(480) 830-3900


We are here to help you take control of your sleep health.

We are the sleep experts and we are here to help you take control of your sleep health.

Most insurance companies do not require a referral to meet with one of our Board Certified Sleep Physicians and providers.

If you are having sleeping problems

Step 1 |  Make an appointment for a sleep consultation to meet with one of our sleep providers.

Step 2 | Your sleep specialist will determine if a sleep study is necessary and prepare a plan for you.

Our Board Certified Sleep Specialists

Wahaj Ahmed, M.D. 

Medical Director, Mesa, Chandler

Dr. Ahmed is board certified in internal medicine, pulmonary disease, critical care medicine and sleep medicine. His practice encompasses all aspects of diagnosis and treatment of pulmonary and sleep disorders.

Maria Martinez, M.D.

Medical Director, Arrowhead

Dr. Maria Martinez is a pediatric pulmonologist in Phoenix, Arizona. She received her medical degree from Universidad de Navarra Faculty of Medicine and has been in practice for 31 years.

Michael Mohan, M.D.

Medical Director, Biltmore

Dr. Mohan is a graduate of Yale University and Harvard Medical School. He went on to complete postgraduate medical training at Massachusetts General Hospital, Beth Israel Deaconess Medical Center, and Boston Children’s Hospital, some of the top-ranked hospitals in the world. He is one of the only physicians in Arizona to have received dedicated Fellowship training in Sleep Medicine, having completed Harvard’s Sleep Medicine Fellowship Training Program in 2016. He has authored journal articles, textbook chapters, and teaching materials on the subject of sleep disorders. Dr. Mohan is board certified in sleep medicine and a member of the American Academy of Sleep Medicine.

James Davis, M.D.

Consulting Physician, Mesa, Chandler

Dr. James Davis completed his Internal Medicine training at Presence Saint Joseph Hospital in Chicago, Illinois. He completed a Pulmonary Medicine Fellowship at Rosalind Franklin University of Medicine and Science in North Chicago, Illinois. He also completed a Sleep Medicine Fellowship at Hennepin County Center in Minneapolis, Minnesota. Dr. Davis is a member of the American Thoracic Society, American College of Chest Physicians, and American Academy of Sleep Medicine. He is triple board certified in Internal Medicine, Pulmonary Medicine, and Sleep Medicine. In addition to managing various pulmonary disorders, Dr. Davis has a special interest in Sleep Medicine. He treats a variety of sleep disorders, including complex sleep-disordered breathing, insomnia, hypersomnia, restless leg syndrome, in both the adult and pediatric patient populations. He also has a particular interest in sleep and its effects on athletic performance. In his free time, he enjoys being active: doing strength and cardiovascular training, hiking, snowboard/skiing, dining out at restaurants, going to the movies, and traveling. He also enjoys spending time with his family and friends.

Leonard M. Moss, M.D.

Medical Director, Scottsdale

Leonard M. Moss, MD has been a board certified sleep physician practicing in Arizona since 2006. He was the first in-clinic provider of sleep medicine consultations at Valley Sleep Center in 2007, starting practice then at the Biltmore Center. Dr. Moss’ education and training were at Washington University in St. Louis, University of Kansas School of Medicine, University of Nebraska Hospitals, and Creighton University Medical School in Omaha, NE. He practiced pulmonary and critical care medicine in Nebraska and Kansas from 1980 to 2006. Dr. Moss is a Fellow of the American College of Chest Physicians and the American Academy of Sleep Medicine. He is Board certified in Sleep Medicine with the American Board of Medical Specialties/ABIM through 2027.

Valley Sleep Center Providers

Kimberly Vana


Kimberly is a sleep health nurse practitioner who actively is involved with national and local sleep organizations. She also has published several sleep research articles. Currently, she is a Clinical Professor at a college of nursing in the Phoenix, Arizona area.

Margena Y. Staten-Branch


Margena is an adult nurse practitioner. She earned her masters degree at the University of Alabama at Birmingham. She has a background in cardiology, chronic disease management and preventative care. She is passionate about sleep medicine because without the diagnosis and treatment of sleep issues many aspects of a persons health can be effected. She is married with five children. She enjoys reading, traveling and spending quality time with her family.

