American Auditory Society Scientific and Technology Meeting February 28 – March 2, 2019 POSTER ABSTRACTS Topic areas and poster numbers: Topic Area Poster Numbers POSTER SESSION I – Thursday – Friday Anatomy and Physiology Poster #1-7 Audiology / Otology Poster #8-17 Auditory Processing Poster #18-25 Cochlear Implants Poster #26-35 Electrophysiologic Responses Poster #36-41 Hearing Loss / Rehabilitation Poster #42-52 Hearing Science / Psychoacoustics Poster #53-66 Hearing Technology / Amplification Poster #67-78 Pediatric Audiology / Otology Poster #79-85 Speech Perception Poster #86-89 Tinnitus Poster #90-92 POSTER SESSION II – Friday - Saturday Anatomy and Physiology Poster #93-99 Audiology / Otology Poster #100-109 Auditory Processing Poster #110-118 Cochlear Implants Poster #119-128 Electrophysiologic Responses Poster #129-135 Hearing Loss / Rehabilitation Poster #136-145 Hearing Science / Psychoacoustics Poster #146-154 Hearing Technology / Amplification Poster #155-166 Pediatric Audiology / Otology Poster #167-173 Speech Perception Poster #174-176 Tinnitus Poster #177-178 ANATOMY and PHYSIOLOGY Poster # 1 L-Serine Reduces ROS Yield in Cisplatin Treated Zebrafish Utricles Elvin Irihamye; Satya Moolani, Western Kentucky University, Lexington, KY Cisplatin is a chemotherapy compound effective against a variety of cancers. However, it can act as an ototoxin and cause hearing loss by promoting reactive oxygen species (ROS) production in auditory tissues. The antioxidant amino acid, L-serine has been hypothesized to lower levels of cisplatin-mediated ROS. In this project, we investigated whether L-serine can reduce cisplatin-mediated ROS production in auditory tissue and potentially act as an otoprotectant during cisplatin chemotherapy. We used a zebrafish utricular tissue culture system and fluorescent ROS indicator dye to spectro-photometrically measure if L-serine could decrease reactive oxygen species levels in cisplatin-treated tissues. We found that cisplatin treatment increased ROS yield in the utricular tissue while L-serine treatment alone did not alter ROS levels. Interestingly, we also found that equimolar L-serine treatment with cisplatin restored ROS to control levels. These results could be due to L-serine acting as an ROS scavenger. However, it is possible that L-serine could chemically inactivate cisplatin in these tissues. Future experiments are needed to see if L-serine can act as an otoprotectant in auditory tissue without mitigating the effects of cisplatin in cancer cells. Poster # 2 The Accuracy of Automated Cortical Parcellation/Labeling for Human Auditory Cortex Barrett Victor St George, BA; Bryan Wong, BS; Frank Musiek, PhD, University of Arizona, Tucson, AZ Previous research has shown that human auditory cortex exhibits pronounced structural variability. Yet it is unclear how automated parcellation/labeling procedures handle such complex macroanatomical variances in this brain region. This study assesses the accuracy of a widely-used automated cortical parcellation/labeling procedure compared to expert manual surface area measures for planum temporale (PT). Additionally, the effects of surrounding auditory cortex morphology on PT surface area and its impact on structural hemispheric asymmetry is examined with respect to both measurement techniques. High-resolution structural MRI brain scans of 50 healthy, right-handed young adults were processed through an automated cortical reconstruction. Automated surface area measures of PT and surrounding auditory cortex structures were based on the Destrieux (2010) cortical parcellation atlas. Cortical surface area of PT, Heschl's gyrus (HG) and planum parietale (PP) were then measured manually in all same 100 hemispheres: state-of-the-art neuroimaging software was used to define virtual clipping planes that exposed PT, HG and PP for subsequent surface area measurements. A significant difference in cortical surface area and hemispheric asymmetry between manually- and automatically-defined labels of 'PT' was found. Examples and discussion of major issues in the automated process which leads to inaccurate anatomical localization of PT are provided and discussed. Poster # 3 Impact of Spontaneous Otoacoustic Emissions (SOAE) on Audiometric Thresholds Glenis Raewyn Long, PhD, Graduate Center of the City University of New York, New York, NY Pim van Dijk, PhD, Department of Otorhinolaryngology, Head & Neck Surgery, Groningen, Netherlands Otoacoustic Emissions which can be detected even when no external sounds are presented are called Spontaneous Otoacoustic Emissions (SOAE). The auditory system is relatively sensitive near SOAE frequencies, resulting in local threshold minima. Internal noise in the cochlear amplifier is thought to be responsible for the