ENT

1. DEAFNESS
H. K Omokanye MBBS, FWACS. FMCORL. MBA
Lecturer-1/ consultant Otorhinolaryngologist
Dept. of Otorhinolaryngology, University of Ilorin
140217

2. Introduction
DEAFNESS:
 Refers to complete loss of hearing in the better ear i.e more than 90-
100 dB.

 Or total loss of hearing.

3. Introduction
HEARING LOSS:
 Is a broad term defined as impairment of hearing.
 Severity may vary from mild to profound.
 Profound HL= Deafness
 It is a great social and educational handicap.

4. Classification
BASED ON:
 Type of HL=> CHL, SNHL, MHL
 Site of lesion: EXT. EAR, MIDDLE EAR, INNER EAR(COCHLEAR,
RETROCOCHLEA; Auditory nerve , CENTRAL)
 Mode of onset=> SUDDEN OR INSIDIOUS.
 RATE OF PROGRESSION
 Degree=> MILD, MODERATE, SEVERE, PROFOUND
 Laterality=> UNILATERAL, BILATERAL
 Aetiology=> INFECTIVE, METABOLIC, NOISE INDUCED

5. Classification HEARING LOSS
CONGENITAL
CONDUCTIVE SENSORINEURAL
SENSORY
(Cochlear)
NEURAL
(Peripheral)
CENTRAL
MIXED
ACQUIRED
CHL SHL or MHL ORGANIC FUNCTIONAL

6. Conductive HL
 Occurs when the sound conducting mechanism of the ear is
defective
 The pathology that interferes with the transmission of sound
could be any where between the EAC to the footplate of
stapes
 May be due to morphological changes in the middle and/ or
external ear.

7. SNHL
Occurs due to abnormality in the
 cochlea,
 auditory nerve,
 neural pathway
 or their central connection with
the auditory cortex

8. Mixed HL
 Occurs when both conductive and sensorineural
abnormalities is responsible for the hearing
impairment

9. WHO grades of hearing
impairment53
Grade of Impairment Audiometric ISO value
(average of 500,1000, 2000, 4000 Hz)
Impairment description
0 (no impairment) 25 dB HL or less (better ear) No or very slight hearing problems. Able
to hear whispers
1 (Slight impairment) 26-40 dBHL (better ear) Able to hear and repeat words spoken in
normal voice at 1 metre
2 (Moderate impairment) 41-60 dBHL (better ear) Able to hear and repeat words using
raised yoke at 1 metre
3 (Severe impairment) 6 1-80 dBHL (better ear) Able to hear some words when shouted
into better ear
4 (Profound impairment including
deafness)
81 dBHL or greater (better ear) Unable to hear and understand even a
shouted voice

10. ACQUIRED CAUSES OF CHL
EXTERNAL CANAL
 WAX/ KERATOSIS OBTURANT
 FOREIGN BODY
 TRAUMA
 OTIITIS EXTERNA
 OTOMYCOSIS
 TUMOURS, OSTEOMA, EXOSTOSIS
 STENOSIS
 FIBOUS DYSPLASIA, WEGENER’S
GRANULLOMATOSIS,
MIDDLE EAR
 ACUTE / CHRONIC OTITIS MEDIA
 BAROTRAUMA
 PERFORATED T.M
 OTOSCLEROSIS
 CONGENITAL MIDDLE EAR DEFECT
 TRAUMA, OSSICULAR DISTRUPTION
 STIFFNESS OR HYPERMOBILITY OF
THE OSSICULAR CHAIN
(RHEUMATOID ARTHRITIS)
 TUMOURS

11. ACQUIRED CAUSES OF SNHL
SENSORY
 PRESBYACUSIS
 MENIERE’S DISEASE
 NOISE INDUCED
HL/ACOUSTIC TRAUMA
 OTOTOXICITY
 HEAD INJURY
 MUMPS, MEASLES, SYPHILIS
 VASCULAR
 RUPTURED ROUND WINDOW
MEMBRENE
NEURAL
 BRAIN TUMOURS
 DEMYELINATING DISEASES
 TRAUMA
 PRESBYACUSIS
 ACOUSTIC NEUROMA
 VIRAL INFECTION OF
AUDITORY NERVE
 INFECTION/INFLAMMATION
OF MENINGIES
 MULTIPLE SCHLEROSIS

