Types and Degrees of Hearing Loss

how do we determine types of hearing loss

Determined by comparing air conduction thresholds

to bone conduction thresholds for each ear

independently

4 types of hearing loss

Conductive

• Sensorineural

• Mixed

• Auditory processing disorders

sudden HL

rapid onset

gradual HL

occurs in small degrees

temporary hL

short duration/reversiblep

permanent HL

not reversible

progressive HL

hearing loss will advance in degrees

AU

both ears

AS

left ear

AD

right ear

monaurally

1 ear

binaural

both ears

flat

less than a 5 dB rise/fall per octave

gradually sloping

5-12 dB decrease per octave

sharply sloping

13 or more dB decrease per octave

rising

low frequency are poorer than high

frequency

noise notch

normal hearing until 4000 Hz then a decrease

what type of audiogram

cookie bite

what type of audiogram

L corner audiogram

hearing loss

Described in terms of:

• Type

• Degree

• Symmetry

• Configuration

• Time of onset (time course)

conductive hearing loss

• Involves obstruction of outer and middle ear

mechanisms

• Characterized by bone conduction thresholds within

normal range (0-20 dB HL) with higher air conduction

thresholds (greater than 20 dB HL)

• Can cause occlusion effect = person usually speaks

in quieter voice than normal because they perceive it

louder than what it actually is

• Opposite of Lombard effect

CHL loss can be overcome if

signal is loud enough

because there is not problem with cochlea

• If amplified = speech discrimination is not impaired

what type of hearing loss

unilateral conductive

what type of hearing loss

bilateral conductive

sensorineural hearing loss

Involves pathology of inner ear

• Two types

• Sensory hearing loss = result of damage to cochlea

• Neural loss = damage to 8th nerve

• Audiogram = sloping air conduction and bone

conduction thresholds are essentially equal (i.e.,

within 10 dB)

• All thresholds outside normal range

recruitment

ochlear phenomenon where there is

non-linear increase in loudness growth, wherein

loudness grows rapidly at intensity levels just above

thresholds but may grow normally at higher levels

diplacusis

where one tone sounds like 2

different pitches in two ears and indication of

retrocochlear disease

sensory hearing loss

damage of cochlea

pts with sensorineural hearing loss present with;

• Recruitment

• Reduction in frequency resolution

(impacts speech understanding)

• Reduced dynamic range

• Word recognition ability is

reduced

neural hearing loss

damage of CN VIII

pts with neural hearing loss present with

Word recognition ability is poorer

than expected based on hearing

loss severity

• Speech recognition declines with

increases in intensity (rollover

phenomenon)

• Auditory adaptation occurs

what type of hearing loss

unilateral sensorineural

what type of hearing loss

unilateral sensorineural with menieres

mixed hearing loss is caused by?

• Result of both OE/ME and IE pathologies

• Combination of both CHL and SNHL

Difference between air and bone conduction

thresholds is known

air bone gap

what type of hearing loss

bilateral mixed

normal hearing

-10 to 15 dB

slight hearing loss

16 to 25 dB (only in children)

mild hearing loss

26 to 40 dB

• Patient may have difficulty understanding speech if it is faint or

distant

• #1 problem in schools

moderate hearing loss

41 to 45 dB

• Listening is strain and he/she often asks for repetition

moderately severe

56 to 70 dB

• pt will only hear well when the speaker is close and talking loudly

severe

71 to 90 dB

profound

91+ dB

symmetry

how much right and left ears mirror each other

assymetrical loss

when one ear has loss and another is normal or one is more severe

noise exposure

sensorineural notch at 3000 or 4000

Hz

ME effusion

rising conductive loss

reflects stiffness tilt

ossicular discontinuity, ME tumor and thickened TM

sloping conductive loss reflects mass tilt

otosclerosis

hardening at footplate of the stapes –

Carhart notch

presbycusis

age related high frequency hearing loss

time of onset

deals with how

long patient has been experiencing

problems

• Describe hearing loss as progressive

versus stable

• Describe it as acute, sudden, or gradual

malingering

• May report functional hearing loss

• Also referred to as non-organic hearing loss (NOHL),

pseudohypacusis or psychogenic hearing loss

pseudohypacusis

inconsistency in audiometric data

• most often seen in children

pschyogenic hearing loss

seen suddenly in girls between ages of 8-12

is malingering more common in boys or girls

boys

impact of hearing loss depends on

• Degree of sensitivity loss

• Audiometric configuration

• Type of hearing loss

• Degree and nature of speech perception deficits

auditory perception

• Communication depends on the

quality of auditory perception of

• Segmentals (individual

phonemes)

• Intensity

• Frequency

• Duration

• Suprasegmentals (rate,

rhythm, intonation)

• Begins before birth

• After birth, the process of

selective listening extends to

speech stimuli within a few

weeks

perception

implies understanding and comprehension – not

just reception of speech

detection

do you hear the sound, yes or no

discrimination

do the 2 sounds sound the same or different?

identification

what is that sound

attention

degree/quality of listeners attention matters

memory

abiltity to retain or store verbal information

closure

bringing speech elements together into a meaningful wholec

cemprehension

what does it mean

slight loss (16-25 dB)

• Perceived as if index fingers are in ears

• Difficulty hearing faint or distant speech

• Child can miss up to 10% of the speech signal at

a distance of greater than 3 feet

• This is amplified in background noise

(imagine a classroom)

• Preferential seating

• FM system??

perception with Mild HL

• Mild Loss (26-40 dB)

• Greater listening difficulties than “plugged-ear” hearing loss

• Can hear but misses parts of speech

• Leads to misunderstanding of message

• 30 dB loss = child can miss up to 25-40% of speech signal

• 40 dB loss = child misses up to 50% of speech signal

• Will frequently have difficulty learning early reading

skills

• Sound/letter association

perception with moderate hL

• Moderate (41-55 dB) hearing loss

• Associated with frequent misunderstanding of signal

• 50 dB hearing loss = child may miss up to 80% of

speech signal

• Without early amplification, child will likely be language

delayed with impaired syntax, limited vocabulary,

disordered speech sound production, and flat vocal

quality

• Even with proper amplification but sufficient background

noise = child will miss much of what is being said as

signal to noise ratio is corrupted

perception with mod-severe hearing loss

• Moderately-severe (56-70 dB) hearing loss

• More affected than those with moderate loss

• If child does not have amplification = 55 dB hearing loss

can cause child to miss up to 100% of speech signal

• If loss is not identified before one year of age = child will

have delayed spoken language, syntax, poor speech

intelligibility and flat vocal quality

• Age at which amplification begins = consistency of using

hearing aid and application of early language treatment

is strongly correlated to success of learning, speech and

language development

perception with severe HL

• Severe (71-90 dB) hearing loss

• Perception of sound is very limited

• Earlier child wears amplification consistently with parents/caregivers providing

language models in activities of daily living and/or intensive language

intervention (verbal or sign or both) increases chances that speech, language,

and learning will develop at relatively normal rate

• Ability for brain to interpret sounds as meaningful input is determined by

patient’s individual ability and intensive intervention prior to 6 months of age

• Hearing loss greater than 70 dB = candidates for cochlear implant (CI)

• 90 dB+ hearing loss = won’t perceive most speech sounds with traditional

hearing aid