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Answer distortion on the epworth sleepiness scale during the commercial driver medical examination

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Title:
Answer distortion on the epworth sleepiness scale during the commercial driver medical examination
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Language:
English
Creator:
Proctor, Keith
Publisher:
University of South Florida
Place of Publication:
Tampa, Fla
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Subjects

Subjects / Keywords:
Daytime sleepiness
Fatigue
Obstructive sleep apnea
Polysomnography
Cpap
Dissertations, Academic -- Environmental & Occupational Health -- Masters -- USF   ( lcsh )
Genre:
non-fiction   ( marcgt )

Notes

Abstract:
ABSTRACT: 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.
Thesis:
Thesis (MSPH)--University of South Florida, 2010.
Bibliography:
Includes bibliographical references.
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by Keith Proctor.
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Title from PDF of title page.
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usfldc handle - e14.4614
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Answer Distortion on the Epworth Sleepiness Scale During t he Commercial Driver Medical Examination by Keith E. Proctor A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Public Health Department of Environment al and Occupational Health College of Public Health University of South Florida Major Professor: Stuart Brooks, M.D. Thomas Truncale, D.O. M.P.H. Chu Hsiang Chang, Ph.D. Date of Approval: April 1, 2010 Keywords: daytime sleepiness, fatigue, obstructive sleep apnea, polysomnography, cpap Copyright 2010 Keith E. Proctor

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i Table of Contents List of Tables ................................ ................................ ................................ ......... ii List of Figures ................................ ................................ ................................ ....... iii Abstract ................................ ................................ ................................ ................ iv Introduction ................................ ................................ ................................ ........... 1 History of the Epworth Sleepi ness Scale ................................ ................... 1 Obstructive Sleep Apnea ................................ ................................ ........... 4 Com mercial Driver Medical Exam ................................ .............................. 5 Materials and Methods ................................ ................................ ....................... 10 Travel Plaza ................................ ................................ ............................. 10 Occupational Medicine Clinic ................................ ................................ ... 1 0 Statistical Analysis ................................ ................................ ................... 1 1 Results ................................ ................................ ................................ ............... 12 Discussion ................................ ................................ ................................ .......... 17 Conclusion ................................ ................................ ................................ .......... 21 References ................................ ................................ ................................ ......... 23 Appendix 1: Travel Plaza Survey Form ................................ .............................. 26 Appendix 2: Travel Plaza and Clinic Raw Data ................................ .................. 28 About the Author ................................ ................................ ...................... End Page

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ii List of Tables Table 1 : Characteristics of Study Population ................................ .............. 1 3 Table 2 : Ca tegorization of Drivers by BMI ................................ ................... 1 3 Table 3 : Categorization of Drivers by Screening Criteria ............................ 16

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iii List of Figures Figure 1: Total ESS compared to BMI at Clinic ................................ ............ 14 Figure 2: Total ESS co mpared to BMI at Travel Plaza ................................ 14 Figure 3: Neck ci rcumference compared to BMI at Travel P laza ................. 15

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iv Answer Distortion on the Epworth Sleepiness Scale During the Commercial Driver Medical Examination Keith E. Proctor ABSTRACT Commercial vehicle drivers are required to maintain Department Of Transportation medical certificati on which entails a Commercial Driver Medical Examination (CDME) and optimally leads to a two year certification. Th e administered by a variety of health care providers including physicians, ad vanced 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 a re 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 responses to eight items regarding the propensity to doze off or fall asleep in different scenarios, thus indicat ing 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.

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1 Introduction History of the Epworth Sleepiness Scale The Epworth Sleepiness Scale (ESS) is a subjective questionnaire designed to ascertain a score representative of daytime sleepiness. Dr. Murray Johns establish ed the questionnaire in the early 19 9 0s with the intention of generating a simplified screening tool to indicate the necessity for further diagnostic testing regarding potential sleep disturbances. The objective was to provide a simple standardized alter native to replace the cu m bersome, time consuming, and expensive multiple sleep latency test (MSLT) and maintenance of wakefulness test (MWT) [1] The MSLT is regarded by some as the gold standard for objective determination of daytime sleepiness [2] but it requires the patient to remain in the exam room nearly all day. R ecently, however, some concerns have been raised regarding the relative weakness of the relationship between the ESS and the MSL T [3] while Dr. Johns maintains that the ESS is the best indicator of daytime sleepiness and the MSLT is the worst of the three tests utilized [4] The ESS questionnaire is designed to be self administered and is comprised of eight questions which indicate a pr opensity to doze during situations where dozing is an unintended outcome. Accurate assessment of this propensity is somewhat difficult as many respondents do not interpret the situations in a similar manner Most clinicians expect that the ESS measures subjective sleepiness, but Dr. Johns maintains that it measures a propensity to

