Diron Cassidy

PT, MPT, GCS (Owner)

Diron Cassidy, Vortex Physical Therapy and BalanceDiron Cassidy is a specialist in balance and vestibular disorders with more than 15 years experience. He earned his undergraduate degree in physiology from the University of California at Davis and his Masters of Physical Therapy from California State University, Long Beach.

He completed the APTA competency course on vestibular rehabilitation at Emory University in 2006 and 2014 and takes regular courses on the latest advancements in vestibular and balance rehabilitation. Diron is a Certified Geriatric Specialist and a PWR!Moves® certified therapist for individuals with Parkinson’s disease.

In addition to his clinical work, Diron is active in the physical therapy community with roles in the APTA at the local, state and national level. He is a Certified Clinical Instructor and enjoys working with PT students.

Diron enjoys fishing and spending time with his family. He is an avid fan of the San Jose Sharks and San Francisco Giants.

Brittany Davidson


Brittany Davidson has been with Vortex since August 2015. She received her Doctor of Physical Therapy degree from the University of Colorado, Denver and completed undergraduate studies in kinesiology at San Diego State University in California.

Her passion for treating neurological conditions started during her training at outpatient clinics in Colorado and Michigan, where she worked with individuals recovering from strokes and spinal cord injuries. She also worked for three years as a physical therapy aide in San Diego while completing her undergraduate studies.

Brittany works with a broad range of patients at Vortex treating vestibular issues and balance impairments. She really enjoys the challenge of treating BPPV and helping people resolve their symptoms. She also helps staff our wellness classes on Thursday afternoons.

A native of San Jose, Brittany enjoys hiking, riding her beach cruiser, racing go-karts, and snowboarding.

Rupali Vyas


Rupali Vortex Physical TherapyRupali Vyas has been with Vortex Physical Therapy and Balance since July 2012. She completed her post-graduate Doctor of Physical Therapy degree from Massachusetts General Hospital, IHP Boston and has been a therapist for more than 10 years.

She regularly takes vestibular courses to increase her expertise and completed the APTA competency course on vestibular rehabilitation in 2015. She is also a PWR!Moves® certified therapist for individuals with Parkinson’s disease.

Prior to moving to the Bay Area, Rupali worked for a neurology practice in Manhattan where she first treated vestibular disorders. She has also worked in both skilled nursing and long-term care settings and enjoys helping seniors lead better lives.

Outside of work, Rupali enjoys spending time with her young daughter and Bollywood dancing.


Cara Cassidy

Office Manager

Cara Vortex Physical Therapy and BalanceCara Cassidy handles the daily management of the practice, which includes scheduling patient appointments, answering questions, coordinating with other medical offices, and insurance billing.

As the primary contact for the clinic, she is the point person for questions about our therapy program or vestibular therapy in general.

Cara leverages her background in communications and customer service to ensure a positive experience for everyone who walks into our clinic.

In her spare time, she loves to travel, read, foster kittens and spend time with her family.