12. ACQUIRED CAUSES OF
SNHL
 Trauma to cochlea or retrocochlear i.e transverse fracture of the temporal
bone
 Inflammatory: labrynthitis- viral, bacteria, spirochaetal
 Noise: noise induced hearing loss
 metabolic: hyperthyroidism
 Familial: progressive sensorineural deafness

13. CONGENITAL CAUSES OF
CHL
 Treacher Collins syndrome (mandibulo-facial dysostosis):
 It is autosomal dominant condition with complete penetrance and
variable expression.
Features:
 Sloping palpebral fissures, fish mouth, malar hypoplasis, colobomas,
microphthalmos, deformed pinna, absent EAC, facial narve palsy,
conductive HL.

14. CONGENITAL CAUSES OF
CHL
 Treacher Collins syndrome (mandibulo-facial dysostosis):
 Orofacial cranial syndrome
 Paget’s disease
 Ossicular anomalies; fixation, malformation, absence, discontinuity,
(fixation of stapes footplate, Fixation of malleus)
 Marfan’s syndrome
 Osteogenesis imperfecta
 Congenital cholesteatoma
 Meatal atresia

15. CONGENITAL CAUSES OF
SNHL
NON-SYNDROMIC: DEAFNESS OCCURING ALONE
 Micheal’s syndrome (complete lack of development of inner ear
structures; no hearing in the affected ear)
 Mondini’s syndrome ( incomplete development of bony and
membranous labyrinth: cochlea with 1.5 turns, only basal turn is
present, inter-scalar septum is absent)

16. CONGENITAL CAUSES OF
SNHL
NON-SYNDROMIC: DEAFNESS OCCURING ALONE
 Scheibe’s syndrome ( cochlearsaccular aplasia with normal bony
labyrinth)
 Bing-Siebenmann syndrome (malformation of membraneous labyrinth
with osseous labyrinth)
 Alexander dysplasia: limited cochlea duct differentiation at the level of
the basal coil(causes high frequency SNHL).
 Large vestibular acquiduct syndrome: it is enlarged more than 1.5
mm on CT

17. CONGENITAL CAUSES OF
SNHL
 SYNDROMIC: DEAFNESS OCCURING WITH OTHER ANOMALIES
 WAARDENBURRG’S SYNDROME (multi-coloured eyes, white
forelock, widest eyes, progressive HL)
 USHER’S SYNDROME ( retinitis pigmentosa,)
 ALPORT’S SYNDROME ( deafness and kindey disease)
 PENDRED’S SYNDROME (deafness and goitre)

18. CONGENITAL CAUSES OF
SNHL
Chromosomal abnormalitie
 Trisomy 13, 15
 Trisomy 21

19. Non genetic
 Intrauterine: TORCHS, DM, environmental hazards
 Perinatal: measles, herpes, chicken pox, HIV,
 Neonatal: LBW, Asphyxia, NNJ, sepsis
 Developmental: delayed auditory maturation.

20. FUNCTIONAL or
PSYCHOLOGICAL HEARING
LOSS
 Hearing loss without any organic cause.
 Broadly includes inability to hear because of psychological causes
with no underlying lesion.
CLASSIFICATION: Conscious and unconscious origin.
 FUNCTIONAL (HYSTERICAL): More common among females. May
be due to acute stress. The patient ceases to hear without being
aware or in control of it i.e the deafness is subconscious, hysterical,
psychosomatic
 MALINGERING (Feigned deafness): the malingerer listens but
pretends not to hear. He is conscious but malingering/feigned

