Alan M.Robinson, Ph.D.

Dr. Robinson is a Research Assistant Professor in the Department of Otolaryngology-Head and Neck Surgery. He conducted his Batchelor of Science Degree in biochemistry at the University of Bath, Avon, England. He received his M.S. and Ph.D. degrees in the biochemistry and molecular biology of steroid hormone regulated gene expression in breast cancer within the Ben May Institute for Cancer Research at the University of Chicago. He conducted post-doctoral research at Northwestern University in otology and olfaction and joined the faculty in 2000. He is currently shifting his focus from the olfactory system to hearing research within the department. Current studies involve prevention of cell death following aminoglycoside treatment in rodents and following noise exposure.

"Inhibition of apoptosis as a means to mitigate hearing loss in mice" (Funded by the E.R. Capita Foundation)

Freshly exposed gerbil cochlea (AC-apical turn of cochlea)

with ossicles (O) still in place and stapedal artery (SA)

as a useful landmark for orientation.

Initial studies were performed in Gerbil with the intention of moving into studies using mice, which are available with transgenic modification of apoptosis-related genes.

The efficacy of the antibiotic minocycline as a therapeutic agent for amelioration of hearing loss in gerbils treated with the ototoxic aminoglycoside, neomycin was investigated. Minocycline is multifaceted in that it exhibits anti-inflammatory, antibiotic and anti-apoptotic properties in several neural and non-neural tissues.

Mid modiolar section of gerbil cochlea demonstrating

cochlear turns (bars) with sprial ganglion (SG) regions

used to quantify spiral ganglion neurons (arrows).

As an anti-apoptotic agent, minocycline would theoretically inhibit apoptosis of sensory cells within the inner ear when exposed to neomycin. Baseline Auditory brainstem Responses (ABR) measurements were made on gerbils prior to experimental treatments. Gerbils then received a single trans-tympanic injection of 40mM neomycin in the left ear and Ringer’s balanced lactate in the right ear and either 0, 1.2 or 1.5 mg/kg intra-peritoneal injection of minocycline in normal saline daily for five days. Day 1 injection was given at commencement of the baseline ABR measurement. Four weeks post-treatment ABR measurements were made and animals sacrificed for histological preparation of the cochleae.

Sprial ganglion neuron nuclei (SGN) within the sprial ganglion

are being quantified in gerbils that either received or did not

receive intra-peritoneal minocycline treatment following

trans-tympanic neomycin in the left ear and Ringer’s balanced

lactate in the right ear. Protection from apoptosis may be

reflected in greater SGN numbers in minocycline treated animals.

Analysis of pre and post treatment ABR measurements demonstrated minocycline amelioration of hearing loss. Quantification of spiral ganglion neurons is under way to determine if there is a correlation with the ABR measurements. Minocycline used in combination with other otoprotective agents is envisioned as a realistic means of preventing hearing loss due to aminoglycoside treatment. A manuscript is in preparation, which will detail the results of this work. This study has lead on to investigation of changes in gene expression in the cochlea mediated by minocycline.

Karen A. Doherty, Ph.D.

"Improving communication for older hospital patents with assistive listening devices"

Hearing in hospitals is difficult for many people, but it is especially challenging for older patients. This is problematic given the importance of the nature of conversations that take place in hospitals, and the fact that approximately 40 percent of the inpatients in hospitals are over 65 years of age (DeFrances, Lucas, Buie, and Golosinskiy, 2008). The purpose of this study is to determine if assistive listening devices (ALD) can be used effectively and independently by older hospital patients to improve hearing.

There are several reasons why ALDs should be made readily available to all older hospital patients. First, a significant number of older individuals have hearing loss.  Specifically, after the age of 60 years one in every three adults will have some degree of hearing loss and after the age of 75 years one in every two adults will have a significant hearing loss (American Academy of Audiology, 2005).  Although many individuals with hearing loss wear hearing aids, it is typical for older hospital patients to leave their hearing aids at home.  This is because hearing aids are very expensive and can get lost or stolen during the patients stay in the hospital. Second, hospitals are noisy and older individuals with and without hearing loss have more difficulty hearing in background noise than younger listeners (Doherty and Desjardins, 2008). Third, physicians and other healthcare workers typically give patients medical information verbally. If doctors and other healthcare workers perceive a patient cannot hear them, they will typically raise their voice to a level that the patient can hear. This level is often loud enough to compromise the patient’s privacy and violate the Health Insurance Portability and Accountability Act of 1996 (HIPAA), which states patients have the right to the protection of the privacy of their identifiable health information. Last, it is important for older patients to be in control of their own healthcare. To do so, they must be able to accurately hear what their physicians and other healthcare providers are recommending as possible treatment options and the risks and benefits associated with each option. If physicians believe their patients cannot understand what they are saying, they may explain important medical information to the patient’s next of kin instead of explaining this information directly to the patient. The results from the present study will provide data on the pattern of use and benefit of using ALDs with older normal-hearing and hearing-impaired hospital patients. This data will be used to support the long-term goal of creating a hospital policy that would require ALDs be made available in the rooms of all older hospital patients.

Monika Kordus, Ph.D.,

University of Iowa Hospitals and Clinics

"Improving Binaural Fitting Procedures of Hearing Aid and Cochlear Implant through Loudness Judgments throughout the Dynamic Range"

Hearing loss is a common handicap among a considerable amount of people worldwide suffering from moderate to profound hearing loss in both ears. In normal hearing persons binaural hearing input is imperative for proper localization of sounds originating from different sources.

The Cochlear Implant

My research interests are focused on hearing impairment and the performance improvement of binaural hearing in patients wearing either cochlear implants in one ear and hearing aids in the contralateral ear (CI+HA) or are implanted bilaterally with cochlear implants in both ears (CI+CI) respectively. Initial steps to achieve this goal include at first the improvement of simultaneous binaural fitting procedures for CI+HA and CI+CI users, rather than adjusting the two devices independently as it is done in current clinical practice.  At second the development and evaluation of new high-rate signal processing in cochlear implants let expect a better speech intelligibility and music appreciation. Valuable data for performing these adjustms s obtained from both CI+HA and CI+CI subjects who are tested in newly developed  more realistic speech perception and localization essays, which utilize spatially separated noise sources. Additional studies aim at the quantification of loudness summation throughout the dynamic range of cochlea implants as well as surveying directionality and speech perception in CI users. Combined with additional psychoacoustic procedures this is one of the most prospective and socially useful application of psychoacoustics.

Michael J. Epstein, Ph.D.

"Automated procedures for the estimation of individual loudness-growth functions for improved hearing-aid fitting"

Michael Epstein - PhotoSecond only to difficulties with understanding speech in noise, poor representations of loudness are a primary complaint for many hearing-aid users. In fact, loudness discomfort or annoyance is often expressed as a primary motivator in the termination of hearing-aid use. It is well known that there is significant variability in the loudness growth of both normal-hearing and hearing-impaired individuals (e.g., Buus and Florentine, 2001; Cox, 1995; Marozeau and Florentine, 2007; Epstein and Florentine, 2005; Whilby et al., 2006). Hearing-impaired listeners with similar thresholds can have vastly different loudness growth functions. In particular, these listeners often substantially differ in the shape of the loudness function in the compressive region making it difficult to predict loudness functions from just a few data points (Hawkins and Naidoo, 1993; Kamm et al., 1978; Valente et al., 1997). Modern hearing aids can compensate for these differences in cochlear compression, however, in most cases, these listeners are fit with similar or identical compression algorithms.

Project Name: "Automated procedures for the estimation of individual loudness-growth functions for improved hearing-aid fitting"