As chair of the ARC, I was honored to work with several distinguished pediatric audiologists on the organizing committee, including Dr. Marlene Bagatto, University of Western Ontario; Dr. Linda Hood, Vanderbilt University School of Medicine; and Dr. Douglas P. Sladen, Mayo Clinic—Rochester. With their thoughtful input, we convened an outstanding program of researchers in our field that attracted 230 attendees!
I also want to acknowledge the organizational support of Dr. Jennifer Shinn, University of Kentucky, and Meggan Olek, the Academy’s director of professional advancement. Their assistance was critical to the success of the conference.
Our charge was to identify a group of speakers who could address a wide-range of current research in childhood hearing loss and connect that work with clinical practice. An exceptional group of investigators showcased their latest discoveries that spanned basic and applied hearing sciences. These six speakers, in addition to 12 posters, stimulated thought and discussion of important issues relevant to serving children with hearing loss and their families.
The following abstracts from each of our speakers summarize their presentations.
The Challenge of Hair Cell Regeneration: How Does Normal Development Inform Future Therapeutics?
Brenda Ryals, PhD, Professor Emerita in Communication Sciences and Disorders, James Madison University, Harrisonburg, Virginia
The ability for birds to regenerate inner ear hair cells after acoustic trauma or ototoxic injury was first discovered more than 25 years ago (Ryals and Rubel, 1988; Corwin and Cotanche, 1988). Not only can adult birds automatically replace hair cells, these regenerated hair cells result in nearly complete recovery of hearing sensitivity (Dooling and Ryals, 1997). Since this discovery, an entire field of auditory research has been established to determine how we might regenerate or replace cochlear hair cells in mammals, particularly humans, after damage or loss.
This presentation summarized current research efforts focusing on small molecule targeting, gene therapy, and stem-cell transplantation for repairing or replacing damaged mammalian cochlear hair cells. The status and future challenges of each approach was discussed. A brief review of human clinical trials using gene therapy as well as molecular approaches was provided. The use of stem cells for future therapeutics for neural growth and replacement was discussed. The role of the audiologist in counseling patients and parents about the status of this line of research was emphasized. Finally, the future role of audiologists in determination of candidacy and quantifying success of treatment was emphasized.
Audiologists will play an important part in determining candidacy and quantifying success as we move forward with future biochemical and pharmacological approaches to hearing restoration. In the early stages of these approaches, it is likely that a combination of prosthetic and pharmaceutical intervention will be used. The audiologist will continue to play a vital role in providing rehabilitation services to all patients for the best outcomes after hearing-loss treatment.
Ryals BM, Rubel EW. (1988) Hair cell regeneration after acoustic trauma in adult coturnix quail. Science 240(4860):1774–76.
Corwin JT, Cotanche DA. (1988) Regeneration of sensory hair cells after acoustic trauma. Science 240(4860):1772–1774.
Dooling RJ, Ryals BM, Manabe K. (1997) Recovery of hearing and vocal behavior after hair cell regeneration. PNAS 94:14206–14210.
Spatial Hearing, Cognitive Load, and Binaural Benefits in Cochlear Implant Users
Ruth Litovsky, PhD, Professor, University of Wisconsin-Madison
In recent years, there has been a change in clinical decisions and criteria regarding eligibility for patients receiving cochlear implants (CIs), leading to increasing number of patients receiving bilateral CIs (BiCIs). Studies to date have demonstrated several functional benefits in BiCI users, who generally perform better with two CIs than with a single CI.
First, sound localization data suggest that children ages five and older with BiCIs can generally discriminate left versus right with small angular differences, and localization errors are generally higher than errors seen in normal hearing (NH) peers. Toddlers (two to three years old) can discriminate left versus right, as shown with a “reaching for sound” task, but they do not appear to have a spatial map when sound localization is tested; for example, when they choose between multiple loudspeakers.