21. FUNCTIONAL or
PSYCHOLOGICAL HEARING
LOSS
 TEST FOR MALINGERING:
 General tests: examine the patient repeatedly and watch his/her
behavior carefully. Tunnibg fork test, and pure tone audiometry will not
be consistent.
 Chimani moos test (modified webber test): Place a tuning fork on the
vertex, patient confirms to hear only on the normal side. Then repeat
webber test with the meatus blocked with finger. he/she will deny hearing
at all.
 Test during sleep: loud noise wakes a malingerer from sleep
 Lambard’s test (reading and noise distraction test)
 Stenger’s test (two tuning fork test)
 Objective tests: ABR, OAE, Acoustic Reflex Test,

22. FUNCTIONAL or
PSYCHOLOGICAL HEARING
LOSS
 TREATMENT:
 Psychotherapy

23. NOISE INDUCED HL
 It is hearing loss caused by chronic exposure to noise of more than
85dB.
 E.g industrial machinaries, power drills, saws, engines etc.
 It causes functional or structural changes in the cochlear
 The effect depends on the frequency. intensity, duration, susceptibility
and pre-existing ear disease.
 Initially the effect will be a Temporary threshold shift (TTS) from
which hearing is reversible when the exposure stops. Or
 Permanent threshold Shift (PTS) which occurs later if the noise
persist causing irreversible damage (permanent deafness).

24. NOISE INDUCED HL
 Degenerative changes in the stria vascularis, hair cells and supporting
cells occur in chronic noise exposure.
 Noise induces vasospasm of the cochlear vessels and anoxia to the
hair cells leading to damage.
 The 4KHz zone of the basilar membrane is in the basal turn of cochlea
and it is the first to be exposed to noise and first to be affected

25. NOISE INDUCED HL
CLINICAL FEATURES:
 Patient usually present with Tinnitus, hearing loss and difficulty in
comprehending speech.
 Pure tone audometry will show a characteristic dip at 4KHz for both air
and bone conduction.

26. NOISE INDUCED HL
PREVENTION:
 Exposure to noise should not be more than 90dB for 8hrs per day per 5
working day of the week.
 Use of ear protectors like ear plugs and muffs should be mandatory for
workers in noisy factories.
 Public awareness and education against noise polution.
 Preemployment and Periodic audiometric screening and ergometrics.

27. OTOTOXICITY
 It’s the capacity of a drug or chemical to damage the inner ear
structure or derange its functions.
 It affects neurons of both cochlear and vestibular nerves
 Drugs include aminoglycosides, cytotoxics, salicylates, quinine,
diuretics. Loop diuretics, macrolides erythromycin,
 They present with tinnitus, hearing loss and vertigo.
 Study have shown that certain individuals may have genetic
predisposition or susceptibility to ototoxic effect of certain drug.

28. OTOTOXICITY
CLINICAL FEATURES:
 Tinnitus is usually the first symptom.
 Deafness and vertigo usually follow later.
 Poor renal function can accentuate ototoxicity to drug.
INVESTIGATION:
 Audiological test will show cochlear pattern of hearing loss.
TREATMENT: withdrawal of the offending drug.
Hearing aids.

29. PRESBYACUSIS
(Senile deafness)
 It’s a sensori-ineural hearing loss which occurs due to aging process.
It is an auditory manifestation of senility. It increases with increase in
chronological age.
 Degenerative changes occur in the cells of the organ of corti and
nerve fibres.
 They present with a slow, progressive deafness, may be associated
with tinnitus, vertigo, distortion of speech, recruitment may be positive.
 AGRAVATING FACTOR: smoking, alcoholism, Coexisting illness, DM,
HBP, Hypothyroidism.
 TREATMENT: Psychological support, drugs, use of hearing aids.

30. SUDDEN HEARING LOSS
TYPES:
 Conductive
 Sensorineural
 Idiopathic sudden sensorineural hearing loss (ISSNHL).
 Sudden sensorineural hearing loss of specific cause.