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2 sleep, which he considers to be a different construct [5] The respondent answers each question using a scale from zero to three corresponding to a no chance of doz ing progressing to chance of doz ing Patient variability is a major source of measurement inconsist ency in the ESS and is influenced by recall bias and testing conditions The ESS attempts to avoid these biases by asking respondents to gage their responses based on propensity to sleep over the past few weeks rather than just at the time of testing [6] One o f the questions asks the respondent to rate the likelihood of dozing while lying down to rest in the afternoon when circumstances permit and i t was believed that anyone other than insomniacs would have some possibility of dozing in this situation [1] Other similarly soporific scenarios are provided as well as scenarios where a positive response would be more indicative of narcolepsy than daytime somnolence, such as sitting and talking to someone. This is necessary since a questionnaire composed only of highly soporific scenarios would not differentiate between sleepy and alert individuals ; therefore, the selection of scenarios were likely chosen to vary from highly soporific to minimally soporific [6] Some ambiguity exists in the question regarding sittin g in a car while stopped for a few minutes in traffic as to whether the question implies the respondent is the driver or the passenger. Because there is an association between daytime sleepiness and motor vehicle accidents, which most often occur while th e vehicle is in question [6]

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3 At the time of this writing, a Pub Med returns over 1000 articles. The ESS has been translated into several di fferent languages and its validity and reliability have been established for use in different countries rendering it the most widely known and extensively used questionnaire for determining daytime sleepiness. Much of its utility is derived from the ability to have respondent s answer the questionnaire while awaiting their scheduled appointment with the medical examiner. The medical examiner can then quickly sum the individual responses and determine the total ESS score. This total score is then used to categorize the respondent as having a normal or increased sleep propensity and those with an increased propensity can then be referred for polysomnography The cutoff scores have changed over time with the initial study indicating that a score of 16 o ut of 24 suggested a high level of daytime sleepiness [1] Later, th e cutoff score was reduced to 9 based on a study involving 104 medical students [7] Presently a cutoff score of 10 is suggested [4, 8] and is the level used most extensively Unfortunately, despite the multitude of websites offering the layperson access to the ESS, no data exist supporting and [9] Many sleep clinicians do not believe that a cutoff score of 10 indicates that a respondent is path ologically sleepy and misunderstandings regarding the use of the ESS can result in undue reliance on its measure of excessive daytime sleepiness [10]

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4 Obstructive Sleep Apnea Daytime sleepiness is the most common behavioral morbidity associated with obstructive sleep apnea (OSA) and t he presence of excessive dayti me sleepiness along with the increased awareness of potential negative consequences of untreated OSA often motivates patients to seek medical evaluation [11] In the population seeking treatment, the bed partner is often the precipitator for seeking medical evaluation of excessive snoring and apneic episodes. Turbulence in the upper airway causes vibrations of the soft palate and the uvula causing audible snor ing which is typically benign for the afflicted, although usually not for the bed partner. People with large tongues, bulky palates or thick necks often have increased airway vibrations. Some of these people may lose the ability for the intrinsic muscles of the throat to keep the airway patent thus leading to obstruction of the airway and subsequent apneic episodes while sleeping, which represents the entity called obstructive sleep apnea (OSA). OSA is a well defined problem with significant and ongoing re search into its etiology and treatment. The National Sleep Foundation estimates that 18 million people suffer from OSA yet the majority of them remain undiagnosed [12] While cranial, facial and upper airw ay soft tissue abnormalities are risk factors for OSA, the most important and repeatedly documented risk factor is obesity [13] and the risk for OSA increases as the BMI increases. One study utilized a combination of clinical symptoms of sleep apnea, cou pled with BMI and ESS scores which were optimized to provide a 93.4% sensitivity and 60% specificity for the presence of OSA [14] Another study revealed that obese drivers having a BMI above 32

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5 kg/m 2 are more likely to be sleepy during the day yet their subjective reports of daytime sleepiness are not reliable [15] In the symptomatic population s eeking relief or treatment, the ESS is widely used and well validated; however, in a population wishing to minimize their disclosure of health problems, the ESS seems to be less reliable [16] Commercial Driver Medical Examination The Department of Transportation (DOT) was established by an act of Co ngress in 1966 and responsibility for commercial driver qualifications was transferred to the DOT following the establishment of the National Highway Traffic Safety Administration in 1970 The Federal Motor Carrier Safety Administration (FMCSA) was established in 2000 pursuant to the Motor Carrier Safety Improvement Act of 1999, with the primary mission of preventing commercial motor vehicle related fatalities and injuries. Commercial motor vehicle (CMV) is a rather broad term and covers the followi ng vehicle types as set forth by 49 CFR 390.5: weighs 10,001 pounds or more; has a gross vehicle weight rating or gross combination weight rating of 10,001 pounds or more; is designed or used to transport 16 or more passengers (including driver) when not for compensation; is designed or used to transport 9 or more passengers (including driver) for compensation. Additionally, a vehicle involved in interstate or intrastate commerce transporting hazardous materials in a quantity requiring placards is also co nsidered a CMV. Further vehicular classifications are used to mandat e when drivers of CMVs require controlled substance testing.