Spatial release from masking (SRM) is a measure of the benefit that spatial cues provide when “target speech” is spatially separated from maskers. SRM is adult-like in NH children, including toddlers. SRM in children with BiCIs varies with the age at bilateral implantation. SRM is poorly developed in children who are ages five years and older who received the second CI by age five, but SRM is similar to that of NH toddlers whose second CI was implanted by 18 months of age.
Benefits from having BiCIs are due to having access to sounds in both ears, which is in fact bilateral hearing, rather than binaural hearing. In listeners with normal hearing, binaural processing occurs because the brain compares the inputs at the two ears, and computes interaural time differences (ITDs) and interaural level differences (ILD). In BiCI users, bilateral rather than binaural hearing prevails because there are limitations in the processing of binaural cues. First, there is lack of coordination between the CIs in the right and left ears. Second, CIs discard temporal fine structure cues, and modulate the amplitude of the speech envelope cues. Third, CIs operate at high stimulation rates (>1,000 pulses per second), where ITD sensitivity is absent.
In fact, in studies using research processors in which pulsatile stimuli are delivered to select pairs of pitch-matched electrodes, show that children and adults with congenital deafness have sensitivity to ILD, but not ITD. Because ITD is an important cue for spatial hearing, an ultimate goal is to improve delivery of ITDs.
Finally, another type of benefit that patients report, but that has not been well studied, is the reduction of cognitive load, aka listening effort. Pupillometry can provide real-time measures of changes in pupil dilation while sentences are heard by subjects. Pupil dilation is an autonomic response of the nervous system that reflects arousal, stress, and, by extrapolation, listening effort. Pupillometry measures show that listening effort is higher for spectrally degraded than for clear speech, and for monaural versus bilateral hearing.
In closing, BiCIs provide functional benefits, including sound localization and segregation of speech from maskers; however, performance is poorer than in NH listeners. Preliminary data show that bilateral hearing can also reduce listening effort.
Developing a Tool to Assess Speech Perception in Infancy
Kristin M. Uhler, PhD, Associate Professor in Physical Medicine and Rehabilitation at the University of Colorado School of Medicine, and Phillip M. Gilley, PhD, Research Scientist, Institute of Cognitive Science, University of Colorado, Boulder
Our work focuses on developing a tool to assess speech discrimination shortly after infants are fit with hearing aids, and to examine how discrimination relates to later language outcomes. Recent work from the Outcomes in Children with Hearing Loss Study (Tomblin et al, 2015) has highlighted the importance of both quality of hearing aid fit and quantity of hearing aid use for later language development (McCreery et al, 2013, 2015; Tomblin et al, 2014, 2015). Younger children and children with milder degrees of loss might be less likely to wear amplification for extended periods of time than older children and children with greater degrees of loss, which might have implications for early language outcomes (Moeller et al 2009; Walker et al, 2013, 2015).
Currently there is not a way to document if an infant can discriminate speech sounds until he or she is able to complete a behavioral head-turn paradigm (e.g., six to nine months of age). The quality of hearing aid fittings is currently limited to verification using commercial equipment and software that is limited to the assessment of the peripheral auditory system. These findings highlight the need for new tools to examine speech discrimination abilities and language outcomes in infants and young children.
We are examining a non-invasive approach to assess infant speech discrimination shortly following the fitting of hearing aids. In a longitudinal study, we are examining the relationships between speech discrimination and later language development. Speech discrimination is assessed by an auditory evoked potential, the time frequency mismatched response (MMRTF), at two months of age, and visual reinforcement infant speech discrimination (VRISD; a conditioned head-turn paradigm) at age seven months. Language outcomes are assessed at 16, 24, 30, and 33 months using a combination of parent report and formal measures of language development. The results presented here represent preliminary analyses from the first two years of this longitudinal study.
Our results concur with previous findings as follows:
- Infants can and do process speech information during sleep.
- These processes include speech discrimination.
- We can observe these processes using advanced EEG analyses (Gilley et al, 2017).
Preliminarily, our results suggest a stronger relationship between MMRTF and VRISD for consonant-vowel contrasts than for vowel contrasts in infants with normal hearing. Finally, early analyses of parent questionnaires suggest that these trends continue for MMRTF and later language outcomes.
