The following article was published in the Second Issue, 1999 of CONTACT, the magazine of the Cochlear Implant Club International, pp.

The Importance of Temporal Bone Study to Cochlear Implantation

Sumiko M. Goldbaum and Saumil N. Merchant, MD

One of the best ways to learn about hearing disorders is by studying the temporal bone. The human temporal bone (see figure 1) is that part of the skull containing the structures of hearing and balance – the middle and inner ears. The inaccessibility of the temporal bone during life has always been a difficult problem for researchers studying hearing disorders. It is only after death that scientists can access the temporal bone to examine the hearing and balance systems. This is one of the key reasons why ear research has progressed more slowly than that of other organs in the human body, such as the eye.

The need to advance temporal bone research in the United States has been recognized since the mid-1950s. The National Temporal Bone Banks Program was established by the Deafness Research Foundation and the American Academy of Otolaryngology in 1960 to identify individuals with ear disorders and register those who would pledge their temporal bones at death for scientific research. Over the course of the next 30 years, nearly 6,000 pledges of temporal bones were made through the Temporal Bone Banks Program. During this time, however, the number of active temporal bone collections and investigators declined and by 1990 there were approximately half the number of active temporal bone laboratories as there were in the mid 1970s.

The NIDCD National Temporal Bone Registry

The National Institute for Deafness and Other Communication Disorders (NIDCD) of the National Institutes of Health recognized this trend and the need to rejuvenate interest in human temporal bone research. In 1992, the NIDCD awarded a contract to the Massachusetts Eye & Ear Infirmary and the Deafness Research Foundation to establish the NIDCD National Temporal Bone, Hearing and Balance Pathology Resource Registry to continue and expand on the activities of the Temporal Bone Banks Program. The Registry not only recruits donors, but also disseminates information about temporal bone donation and research to the public and biomedical community, develops and implements professional educational activities, conserves human temporal bone collections which are at-risk of being destroyed, and maintains a computerized database of all temporal bone collections in the United States.

All 26 temporal bone laboratories in the United States collaborate with the Registry. The Registry’s computerized database contains information on over 12,000 temporal bone specimens currently contained in these collaborating laboratories. Scientists can make use of the database (at no cost) for their research studies. The Registry also encourages human temporal bone professional educational activities and investigative collaborations in the study of hearing and balance disorders. On April 23rd this year, the Registry and the House Ear Institute, one of the collaborating laboratories, will host the 3rd Temporal Bone Histopathology Workshop for scientists and clinicians interested in the study of the human auditory and vestibular systems. These workshops carry no registration fees and are designed to provide up-to-date information on a variety of temporal bone techniques and disorders.

Cochlear Implants and Temporal Bone Research

The services of the Registry and the thousands of temporal bones in the country’s temporal bone collections have become a vital resource for scientists researching hearing and balance disorders. Unfortunately, there are still certain otologic disorders and conditions that are underrepresented in the collections. Cochlear implants fall into this category. While over 18,000 individuals have received cochlear implants, temporal bones from less than 30 patients (with an implant) currently exist in the US temporal bone collections. As a result, research on the effects of cochlear implantation on the human ear have been limited and there is scarcity of information in the literature.

The temporal bone protects the delicate organs of hearing and balance. The value of temporal bone research for cochlear implant users cannot be overstated. In addition to improving our understanding of how the structures of the inner ear are affected by various types of hearing loss, by studying the post mortem bones of current cochlear implant users, scientists will be able to understand the impact of the cochlear implant on the ear. They will be able to determine whether an implant actually worked the way it was designed to work, whether the implant caused any trauma to the ear, and if there is a better way to design the implant to work more efficiently. The information obtained from this research will help both physicians and their patients make more informed decisions based on a better understanding of the benefits different people get from the implant and what surgical strategies might be used during implantation.

Temporal Bone Donation to Help Cochlear Implant Research

Anyone who is a current cochlear implant user is an ideal candidate to be a donor. If you are interested in learning more about the National Temporal Bone Registry, or to learn how you can pledge your temporal bones to research, visit the Registry’s web site, call, email, or write to the Registry at following address.

NIDCD National Temporal Bone Registry
Massachusetts Eye & Ear Infirmary
243 Charles Street, Boston, MA 02114-3096
(800) 822-1327 (voice), (888) 561-3277 (TTY)
email: tbregistry@meei.harvard.edu, URL: http://www.tbregistry.org

Sumiko M. Goldbaum is Coordinator of the NIDCD National Temporal Bone Registry.
Saumil N. Merchant, MD is an otologist at the Massachusetts Eye & Ear Infirmary and Harvard Medical School and is Co-Principal Investigator of the NIDCD National Temporal Bone Registry.