31. SUDDEN CONDUCTIVE
HEARING LOSS.
CAUSES:
 Trumatic perforation of tympanic membrane.
 Foreign body in the external auditory canal
 Haemotympanum
 Ossicular dyscontinuity
 Aerotitis
TREATMENT:
 Directed to the underlying cause

32. IDIOPATHIC SUDDEN
SENSORINEURAL HEARING
LOSS.
 It’s a deterioration of hearing involving
1- more than 30dB
2- in at least 3 contiguous frequencies.
3- occurring within 3 days duration.
It is a diagnosis of exclusion i.e other specific causes should be ruled out
Causes:
 Exact aetiology is not known
Prognosis:
2/3rd of patients recover fully within 2 weeks

33. It’s a deterioration of hearing involving more than 30dB in at least 3
adjacent frequencies. occurring within 3 days.
Specific Causes:
 May be due to vascular: vasospasm, thrombosis of inner ear end
arteries.
 Oval window rupture
 Viral infection: mumps, herpes zoster cochleitis
 Other infections: Encephalitis, Syphilis
 trauma, perilymph fistula,
 Acoustic neuroma, immune complex, psychogenic, endolymphatic
hydrops.
SUDDEN SENSORINEURAL
HEARING LOSS OF
SPECIFIC CAUSE.

34. Specific Causes:
 Ototoxic drugs
 Multiple schlerosis
 Cogan’s disease
 Haematological: hyperviscosity syndromes, sickle cell disease
 0titic Barotrauma
 Autoimmune Ag-Ab mediated destruction of Cochlea
SUDDEN SENSORINEURAL
HEARING LOSS OF
SPECIFIC CAUSE.

35. SUDDEN SENSORINEURAL
HEARING LOSS OF
SPECIFIC CAUSE.
Treatment:
 Strict bed rest,
 Steroid in tapering dosage, Tab prednisolone 1mg/kg
 Antiviral agents. Valcyclovir 1g tds for 5days
 I.v Low molicular weight dextran IV BD for 5days,
 Iv histamine
 vasodilator drugs (beta histidine, nicotinic acid),
 O2, Carbogen 5% carbon dioxide and 95% oxygen inhalation increase
perilymph oxygen tension.
 Transtympanic steroid injection may be of benefit

36. CHILDHOOD DEAFNESS AND
DEAF MUTISM
 Deaf mutism is the inability to acquire speech due to profound
congenital or early acquired childhood sesorineural deafness in both
ears.
 Profound or total deafness refers to hearing loss above 90dB.
 For normal speech, child must hear sounds, imitates the words and
talks with time.
 The process is lost in deaf mute.

37. Childhood deafness and
deaf mutism
 It presents a special problem to ORL surgeon because of difficulties in
detecting the deafness before the age of one.
 Causes can be congenital or Acquired.
 Congenital can be genetic and non-genetic.
 Genetic involve conductive or sensorineural apparatus anomalies.

38. Neural plasticity
 Ability of the CNS to be programmed to learn a task.
 Auditory plasticity and ability to listen is lost by the age of 8 years
 whilest the ability to develop good speech articulation occurs if speech
sounds are heard by the age of 3 years.

39. Neural plasticity and Childhood
deafness/ deaf mutism
Classification:
 Prelingual: become deaf before acquiring speech
 Post lingual: speech acquired before becoming deaf.
 Perilingual: become deaf around time of speech development

40. Management of congenital
SNHL
 Normal hearing is necessary for development of speech, hence,
patient with severe HL fail to develop speech and thus remain deaf-
mutes.
 Early detection and treatment is the goal
 Refer patient to ENT surgeon on time for comprehensive
audiometry test and management

41. Management of congenital
SNHL
 In developed countries, routine hearing screening of the newborn
is the common practice.
 This practice is not yet popular in developing countries.
 Parent are usually the first to suspect that the child is not hearing
well.
 Such suspicion should not be ignored but be followed with
comprehensive investigation

42. Early detection of deafness
Investigates babies if there is parental suspicion due to:
 Failure to respond to sound properly.
 Failure to utter common words by 18 months to 2 years of age.

