Outcomes of School-aged Children Using Advanced Hearing Aid Features Outcomes of School-aged Children Using Advanced Hearing Aid Features Susan Marshall, M.A.
Agenda Review current research regarding directional microphones Outcomes of children using Widex Directional and NR systems Review Linear Frequency Transposition Outcomes of children using Widex Linear Frequency Transposition Summary
What is the impact of adaptive directionality and NR on Language Development? Modern Directional and NR Hearing Aid features AAA Pediatric Guidelines 2003 Directional Microphone Use: “Type of microphone should be dictated by the age and abilities of child…Benefits and limitations of directional microphones with children currently unknown” Noise Reduction System Use “cannot be recommended until data relative to their effectiveness become available. “
Questions: It is 2010; what do we know now? Are these features appropriate to use in pediatric amplification? Are they efficacious? Is there a negative impact on language?
Importance of improving SNR Greater audibility than adults for equivalent sentence recognition (Stelmachowicz et al, 2000) Greater SNR than adults to recognize speech in multi-talker babble (Fallon 2000, Fallon 2002) The best way to improve SNR is an FM system FM systems are not used all day or every day What about HA directional microphones?
Directional mics for infantsChing et al (in review) Quantify the potential benefit of directional mics for young children (11 month to 6 years) in their real life listening environment Defining the limitations of directional mic use due to head movement and acoustics of listening environment • How often does the child turn to a speaker in a real life situation? • What proportion of a childs everyday life would he/she benefit from a directional microphone system? • What is the effect of directionality measured with STI?
Directional mics for infantsChing et al (in review) The effect of directionality was quantified by the STI showing: • Increase (1,5 to 3 dB) when facing forwards • Decrease (-1.5 to -2.8 dB) when facing sideways and backwards
Findings..Ching et al (in review) Based on calculations of head orientation, STI and everyday listening situations… Message for clinicians on optimising outcome.. • Fit children early in life • Fit with adaptive microphone • Council on maximizing the directional advantages
Impact of DNR on pediatric performanceBentler et al (Como, 2008) Determining the effectiveness of DNR in use with children 50 subjects, NH 6-10 year olds Childrens HINT – SNR 50 % as reference point for each subject
Impact of NR on pediatric performanceBentler et al (Como, 2008) Aim to investigate impact of digital noise reduction on pediatric performance Does DNR for children impact: • Speech perception? • Novel word learning? • Sound quality?
Impact of NR on pediatric performanceBentler et al (Como, 2008) Outcome measures made using: • CASPA (Boothroyd, 2006) • Novel word learning paradigme (Stiles et al, 2008) • Happy faces categories (Wong et al, 2001) Different stimuli used: • Two settings of DNR-on, plus DNR-off • Two noise types (babble, random) • Four different SNR
Findings..Bentler et al (Como, 2008) • Speech perception is enhanced • Novel word learning is not compromised • Sound quality is improved Overall positive indications for the use of DNR with NH children!
Directional Microphone Technology Directional Microphone and Noise Reduction Technology
Adaptive Directional Microphone SystemsKeeping directional “safe” for children An Adaptive Directional Microphone System Should- High Activation Threshold Only operate at poor SNR’s Use a slow activation time Work in tangent with a very low CT Do not require any switching- fully adaptive
Widex Directional Microphone Systems • Integrate safety features to ensure audibility: • Low compression threshold, high activation threshold, etc • Provide consistent audibility of speech from all directions • Maintain an omni-directional mode when speech is dominant Optimize signal-to-noise ratio (SNR) in noisy listening situations • Meeting the requirements of children for a higher SNR • Ease of listening in acoustically challenging situations
Widex Noise Reduction Systems Integrate safety features to ensure audibility: Classic NR: high activation threshold, slow activation time, sensitive to speech frequencies, etc Speech Enhancer:Optimize SII in noise - Ease of listening in acoustically challenging situations
Effects of digital noise reductionSpeech Enhancer based on SII In noise or reverberation the noise reduction system dampens unwanted noise enhancing the SNR making speech more audible The theory of the Speech Intelligibility Index (SII) is used for optimization of signal-to-noise ratio (SNR) Combining directional microphone and noise reduction gives a further SNR improvement Iiband importance function Aiband audibility function n number of bands / channels
Audible speech with classic noise reduction Speech Enhancer Considerably more audible speech with the Speech Enhancer Guarantees highest possible SII in all listening conditions! SII is correlated with speech recognition scores