In a small sample of subjects with hearing loss, similar trends have been observed for MMRTF, VRISD, and language outcomes. Furthermore, we have observed potential benefits of MMRTF to inform amplification outcomes as evidenced by differences in brain responses with and without hearing aids.
Taken together, these early results suggest informative correlations between a variety of speech and language measures at different ages throughout development. We are optimistic that these measures will provide insights into other factors affecting hearing aid outcomes, such as those factors relating to the quality and quantity of hearing aid use.
Gilley PM, Uhler KM, Watson K, Yoshinaga-Itano C. (2017) Spectral-temporal EEG dynamics of speech discrimination processing in infants during sleep. BMC Neuroscience 8:34.
McCreery RW, Bentler RA, Roush PA. (2013) Characteristics of hearing aid fittings in infants and young children. Ear Hear 34(6):701–710.
McCreery RW, Walker EA, Spratford M, Oleson J, Bentler R, Holte L, Roush P. (2015) Speech recognition and parent-ratings from auditory development questionnaires in children who are hard of hearing. Ear Hear 36:60–75.
Moeller MP, Hoover B, Peterson B, Stelmachowicz P. (2009) Consistency of hearing aid use in infants with early-identified hearing loss. Am J Audiol 18:14–23.
Tomblin JB, Oleson JJ, Ambrose SE, Walker E, Moeller MP. (2014) The influence of hearing aids on the speech and language development of children with hearing loss. JAMA 140(5):403–409.
Tomblin JB, Walker EA, Mccreery R, Arenas MA, Harrison M, Moeller MP. (2015) Ear and hearing outcomes of children with hearing loss: Data collection and methods. Ear Hear 36:14–23.
Walker EA, Mccreery RW, Spratford M, Oleson JJ, Van Buren J, Bentler R, Roush P, Moeller MP. (2015) Trends and predictors of longitudinal hearing aid use for children who are hard of hearing. Ear Hear 36:38–47.
Walker EA, Spratford M, Moeller MP, Oleson J, Ou H, Roush P, Jacobs S. (2013) Predictors of hearing aid use time in children with mild-to-severe hearing loss. Lang Speech Hear Serv Sch 44(1):73–88.
Top 10 Technical Tune-Ups for Best Practices in Pediatric Amplification Child Amplification
Susan Scollie, PhD, Associate Professor at the Child Amplification Laboratory, National Centre for Audiology, University of Western Ontario, London, Ontario, Canada
Best practices in pediatric hearing aid fitting are described in the recently issued Academy (2013) Clinical Practice Guidelines. However, clinicians who wish to provide these best practices might need a bit more detail in order to find specific steps, stimuli, and strategies that work with specific equipment.
In our program, we have developed a protocol document that fulfills the spirit of the Academy guidelines, but that is also tailored for use on specific equipment and in a specific practice context (available at www.dslio.com). In this presentation, I reviewed the evidence behind 10 technical tune-ups from our protocol that practicing audiologists can consider for adoption into their routine practices.
The basics start with making routine use of real-ear verification with re-verification and re-fine tuning over time, given recent evidence that this essential step is still not always applied even for our youngest patients (McCreery et al, 2013). This basic practice can support routine access to using aided Speech Intelligibility Index (SII) values with a normed score sheet to aid interpretation of the fitting (Bagatto et al, 2016; score sheet at www.dslio.com). Fitting timeliness can be enhanced with a strong focus on using earmolds for visual reinforcement audiometry (VRA) to support early ear-specific audiometry (see Bagatto and Scollie, 2011 for illustrations and tips) with appropriate real-ear-to-coupler difference (RECD) corrections (Moodie et al, 2016). We can also support children with mild and unilateral losses by adopting clear protocols for intervention (Bagatto and Tharpe, 2014; Cincinnati Children’s Hospital, 2009) in combination with loaner aids for trials if candidacy is uncertain.
