Leadership & Staff


Diana Hanyak

Chief Executive Officer

With over 25 years experience in hospital administration, Diana is responsible for the leadership and operations of HealthSouth Tustin Rehabilitation Hospital as chief executive officer.  Diana’s healthcare experience includes roles in business development, strategic planning and operations in general acute, acute psychiatric, and most recently as CEO of Kindred Hospital in Santa Ana, California for over nine years.  Diana’s personal philosophy is that the patient is at the center of everything we do.  She believes that by creating a positive workplace that inspires our caring staff to continually focus on quality and service, the hospital will attract and retain the best healthcare professionals.  Diana holds a master's degree in healthcare administration and is a member of the American College of Healthcare Executives.

Ann Vasile, M.D.

Ann Vasile, M.D.

Medical Director

Dr. Ann Vasile began her clinical practice in 1993 and is currently serving as medical director* of HealthSouth Tustin Rehabilitation Hospital. In addition, she serves as medical director at Paradigm Medical Director and a partner at Rehabilitation Associates Medical Group. Throughout her career, she has been involved in multiple leadership roles in spinal cord injury and rehabilitation. She received her medical doctorate from Albany Medical College in New York then completed a residency in physical medicine and rehabilitation at New York University’s Rusk Institute of Rehabilitation Medicine and the University of California, Irvine. Dr. Vasile has held board certification in physical medicine and rehabilitation since 1994, and has held a second specialty board certification in spinal cord Injury medicine since 1999. She remains actively involved in rehabilitation, research, advocacy and innovative interventions to improve function and quality of life for disabled persons throughout the continuum.

* The hospital provides access to independent physicians.

Gretchin Pecher

Gretchin Bitner, MPT

Director, Therapy Operations

In her role as DTO, Gretchin brings a wealth of experience that includes more than 14 years in the acute rehabilitation level of care. After joining the HealthSouth Tustin Rehabilitation Hospital team as a staff physical therapist in June 2003, Gretchin was eventually promoted to director of Therapy Operations in February 2008.  She currently serves as an active member in both the Orange County Stroke Rehabilitation Network and on the Program Advisory Committee for the Physical Therapist Assistant Program at Concorde College.  Gretchin earned both her bachelor’s degree in Biology and master’s degree in Physical Therapy from Slippery Rock University.
Maryam Jouharzadeh

Maryam Jouharzadeh, Pharm.D.

Director, Pharmacy

Maryam  graduated with a bachelor's degree in biology from the University of California at Irvine in 2001.  She earned her doctorate of pharmacy in 2008 from Loma Linda University, where she also completed all of her clinical rotations.  Maryam started her pharmacy career in Louisiana, working in both direct patient care and in retail as a director of pharmacy for CVS.  A preceptor for pharmacy students since 2009, she also received her immunization certification from American Pharmacists Association in 2010.  Throughout her career endeavors, Maryam's philosophy has been to adhere to the core value of emphasizing customer satisfaction as the center of any successful operation.  Maryam currently holds an active pharmacist license in the states of Louisiana and California.

Paula Redmond

Paula Redmond


Paula joined HealthSouth Tustin Rehabilitation Hospital in 2006.  In her involved role as Controller, she has the oversight of several business functions within the hospital including accounts payable and receivable, billing, health information management and materials management.  Paula has spent the last 15 years of her career in healthcare, and before joining HealthSouth she worked in several industry sectors including general acute care, cardiac specialty care, and as practice administrator for a multi-specialty group.  She is a graduate of Cal Poly Pomona, where she earned her bachelor’s degree in Accounting.
JoAnn Roiz

JoAnn Roiz

Director, Human Resources

JoAnn is certified as a Professional in Human Resources (PHR). She brings more than 25 years of human resource management expertise to HealthSouth Tustin Rehabilitation Hospital.  Having worked in several business environments including small business, retail and manufacturing, she brings a wealth of knowledge to her role as director of Human Resources.  JoAnn has been with the hospital since 2007, and is currently an active member of the Society of Human Resources Management (SHRM), the American Society of Healthcare Human Resources Management (ASHHRA) and the Professionals in Human Resources Association (PIHRA).
Lindsey Taylor

Lindsey Taylor

Director of Case Management

Lindsey has more than 10 years of experience in healthcare, with focus in the areas of case management discharge planning, payor and physician relations and social services.  She has worked for HealthSouth Tustin Rehabilitation since 2008.  She earned an undergraduate degree in psychology from the University of California at Santa Barbara.  

Ben Zavala

Ben Zavala

Director, Plant Operations

Ben has been head of Plant Operations at HealthSouth Tustin Rehabilitation hospital for close to a decade.  Before joining the hospital, Ben’s extensive experience included 18 years of supervisory service in several long term care facilities, including Alzheimer’s units.  In addition to the invaluable expertise Ben has acquired through his many years of healthcare experience, he’s also earned certification in HVAC, plumbing and electrical systems.  Ben also serves as the hospital’s safety and security officer and was awarded our prestigious Employee of the Year award in 2009.