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6 The Medical Program is one of the ey P rograms within the FMCSA and is s by ensuring commercial motor vehicle ( CMV ) drivers engaged in interstate commerce are physically qualified. Interstate commerce is that in which trade, traffic or transportation occurs across state lines while intrastate commerce does not cross state li nes. It is important to note that it is the cargo being transported not the driver, that dictates whether the commerce is interstate or intrastate and many states have adopted the federal guidelines for certification of intrastate CMV drivers. Physical qualifications for drivers are contained in 49 CFR 391 which requires that e ach o perator of a CMV undergo a periodic medical examination to ensure medical suitability to operate such a vehicle. The examination has specific criteria and drivers can only be medically certified for a maximum of two years while there are many circumstances, such as hypertension, whereby the duration of certification would be less than two years [17] During the course of the examination, drivers are required to fill out the health history portion of the Medical Examination Report form which consists of 25 line items requiring either Interestingly, the bulk of the questions in the health history section seems to focus on heart attack, stroke, hypoglycemic events etc., yet these medical conditions are only implicated in 4% of CMV crashes [16] The health history section is si gnature and the date that the form was filled out The Medical Examination

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7 Report form was originally a two page document, but in 2000 a new nine page CDME form was created and includes a single line item entry requiring drivers to indicate whether they have a sleep disorder, pauses in breathing whi le asleep, daytime sleepiness or loud snoring [18] ; however, the form provides no further guidance regarding diagnosis, treatment or follow up [19] Denial is an obstacle to obtaining an adequate sleep disorder history since respondents often refuse to admit that they snore or they attribute their sleepiness to factors such as a hectic lifestyle, all of which deter screening for excessive sleepiness by history alone [20] Because undiagnosed OSA poses hazards in commercial truck driving, effective and simple screening methods are essential in clinical settings in which a full sleep evaluation, including overnight polysomnography is not practical or feasible [20] For this reason, many medical examiners elect to supplement this single line item with a subjective questionnaire, such as the ESS. The physical exam portion of th e report only requires entries for height and weight, but it is advised that medical examiners also enter a calculation of BMI on the form, since BMI is a u seful correlation for the risk of OSA [17] C ommercial driving operations place individuals at a higher risk for obesity due to long and mostly sedentary driving hours, irregular schedules and limited food options [21] One particular study revealed that OSA is common in CMV operators with 28% of participants having some degree of OSA [22] The utility of the ESS, or other subjective questionnaires, has been questioned in this population of respondents where an elevated score coul d hinder attainment of medical certification [16, 23]

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8 Currently the medical exam can be complete d by a person licensed to perform physical examinations including, a doctor of medicine (MD), doctor of osteopathy (DO), doctor of chiropractic (DC), physician assistant (PA) or an advanced practice nurse (ARNP). The medical examiner should be familiar with 49 CFR 391 specifically Subpart E, and be aware of the physical and emotional demands associated with operating a CM V both for the wellbeing of the driver and in the interest of public safety Once a driver is medically qualified, the driver can use the medical certificate in the performance of any task required of CMV operators for any company [24, 25] This is one of the motivations behind the ommendation to require certification and training of medical examiners performing CDMEs [17] The Large Truck Crash Causation Study (LTCCS) analyzed several factors related to truck crash es and assigned codes to four types of driver errors [26] One such driver err or code river falling asleep, suffering a disabl ing heart attack or seizure, or becoming physically impaired for another reason. The FMCSA found that truck drivers were at fault in over 80% of crashes [26] and the driver admitted to falling asleep in 7% of these crashes [23] Da ytime somnolence associated with OSA has been widely recognized as a potential cause of motor vehicle crashes. For this reason, screening recommendations have been developed for CMV operators with possible or probable sleep apnea. Unfortunately, many of the current methods of screening for OSA have either a poor sensitivity, poor specificity or both [20] Because an elevated risk to public safety is associated with OSA in the CMV operator

