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MOTORISTS WITH A SLEEP DISORDER MAY BE MORE DANGEROUS THAN A DRUNK DRIVER

A California study compared reaction times of the alcohol impaired to those with mild to moderate sleep disorders.

New Orleans -- A research study team has found that a patient, average age of 47 years, suffering from mild to moderate sleep disordered breathing, has a comparable or worse reaction time than a healthy, non-sleepy subject, 29 years old, who, due to blood alcohol level, is impaired or unable to legally drive a motor vehicle in most states. Essentially, driving or engaging in safety-sensitive activities while sleepy may be as dangerous or the same as driving under the influence of alcohol, or driving drunk.

Decades ago, those concerned with public safety determined that reaction times deteriorated with increasing blood alcohol concentrations. Laboratory results and vehicular accidents demonstrated the harmful relationship between excessive alcohol use and the operation of a motor vehicle. These findings led to the establishment of legal limits for blood alcohol levels in automobile operators.

The researchers, in their study, "A Comparative Model: Reaction Time Performance in Sleep Disordered Breathing Versus Alcohol Impaired Controls," find that performances at home or work may undergo significant and detrimental changes due to sleep-disorders. The authors are Nelson Powell, MD, Clinical Professor , Department of Psychiatry and Behavorial Science, Stanford University Medical School, and Co-Director, Stanford Sleep Disorders and Research Center, Stanford, CA; Robert W. Riley, MD, Clinical Associate Professor, Department of Psychiatry and Behavorial Science, Stanford University Medical School and also a member of the Stanford Sleep Disorders and Research Center; Kenneth Schechtman, PhD, Associate Professor of Biostatistics, Washington University School of Medicine, St. Louis, MO; Marc Blumen, MD, Assistant Professor of OtolaryngologyˆHead and Neck Surgery, Hospital Foch, Suresnes, France; David F. Dinges, PhD, Chief, Division of Sleep Chronobiology, University of Pennsylvania School of Medicine and Center for Sleep & Respiratory Neurobiology, Philadelphia, PA; and Christian Guilleminault, MD, Professor, Department of Psychiatry and Behavorial Sciences, Stanford University Medical School, Stanford, CA.

The results were presented before the American Academy of OtolaryngologyˆHead and Neck Surgery Foundation Annual Meeting and Oto Expo being held September 26-29, at the Ernest N. Morial Convention Center in New Orleans, LA. At the gathering, the Academy's 13,000 members will have the opportunity to hear the latest research in the diagnosis and treatment of disorders of the ear, nose, throat, and related structures of the head and neck.

Methodology.

The study was designed to compare reaction time-performance in patients with sleep disordered breathing to those in healthy young adults challenged with alcohol. The research subjects were organized into two groups:
Alcohol Control Group. Eighty subjects were recruited with no history of snoring or sleep disorders, drug, or alcohol abuse. Inclusion criteria demanded the subjects be adults (age 21-60), light drinkers (wine or one hard alcohol drink with dinner or occasional weekend drinking), or very moderate drinkers (one to two drinks daily). Those who used alcohol on a more extensive basis (three drinks or more daily) were excluded.

Sleep Group.

One hundred-thirteen patients were selected to participate in this study after documentation of sleep-disordered breathing by nocturnal polysomnography.

Control Group

Eleven subjects who were non-sleepy and did not drink were selected to complete a ten minute psychomotor vigilance task test four times in succession to assess the potential for learning or fatigue affect associated with repeated testing of reactions times.

The testing included the following:

Breath Ethanol Testing.

(Alcohol Control Group) An Intoxilyzer model 5000, approved by Department of Transportation, was used for all breath alcohol concentration (BAC) measurements. The alcohol group received 200 milliliters of 80 proof vodka mixed with orange juice (a screwdriver) to reach a blood alcohol count of the final BAC of 0.08g/dl. Successive tests to measure reaction were then taken.

Activity Monitoring.

(Alcohol Control Group and Control Group) An actigraph was worn on the wrists of the alcohol and control groups to ensure they were not sleep deprived prior to the test date.

Reaction Time Testing.

(All groups) All study subjects performed simple visual reaction time testing using a psychomotor vigilance task instrument, a hand-held portable microprocessor controlled instrument highly sensitive to a sustained attentional process.

Results:

Key findings of the study were:

* For all tabulated measures, the reaction time performance measures of the 113 subjects with sleep disorders were worse that the corresponding rates of the alcohol-challenged subjects when the Blood Alcohol Level was 0.057g/210L, above the standard that is permissible to drive a commercial vehicle in California. These results could not be explained by sex or age differences.

* The reaction times of the sleep group were equal or worse than the reaction times of the alcohol group when the mean Blood Alcohol Level was 0.08g/dl (driving under the influence in California).

* The maximum reaction time of any of the sleep group (566 + 207 milliseconds) was comparable or worse than any of the worst performances found in the alcohol group.

Conclusion.

Men and women suffering from mild to moderate sleep disordered breathing can have their reaction times to external stimulus slowed by this medical disorder. If not addressed, their actions may result in serious injury and property damage in the home, workplace, and on the road.

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Editor's Note: For a copy of this study or an interview with Dr. Powell, contact Ken Satterfield at 703-519-1563 (through 9-21); 9/23-29, call the Annual Meeting Â鶹´«Ã½room at 504-670-5409.