Diron Cassidy

PT, MPT, GCS (Owner)

Diron Cassidy, Vortex Physical Therapy and BalanceDiron Cassidy is a vestibular specialist with more than 15 years of experience. In addition to  successfully completing three of the APTA Vestibular Rehabilitation Competency Courses, he stays on top of the latest advancements in vestibular and balance rehabilitation through advanced professional courses and events.

In addition to his clinical work, Diron has been an active member of the local CPTA chapter. He enjoys working with his team to develop their vestibular therapy expertise, and teaching students during their clinical rotations.

In his free time, Diron enjoys fishing and watching the San Jose Sharks and San Francisco Giants.

Professional Certifications and Competencies

  • Board-Certified Clinical Specialist in Geriatric Physical Therapy (2014)
  • Certified Clinical Instructor (2013)
  • APTA Competency Course on Vestibular Rehabilitation (2006)
  • APTA Competency Renewal on Vestibular Rehabilitation (2014)
  • APTA Competency Course on Cervicogenic Dizziness (2015)
  • PWR!Moves® certified therapist for individuals with Parkinson’s disease (2014)


  • BS in Physiology, University of California at Davis
  • Master of Physical Therapy, California State University, Long Beach

Johanna Kerr


Johanna (Jo) Kerr recently joined Vortex Physical Therapy and Balance. Her interest in neurological and vestibular therapy started when she did her training at an outpatient clinic in San Francisco, where she worked with patients with Parkinson’s disease and multiple sclerosis.

In October 2018, she becomes a PWR!Moves® certified therapist for individuals with Parkinson’s disease. She will be treating Parkinson’s patients as part of Vortex’s balance therapy practice, along with other adults who experience balance issues.

Jo is passionate about helping individuals improve and maintain their functional mobility, so they are able to do the things they love in life. She is taking courses in vestibular rehabilitation and looks forward to working with our dizzy patients.

In her spare time, Jo enjoys going to the gym, hiking around the Bay Area, watching football and traveling to new places.

Professional Certifications and Competencies

  • PWR!Moves® certified therapist for individuals with Parkinson’s disease (2018)


  • BS in Zoology and Spanish, University of Wisconsin, Madison
  • DPT, University of California, San Francisco/ San Francisco State University

Brittany Curry


Brittany (Davidson) Curry has been with Vortex since August 2015. 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.

Since joining Vortex, Brittany has focused on specializing in vestibular and balance rehabilitation and she recently completed the APTA Competency Course on Vestibular Rehabilitation. She enjoys working with people to resolve their symptoms and get back to living an active life. Brittany continues to take advanced courses in vestibular and balance rehabilitation.

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


Professional Certifications and Competencies

  • APTA Competency Course on Vestibular Rehabilitation (2018)


  • BS in Kinesiology, San Diego State University, San Diego CA
  • DPT, University of Colorado, Denver CO

Cara Cassidy

Office Manager

Cara Vortex Physical Therapy and BalanceCara 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.

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

When she has spare time, she enjoys reading, traveling, fostering kittens and spending time with her family.