43. Early detection of deafness
 Babies at risk should be screened every 6 months
RISKS:
 Babies born to consanguinous parents
 Babies born to mothers with Infection in early pregnancy. i.e: rubella,
toxoplaxmosis, german measles, herpes, syphilis
 Use of ototoxic drugs in pregnancy
 Perinatal complications like prematurity, anoxia, haemolytic disorders,
low birth weight < 1.5kg.
 Perinatal viral infection, meningitis, jaundice

44. Test of hearing acuity
Reflexes: birth to 2 months
 Startle reflex: new born respond to loud sound by moving the head,
legs and arms.
 Cochleopalpebral (auriculo-palpebral) reflex: a loud noise made near
a healthy infant causes the child to bling eyes (closure of palpebral
fissure)
 Occulo gyric reflex: at 16 wks, loud sound produces horizontal
movement of the eye balls.

45. Test of hearing acuity
 Test:
 Clap test: to test localization of sound; at 24 wks child is able to
localize sound.
 Similarly, any sound made at 2-3 feets from the head of the baby: a
baby with normal hearing will turn his head towards the sound source
at the age of 7-9 months.

46. Test of hearing acuity
 Free field audiometry: hearing can be assessed by placing the child
between two loud speakers in a sound proof room. (after 6 months of
age)
 Visual reinforcement audiometry: the child is conditioned to turn in
the direction of sound which is reinforced by light
 Play audiometry: child is conditioned or taught to play in response to
the sound. (children above 2-5 years)
 Pure tone audiometry: above 5 years

47. Test of hearing acuity
Objective tests of hearing:
 brain stem evoked response audiometry (BERA or ABR),
 Otoaccaustic emission (OAE)
 Electrocochlography
 Imoedance audiometry (tympanometry)

48. DEAF-MUTE
Evaluation
Family history
 Any family history of deafness?
 Are the mother and father related?
 How many siblings, any of them hearing impaired?
Pregnancy, labor and delivery history (Past history of mother)
 Any history suggestive of syphilis, maternal rubella etc. in pregnancy?
 Was the pregnancy termed?
 Was labor eventful?

49. DEAF-MUTE
Evaluation
Past history of child’s general health
 Was there any history of birth asphyxia
 Any history of neonatal jaundice, kernicterus,
 History of any perinatal illness and treatment up to date
Developmental history (speech)
 At what age, if at all dis the child developed speech, did the child
babbles at earlier age?
 Did the child speak with normal tone? Any problem pronouncing
consonants?

50. DEAF-MUTE
Evaluation
Developmental history (hearing)
 Does the mother communicate with the child with voice or signs?
 Can the child hear when spoken to from another room?
 What is the longest distance from where the child can hear a when
spoken to?
 Does he reacts to the noise of a motor car or door bell?

51. DEAF-MUTE
Evaluation
Age of on set:
 At what age was deafness first suspected.
State of development
 What standard of education has the child reached?
 Any evidence of abnormal behavior or extreme introversion?
 What is the school report of child’s intelligence and performance?

52. Treatment of deaf child
 Bilateral hearing aid
 Cochlea implantation
 Auditory training
 Language communication

53. HEARING AIDS
 It is an electro-acoustic device that amplifies sound to improve
hearing.
 it assists the hearing impaired individual to hear better.
 The signal processing system may be analog or digital

54. Hearing AIDS
Basic Components:
 A Microphone: that converts sound to eletrical energy
 Amplifier: amplifies the electrical sound energy to a louder volume
 A receiver: converts the amplified electrical energy back to sound waves to
be delivered into the ear
 A power source: cell batteries.