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9 population, a task force was convened and consisted of members from the American College of Chest Physicians, th e American College of Occupational and Environmental Medicine and the National Sleep Foundation to address this safety hazard [24, 25] This task force developed screening recommendations for identifying commercial drivers w ith probable OSA which include criteria based on both subjective responses and physical exam findings. The subjective responses include the single question on the CDME form which asks if the applicant has sleep disorders, pauses in breathing while asleep, daytime sleepiness or loud snoring along with a supplemental questionnaire, such as the ESS. The task force recommends that drivers receive a 3 month medical certificate pending an evaluation for sleep disorders if their ESS score is greater than 10 whil e drivers with an ESS score greater than or equal to 16 should be taken out of service pending evaluation [24, 25] Because commercial drivers depend on medical certification for their livelihood, it is hypothesized that these subjective responses regarding daytime sleepiness are distorted in an effort to attain optimal DOT certification. Based on this hypothesis, when the ESS is administered in a non threatening environment, such as a travel plaza, a difference in the mean ESS score is expected wh ich should correlate with BMI and neck circumference.

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10 Materials and Methods Travel Plaza Fifty commercial drivers were surveyed at a travel plaza near a major interstate in Florida. Participation was completely voluntary and participants were offered a $5.00 gift card for use in the travel plaza. The survey was absolutely anonymous and did not include any company or driver identification. The survey included the single line item question from the history portion of the CDME form as well as all eight items from the ESS. Participants also had their height and weight recorded and neck circumference measured. D emographic data such as age and prior diagnosis of OSA diagnosis w ere obtained and those diagnosed with OSA were further questioned regarding CP AP usage. rounded down to the nearest half inch while their weight was rounded down to the nearest whole pound. This practice was employed due to the fact that the drivers remained fully clothed with their shoes on during he ight and weight assessment as this was conducted outdoors at the travel plaza Body m ass index of each driver was calcu l ated using the following equation: BMI = [ ( weight in pounds) / ( height in inches) 2 ] X 703 Occupational Medicine Clinic An occupational medicine clinic that performs CDMEs for a large region was chosen as the comparison location which was within the same region as the

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11 travel plaza and is in close proximity to the same major interstate This particular clinic conducts between 60 and 70 CDMEs each month and administers the ESS to 100% of the applicants for the DOT medical certificate, regardless of response to the history portion of the CDME or any objective findings. Each applicant for the medical certificate also has their height and weight recorded, but this clinic does not calculate BMI. Therefore, BMI was calculated using the above mentioned equation from the height and weight measurements recorded on the CDME form. Once BMI was calculated, the CDMEs were used to form matched pairs with the participants from the travel plaza survey. A matched pair consisted of a participant at the travel plaza and a CDME from the occupational medicine clinic having BMI reading s with a difference no greater th an 0.2 kg/m 2 Unfortunately, the occupational medicine clinic in this study did not obtain neck circumference measurements which prevented a comparison of this metric. Statistical Analysis A statistical comparison was conducted between the ESS scores o btained at the occupational m edicine clinic and at the travel plaza using an independent 2 tailed t test with a 95% CI generated. Statistical analyses were performed using SPSS Version 18.0 (SPSS Inc., Chicago, Illinois). Statistical significance was accepted when p was < 0.05. Because matched pairs for BMI were utilized, no statistical analyses or comparisons of BMI were generated between the two groups.

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12 Results A total of 100 ESS quest ionnaires were reviewed, fifty of which were filled out in a local occupational health clinic during a Commercial Driver exam and the other fifty attained at a local travel plaza Twelve drivers met the objective consensus criteria of BMI greater than 35 kg/m 2 at both the travel plaza and the o ccupational medicine clinic. However, none of the drivers at the clinic that met the objective BMI criteria had an ESS greater than 10 while three of the drivers at the travel plaza meeting the criteria had an ESS greater than 10 One examinee at the occupational medicine clinic had answered affirmatively to the historical question on the CDME regarding sleep disorder s excessive daytime sleepiness or snoring ; h owever, there was no indication that this driver had r eceived any follow up to this affirmative response. A total of nineteen drivers at the travel when the CDME question was asked verbally Interestingly, t wo of the respondents at the travel plaza that answered in the affirmative had BMI values less than 2 5 kg/m 2 and neck circumference s of 16 inches or less Most of the respondents qualified their positive responses and denied any sleep disorders but stated that they snored or that their bed partner reported that they snor ed

