Graduation Year


Document Type




Degree Granting Department

Environmental and Occupational Health

Major Professor

Stuart Brooks, M.D.

Committee Member

Thomas Truncale, D.O., M.P.H.

Committee Member

Chu-Hsiang Chang, Ph.D.


daytime sleepiness, fatigue, obstructive sleep apnea, polysomnography, cpap


Commercial vehicle drivers are required to maintain Department Of Transportation medical certification which entails a Commercial Driver Medical Examination (CDME) and optimally leads to a two-year certification. The examination must be performed by a licensed "medical examiner" administered by a variety of health care providers including physicians, advanced registered nurse practitioners, physician assistants and doctors of chiropractic. Unfavorable findings in the examination can yield either a shortened medical certification period or denial of certification. Sleep disorders including sleep apnea are assessed by a single question located in the health history portion of the CDME form which is filled-out by the examinee. A positive response to this single item often prompts the medical examiner to further supplement this question using a subjective questionnaire, such as the Epworth Sleepiness Scale. This particular questionnaire generates a total score based on the examinee's subjective responses to eight items regarding the propensity to doze-off or fall asleep in different scenarios, thus indicating daytime sleepiness. Commercial drivers depend on the medical certification for their livelihood and it is hypothesized that subjective responses regarding daytime sleepiness are distorted in an effort to attain optimal DOT certification.