55. Types of hearing AIDS
EAR LEVEL AIDS
 Body worn (BW): worn at chest level, ha advantage of greater gain.
suitable for severe hearing loss
 Post aural (BEHA- behind the ear): Has a stronger battery source
and greater output. Suitable for moderate HL.
 In the canal (ITC/ITE): better cosmetic appeal, smaller out put.
Suitable for mild HL.
 Spectacle hearing aid: fitted to the handle of an eye glasses
 Completely in the canal hearing aid: improved ITC

56. Types of hearing AIDS
behind the ear

57. Types of hearing AIDS
in the canal

58. Types of hearing
AIDS
Completely in the
canal hearing aid

59. Types of hearing AIDS

60. Types of hearing AIDS
body worn

61. Types of hearing AIDS
EAR LEVEL AIDS
 Bone anchored hearing aid: has a bone vibrator (instead of a
receiver) that fits over the mastoid to pass sound into the cochlea.
Suitable for discharging ear or where the is canal atresia.
 CROS aids (Contralateral routing of signals): the microphone is
placed in the poorer ear and routed to an ear phone mounted behind
the good ear.

62. Types of hearing AIDS
Bone anchored

63. Types of hearing AIDS

64. Middle ear implantable hearing
aid

65. Types of hearing AIDS
IMPLANTABLE AIDS
ACTIVE MIDDLE EAR IMPLANTS (MEI)
 Uses the direct drive of the ossiclar chain.
 Sound is converted into mechanical energy and directly transmittted
to ossicular chain which it vibrates in response to the converted
sound signal.
 The device is coupled directly to the ossicle
 It uses either a piezo electric crystals (sensor) or electromagnetic
mechanism

66. Types of hearing AIDS
ACTIVE MIDDLE EAR IMPLANTS (MEI)
 Vibroplasty: the MEI is attached to the round window.
 Suitable in moderate to severe cochlear hearing loss or SNHL
 CHL with total loss of ossicles or failed tympanoplasties
 MHL in cases of otoschlerosis
 It is able to treat SNHL, CHL and MHL

67. Indications
 Conductive hearing loss
 Mixed hearing loss.
 Sensorineural hearing loss
 Failed medical treatment.
 Refusal of surgical intervention.
 Contraindicated surgery

68. Choice of hearing aid
FACTORS
 Type of hearing loss
 Site of lesion
 Other pathologies:
 Patency of the EAC, ear
discharge etc.
 Cost
 Type
 Amplification character
 Ear mould
 general

69. COCHLEAR IMPLANT
 It is an electrical device which emulate the transducer function of the
cochlear thereby stimulating the auditory nerve and restoring hearing
 It bye passes the outer and middle ear
 Causes electrical stimulation of the spiral ganglion

70. COCHLEAR IMPLANT
DEVICE COMPONENT
External component (placed behind the ear)
 Speech processor (with inbuilt-microphone)
 Radio frequency coil with magnet
Internal component
 Receiver/stimulator package.
 Active stimulating electrode
 Ground electrode

71. COCHLEAR IMPLANT

72. COCHLEAR IMPLANT

73. COCHLEAR IMPLANT

74. COCHLEAR IMPLANT
 First the sound is captured by a microphone. The microphone send
signal to the speech processor. Sound signal is converted to electrical
pulses by speech processor
 The radiofrequency link effect communication between the speech
processor and the implant.
 The receiver/transmitter decode the signal and present it to the
stimulation electrode within the cochlea.
 The sound energy is distributed to the cochlear in a frequency specific
manner along the basilar membrane.

75. COCHLEAR IMPLANT
INDICATION
 Deafness due to cochlear pathology.
 (central and auditory nerve causes are contraindication)
 Bilateral severe to profound SNHL
 Residual hearing with no speech understanding or speech
development using hearing aid.
 Prelingual deafness congenital or acquired before speech
development
 Post lingual deafness

76. AUDITORY BRAIN STEM
IMPLANT
INDICATION
 Retrocochlear deafness: when the point of lesion is beyond the
cochlea.
 Neurofibromatosis (NF2) patients with bilateral vestibular
schwannomas.

77. ASSISTIVE
COMMUNICATION
 Speech/ Lip reading: observing movement of lip and tongue.
 Auditory training with cue speech:
lip reading plus hand signs
 Finger spelling
 Telecommunication devices for the deaf (TDD)
 Telephone devices
 Computer technology

78. LAST
SLIDE