known variability of SOAE amplitude and Phase. Potentially, this internal noise also determines tone-detection thresholds. This was investigated in a tone-detection experiment, where the ability to detect a tone was compared to the behavior of SOAEs in presence of the tones. Near threshold tones can capture the emission making it oscillate at the same frequency as the external tones, maintaining a stable relative phase. Investigation of the phase of SOAE during stimulation by near- threshold tones suggests that under these circumstances, the internal noise in cochlear amplification potentially plays minimal role in limiting the ability to detect a weak near-threshold tone. Poster # 4 WITHDRAWN Poster # 5 Use of Stimulus-Onset Jitter to Cancel Short-Latency SSOAE Energy James Douglas Lewis, PhD; Amy Mashburn, BS, University of Tennessee Health Science Center, Knoxville, TN Synchronized-spontaneous otoacoustic emissions (SSOAEs) are slow-decaying OAEs that persist up to several-hundred milliseconds post-stimulus. If the inter-stimulus interval is sufficiently short, SSOAEs may contaminate the stimulus window of the adjacent epoch. In medial-olivocochlear reflex (MOCR) assays, SSOAE contamination will present as a change in the stimulus between quiet and noise conditions, since SSOAEs are sensitive to MOCR activation. Traditionally, a change in the stimulus between MOCR conditions implicates acoustic reflex activation by the noise; however, this interpretation is potentially confounded by SSOAEs. This study examined the utility of jittering stimulus onset to desynchronize and cancel short-latency SSOAE energy. Transient-evoked (TE) OAEs were measured from 12 subjects in contralateral-quiet and -noise conditions. Clicks were presented at fixed and quasi-random intervals (by introducing up to 0.5-ms of jitter). For the fixed-interval condition, spectral differences in the stimulus window between quiet and noise conditions mirrored those in the SSOAE analysis window, consistent with SSOAE contamination. In contrast, spectral differences stemming from SSOAEs were absent in the stimulus window for the quasi-random-interval condition. Temporal jitter also facilitated identification of the TEOAE and improved estimates of TEOAE latency. MOCR, TEOAE and wideband immittance applications are all expected to benefit from stimulus-onset jitter. Poster # 6 Reflections and Reflectance of Non-Uniform Ear Canals Kren Rahbek Norgaard, MS, Technical University of Denmark, Kgs. Lyngby, Denmark Christopher Shera, PhD; Karolina Charaziak, PhD, University of Southern California, Los Angeles, CA The ear-canal reflectance is useful for quantifying the conductive status of the middle ear because it can be measured at a distance from the tympanic membrane. Deriving the reflectance requires decomposing the total pressure into its incident and reflected components, which is usually achieved from the measured ear-canal impedance using the characteristic impedance. The characteristic impedance characterizes the ratio of sound pressure to volume flow of a propagating wave in a uniform waveguide, however, in non-uniform waveguides, the impedance of a propagating wave is complex and depends on the direction of propagation. These wave impedances are generally required to decompose the pressure into its incident and reflected components. The ear canal is inherently non-uniform and it may be necessary to employ such wave impedances to characterize the reflectance at the position of a non- uniformity in the ear canal. This presentation will discuss the concept of what one considers a reflection and investigate mechanisms that generate reflections in non-uniform waveguides. The physical properties of the analytical wave impedance of various types of horns will be discussed, and their applicability will be investigated in characterizing the ear-canal reflectance in a simulated non-uniform acoustic load similar to the human ear canal. Poster # 7 Effects of Tonic Muscle Activation on Amplitude-Modulated Cervical VEMPs (AMcVEMPs) Andrew Philip Thorne, BA; Christopher Clinard, PhD; Erin Piker, PhD, James Madison University, Harrisonburg, VA The purposes of this study were 1) to characterize the effects of tonic electromyogram (EMG) activation on AMcVEMPs, 2) to compare interaural asymmetry ratios across AMcVEMP analysis methods, and 3) to characterize nonlinear response properties of AMcVEMPs. Young adults (ages 21-24) with no known vestibular lesions or middle ear pathologies participated in this study. Stimuli were 500 Hz tones amplitude modulated at 37 Hz. Five EMG conditions were tested: 0, 30, 50, 70, and 90 uV. AMcVEMPs were analyzed using FFT-based analyses which included amplitude, SNR, and phase coherence. As expected, AMcVEMP amplitude increased linearly