The combination of extended wakefulness [[e.g., lack of sleep]] and low-dose alcohol has significant adverse effects on a person’s ability to drive, and elevates the risk of getting into a vehicular accident, according to a study published in the October 1 issue of the journal SLEEP.

The study, authored by Mark E. Howard, PhD, of the Institute for Breathing and Sleep in Heidelberg, Victoria, Australia, focused on 19 volunteer professional drivers, who participated in a driving simulation and the Psychomotor Vigilance Task. The subjects were measured in a rested state (12-15 hours awake) and after extended wakefulness (18-21 hours awake) during two sessions. Alcohol was administered during one session, with performance measured at blood alcohol concentrations (BAC) of 0.00 percent, 0.03 percent and 0.05 percent in a non-sleep deprived state, and at 0.03 percent after extended wakefulness (at 1 a.m. and at 3 a.m.). During the second session, tests were performed at the same times without alcohol.

According to the results, extended wakefulness, combined with low-dose alcohol (0.03 percent BAC), resulted in more lapses and greater variation in lane position and speed than did a BAC of 0.05 percent in a rested state.

“In addition to alcohol, sleepiness also increases the risk of road crashes. It is estimated that 15 to 30 percent of traffic accidents are directly related to driver sleepiness, as determined by crash circumstances. Although there are conclusive data regarding the separate effects of alcohol and sleepiness on driving, in real-life situations it is common for these two conditions to occur simultaneously (alcohol-related accidents occur more commonly in the early hours of the morning). The combination of legal low-dose alcohol and extended wakefulness results in impairment worse than that at an alcohol level known to increase accident risk. Avoiding alcohol when driving after extended wakefulness may reduce accident risk,” said Dr. Howard.

Those who think they might have a sleep disorder are urged to discuss their problem with their primary care physician, who will issue a referral to a sleep specialist.

Timing of media exposure plays a vital role in outcomes

Daily television viewing for two or more hours in early childhood can lead to behavioral problems and poor social skills, according to a study of children 2.5 to 5.5 years of age conducted by researchers at the Johns Hopkins Bloomberg School of Public Health. The Hopkins researchers found that the impact of TV viewing on a child’s behavior and social skills varied by the age at which the viewing occurred. More importantly, heavy television viewing that decreased over time was not associated with behavior or social problems. The American Academy of Pediatrics recommends that children under age 2 watch no television while children age 2 and older are limited to no more than two hours of daily viewing. The study is published in the October 2007 issue of Pediatrics.

“A number of studies have demonstrated negative effects of heavy television viewing. However, timing of exposure is an important consideration as reducing viewing to acceptable levels can reduce the risk of behavioral and social problems,” said Kamila Mistry, MPH, lead author of the study and a doctoral candidate in the Bloomberg School’s Department of Population, Family and Reproductive Health.

For the study, the research team analyzed data for 2,707 children collected from the Healthy Steps for Young Children national evaluation. Parents were surveyed about their child’s television viewing habits and behavior at 2.5 and at 5.5 years of age.

Sixteen percent of parents reported that their children watched two hours or more of television daily at 2.5 years of age (early exposure), while 15 percent reported that their children watched two hours or more of television daily at 5.5 years of age (concurrent exposure). One in five parents reported that their children watched two hours or more of television daily at both 2.5 years and at 5.5 years of age (sustained exposure). Sustained exposure to television was associated with behavioral problems. However, early exposure that was subsequently reduced was not a risk for behavior problems. Concurrent viewing was associated with fewer social skills, while sustained and early viewing had less of an impact on social skill development.

The study also found that having a television in the child’s bedroom at 5.5 years of age was associated with behavioral problems, poor social skills and poor sleep. Forty-one percent of the children included in the study had a television in his or her bedroom.

“Children who reduced their viewing by 5.5 years of age were not at greater risk for behavior and social problems,” said Cynthia Minkovitz, MD, MPP, senior author of the study and associate professor with the School’s Department of Population, Family and Reproductive Health. “It is vital for clinicians to emphasize the importance of reducing television viewing in early childhood among those children with early use.”