The document discusses paracusis, which refers to auditory perception disturbances other than hearing loss, and hyperacusis, an exaggerated reaction to ordinary sounds, providing neurological conditions associated with hyperacusis such as migraine and depression. It also examines theories of hyperacusis related to serotonin dysfunction and plasticity in the central auditory system due to sensory deprivation from hearing loss.

2. Kasr-Al-Aini
School of
Medicine CAIRO UNIVERSITY,
EGYPT

3. Tinnitus?
Dysacusis??
Mohamed Ibrahim Shabana
Prof. of Audiological medicine
Cairo University

4. “…only my ears whistle and buzz continuously
day and night. I can say I am living a wretched
life.”
Ludwig Von Beethoven - 1801

5. The scream of the Nature by Edvard Munch
Der Schrei der Natur

6. Paracuses and Hyperacusis
Neurophysiological models

7. Paracuses
• Disturbance in auditory perception (other than
loss of hearing sensitivity)
• Musicians are more sensitive to detecting it,
people infrequently complain about it (unable to
recognize, confuse, mildly irritating..)
• Hyperacusis is the most clinically encountered
type

8. Paracuses
• Intensity-related phenomena
• Frequency-related phenomena
• Localizing dysfunction

9. Frequency-related phenomena
• Diplacusis:
– Double hearing (sound will have a different tone in
each ear)
– Meniere’s disease? First to disappear on treatment?
– Cochlear otosclerosis, fenestration operations
– Potassium iodide medication, chloroform inhalation

10. Diplacusis
• Damage to the fine tuning mechanism of the
organ of corti (outer hair cell dysfunction?)
• Lower intelligibility of speech, the benefits of
hearing aids are debatable
• PTA, speech discrimination, otoacoustic
emissions
• Diplacusimetry, psychoacoustic tuning curves

11. Sound localization dysfunction
• Intensity and phase difference of sounds are
important for sound directionalization
• Time difference, the role of the auricles
• Dysstereoacusis:
– Can be seen frequently in patients with supra
tentorial lesions (central dysfunction)
– Can be the presenting symptom in vestibular
shwannoma

12. Intensity-related phenomena
• Paracusis Willisii:
– Frequently mentioned with otosclerosis
– But it is a general feature of conductive hearing loss
– Patient’s can hear better in noisy environment
– People tend to raise their voices in noisy
environment?

13. Hyperacusis
• Unusual tolerance to ordinary environmental
sounds (Vernon, 1987)
• Consistently exaggerated or inappropriate
responses to sounds that are neither threatening
nor uncomfortably loud to a typical person
(Klein et al, 1990)
• It is abnormally strong reaction to sound
occurring within the auditory pathways, but it
involves limbic system (emotional reaction),
Sympathetic, reticular formation (arousal and
alerting), and pre-forntal area (awareness and
cognition) (Jastreboff&Hazell 2004)

14. Other terms
• Loudness recruitment:
– Abnormal growth of loudness due to cochlear
hearing loss, and in particular OHCs dysfunction
(mechanism?)
– Sounds of moderate intensity perceived as
uncommonly loud (ABLB, SISI score?)
– Reduced dynamic range, steeper than usual input
output function on the Cochlear basilar membrane
– Great spread of excitation of the basilar membrane.

15. Other terms
• Phonophobia: (fear is the dominant emotion)
– Emphasises the emotional impact of the sensitivity
to sounds, used more in neurological literature
– Phonophobia/photophobia accompanying migraine
attacks
– Misophonia: A term to describe disliking of sound
without the phobic element (Jestreboff, 2003)

16. Other terms
• Noise sensitivity in psychiatric disorders:
– Startle reflex in post traumatic stress disorders
– The association of noise sensitivity and depression
– Improvement of hyperacusis after treatment of
depression in tinnitus patients?

