SPED 537 ECSE MethodsMultiple DisabilitiesCh 6 & 7

Deborah Chen, Ph.D.California State University,

NorthridgeApril 3-4 2006

Types of Hearing Loss Conductive Sensorineural Mixed Progressive Central auditory processing

disorder

Intensity of Sound Decibel (dB) 0 dB – softest sound 25 dB – whisper 50 dB – speech 90 dB – food blender 110 dB – rock concert 140 dB - firecracker

Logarithmic Scale 0 dB = softest sound heard 20 dB = 10 x 10 louder than 0 dB 20 dB hearing loss = hearing 100

times less than normal

Frequency of Sound Hertz or cps Low to high Vowels Consonants Voices

Figure 1

Speech Banana

Figure 2

Comparison of the Frequency and Intensity

of Various Environmental and Speech Sounds

Degree of Hearing Loss Mild: 15 – 30 dB Moderate : 30-50 dB Moderate-severe 50-70 dB Severe 70-90 dB Profound > 90dB

Causes of Hearing Loss in Young Children

40-60% genetic causes 10% congenital infections 10% meningitis 17% NICU Rest unknown

Incidence of Hearing Loss 30 infants born each day in US Hearing loss occurs 20 x more

frequently than PKU (phenlyketonuria)

1 in 1000 have severe-profound loss

4-5 in 1000 have mild-moderate loss

Significance of Early Detection By 6 months > language outcomes

than those detected later Average age of diagnosis 12-25

months Average age for detecting mild

loss 5-6 years

Newborn Screening Most hospitals screen “at risk” Identifies only 50 % children A.B. 2780 required all CCS

approved hospitals to implement UNIVERSAL newborn hearing screening by 12/02

400,000 (>70%) newborns in CAhttp://www.dhs.ca.gov/pcfh/cms/NHSP

Universal Newborn Hearing Screening

Costs $25-45 hospital-based screening.

Two electrophysiological tests: Screening auditory brainstem

responseSABR Otoacoustic emissions OEA

Impedance or Acoustic Immitance Tests Tympanometry

Acoustic Reflex

Behavioral Tests (Infants) Behavioral Observation

Audiometry(BOA)

Visual Reinforcement Audiometry (VRA)

Objective Tests Auditory Brainstem Response (ABR) Brainstem Evoked Response (BSER) Brainstem Auditory Evoked

Response (BAER)

Otoacoustic emissions (OAE)

Behavioral Tests Tangible Reinforcement Operant

Conditioning (TROCA) Visual Reinforcement Operant

Conditioning (VROCA)

Conditioned Play Audiometry (CPA)

Audiogram

Graph that shows: - hearing thresholds

- at different frequencies - and loudness levels - by air conduction and - bone conduction

Audiogram

Provides information on: Type of hearing loss Degree of loss Slope of loss Sounds child can or cannot hear

Figure 1

Pure Tone Audiogram

Normal Hearing

Right

Figure 2

Pure Tone Audiogram

Moderate to moderate-severe SNHL

= air conduction

= bone conduction

Figure 3

Pure Tone Audiogram

Mild Conductive Hearing Loss

Figure 4

Audiogram of a Moderate Hearing Loss

Figure 5

Illustration of

Sensorineural Hearing Loss

Figure 6

Illustration of

Conductive Hearing Loss

Degree of Hearing Loss Slight: may miss 10% speech when

further than 3’ away Mild: may miss 25-40% speech Moderate: may miss 50-75% Moderate-Severe: may miss 100% Severe: Responds to loud sounds 1”

away Profound: Relies on visual cues and

vibrations