Diron Cassidy

PT, MPT, GCS (Owner)

Diron Cassidy, Vortex Physical Therapy and BalanceDiron Cassidy is a vestibular specialist with more than 18 years of experience treating people with vestibular, neurological and balance related diagnoses. He has extensive education in this area of specialization and has successfully completed APTA Vestibular Rehabilitation Competency Courses at Emory and Duke Universities.

As the clinic director at Vortex, he works closely with his physical therapists to develop their vestibular expertise. Education is prioritized in the clinic, and he and his team stay on top of the latest advancements in vestibular and balance rehabilitation through advanced professional courses,reading and professional events.

Diron is currently focused on treating concussions and complex vestibular cases. However, he oversees all therapy at the clinic and consults on cases as needed.

In his free time, Diron enjoys fishing in the Delta and watching his favorite sports teams- the San Francisco Giants and San Jose Sharks.

Professional Certifications and Competencies

  • Board-Certified Clinical Specialist, Geriatrics (2014)
  • Certified Clinical Instructor (2013)
  • APTA Vestibular Rehabilitation Competency Course (2006)
  • APTA Advances in Vestibular Rehabilitation: Competency Renewal Course (2014)
  • APTA Cervicogenic Dizziness Competency Course (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 joined Vortex Physical Therapy and Balance in 2018 She is a PWR!Moves® certified therapist for individuals with Parkinson’s disease and enjoys working with those who are dealing with dizziness and imbalance issues.

Her interest in neurological and vestibular therapy started during her training at an outpatient clinic in San Francisco, where she worked with patients with Parkinson’s disease and multiple sclerosis. She is passionate about helping individuals improve and maintain their functional mobility, so they are able to do the things they love.

Jo is a fluent Spanish speaker and sees our patients for whom Spanish is their primary, preferred language.

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 Curry has been part of the Vortex team since August 2015. She sees people with a wide-variety of vestibular, neurological and balance issues. In addition to her experience here, she has completed extensive training and coursework in vestibular rehabilitation, including successfully passing the APTA Competency Course on Vestibular Rehabilitation at Emory University.

She enjoys working with people to resolve their symptoms and get back to living an active life. She 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 Vestibular Rehabilitation Competency Course (2018)


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

Amanda Kelch


Amanda Kelch is a Neurologic Clinical Specialist (NCS) who moved to the Bay Area from Michigan in 2018.

After receiving her DPT, she completed a one-year neurological residency at Mary Free Bed Rehabilitation Hospital in Grand Rapids, the fifth largest rehabilitation hospital in the US. There, she worked with people recovering from stroke, brain injury, spinal cord injury, concussion, vestibular dysfunction, and other neurological conditions in both inpatient and outpatient settings.

Her residency experience has helped shape how she approaches patient care and is a big benefit to her patients at Vortex who come in with vestibular and neurological issues.

Amanda enjoys hiking and biking with her husband, taking their dog for long walks, and reading.


Professional Certifications and Competencies

  • LVST BIG Certification (2017)


  • BS in Clinical Exercise Science, Grand Valley State University, Allendale, MI
  • MS of Health Science in Biomedical Sciences, Grand Valley State University, Allendale, MI
  • DPT, Grand Valley State University, Allendale, MI

Cara Cassidy

Office Manager

Cara 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.