrise alarm compared to the normal alarm. This supports the idea of using light as a countermeasure to sleep inertia. Reducing the effects of sleep inertia and sleepiness has implications for the entire population. Being less sleepy improves cognitive function and driving performance (Jackson et al., 2013; Thompson et al., 2014). Additionally, it has a positive effect on mood and energy of people with winter depression (Norden & Avery, 1993).