Outcome measures can assist in determining whether loaner or owned aids are providing benefit, and tracking incremental benefit over time (Bagatto et al, 2016; Glista et al, 2014). Fittings with modern signal processing can be used more accurately with routine verification and fine tuning of the strength of frequency lowering (Scollie et al, 2016a) and/or the strength and speed of noise reduction systems (Scollie et al, 2016b).
Finally, patients who use abutment-based bone conduction hearing aids can now receive prescribed frequency responses (Hodgetts and Scollie, 2017), with verification systems soon to be available. Although these systems still require further validation and development to address the common use of headband-worn bone conduction aids in young children, these recent developments are a step in the right direction. These technical tune-ups represent years of evidence and research, but are mostly available for use in clinical practice right now. Aimed at enhancing both accuracy and evidence-based use of technology, they might have something to offer your practice, your program, or your department.
American Academy of Audiology (2013). American Academy of Audiology Clinical Practice Guidelines on Pediatric Amplification. http://www.audiology.org/resources/documentlibrary/Documents/PediatricAm... (Accessed January 14, 2017).
Bagatto MP, Moodie ST, Brown CL, Malandrino AC, Richert FM, Clench DA, Scollie SD. (2016) Prescribing and verifying hearing aids applying the American Academy of Audiology Pediatric Amplification Guideline: Protocols and outcomes from the Ontario Infant Hearing Program. J Am Acad Audiol 27(3):88–203.
Bagatto M, Scollie S. (2011) Current Approaches to the Fitting of Amplification to Infants and Young Children. In: Comprehensive Handbook of Pediatric Audiology. Plural Publishing, 527–552.
Bagatto MP, Tharpe AM. (2014) Decision Support Guide for Hearing Aid Use in Infants and Children with Minimal/Mild Bilateral Hearing Loss, A Sound Foundation Through Early Amplification 6th International Conference Proceedings, Phonak AG: Stafa, 145–151.
Cincinnati Children’s Hospital Medical Center. (2009) Audiologic management for children with permanent unilateral sensorineural hearing loss, Cincinnati Children’s Hospital, 1–13.
Glista D, Scollie S, Moodie S, Easwar V. (2014) The Ling 6 (HL) test: Typical pediatric performance data and clinical use evaluation. J Am Acad Audiol 25(10):1008–1021.
Hodgetts B, Scollie S. (2017) DSL Prescriptive Targets for Bone Conduction Devices: Adaptation and Comparison to Clinical Fittings. Intl J Audiol http://dx.doi.org/10.1080/14992027.2017.1302605 (Accessed January 14, 2017).
McCreery R, Bentler R, Roush P. (2013) The characteristics of hearing aid fittings in infants and young children. Ear Hear 34(6) http://dx.doi.org/10.1097/AUD.0b013e31828f1033 (Accessed January 14, 2017).
Moodie S, Pietrobon J, Rall E, Lindley G, Eiten L, Gordey D, Davidson L, Moodie KS, Bagatto M, Haluschak MM, Folkeard P, Scollie, S. (2016) Using the real-ear-to-coupler difference within the American Academy of Audiology Pediatric Amplification Guideline: protocols for applying and predicting earmold RECDs.
J Am Acad Audiol 27(3):264–275.
Scollie S, Glista D, Seto J, Dunn A, Schuett B, Hawkins M, Pourmand N, Parsa V. (2016a) Fitting frequency-lowering signal processing applying the American Academy of Audiology pediatric amplification guideline: Updates and protocols. J Am Acad Audiol 27(3):219–236.
Scollie S, Levy C, Pourmand N, Abbasalipour P, Bagatto M, Richert F, Moodie S, Crukley J, Parsa, V. (2016b) Fitting noise management signal processing applying the AAA pediatric amplification guideline: Verification protocols. J Am Acad Audiol 27(3):237–251.
