SPED 537 ECSE Methods Multiple Disabilities Ch 6 & 7

SPED 537 ECSE MethodsMultiple DisabilitiesCh 6 & 7 Deborah Chen, Ph.D. California State University, Northridge April 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 CA http://www.dhs.ca.gov/pcfh/cms/NHSP

Universal Newborn Hearing Screening Costs $25-45 hospital-based screening. Two electrophysiological tests: • Screening auditory brainstem response SABR • 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

SPED 537 ECSE Methods Multiple Disabilities Ch 6 & 7