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13 Table 1: Characteristics of study population Characteristic Clinic Travel Plaza Mean Range Mean Range Age 42.0 21 65 45.5 26 63 Weight 208.8 118 305 221.6 125 312 BMI 31.6 19.8 46.2 31.6 19.9 46.1 ESS Score 2.8 0 10 6.7 0 21 Table 2 : C ategorization of drivers by BMI BMI Category BMI (kg/m2) Number of drivers at each the Clinic and the Travel Plaza Normal < 25 6 Overweight 25 29.9 12 Obese > 30 32 Consensus Criteria 35 12

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14 Figure 1: Total ESS compared to BMI at occupational m edicine c linic Figure 2: Total ESS compared to BMI at travel plaza 0 5 10 15 20 25 15 20 25 30 35 40 45 50 ESS Score BMI kg/m 2 0 5 10 15 20 25 15 20 25 30 35 40 45 50 ESS Score BMI kg/m 2

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15 S tatistical analyses were performed of the BMI values and the total ESS scores obtained at both the travel plaza and the occupational medicine clinic When the data from the survey conducted at the travel plaza was compared to the data acquired from the occupational medicine clinic, a difference in the mean ESS total score of 3.86 (95% CI: 2.56, 5.15) was obtained and conf irmed to be statistically significant with a p <0.001 Although the difference was statistically significant, it was not clinically significant as the mean ESS total score (6.7) at the travel plaza was below the action level for requiring a sleep study. In comparing the BMI to the ESS total scores, no significant correlation existed at either the occupational medicine clinic or the travel plaza. The neck circumference measurements obtained at the travel plaza, however, did correlate well with the BMI rea dings obtained from these drivers with a positive Pearson Correlation value of 0.756. Figure 3: Neck circumference compared to BMI at travel plaza 18 22 26 30 34 38 42 46 13 15 17 19 BMI (kg/m 2 ) Neck Circumference

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16 Nine drivers at the travel plaza would have screened positive based on ESS score < 10. Five of the drivers at the travel plaza with a total ESS score >10 fell below the consensus criteria for both BMI and neck circumference measurements. Although these drivers meet the consen sus criteria for polysomnography based on their res p onses to the ESS, they would have been mis sed by objective criteria alone. Therefore, if they were less than forthcoming with their responses to the subjective questionnaire, they would not raise any cli nical suspicion for excessive daytime sleepiness. Table 3 : Categorization of drivers by screening criteria BMI Clinic Travel Plaza (kg/m 2 ) ESS > 10 ESS > 10 < 35 0 39 5 34 0 11 2 9

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17 Discussion One needs not travel very far down the interstate to notice the abundance of tractor trailers occupying the road and anyone that has witnessed a crash involving one of these tractor trailer s can attest to the severity of the outcome The laws of physics dictate that an out of con trol vehicle weighing nearly 80,000 pounds traveling at highway speeds cannot stop quickly and will destroy everything in its path until it eventually comes to rest. Therefore, the potential for OSA related daytime sleepiness among CMV operators creates a considerable public health hazard. The ESS is one tool currently used by clinicians, patients, the pharmaceutical industry and academic centers to gauge excessive daytime sleepiness. However, more deliberation is required regarding the use of the ESS an d other alternative subjective measures for assessment of sleepiness and the possible downside of false positive screening should not be taken lightly While the ESS has a high degree of internal consistency and ESS scores relate to clinical outcomes such as traffic accidents [6] its use in screening commercial drivers poses some significant limitations. Ideally, objective findings indicative of preponderance towards OSA could be used in the CDME setting. Although anatomical and physiological properties of the upper airways associated with sleep apnea are more commonly found in the obese population, many people with sleep related disorders are not obese. Thi s is a precarious situation for the health care practitioner performing the CDME as objective findings will not

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18 always correlate with excessive daytime sleepiness. The joint task force elected to use a BMI measurement of 35 or greater as their screening c riteria to maximize the specificity of this screening metric [24, 25]. T he most notable bias in this study relates to the inability to survey all of the drivers at the travel plaza. Self selection bias of the participants could have occurred as those wil ling to have their height and weight recorded may have yielded lower BMI readings than those that avoided participation. S elf exempt ion also may have been attributable to the distrust of government officials and trepidation over further governmental regulation on the trucking industry. Many of the commercial drivers, and particularly those that refused to participate, questioned the sponsorship of the research, often assu ming the researchers worked for the FMCSA or the DOT. Even after repeated assurance that no direct government entity was involved in the study, the drivers remained skeptical. Based on multiple conversations with surveyed drivers, this distrust stems fro m the increased regulations placed on the trucking industry to prevent fatigue. Fatigue is closely regulated by Title 49 of the Code of Federal Regulations, Part 395 and by the FMCSA through limiting hours of service (HOS) of interstate commercial truck a nd bus drivers. The FMCSA reviewed existing research on fatigue and worked with organizations such as the Transportation Research Board of the National Academies and the National Institute for Occupational Safety and Health in establishing these HOS rules Companies with drivers in their employ that have demonstrated serious patterns of HOS violations will soon

