Tuesday, June 24, 2014

Commercial Drivers Still at High Risk From "Drowsy Driving"

The issue of sleep-deprived or "drowsy" driving has made the news again following the tragic June 7 accident involving the comedian Tracy Morgan. Prosecutors say that the Walmart truck driver whose tractor-trailer slammed into a van, critically injuring Mr. Morgan and killing another passenger, had not slept in over 24 hours.
Drowsy driving is a leading cause of crashes and highway fatalities, according to federal officials: more than 30,000 people die on highways annually in the United States and crashes involving large trucks are responsible for one in seven of those deaths.
Federal rules introduced last year reduced the maximum workweek for truckers from 82 to 70 hours, after which drivers have a mandatory 34-hour resting period. This “restart” must include two periods between 1 a.m. and 5 a.m. to allow drivers to rest at least two nights a week: they cannot drive for more than 11 hours a day and must have a 30-minute break in their schedule.

But the trucking industry has been battling to get the new nighttime-break regulations repealed. On June 6, Senator Susan Collins, Republican of Maine, pushed an amendment through the Senate Appropriations Committee that would freeze the rules, pending further studies. Ms. Collins said the administration had failed to take into account that the new rules would put more trucks on the roads during peak traffic hours. Trucking officials and executives also said that drivers needed to be afforded maximum flexibility in their work and should not be told when to rest.

Safety investigators said that sleepy or drowsy driving is a far more common problem than most people realize, but how extensive the problem is remains a matter of debate, partly because it is difficult to obtain evidence that drivers fell asleep. In 1990, a National Transportation Safety Board study of 182 heavy-truck accidents in which the truck driver died concluded that fatigue played a role in 31 percent of the cases, more than alcohol or drugs.
But the American Trucking Associations said that a federal database of fatal crashes cited fatigue in less than 2 percent of police reports about accidents involving trucks; a more accurate estimate, they claim, is that driver fatigue plays a role in about 7 percent of truck crashes. “Until we have a blood test for determining fatigue, all estimates are likely going to under-report fatigue, because the dead don’t speak and the living often plead the Fifth, especially if they are facing criminal charges,” said Deborah A. P. Hersman, former chairwoman of the N.T.S.B. and now the president and chief executive of the National Safety Council.

The Transportation Department has proposed that all interstate commercial truck and bus companies be required to use electronic logging devices to increase compliance with driving-hour rules. Paper logs are easier to manipulate and more difficult for law enforcement officials to verify. The comment period for the rule is scheduled to end this month. Some commercial truck fleets already such devices. For instance, Walmart’s trucks have GPS and electronic logging systems, which track where the vehicles are and what they are doing. A Walmart spokeswoman said the truck involved in the accident that injured Mr. Morgan, who remains in a New Jersey hospital, was also outfitted with anti-collision technology, which is supposed to alert drivers if there is a car in a neighboring lane when they activate their turn signal, for example. It is also supposed to slow the truck down automatically if it is approaching slow-moving or stopped traffic. Citing the incomplete investigation, Walmart declined to provide specifics on the accident or the driver’s schedule in the days leading up to the crash.

Excessive daytime sleepiness is a common problem in today's society. It is so common that in some circles people almost consider it a normal aspect of a productive society. The fact is that daytime sleepiness and fatigue are leading causes of accidents, both on the job and on the road. The cost to society is estimated in billions of dollars per year. There are several common causes for increased daytime sleepiness. The simplest cause of daytime sleepiness that can be corrected results from insufficient sleep. The average person requires 7 to 8 hours of sleep per night. If a person routinely gets less than this, it will most likely cause excessive daytime sleepiness. Another common problem can be sleeping in a noisy environment. This can cause many short awakenings, so brief that a person doesn't remember them the next morning. This results in non-restful sleep with resulting excessive daytime sleepiness. If a person gets 8 hours of sleep a night and still feels sleepy during the day, one should consider that they may have a medical problem which hinders their ability to obtain restful sleep.
For more information on the causes of "drowsy driving" and how you can get treatment for the sleep-related issues involved, visit Dr.Simmon's website at houstonsleep.net.

Truckers Resist Rules on Sleep, Despite Risks of Drowsy Driving (NYT, June 16, 2014

Monday, June 9, 2014

Good Sleep Helps Consolidate and Strengthen New Memories

In a recent article published in Science Magazine, researchers from NYU Langone Medical Center have shown that sleep after learning encourages the growth of dendritic spines, tiny protrusions that connect brain cells and facilitate the passage of information across synapses. The laboratory  research, conducted on mice, concludes that the activity of brain cells during deep or slow-wave sleep after learning is critical for such growth.

These findings provide important physical evidence to support a hypothesis that sleep helps consolidate and strengthen new memories, and they show how learning and sleep can cause physical changes in the motor cortex, a brain region responsible for voluntary movements. 
It is well known that sleep plays an important role in learning and memory, but the underlying physical mechanism responsible weren't understood until now. On the cellular level, brain cells that spark as we digest new information during waking hours "replay" during slow-wave sleep, when the brain waves slow down and rapid-eye movement and dreaming stop. Scientists have long believed that this nocturnal replay helps us form and recall new memories, yet the structural changes of this process have remained poorly understood.

The scientists employed mice which had been genetically engineered with a fluorescent protein in their neurons. Using a special laser-scanning microscope that illuminates the fluorescent proteins in the motor cortex, they were then able to track and image the growth of dendritic spines along individual branches of dendrites both before and after the mice learned to balance on a spinning rod.
They trained two sets of mice: one set spent an hour on the spinning rod and then slept for 7 hours: the second trained for the same period of time but was kept awake for 7 hours. The sleep-deprived mice experienced significantly less dendritic spine growth than the well-rested mice.

The scientists also showed that brain cells in the motor cortex that activate when mice learn a task reactivate during slow-wave deep sleep. Disrupting this process prevents dendritic spine growth. Their findings offer an important insight into the functional role of neuronal replay -the process by which the sleeping brain rehearses tasks learned during the day- observed in the motor cortex.