Measuring Fatigue in School-Age Children with Hearing Loss
Benjamin W. Y. Hornsby, PhD, Associate Professor in the Department of Hearing and Speech Sciences, Vanderbilt Bill Wilkerson Center, Vanderbilt University School of Medicine, Nashville, Tennessee
Contributing Authors: Fred Bess, Stephen Camarata, Hilary Davis, and Ronan McGarrigle
Hearing loss and background noise are known to impact children’s speech understanding and academic achievement negatively. However, the negative effects of hearing loss on children are diverse and pervasive. Consistent with long-held beliefs, recent research suggests that listening-related fatigue can be another important, but understudied, consequence of hearing loss. This presentation reviewed the multidimensional construct of fatigue and its potential impact on children with hearing loss (CHL) and adults with hearing loss (AHL).
We first defined fatigue subjectively as a mood or feeling of tiredness, exhaustion, lack of energy, and/or a reduced desire or motivation to continue a task (Hornsby Naylor Bess, 2016). Feelings of mild fatigue due to sustained mental or physical effort are common, even in healthy populations. However, these feelings tend to resolve quickly with brief rests or breaks. This presentation focused on issues related to more severe, recurrent, fatigue. This type of fatigue, which is uncommon in healthy populations, is frequently observed in those suffering from chronic illnesses (e.g., cancer or multiple sclerosis) and can have significant negative effects on quality of life. Current methods for assessing fatigue, with a specific focus on generic subjective methods, were also discussed. Results from a review of the literature revealed that no validated measures designed to assess listening-related fatigue exist.
Next, recent and ongoing research using generic, validated, measures to examine subjective fatigue in AHL and CHL were evaluated and discussed. Results highlighted that AHL and CHL were at increased risk for fatigue compared to normative and control group data. For example, AHL were twice as likely to report severe fatigue and four times as likely to report severe vigor deficits compared to age-matched normative data (Hornsby and Kipp, 2016). CHL reported fatigue ratings that were similar, or greater, in magnitude than those reported by children suffering from multiple severe health conditions, such as cancer, multiple sclerosis, and rheumatoid arthritis (Hornsby et al, 2014).
Although AHL and CHL were found to be at increased risk for fatigue, variability in fatigue ratings was quite large in both groups. The roles of several factors that might modulate fatigue were discussed. Interestingly, degree of hearing loss was not associated with subjective fatigue ratings in either AHL or CHL. In CHL, language ability and receptive vocabulary were associated with fatigue; specifically, as language and vocabulary abilities improved, overall fatigue and cognitive fatigue declined (Hornsby et al, 2017)
Finally, we described our ongoing work developing a new subjective measure targeting listening-related fatigue—the Vanderbilt Fatigue Scale (VFS) for AHL (VFS-AHL) and CHL (VFS-CHL). We are currently collecting data using preliminary versions of the scales. These data will be analyzed using Classical Test Theory and Item Response Theory to assess the underlying factor structure of listening-related fatigue in AHL and CHL, and identify high quality items for the final version of the scales.
Research supported by grants from IES (IES #R324A150029, Bess, PI), NIDCD/NIH (R21 DC012865-01A1, Hornsby, PI), and Starkey, Inc. (Hornsby, PI).
Hornsby BWY. (2016) Understanding Listening-Induced Fatigue in School-Age Chidlren with Hearing Loss. Presented at 7th International Pediatric Audiology Conference. Retrieved from https://www.phonakpro.com/us/en/training-events/events/past-events/2016/... (Accessed May 20, 2017).
Hornsby BWY, Kipp AM. (2016) Subjective ratings of fatigue and vigor in adults with hearing loss are driven by perceived hearing difficulties not degree of hearing loss. Ear Hear 37(1):e1–e10.
Hornsby BW, Naylor G, Bess FH. (2016) A taxonomy of fatigue concepts and their relation to hearing loss. Ear Hear 37 Suppl 1, 136S–144S.
Hornsby BWY, Werfel K, Camarata S, Bess FH. (2014) Subjective fatigue in children with hearing loss: Some preliminary findings. Am J Audiol 23(1):129–134.
Next year, the Academy Research Conference will celebrate its 10th anniversary. The theme of ARC 2018 will be Genetics and Hearing Loss and will be chaired by Kathleen Arnos, PhD. ARC will be held on April 18 in Nashville, Tennessee.