Speech Enhancement System “Safest” kind of NR in terms of preserving audibility Use of the SII in noisy environments Vacuum Driving in Car
Retrospective Study of Children UsingDirectional Microphones and Noise Reduction System Retrospective Study of Children Utilizing Automatic Directional Microphone and Noise Reduction Systems
I. Language Outcomes • Many clinicians utilize advanced technology/ special processing for their pediatric fittings • This has presented us with some outcome information for standard tests of speech/language, ie. PLS, OWLS, GFTA Participating Facilities Arkansas Children’s Hospital, Little Rock AR Cincinnati Children’s Hospital, Cincinnati OH Hearing Health Center, Chicago, IL House Ear Institute, Los Angeles, CA Integris Baptist Medical Center, Oklahoma City, OK Kansas University Medical Center, Kansas City, KS Long Island Jewish Medical Center, New Hyde Park, NY New England Center for Hearing Rehabilitation, Hampton, CT Oakland Children’s Hospital, Oakland , CA University of Miami Medical Center, Miami FL Enrolled < 5 yrs Enrolled >5 yrs
I. Adaptive directional and NR strategies for 49 children fit with adaptive features at various agesII. Sub-group of 10 pre-school aged children Language Outcomes
Samples: Standard Tests of Language Preschool Language Scale (PLS) Oral and Written Language Scales (OWLS)
Vocabulary • PPVTIII Ages / Grades: 2:6 - 90+ Years 26
Changes in Average Standard Score over Time for normal-hearing children 100 Standard Score Time- Post Fitting
Progress on Standard Language Tests • Each dot is a child’s score on a standard speech or language test • Dot’s are connected when there is longitudinal data for the same test • Horizontal line= Average progress • Upward-sloping line= greater than average progress
Progress of Children by Age • Each line represents progress of an individual child over time on a specific speech/language assessment tool • Note: Dark line is average progress • Children enrolled in PHAP and using advanced features early (enrolled < 5 years) progress at a rate faster than average: Upward sloping line • Children enrolled later (> 5 years) do not experience the same rate of progress but still progress at a rate higher than average
II. Sub-group of Preschool Children • 10 children age 4 months- 3 years • - received services at same facility • - for 7, advanced HA’s were first HA’s • - followed for at least one year post-fitting
II. Sub-group of Preschool Children • Total Language Score is displayed as a function of time post-fitting with advanced hearing aids • Average performance is indicated in bold black line • On average, the group achieves average (SS=100) performance by 6 months post-fitting and exceeds average by 12 months post-fitting
Longitudinal Findings Longitudinal Findings of Children Utilizing Directional Microphone and NR Systems
Acknowledgement Susan Marshall Patti Stenger Natalie Thiele Debra Quick Margaret Pikora Special School District of St. Louis County
School-aged Children Using Adaptive Directional and NR Systems • 19 children in original study, fit with Widex Diva 9 or 19 • 10 from same facility followed 3 years post • 10 Children age 6, 1 to 12,9 years • Experienced HA users • Essentially normal Speech/Lang development (within 1-1/2 years of chronological age)
19 Children from 2 facilities examined in 3 conditions: Adaptive Directional Microphone Noise Reduction Omnidirectional Mode Double-blind design Children/parent/clinician unaware of condition Wore each for 6 weeks Subjective assessment after 1 week WR (%) after 6 weeks of use at various SNR’s Locator Adaptive Directional Microphones
What audiologists measured: Speech Recognition3 conditions: Omni, Locator(adaptive directional, Omni + NR
Research findingsDir mics for school-age children In speech front vs. noise back stituations school-age children have a SNR advantage of .. • 4.7-8 dB in the sound field (Gravel, 1999) • 5.5-8 dB in the sound field (Kuk, et al, 1999) • 3 dB in the classroom (Ricketts and Galster, 2007) • 7.5 dB in the sound field (Auriemmo, et al, 2009)
Efficacy of Adaptive Directional Microphones • Directional benefit estimated at 7.5 dB • No benefit measured for NR, but no detriment either • Subjective findings support Locator use, even in environments where a traditional directional instrument would not be ideal, i.e., desired sounds originating from behind or sides
Speech Recognition over time * * *At SNR =0, 2 yr post sig from 1 yr post*At SNR =-10, 1 yr post sig from baseline
Acclimatization: Word Recognition Performance Over Time *At SNR =0+5 3 yr post sig from baseline*At SNR =-10, 3 yr post sig from baseline
Receptive and Expressive Speech/LangOWLS Progress * OWLS Composite (most pairs significant) 44
An additional measure- CASLReceptive and Expressive Speech/Lang 45
Speech/Language Outcomes:3 Years Post Use of Adaptive Directional and Noise Reduction Systems
Scatter plots: Looking at Individual Data • Group data is important for making statistical inferences • Individual scores are also important for learning about the particular child and his or her progress over time and re: his or her peers