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

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

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

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

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

Prerequisites  Assuming the child has been fitted with HA/CI  Assuming the technology is programmed optimally  Assuming the child is wearing the HA/CI all waking hours  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?  The degree to which spoken language is audible to a child  Goal: 100% of the speech signal is audible 100% of the day Acoustic access is under ADULT CONTROL

Environmental Factors Affecting Acoustic Access NOISEDISTANCE REVERBERATION

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

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

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

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

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

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

Affects of Reverberation  Normal hearing adults can adequately discriminate speech in reverberations times of.75 to 1 second  Children with hearing loss require reverberation times of.5 seconds Anechoic chamber = 0 seconds Typical classroom = 1.6 seconds

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

Boothroyd Demonstration  Distance  Noise  Reverberation Boothroyd, A., Phonic Ear Sound field tutorial 1.4a Room Acoustics and Speech Perception: The Basics

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

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

Bibliography  American National Standards Institute. (2002). Acoustical performance criteria, design requirements, and guidelines for schools (S ). New York: American National Standards Institute (ANSI S12.60).  Boothroyd, A. (2004). Room acoustics and speech perception. Seminars in Hearing, 25(2),  Cole, E.B., and Flexer, C. (2008). Children with hearing loss: Developing listening and talking birth to six. San Diego, CA: Plural Publishing.  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.

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