Eric Noll


Eric is a board certified Adult-Gerontology Acute Care Nurse Practitioner and Graduate of Grand Canyon University. He has worked in the medical field for 17 years and has a wide range of experience, with a passion for cardiology and particular interest in sleep disorders and their impact on the heart. In his free time Eric enjoys fishing, wake boarding, snowboarding and spending time with his wife and 3 year old son.

Christina Miller


Christina grew up in Montana, then moved to Arizona for the warm weather. She attended Grand Canyon University as an undergraduate and went on to obtain her Family Practice Nurse Practitioner degree through University of Phoenix. Christina is the mother of three boys and has come to love soccer, hockey, and most outdoor events through them. Her free time is spent reading or enjoying a nice meal with husband. Sleep medicine became Christina’s passion through personal experiences – losing a loved one to sudden cardiac death, being the spouse of a snorer, and her own experience with fragmented sleep. Christina’s mission at Valley Sleep Center is to help people achieve better health through better sleep.

Spotlight Team Members

Breanne Wasson

Marketing Representative

Breanne joined Valley Sleep Center 4 years ago. As a Supervisor of our Scottsdale location and now a Marketing representative, she continues to exemplify her contribution as a valuable team member. She has worked directly with our Patients to assist them in coordinating their sleep care needs while working in our Clinic locations and understands what it takes to provide quality customer service. Breanne has taken her understanding of customer care and now works with our Provider community to facilitate and educate our Providers. She assists them in understanding how our Sleep Centers can help Patients with their sleep health problems. Breanne has demonstrated a commitment to quality care and team work in order to provide excellence in Patient care.

Helen Baubie

Respiratory Therapist

I am a native of Arizona, married and have one son. I have been a Respiratory Therapist since 1994. I have worked with sleep patience since 2003. The reason I love to work with patients that have obstructive sleep apnea is because I feel it is rewarding to me because I get to see them when they are sleep deprived and I can have them as patients for years. I get to see the progression of their lives changing from being treated. I think my best quality is I really listen to what my patients are saying. I feel that really helps me to help them and others that have the same issues. I learn new things everyday even though I have been in the field for years there is always something I learn.

Barbara LaSota

Sleep Technologist

I have personally been involved with the success of CPAP for many years with my family. Since I can remember I had always wanted be a sleep tech. I had been going to school for a few years and it was time to decide what I wanted to do when I grew up. The PSG program was very enticing so I took the leap and here I am. Working graveyards with some of the most amazing people that call themselves “sleep techs”.

Oscar Palmar

Resupply Coordinator

Oscar P. has been a great addition to VST Team. His politeness and positivism are great to be around. He has made a great impact on processing benefits and supply orders for our Replenishing program. His attendance, accuracy and foremost his attitude exemplify an outstanding team member.




Sleep Care Coordinator

Paulina has exemplified the Attitude, Attendance and Accuracy the 3 A’s stand for.  She has been with Valley Sleep Center since 2012 and has been dedicated and committed to Valley Sleep Center and our Patients.  She has always gone above and beyond to assist the Providers in our Arrowhead location, our Patients and our Team members in every location.



John Bradley

Senior Sleep Technologist

John was registered in sleep in 1998 after completing his training at Stanford University’s Sleep Training Program, one of the first and most prestigious in the country.  He has worked at various facilities in Arizona throughout his career and has been with Valley Sleep Center for over ten years now.  John has considerable experience in Polysomnography and is well liked by his peers and the patients he serves. He has extensive experience working with Positive Airway Pressure including advanced modes of therapy in order to help correct patients breathing problems related to Apnea and other causes.  In addition, he has been involved in many challenging cases where PAP therapy is difficult for the patient to tolerate and use. However, with patience, patient interaction, special therapy modes and techniques he has been very successful in getting patients an optimal titration.  John often is our go-to Titration Technologist in the cases that are a challenge.





For most insurance plans, you do not need a primary care referral to meet with our board certified sleep physicians.