Come Meet Our Audiologists at Hearing Assessment Center, LLC

At Hearing Assessment Center, LLC, we’re committed to helping our patients restore their hearing and improve their quality of life. Armed with the latest hearing loss treatments, we’ll help you get back to doing what you love. Meet our team of highly qualified audiologists and hearing experts.

Rory Cernik, Au.D., CEO/President, Doctor of Audiology

Rory Cernik, Au.D.

CEO/President, Doctor of Audiology

Dr. Rory D. Cernik is our Director of Clinical Services at the Hearing Assessment Center. He has received extensive training from some of the brightest minds in audiology.

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Upon graduating audiology school, Dr. Cernik received his foundational training from Drs. Jim McDonald and Steve Seipp. “I was fortunate to be around Drs. McDonald and Seipp. I hope I can inspire young audiologist as they inspired me.” – Dr. Cernik

Often, patients will drive quite a few hours to spend time with Dr. Cernik. His passion is to properly educate his patients and rehabilitate the cognitive aspects of their hearing loss. He also practices general audiology. Dr. Cernik is currently seeing patients in our Lutherville location.

Expertise and Experiences

  • Created Hearing Assessment Center, LLC in Maryland and Virginia, a multi-location, multi-audiologist private practice that SERVES patients in Baltimore and surrounding areas
  • His practice specializes in: the diagnosis and treatment of hearing loss, the brain’s auditory processing capability, tinnitus origins, and assessment of your cognitive load (meaning how hard your brain works to separate speech from background noise)
  • Mentoring and training of doctoral students from local universities
  • Interviewed on WBAL and WCBM; weekly Baltimore Hears You segments
  • TV commercial, WBAL
  • Mentored by world renowned tinnitus researchers and continually is recognized nationally by his peers
  • Specializes in industrial audiology and worker’s compensation claims. He has examined hundreds of local fireman and police officers
  • He has seen and impacted over 5000 lives in our community
  • Specializes in pain free cerumen (ear wax) removal and maintenance
Donald A. Guillen, Au.D., Doctor of Audiology

Donald A. Guillen, Au.D.

Doctor of Audiology

Dr. Donald A. Guillen earned his doctorate from Towson University and completed his clinical fellowship at the Hearing Assessment Center under the tutelage of Dr. Rory Cernik.

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During his doctoral studies, his research focused heavily on the effect of degraded listening conditions (background noise and reverberation) on cochlear filtering as well as auditory brainstem encoding in normal and hearing impaired individuals. In particular, he was interested in understanding why hearing impaired individuals have a difficult time understanding speech in noisy environments while normal hearing individuals do not. He utilizes this in-depth understanding to properly treat hearing impairment clinically, as the applicability of this research is integral to the recommendations he makes on a daily basis. He now dedicates much of his time to the thorough evaluation and treatment of individuals with chronic tinnitus and hyperacusis. He has established himself in the community as a caring and well-versed tinnitus professional who has treated and assisted many of these individuals.

Dr. Guillen also thoroughly enjoys educating patients on the dangers of untreated hearing loss and serves as a Community Ambassador. He is passionate about the importance of addressing hearing loss. He frequently performs talks and provides hearing screenings at senior centers, local military retiree centers, hunting clubs, and other local organizations. Under this role, he has also had the privilege of assisting the international community through his work with the St. Clare Medical Outreach program, a Baltimore based program, which looks to lessen healthcare disparities between immigrants/refugees and the general population. Dr. Guillen has demonstrated a strong commitment to serving our local veterans and has taken on a leadership role in this area. Currently, Dr. Guillen is seeing patients in our Lutherville and Bel Air locations.

Expertise and Experiences

  • Spanish-proficiency certification from the University of Alcalá de Henares in Madrid. Dr. Guillen is the only bilingual audiologist in the Baltimore Metro Area.
  • Highly specialized in cerumen (ear wax) removal utilizing only non-abrasive methods to ensure a pain free experience.
  • Specializes in industrial audiology and worker’s compensation claims. Has worked with numerous firefighters and police officers in the area, providing rehabilitative treatment to many of these individuals.
  • Accredited provider for the Hear Now Foundation program.
  • His professional interests and expertise include: tinnitus evaluation, tinnitus retraining therapy, the diagnosis and treatment of hearing loss, geriatric audiology, and cognitive hearing deficits and processing disorders.
Nikki Butler, Au.D., Doctor of Audiology

Nikki Butler, Au.D.

