Dan Root, M.D. *RETIRED IN FEB. 2025
Sleep Specialist
Dr. Root has been practicing medicine in Portland since his residency at OHSU in 1991. He is Board Certified in Sleep Medicine, and founded Oregon Sleep Associates (OSA) in 2005 in order to bring a more patient oriented approach to Sleep Medicine in Portland. In recognition of the success of OSA, he was awarded as one of Portland Monthly Magazine’s Top Doctors in Sleep Medicine for 2013.
He did his undergraduate work at Williams College where he received a Bachelor of the Arts in Political Science, and then went to Medical School and Fellowship training at Baylor College of Medicine. He is a member of the American Academy of Sleep Medicine, the Multnomah Medical Association, and the Oregon Medical Association.
He enjoys spending time with his family, cooking, cycling, supporting Canoe Island French Camp, and the Portland Timbers.
Anas Rihawi, MD, MPH
Sleep Specialist
Dr. Anas Rihawi, MD, MPH is a board‑certified sleep medicine physician who practices pulmonary and critical care medicine at Oregon Health & Science University. He trained at St. Elizabeth’s Medical Center in Boston and the University of Arizona. Dr. Rihawi holds a Master of Public Health degree from Johns Hopkins University and is an active member of the American Academy of Sleep Medicine. Through his collaboration with Oregon Sleep Associates, Dr. Rihawi delivers attentive, high‑quality sleep care with a focus on patient well‑being and an exceptional experience.
Matthew Keeslar, PA-C
Physician Associate
A former actor who successfully transitioned into a career as a certified Physician Assistant (PA-C) and medical instructor. Born in 1972, he is known for his roles in films like Waiting for Guffman, The Last Days of Disco, and Scream 3, as well as the sci-fi dramedy The Middleman.
After a decades-long career, Keeslar retired from acting in 2010 to pursue science. He graduated Phi Beta Kappa from Reed College with a biology degree in 2014, following initial coursework at Portland Community College. He went on to earn a Master of Physician Assistant Studies from Oregon Health & Science University (OHSU).
Now a practicing clinician in Oregon, Matt also served as an instructor at the OHSU School of Medicine. He has worked in urology and men's health, urgent care, and pediatrics.
Erin McPeak MSPAS, PA-C
Physician Associate
Erin is an NCCPA Board-Certified Physician Assistant (PA-C) specializing in Sleep Medicine since 2018. She has been a PA-C since 2011 with prior experience in Neurosurgery, Orthopedics, and Family Medicine. She joined OSA in 2025 as a telehealth only Provider.
Erin earned a Master of Physician Assistant Studies from Butler University in Indianapolis, IN in 2011 and she is a proud fan of the Butler University Bulldogs.
Erin is passionate about taking the time to understand each patient’s unique background and challenges with a patient-centered holistic approach to compassionate care. She is dedicated to providing her patients with clear communication, education, and a collaborative approach to patient care with empathy.
Erin believes that restful, restorative, and a good quality night’s sleep is essential to improve overall quality of life, physical and psychological health, and well-being.
Erin enjoys staying active with swimming, running, working out, gardening, craft and baking projects, spending time with family and friends, and playing with Aari her Australian Shepherd.