Audiology 2- Pathology Flashcards
What are the British Society of Audiology Descriptors for degree of hearing loss
0dB HL= average hearing threshold for young, healthy ears
less than 20 dB= normal hearing
21-40 dB= mild hearing loss
41-70 dB = moderate hearing loss
71-95 dB = severe hearing loss
more than 95 dB = profound hearing loss
Incidence of bilateral HL in new born children
estimated to be between 0.5- 2.1 per 1000 live births. Mostly sensory- neural
around 900 children per year in the UK
What is the prevalence of hearing loss in the UK?
- 12 million people, mostly older adults (one in five to one in six of the population)
- nearly 9 million are aged 60 and over
- more than 900,000 people in the UK severely or profoundly deaf
- more than 50,000 deaf children in the UK, may more experience temporary hearing loss
- approx. 87,000 deaf sign language users
- 356,000 deaf-blind people
- one in ten adults in the UK have mild tinnitus and up to 1% have tinnitus that affects their quality of life
What is conductive hearing loss?
- a problem conducting sound waves through the outer ear, tympanic membrane or middle ear
- no damage to the cochlea or auditory nerve
what is the incidence and prevalence of conductive hearing loss in children?
- cumulative incidence birth- 6 years is 80%
- Prevalence: up to 20% of children (6 and under) might be expected to fail a sweep test due to mild/moderate hearing loss caused by conductive loss in the winter, 10% in summer
- likely to persist in 5% of children
- risk is increased for some e.g. downs syndrome or cleft palate
what is otitis externa and what are the causes?
- An acquired outer ear pathology
- A general infection often involving often the whole skin of the external canal.
- May be a slight irritation, or acute disease
causes:
- bacteria (predisposition swimming)
- viral
- fungal
- trauma
- dermatitis
What is acute suppurative otitis media (acute otitis media)?
- an acquired middle ear pathology
- a bacterial middle ear infection often from an upper respiratory tract infection, the bacteria travels up the eustachian tube from the throat and causes an infection
- initially a mild hearing loss, with slight pain, can rapidly progress to an increased conductive hearing loss and excruciating pain, can also have fever, nausea and vomiting
- in severe cases, white pus in the middle ear cavity causes the TM to bulge outwards. Could cause the TM to burst
What is chronic Suppurative Otitis Media (Chronic Otitis Media)?
- an acquired middle ear pathology
- follows an acute infection which has not been fully resolved. Infection becomes chronic producing irreversible changes to the middle ear mucosa
- a disorder of the middle ear cavity, characterised by hearing loss and persistent or recurrent discharge via a central (safe) or marginal (unsafe) perforation
management:
- keep water out of ear to avoid further infections introduced via the perforation
- overt local infection needs treating with aural toilet and antibiotic drops and suction
- small central perfs may close spontaneously, larger perfs may require a myringoplasty
- marginal pers- obvious infection needs to be treated, must be a suspicion of the presence of a cholesteatoma which needs to be removed
What is serous Otitis Media?
- characterised by the presence of thin watery clear/ straw coloured fluid in the middle ear cleft
- failure of the eustachian tube aerate the middle ear. Air is still being absorbed into middle ear space but no new air is coming through Eustachian tube due to blockage. This causes negative pressure and causes a thin watery fluid to build up behind the ear drum
-presents as: hearing loss, ear pressure, mild earache/ discomfort, blocked feeling in ear, clicking or popping type tinnitus
- management: watchful waiting, allergy tests, advice on dust, avoid exposure to cigarette smoke
What is Otitis Media with Effusion, secretory Otitis Media and what is it caused by?
- glue ear
- characterised by the presence of think, sticky, mucoid effusion in the middle ear with retracted TM
- caused by a prolonged failure of he Eustachian tube to aerate the middle ear (ET blockage). Often develops after a cold or middle ear infection, but not an infection itself
- presents as; hearing loss, discomfort, a blocked feeling. In children; inattentive, slow speech/ languge development in chronic cases
How is glue ear managed?
- watchful waiting, allergy tests, advice on dust, avoid exposure to cigarette smoke, auto-inflation
- can be slow to resolve- 40% in one month, 65% in 2 months, 75% in 3 months and may occur
- if the problem is not resolved, a myringotomy may be performed, fluid removed and grommet inserted
grommets
- keep the middle ear aerated
- prevents recurrence of gluve ear while in situ
- stay in place for 3-18 months and then spontaneously extrude
- eardrum heals
Hearing aids
- for children with chronic glue = ear, especially recurrent glue ear after grommets
classroom management
- front of class
- focussing attention
- reducing background noise
- checking if they have heard
What are central (safe) perforations?
