Effects of Litebook EDGE™ Phototherapy on Academic Performance and Functional Brain Activity in Non-Depressed Adolescents

As children pass through puberty the timing of their sleep-wake cycle shifts and they experience a strong urge to stay up and awaken late. Hence, a large percentage of normal adolescents arrive at school each day with an insufficient amount of sleep, which can take a substantial toll on their academic performance.

A growing number of human studies show that sleep promotes learning and memory. Conversely, sleep deprivation has a negative impact on cognitive and behavioral functions. Relatively few studies have examined effects of sleep deprivation on cognitive performance in adolescents. In these studies, total sleep deprivation was associated with impaired memory performance and diminished computational speed, while, partial sleep deprivation was associated with deficits in reasoning and verbal creativity. For example, male adolescents sleeping more than 8 hours per day had significantly higher reasoning ability than their peers who slept for less than 8 hours per day. Some studies reported that simpler cognitive processes such as working memory and computational speed may not be significantly affected by a single night of sleep limited to 4 to 5 hours. However, even mild sleep restriction of an hour or more, when persistent across days, can lead to memory problems as severe as seen following total sleep deprivation.

The sensitivity of the adolescent brain to subtle sleep impairments was highlighted in a study where 12-14-year-olds were allowed to play stimulating computer games or watch television right before bedtime. This experience prolonged sleep latency, increased stage 2 sleep and reduced slow wave sleep. This modest degree of sleep restriction significantly impaired verbal memory consolidation Suboptimal sleep duration in adolescents was also associated with poor performance on a serial digit-learning test during morning testing sessions, but not in afternoon sessions. Between 58-68% of high school students surveyed in Ontario report that they feel "really sleepy" between 8 and 10 A.M. Thus, achievement in early morning classes may suffer the most in sleep-deprived adolescents.

Fortunately, sleep only needs to be extended by a modest amount to enhance cognition in children. Sadeh showed that performance on memory, attention and vigilance tasks in children improved significantly after 1 hour of sleep extension on three consecutive nights. Gais and Backhaus have also shown the beneficial effects of sleep on memory consolidation in children and adolescents.

Overall, there is compelling scientific evidence that schoolchildren, particularly adolescents, are chronically sleep deprived, that the degree of sleep restriction they experience exerts demonstrable effects on memory encoding, consolidation and processing speed, and that even a modest increase in sleep will result in measurable improvements in cognitive function. The primary reason that adolescents are sleep deprived is due to a naturally occurring phase delay in their biological clock, resulting in a propensity to stay up until late in the evening which is incompatible with the early rise times schools typically require. Light treatments at the appropriate time can phase advance the biological clock, potentially reversing this problem.