Objective Tests for Sleep Disorders
When indicated, objective sleep tests may be required to determine the presence
of a sleep disorder.
Objective tests for sleep disorders include:
- Polysomnography in a controlled sleep laboratory.
- Napping tests:
- Maintenance of wakefulness test.
- Multiple sleep latency test.
- Apnea – airflow ceases for more than 10 seconds.
- Hypopnea – airflow decreases for more than 10 seconds.
Severity (apnea-hypopnea index):
- Mild – 5+ episodes/hour.
- Moderate – 15+ episodes/hour.
- Severe – 30+ episodes/hour.
More than 30 episodes per hour of sleep is considered a diagnosis of obstructive
Self-Reported Sleepiness Surveys
Simple sleepiness surveys may be useful for obtaining driver self-assessment of
sleepiness status. Examples of sleepiness surveys include:
- Epworth sleepiness scale.
- Stanford sleepiness scale.
- Functional outcomes of sleep questionnaire.
NOTE: Self-reported sleepiness does NOT always correlate with objective
testing (polysomnography). The driver may not perceive sleepiness as excessive or
may be hesitant to disclose sleepiness.
For more information, see
Tech Brief: A Study of Prevalence of Sleep Apnea Among Commercial Truck Drivers.
The complete text of the medical conference reports can be accessed from FMCSA Medical Reports.