The DOT Medical Examination x In addition to attempting to collate the most recent “official” guid- ance from FMCSA, recommendations from FMCSA advisory groups (that have not been formally adopted), and the medical literature, this edition will attempt to clarify many of the confusing issues that have arisen from the NRCME. But, as many of you know, I am very careful in separating what is regulation, FMCSA guidance, other information, and my opinion, and will continue to do so. It has always been true that FMCSA expects examiners to consider the guidance as a starting point, and that they will utilize current best medical practice in reaching their final certification determination. The sixth edition beings us into the electronic age the elec- tronic version will have updates at least twice a year. I suspect that some would prefer only the traditional hard copy and some only the electronic but from the beginning, I envisioned this as a bundled prod- uct—both paper and electronic. I could not see any value in preparing a book that would be out of date possibly before it was published. I continue to be grateful to those who have contributed to earlier editions of this book: Dr. Sam Caughron, Dr. Tuenis Zondag, Dr. Kurt Hegmann, and, of course, to Dr. Eric Wood, who joined with the prior edition and continues to put up with me. The support and encourage- ment by Curtis Vouwie of OEM Press continues to be invaluable. And, of course, I want to thank my family for their support: Dave, who accepts my quirks, and “the girls.” Many of you have heard me refer to the Alissa and Sara test, the ultimate criteria to evaluate whether an individual is safe to drive a bus or other commercial motor vehicle. When I started in occupational medicine and with the training pro- grams for commercial driver medical examiners, Alissa was an infant and Sara only a dream. As the CDME process has progressed since the first edition, so have they both are now confident young women. We hope this sixth edition meets your expectations and needs. And please remember: The information contained in this book is based on documents provided by FMCSA, its expert panels, and the medical literature. The information in this book should be used as guidance unless specifically indicated as regulation. Sound medical knowledge and an understanding of the underlying disease process, its treatment, and prognosis must guide the final medical certification determination. —Natalie P. Hartenbaum, MD, MPH, FACOEM