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19 be required to install electronic on board recorders (EOBRs) in all of their vehicles [27] Trip distance was found to have the most pronounced effect on the percentage of fatal crashes and local or short haul truck involvement in fatigue related fatal crashes is a fraction of that of over the road trucks [27, 28] Although frequently referred to synon y mously, fatigue should be differentiated from sleepiness. Fatigue is generally described as a condition where maintenance of motor and mental energy levels becomes increasingly difficult and is reliev ed by rest, as opposed to sleep [29] While fatigue and sleepiness often seem to share a common basis of non restorative sleep, their relationship is still poorly described and understood [29] Fatigue involves other factors such as eye strain, back pain and general muscle exhaustion due to factor s related to operating and controlling a CMV. The common practice of having drivers participate in the loading and unloading of their cargo adds to their level of fatigue [30] Other factors related to fati gue include somewhat intangible conditions such as depressio n and even low job satisfaction and additional stress factors such as multi trailer configurations, weather extremes, traffic congestion and frequent interactions with aggressive drivers may also contribute to driver fatigue. Insufficient recovery has an additive effect on fatigue and one study found that nearly half of the respondents (47%) indicated that they began the new workweek already feeling tired or fatigued [30] As previously mentioned, the ESS is not a diagnostic tool, but rather indicates a propensity for unintentional dozing and, for this reason, it is not capable of distinguishing between pathological sleepiness and fatigue. Compoundi ng this problem is the

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20 fact that many respondents describe their sym p toms interchangeably as sleepiness and tiredness. The survey at the travel plaza was conducted on two different days, one week day in the late morning and one Satur day in the early afternoon. Although fatigue of drivers may cause a bias in their answers to the ESS, the time of day the survey was conducted would likely bias the results towards the null hypothesis. Many of the drivers that were surveyed on a ove time, or out of service, requirements. The surveys conducted during the work week were performed in the late morning, just prior to lunchtime. Driver fatigue would likely have a greater impact on ESS scores near the end of the day, after driving many hours without rest or at the end of the work week. This fatigue effect is also somewhat minimized in the clinical setting since drivers typically present for the CDME before their work shift or during their lun ch break.

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21 Conclusion This cross sectional study was intended to evaluate the use of the ESS in a population of respondents where answer distortion could be perceived as advantageous. The importance of this study rests in the fact that OSA is prevalent in commercial drivers and has potentially disastrous consequences within the public health domain The results of the study reveal some important limitations in the use of a subjective m easure of daytime sleepiness in a population of CMV operators during the CDME. None of the respondents in the clinical setting met the task force consensus criteria for an ESS greater than 10. However, t he results observed from the ESS administered in a non threatening completely anonymous environment did indicate an increase in the total ESS score which was statistically significant. A lthough the findings were not necessarily clinically significant, an unexpected yet noteworthy finding was that five drivers that would not meet objective screening criteria had ESS scores greater than 10. Although answer distortion on subjective responses to both the history portion of the CDME and the ESS remains a problem, the responses to these items may be the only viable method for identifying commercial drivers with sleep disorders or excessive daytime sleepiness that do not meet any objective criteria for further diagnostic testing. Alternatively, drivers meeting objective criteria for further testing with legi timate ESS scores < 10 will have to undergo some form of sleep study which is both expensive and time consuming.

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22 Unfortunately, the possibility for answer distortion on subjective questionnaires, such as the ESS, precludes the CDME examiner from determini ng which scores are legitimate thus compelling the examiner to require further diagnostic testing based on objective criteria alone.