- a perforation in the pars tensa of the TM which does not involve the annulus
- not usually associated with intracranial spread of infection
- usually the result from acute otitis media and represent a failure in the hearing of TM
- may follow trauma
Presents as:
- hearing loss
intermittent discharge following an upper respiratory tract infection or after the entry of water in the ear
- can range from a pinhole to virtually total
- middle ear may be dry or infected
- in severe infected cases pus drains out through the perf in TM
management:
- keep ear dry
- infection may need antibiotics
- small perfs often heal, large perfs require tympanoplasty surgery
What are traumatic perforations?
- normally in the pars tensa
- usually result from violent changes in air pressure in EAM or ME (from a slap on the ear or explosion) or direct injury to the TM (e.g. with a cotton bud)
- presents as: pain, bleeding, hearing loss, tinnitus and occasionally vertigo
What is an unsafe marginal/ attic perforation?
- perf which involves the annulus or attic region of the TM. Unsafe since they lead to the spread of infection and are frequently associated with cholesteatoma
management
- requires examination under operating microscope and normally surgery and regular follow up
What is otosclerosis?
- a progressive disease that usually causes symptoms in early adult life. Appears more often in women
- disease caused by laying down of spongy bone around the oval window. The effect is fixation of the stapes. Hearing loss may also have sensori-neural element
presents as:
- hearing loss, bilateral in 85% of cases
- may be tinnitus, occasionally vertigo
- often conscious they will hear better in noisy environments
managed by:
- hearing aid or operation
- hearing aids work well with conductive losses
-operation- stapedectomy (stapes replaced with prothesis)
What is presbycusis and how does it present?
acquired sensory hearing loss
old age deafness
caused by loss of sensory hair cells and other aging processes in the cochlea
most common sensory impairment among older people. 70% of people over 70 have hearing loss
Presentation:
- bilateral
- symmetrical
- sensory
- high frequency
- slowly progressive
What is sensory hearing loss (congenital)?
- present at birth
- over 900 children born each year with hearing loss
- half have genetic causes, half non genetic
Genetic causes:
- syndromes such as usher’s syndrome
- connexin 26 mutations
non- genetic causes:
- prenatal infections: Toxoplasmosis, other, rubella, cytomegalovirus, herpes (TORCH)
- prei/ postnatal
what is noise induced hearing loss?
- acquired sensory hearing loss
- caused by prolonged exposure to loud noise
- intense noise over stimulates the hair cells causing sensory causing sensory hearing loss
- if caused by a sudden exposure to a very loud noise, called acoustic trauma
Symptoms
- bilateral temporary and permanent hearing loss with a 4kHz notch and bilateral temporary and persistent/ permanent tinnitus
what is neural hearing loss?
- results from damage to auditory nerve and are relatively rare
- no typical hearing loss pattern
- often discrimination is very poor with neural losses
- neural hearing losses when associated with tumours are usually unilateral
- may also be associated with tinnitus and vertigo
congenital
- auditory neuropathy spectrum disorder
acquired
- neoplastic- tumour e.g. acoustic neuroma.
what is auditory processing disorder?
- transformations of the acoustic signal occurring at a neural level in auditory perception at cortical level
- impaired neural function
- poor perception of sounds
- reduced ability to listen
- both auditory and cognitive elements
- found along side other symptoms/ diagnosis e.g. poor language, literacy or attention or autism
Presents as:
- hearing difficulties but normal audiograms
- often children who struggle to listen, especially with poor quality speech
- hearing difficulties with lots of background noise
- may be associated learning difficulties, poor performance, behavioural issues
Management:
- good listening conditions
- compensatory strategies such as speaking slowly, providing handouts/ visual teaching materials
- improve listening skills e.g. through auditory training
what is an acoustic neuroma?
- benign primary intracranial tumour of the myelin- forming cells of the vestibulocochlear nerve (CN VIII)
- about 10 acoustic neuromas newly diagnosed each year
Presentation:
- progressive unilateral deafness with poor speech discrimination and tinnitus
- unsteadiness
- headache
- facial nerve problems
what is recruitment of hearing?
- reduced dynamic range of hearing, so unable to hear quiet sounds but finds loud sounds uncomfortable (which are perceived as similar in loudness or louder than in normal hearing individuals).
- known as loudness recruitment
- caused by the loss of the outer hair cells from the cochlea
