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Professional Staff

The Partners of Guam Hearing Doctors


Renee L.G. Koffend

Renee L.G. Koffend has a Doctorate Degree in audiology.  Dr. Koffend is a member of the American Speech-Language & Hearing Association. She completed her clinical fellowship in 1990.  She is licensed to practice both on Guam and in the state of Illinois.  She was the senior audiologist at the prestigious, Chicago ENT.


Jerry R. Castro

Jerry R. Castro is an American Board of Otolaryngology certified doctor.  He specializes in treatment and surgery for diseases of the ear, nose and throat.  Dr. Castro has completed two fellowships: Head and Neck Oncologic Surgery at Memorial Sloan-Kettering Cancer Center (2007) and Microvascular Reconstructive Surgery of the Head and Neck at Beth Israel Medical Center (2014).

Both Dr. Koffend and Dr. Castro are Chamorro, born and raised on Guam.

Medical Assistant

Grace Nivera

Grace Nivera is a medical assistant with an Associate Degree from Guam Community College.  She has been in the hearing industry for over 8 years.   She is familiar with the challenges and struggles of hearing loss and its impact on communication and learning.  Grace is able to establish immediate rapport with patients so that they are comfortable in our clinic.  Grace is fluent in Tagalog.


Adult patients typically struggle with the isolation and embarrassment of hearing loss for several years before they have the courage to take action. With that in mind, it is my goal that every patient’s experience with me is both informative and positive. We strive to offer better hearing solutions so they may fully enjoy their daily activities, remain active and socially connected with friends and family.

Pediatric patients with even a mild hearing loss may suffer from significant speech-language delay. Additionally, any degree of hearing loss may adversely impact academic and social achievement. We have the technology to evaluate children as young as 1-day old and fit hearing aids on babies as young as 3 months old. Early Intervention is critical in providing babies with hearing loss the opportunity to perform as well as their hearing peers.


  • Pediatric & Adult audiology
  • Hearing Aid Selection & Fitting: digital and wireless products
  • Assistive Listening Devices
  • Blue tooth enable Devices
  • Smart Phone compatible Devices
  • Consultation and Education: hearing loss and hearing loss prevention
  • Custom hearing protection and recreational ear pieces for hunters, musicians and motor and water sports enthusiasts.
  • Tinnitus Evaluation
  • Hearing loss and Tinnitus Rehabilitation


GHD is able to evaluate and match lifestyle with technology and budget.  We partner with agencies that have been awarded federal funding and grants for hearing aids and/or assistive listening devices for individuals with hearing loss.

We assist our patients through the eligibility and acceptance process in obtaining financial assistance for hearing devices.

Everyone has the right to better hearing!

Prices range from $1000 to $2, 200 per instrument.  All products come with a comprehensive service warranty, loss & damage warranty, and batteries.

The average life span of hearing aids is 3-5 years.  GHD provides a comprehensive service package for worry-free, hearing.


We participate with Medicare, Medicaid, MIP and local carriers.

  • NetCare
  • Select Care
  • StayWell
  • TakeCare

Guam Hearing Doctors offers diagnostic audiological evaluations, hearing loss rehabilitation, hearing aids, tinnitus treatment solutions, custom ear pieces for hearing loss prevention or recreational activities, education and counseling to improve communication.


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