Doctor of Audiology

Dr. Nicolette “Nikki” Butler is the audiologist at our Warrenton, Virginia office. Dr. Nikki received her doctorate at East Tennessee State University.

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She completed her residency at the Alaska Hearing and Tinnitus Center in Anchorage, Alaska. She has done extensive research in the area of auditory Working Memory. Working Memory is how the brain stores input from the ears. Her team focused on the relationship between speech comprehension and Working Memory. She has presented her research and some of the biggest events in the audiology world.

Dr. Nikki is certified by the American Board of Audiology. This certification demonstrates a commitment to professional standards, ethical practices, and continued professional development. Only 15% of audiologist have this distinction. She also holds a certificate in Tinnitus Management. Only a select few doctors have this qualification. People who suffer from tinnitus actively seek out Dr. Nikki’s care; often times, patients will drive several hours for her treatment and care.

Dr. Nikki is the most passionate audiologist you will find. She has dedicated her life to helping those in her community who suffer from hearing loss and tinnitus. She understands how important hearing is to everyone’s cognitive health and overall quality of life. Her main goal is to educate every single patient and, if necessary, treat these individuals with the highest level of care. Since moving to VA from Alaska, Dr. Nikki has developed a very strong reputation in the community.
When she is not serving her community, Dr. Nikki enjoys cooking, drinking copious amounts of coffee and exploring Virginia with her husband and two dogs.

Karson Marvel, Au.D., 
Doctor of Audiology

Karson Marvel, Au.D.

Doctor of Audiology

Dr. Karson Marvel is one of the audiologists who practices in our
Lutherville office. She also sees the residents of Broadmead Retirement Community to provide superior and convenient hearing healthcare.

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Dr. Marvel earned her doctorate at Towson University and completed her fourth year externship under Dr. Rory Cernik. She is American Board of Audiology Certified (ABAC) and a fellow of the American Academy of
Audiology (F-AAA).

Dr. Marvel is passionate about welcoming patients into the practice as she establishes relationships with patients. She accomplishes this by listening and educating patients about hearing health care, communication strategies, and appropriate treatment options. During Dr. Marvel’s graduate studies, she completed extensive research on auditory processing abilities in adults. She eagerly assists patients to achieve improved communication with their loved ones.

When not in the office, Dr. Marvel enjoys spending time with her family and friends, hanging out with her dog, and traveling to the beach.

Casey Freed, Au.D., Doctor of Audiology

Casey Freed, Au.D.

Doctor of Audiology

Dr. Casey Freed is one of our audiologists who practices primarily in the Perry Hall office. Dr. Freed earned her Doctor of Audiology from Towson University.

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During her graduate studies, she completed research investigating the localization ability of those with hearing loss using hearing aids and personal sound amplification products (PSAPs).

With a strong commitment to helping patients with hearing difficulties, Casey has dedicated her career to improving the lives of those she serves. Whether it is fitting patients with hearing devices, conducting comprehensive testing, performing cerumen management, or offering counseling and support, Casey approaches every case with empathy and expertise.

In addition to her professional accomplishments, Casey is a loving wife to her husband, Bryn,and enjoys spending time with her family. She was born and raised in Bel Air, attended high school at Notre Dame Prep in Towson, and attended Towson University for both her undergraduate and graduate degrees. Needless to say, she is a local to the area and cannot wait to raise her family here!

Outside of work, Casey is an avid tennis player, beach-lover, and loves to immerse herself in good book whenever she has free time.

Our Story and Mission

We take pride in helping our patients improve their quality of life.

Patient Testimonial

One of our loyal and devoted patients speaks about her experiences with hearing loss. See more reviews.