Dodo Youyou Hearhear Meme The Listening Environment Molly

Dodo Youyou Hearhear Meme? The Listening Environment Molly Lyon, M. A. , CCC-A/SP LSLS AVEd Via Christi Hospitals January 21, 2011

Objectives Ø Participants will understand the concept of acoustic access and its importance in developing listening skills Ø Participants will become familiar with the environmental factors affecting audition Ø Participants will learn about the application of using FM technology in children

Listening in Children Some Food for Thought… Ø Children do not know what they don’t hear Ø Children do not expend the mental energy to comprehend a degraded, low intensity speech signal comprised of vague, unfamiliar words Ø They do not “go back” in auditory space and try to figure out what they didn’t hear

Ø Children do not hear and process oral language at adult-like levels until around age 13 Ø Language acquisition is a work in progress Ø As language and worldly knowledge increases the less reliant we are on precision hearing Ø Adult: 10% earwork and 90% brainwork Ø Child: 90% earwork and 10% brainwork

Transparency Ø For young listeners, the speech signal must be crystal clear, or “transparent” before true and optimal comprehension and language growth can occur Ø The listening environment is critical to the development of auditory skills

Prerequisites Ø Assuming the child has been fitted with HA/CI Ø Assuming the technology is programmed optimally Ø Assuming the child is wearing the HA/CI all waking hours Ø Little ears are now ready to listen, but…

A Moving Target HEARING LOSS is the only handicapping condition in which the disabling effect is in a constant state of flux. The negative impact of hearing loss can range from being nearly nonexistent to completely rendering an individual’s ability to use audition useless.

What is Acoustic Access? Ø The degree to which spoken language is audible to a child Ø Goal: 100% of the speech signal is audible 100% of the day Acoustic access is under ADULT CONTROL

Environmental Factors Affecting Acoustic Access NOISE DISTANCE REVERBERATION

Background Noise Ø Speech-To-Noise ratio (S/N) is critical Ø Relationship between the primary signal (speech) and background noise. Ø Noise sources include other talkers, heating or cooling systems (HVAC), timers, bells, alarms, computer hums, CD’s, radios, TV’s, wind, pets, etc. Ø Homes are typically quieter than classrooms

Allowable Signal-to-Noise Ratios Ø Adults with normal hearing require a S/N ratio of +6 d. B (approximately twice as loud as background noise) Ø Children with hearing loss require a S/N ratio of +15 to +20 d. B

Distance Ø Sound is degraded as it is propagated through space Ø Rapid Speech Transmission Index (RASTI study, Leavitt and Flexer, 1991) Ø Integrity of a speech signal was measured at 17 different distances

RASTI Results Ø Approximately 4 feet – RASTI score 83% (critical speech information lost = 17%) Ø Approximately 25 feet – RASTI score = 45% Ø Perfect RASTI score was only able to be obtained at a distance of 6 inches from the RATSI transmitter.

Distance and Decibels Ø Ø Double the distance, lose 6 d. B of intensity Every decibel is critical to children with hearing loss Distance Decibel 6” 60 d. B 12” 54 d. B 2’ 48 d. B 4’ 42 d. B 8’ 36 d. B 16’ 30 d. B 32’ 24 d. B

Reverberation (Echo) DEFINITION: Ø The time it takes in seconds from the moment a sound is stopped until the sound level has diminished 60 d. B.

Affects of Reverberation Ø Normal hearing adults can adequately discriminate speech in reverberations times of. 75 to 1 second Ø Children with hearing loss require reverberation times of. 5 seconds Anechoic chamber = 0 seconds Typical classroom = 1. 6 seconds

Reverberation Issues Ø Reverberant sounds mask high frequency sounds Ø Greater absorption of high frequency than low frequency sounds Ø Elongations of vowels Ø Smears transitions Ø Eliminates silent gaps

Boothroyd Demonstration Ø Distance Ø Noise Ø Reverberation Boothroyd, A. , Phonic Ear Sound field tutorial 1. 4 a Room Acoustics and Speech Perception: The Basics

FM Use in Children Ø Significantly improves and maintains speaker’s voice over background noise Ø Eliminates effects of distance Ø Reduces effects of reverberation Ø Child is able to receive consistent speech signal

Listen … Hearing Aid only Hearing Aid + FM Soundfield Demonstration FM mic only

Bibliography American National Standards Institute. (2002). Acoustical performance criteria, design requirements, and guidelines for schools (S 12. 60 -2002). New York: American National Standards Institute (ANSI S 12. 60). Ø Boothroyd, A. (2004). Room acoustics and speech perception. Seminars in Hearing, 25(2), 155 -166. Ø Cole, E. B. , and Flexer, C. (2008). Children with hearing loss: Developing listening and talking birth to six. San Diego, CA: Plural Publishing. Ø Crandall, C. C. , Smaldino, J. J. & Flexer, C. (eds). (2005). Sound-field amplification: Applications to speech perception and classroom acoustics (2 nd ed. ). Clifton Park, NY: Thomson Delmar Learning. Ø

Davis, J. (Ed. ). (1990). Our forgotten children: Hard-ofhearing pupils in the schools. Bethesda MD: Self Help for Hard of Hearing People. Ø Flexer, C. (2004). The impact of classroom acoustics: Listening, learning and literacy. Seminars in Hearing, 25(2), 131 -140. Ø Northern, J. L. , & Downs, M. P. (2002). Hearing in children (5 th ed. ). Baltimore: Lippincott Williams & Wilkins. Ø