Audiology Faculty Research
Dr. Chris Sanford
Audiology Research Lab: Current Project
Conventional clinical tests of middle-ear function are useful for identifying some types of middle-ear pathologies but have not been useful for predicting the presence or degree of conductive hearing loss associated with a given pathology. While emerging research shows that relatively new, wideband (broad frequency range) aural acoustic tests have this potential dual use, normative data is lacking for individuals across a broad age range and for a variety of middle-ear pathologies. The aim of one study, currently underway, is to obtain wideband acoustic measurements from infants, children and adults with a variety of middle-ear pathologies. It is hypothesized that different middle-ear pathologies will be characterized by significantly different wideband aural acoustic responses. Data is currently being gathered at the ISU Audiology clinic and at an ENT physician’s office, here in Pocatello.
A portion of this study is funded by an Idaho State University, Faculty Research Committee Grant, FRC 1024 (Co-Principal Investigators: Chris Sanford and Jeff Brockett).
The long-term goals of this current program of research are to combine results from the present project with those of future studies involving infants, children and adults with normal middle-ear function, to assess the sensitivity and specificity of these wideband tests in terms of 1) detection of middle-ear pathology and prediction of conductive hearing loss, and 2) monitoring of middle-ear surgery outcomes. An improved, objective diagnostic test to identify middle-ear disorders and conductive hearing loss has the potential to provide more accurate audiologic information for individuals of any age, but would be especially useful in difficult to test populations such as young children and infants.
Recent Publications
Keefe, D.H., Fitzpatrick, D.F., Liu, Y., Sanford, C.A. & Gorga, M.P. (2010). Wideband acoustic reflex test in a test battery to predict middle-ear dysfunction. Hearing Research, 263, 52-65.
Sanford, C.A., Keefe, D.H., Liu, Y., Fitzpatrick, D.F., McCreery, R.W., Lewis, D.E. & Gorga, M.P. (2009). Sound conduction effects on DPOAE screening outcomes in newborn infants: Test performance of wideband acoustic transfer functions and 1-kHz tympanometry. Ear and Hearing, 30(6), 635-652.
Recent Presentations
Sanford, C.A., Keefe, D.H., Ellison, J.C., Fitzpatrick, D.F. & Gorga, M.P. (2010). Wideband Acoustic Transfer Functions Predict Conductive Hearing Loss in Children. Poster presentation at the American Auditory Society, Scientific and Technology Meeting, March, Scottsdale AZ.
Dr. Curtis Billings
Area(s) of Research/Scholarly Interest:
I use a brain-behavior approach (auditory evoked potentials and psychophysical methods) to understand the effects of auditory deprivation and stimulation on the brain. This includes interests in the neural effects of hearing aids, hearing impairment, aging, auditory training, and listening in background noise. The long-term goal of this research program is to improve diagnosis and treatment of individuals with hearing impairment by determining how experience-related changes in the brain facilitate and/or inhibit successful auditory rehabilitation. My scholarly contributions to the field have come in four main areas:
1) Aided cortical auditory evoked potentials. There is currently a strong interest among both audiologists and hearing researchers to find a physiological measure that can be used as a marker of how amplified sounds are processed by the brain (e.g., hearing aid fitting) or how the brain changes with exposure to amplified sounds (i.e., hearing aid acclimatization). My research has clarified the uses and limitations of aided cortical auditory evoked potentials. We are investigating what the neural, cognitive, and behavioral effects of hearing aids are both in the short-term (i.e., audibility effects) and in the long-term (i.e., acclimatization effects).
2) Brain-behavior approach to understanding speech in noise. Understanding speech in the presence of background noise is a challenge that has been studied for many decades. My approach has been to use electrophysiology as a complement to behavioral outcomes, which, in turn, may improve our understanding of variability that occurs across individuals and assist in tailoring assessment and/or treatment plans to the needs of the individual patient. In my laboratory we have demonstrated that when background noise is present, neural coding of signal-to-noise ratio, rather than absolute signal level, dominates amplitude and latency characteristics of the cortical auditory evoked response. In addition, we have successfully established electrophysiological measures that predict behavioral auditory performance with considerable accuracy.
3) Brainstem encoding of dynamic stimuli. Envelope-following and frequency-following brain responses to dynamic speech-like and speech stimuli may help clinicians to identify auditory deficits that may need specialized rehabilitation. We have worked to characterize the neural representation of dynamic stimuli at the level of the brainstem to improve our understanding of how formant transitions are encoded in the auditory system in impaired populations.
4) Central auditory and cognitive contributors to hearing. Both top-down and bottom-up processes are important to consider when characterizing speech-in-noise understanding. Our work has explored the top-down compensation processes of cognition in speech understanding in noise. In addition, we have explored audiometric results across the Veteran population to determine the prevalence of “normal hearing” Veterans seeking care in VA audiology clinics nation-wide. The complaints of difficulties in background noise when traditional audiometric testing such as pure-tone audiometry is within normal limits presents a challenge for audiologists. I have worked to start to characterize the extent of this problem clinically.
Publications and Creative Work
Billings CJ, Olsen TM, Charney L, Madsen BM, Holmes C. (2023). Speech-in-noise testing: an introduction for audiologists. Seminars in Hearing, 45(1):1-28
Molis MR, Bologna WJ, Madsen BM, Muralimanohar R, Billings CJ. (2023). Frequency following responses to tone glides: effects of age and hearing loss. Journal of the Association for Research in Otolaryngology: JARO, 10.1007/s10162-023-00900-7. Advance online publication.
Bologna WJ, Molis MR, Madsen BM, Billings CJ. (2023). Effects of age on brainstem coding of speech glimpses in interrupted noise. Hearing Research. 434, 108771. Billings CJ, Madsen BM,
Grush LD, Koerner TK, McMillan GP, Bologna WJ. (2022). Oddball paradigm complexity in multi-token auditory evoked potentials. Neuroscience Letters, 788(136856):1-7
Koerner, T. K., Muralimanohar, R.K., Gallun, F.J., Billings, C.J. (2020). Age-Related Deficits in Electrophysiological and Behavioral Measures of Binaural Temporal Processing. Front Neurosci. 14:578566.
Papesh, M.A., Stefl, A.A., Gallun, F.G., Billings, C.J. (2020). Effects of Signal Type and Noise Background on Auditory Evoked Potential N1, P2, and P3 Measurements in Blast-Exposed Veterans. Ear Hear. 42(1):106-121.