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23 References 1. Johns, M., A new method for measuring daytime sleepiness: the Epworth sleepiness sc ale. Sleep, 1991. 14 (6): p. 540 545. 2. Wise, M.S., Objective measures of sleepiness and wakefulness: application to the real world? J Clin Neurophysiol, 2006. 23 (1): p. 39 49. 3. Chervin, R. and M. Aldrich, The Epworth Sleepiness Scale may not reflect objective measures of sleepiness or sleep apnea. Neurology, 1999. 52 (1): p. 125. 4. Johns, M.W., Sensitivity and specificity of the multiple sleep latency test (MSLT), the maintenance of wakefulness test and the Epworth sleepiness scale: Failure of the MS LT as a gold standard. Journal of Sleep Research, 2000. 9 (1): p. 5 11. 5. Chervin, R., Epworth sleepiness scale? Sleep Medicine, 2003. 4 (3): p. 175 176. 6. Miletin, M. and P. Hanly, Measurement properties of the Epworth sleepiness scale* 1. Sleep Medicine, 2003. 4 (3): p. 195 199. 7. Johns, M., Reliability and factor analysis of the Epworth Sleepiness Scale. Sleep, 1992. 15 (4): p. 376 381. 8. Johns, M., Sleepiness in different situations measured by the Epworth Sleepiness Scale. SLEEP NEW Y ORK 1994. 17 : p. 703 703. 9. Avidan, A.Y. and R.D. Chervin, ESS dot com. Sleep Med, 2002. 3 (5): p. 405 10. 10. Tachibana, N. and M. Taniguchi, Why do we continue to use Epworth sleepiness scale? Sleep Med, 2007. 8 (5): p. 541 2. 11. Rosenthal, L. and D Dolan, The Epworth sleepiness scale in the identification of obstructive sleep apnea. The Journal of nervous and mental disease, 2008. 196 (5): p. 429. 12. DROBNICH, D., A National Sleep Foundation's conference summary: the national summit to prevent dro wsy driving and a new call to action. Industrial Health, 2005. 43 (1): p. 197 200. 13. Young, T., J. Skatrud, and P. Peppard, Risk factors for obstructive sleep apnea in adults. JAMA, 2004. 291 (16): p. 2013.

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24 14. Lim, P.V. and A.R. Curry, The role of history, Epworth Sleepiness Scale Score and body mass index in identifying non apnoeic snorers. Clin Otolaryngol Allied Sci, 2000. 25 (4): p. 244 8. 15. Dagan, Y., et al., Body Mass Index (BMI) as a first line screening criterion for detection of excessive daytime sleepiness among professional drivers. Traffic Inj Prev, 2006. 7 (1): p. 44 8. 16. Talmage, J., et al., Consensus criteria for screening commercial drivers for obstructive sleep apnea: evidence of efficacy. Journal of Occupational and Environmenta l Medicine, 2008. 50 (3): p. 324 329. 17. Hartenbaum, N., ed. The DOT Medical Examination: A Guide to Commercial Drivers' Medical Certification Fourth ed. 2008, OEM Press: Beverly Farms, MA. 310. 18. Physical qualification of drivers; medical examination ; certificate. Federal Motor Carrier Safety Administration (FMCSA), DOT. Final rule. Fed Regist, 2000. 65 (194): p. 59363 80. 19. Hartenbaum, N., et al., Truckers with OSA, should they be driving? J Occup Environ Med, 2006. 48 (9): p. 871 2. 20. Friedman, M., et al., Screening for obstructive sleep apnea/hypopnea syndrome: Subjective and objective factors. Otolaryngology Head and Neck Surgery, 2010. 142 (4): p. 531 535. 21. Wiegand, D.M., R.J. Hanowski, and S.E. McDonald, Commercial drivers' hea lth: a naturalistic study of body mass index, fatigue, and involvement in safety critical events. Traffic Inj Prev, 2009. 10 (6): p. 573 9. 22. Pack, A., D. Dinges, and G. Maislin, Study of Prevalence of Sleep Apnea among Commercial Truck Drivers. 2002., 2 002. 23. Parks, P., et al., Screening for obstructive sleep apnea during commercial driver medical examinations. Journal of Occupational and Environmental Medicine, 2009. 51 (3): p. 275. 24. Hartenbaum, N., et al., Sleep apnea and commercial motor vehicle operators: Statement from the joint task force of the American College of Chest Physicians, the American College of Occupational and Environmental Medicine, and the National Sleep Foundation. Chest, 2006. 130 (3): p. 902 5.

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25 25. Hartenbaum, N., et al., Sleep apnea and commercial motor vehicle operators: statement from the joint Task Force of the American College of Chest Physicians, American College of Occupational and Environmental Medicine, and the National Sleep Foundation. J Occup Environ Med, 2006. 48 (9 Suppl): p. S4 37. 26. Blower, D. and K. Campbell, The large truck crash causation study. Federal Motor Carrier Safety Administration, Washington, DC, Tech. Rep. UMTRI 2002 31, 2002. 27. Heaton, K., Truck driver hours of service regulations: the coll ision of policy and public health. Policy Polit Nurs Pract, 2005. 6 (4): p. 277 84. 28. Campbell, K., Short Haul Trucks and Driver Fatigue. Ann Arbor, 1997. 1001 : p. 48109 2150. 29. Neu, D., et al., Do 'Sleepy' and 'Tired' Go Together? Rasch Analysis of t he Relationships between Sleepiness, Fatigue and Nonrestorative Sleep Complaints in a Nonclinical Population Sample. Neuroepidemiology, 2010. 35 (1): p. 1 11. 30. Morrow, P.C. and M.R. Crum, Antecedents of fatigue, close calls, and crashes among commercial motor vehicle drivers. J Safety Res, 2004. 35 (1): p. 59 69.

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26 Appendix 1: Travel Plaza Survey Form

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27 Appendix 1 Do you have any of the following? Sleep disorders, pauses in breathing while you sleep, daytime sleepiness, or loud snoring? Yes / No Use the following scale to choose the most appropriate number for each situation: 0 = no chance of dozing 1 = slight chance of dozing 2 = moderate chance of dozing 3 = high chance of d ozing Situation Chance of Dozing Sitting and reading Watching TV Sitting inactive in a public place (e.g. theater or a meeting) As a passenger in a car for an hour without a break Lying down to rest in the afternoon when circumstances permit Sitting and talking to someone Sitting quietly after a lunch without alcohol In a car, while stopped for a few minutes in traffic Total: Age Height BMI Weight Neck circumference Ever diagnosed with sleeping disorder (e.g. sleep apnea)? Use CPAP or BIPAP (breathing machine)? How often? Current certification: < 1 year 1 year 2 years

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28 Appendix 2: Travel Plaza and Clinic Raw Data

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29 Appendix 2 Travel Plaza Occupational Medicine Clinic BMI ESS Total CDME Neck Circ BMI ESS Total CDME 19.9 6 0 14 19.8 7 0 22.3 3 0 15.5 22.5 0 0 23.7 10 1 16 23.7 5 0 24 5 0 17 24 1 0 24.4 4 1 15 24.3 5 0 24.7 7 0 15 24.8 4 0 25.4 8 0 16.5 25.4 1 0 25.7 6 1 14.5 25.9 4 0 27 4 0 16.5 27.1 0 0 27.3 3 0 16.5 27.3 1 0 27.8 4 1 17.5 27.9 1 0 27.9 5 0 14 28 4 0 28.1 5 1 17 28.2 3 0 28.6 10 0 16 28.4 3 0 28.9 7 0 18 28.7 4 0 29 14 0 16.5 29 3 1 29 5 0 17 29.1 3 0 29.4 3 0 17 29.4 10 0 30.1 13 0 17.5 30.1 1 0 30.3 3 0 16.5 30.2 2 0 30.5 17 1 17.5 30.6 4 0 30.6 7 0 17 30.6 4 0 30.7 6 0 16.5 30.7 3 0 30.8 0 1 18 30.8 0 0 30.9 0 0 16 30.9 2 0 31.3 9 0 18.5 31.3 2 0 31.6 11 0 17 31.6 7 0 31.7 8 0 17 31.7 1 0 31.7 3 0 17 31.7 5 0 32.1 4 0 16.5 32.1 4 0 32.5 9 1 17 32.4 2 0 32.9 7 0 18 32.9 1 0 33 21 1 16.5 32.9 0 0 33 10 1 17 33 3 0 33.1 6 1 18 33 1 0 33.4 7 0 16.5 33.3 1 0 34.2 4 0 18 34.1 3 0 34.6 1 1 17.5 34.7 3 0 35.6 11 0 17.5 35.5 2 0 35.6 7 0 18 35.6 3 0 36.2 4 1 18.5 36.2 3 0 36.5 2 1 18.5 36.7 3 0 38.1 12 1 17.5 38.1 1 0 38.8 9 1 17.5 38.7 4 0

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30 Appendix 2 Continued Travel Plaza Occupational Medicine Clinic BM I ESS Total CDME Neck Circ BMI ESS Total CDME 39.1 7 0 18 39.1 3 0 39.3 11 0 19 39.2 3 0 39.3 9 1 18.5 39.3 2 0 40.9 4 1 18 41 2 0 42.3 3 0 19 42.3 2 0 46.1 2 1 18.5 46.2 6 0

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About the Author Keith E. Proctor was born and raised in Lakeland, Florida. He enlisted in the U.S. Navy in 1985 where he served onboard two aircraft carriers and a Marine transport ship as an engineroom mechanic He was enlisted for eighteen years prior to starting medical school. He graduated with a B.S. in Manufacturing Engineer ing Technology from the University of West Florida in 2001 He was the recipient of a Navy Health Professions Scholarship and completed a D.O. from the Edward Via Virginia College of O steopathic Medicine in 2007. He was subsequently accepted into the Nav y Active Duty Delay for Specialists program allowing complet ion of graduate medical educati on in Occupational Medicine. Keith is return ing to the Navy to continue his active duty career as a physician.


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ABSTRACT: 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.
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