17. Hyperacusis and tinnitus
• 9 % point prevalence (Andersson, 2002)
• 40-60% in patients attending tinnitus clinic
• In patients with primarily hyperacusis complaint,
tinnitus estimates varies between 86% (Anari et
al, 1999) and 21% (Andersson et al, 2002)
• Hyperacusis as a precursor to the development
of tinnitus

18. Severe hyperacusis
• 4-5% of population have severe tinnitus
• 40% of these have significant hyperacusis
• Severe hyperacusis : 2%
– Jastreboff, 2000
– Baguley and Andersson, 2007

19. Medical conditions ass. With
hyperacusis
• Peripheral:
Bell’s palsy, Ramzy Hunt syndrome, Post
stapedectomy, perilymph fistula
• Central:
Migraine, Depression, Post-traumatic stress, Head
injury, Lyme disease, Williams syndrome,
Autism

20. Neurophysiological models
and mechanisms
• Hyperactivity of the auditory nerve (Moore,
1995)
• 5-HT (Marriage and Barnes, 1995)
• Endogenous opioid peptides ( Sahley et al,
1996 )
• Auditory efferent dysfunction
• Plastic change leading to increased central
auditory gain

21. Serotonin ( 5-HT)
• First recognized as a powerful vasoconstrictor
and isolated by Page (1948)
• 5 Hydroxytryptamine (5-HT)
• Naturally produced in the pineal gland, and its
precursor (amino acid Tryptophan) is rich in
bananas, milk, Turkey, plums
• 90% of Serotonin in the body is in the intestine

22. 5-HT
• One role of 5-HT, is as a neurotransmitter,
regulating various functions like sleep, memory
and learning, temperature regulation, mood,
appetite, behaviour, cardiovascular function,
muscle contraction, endocrine regulation and
depression.
• 5-HT released at synaptic clefts in the brain
regulate protein binding and change electrical
state of the cell, either stimulatory or inhibitory

24. 5-HT and depression ( The
molecule of happiness)
• Low serotonin levels are believed to be the cause
of many cases of mild to severe depression
which can lead to symptoms such as anxiety,
apathy, fear, feelings of worthlessness, insomnia
and fatigue. The most concrete evidence for the
connection between serotonin and depression is
the decreased concentrations of serotonin
metabolites in the cerebrospinal fluid and brain
tissues of depressed people

25. Serotonin ( 5-HT )
• Serotonergic fibres and terminal endings found
throughout central auditory pathway (Raphe
Neucli) through the medulla, pons and midbrain
• Postulated role of modulating sound perception
or determination of significance
– ( Thompson et al, 1994, Simpson and Barnes, 2000 )

26. Marriage and Barnes (1995)
The Journal of Laryngology and Otology
October 1995, Vol. 109, pp. 915-921
Neurological conditions associated with
hyperacusis:
(a) Migraine (Solomon et al, 1992).
• (b) Depression (Carmen, 1973).
• (c) Pyridoxine deficiency (Oppe, 1992).
• (d) Benzodiazepine dependence (Lader, 1984).
• (e) Musicogenic epilepsy (case study by Fujinawa
et al, 1977).

27. Neurological conditions
associated with Hyperacusis
• (f) Tay-Sach's disease or gangliosidosis type 2
• (Gordon et al, 1988; Gascon et al, 1992).
• (g) Post-traumatic stress disorder.
• (h) Chronic/post-viral fatigue syndrome (CFS/
PVFS) or myalgic encephalomyelitis (ME)
(Behan and Bakheit, 1991; Merry, 1991).

28. Hypothesis
• Many conditions associated with hyperacusis,
especially Migraine and tinnitus (probably
accounts for 90% of cases of hyperacusis), are
strongly related to dysfunction in 5-HT
metabolism, probably reduction of 5-HT activity
in the forebrain

29. Problems with 5-HT
hypothesis
• Non-specific ( Phillips and Carr, 1998 )
– A Cochrane review has found no evidence of the
its effects on tinnitus treatment
– Interest in the states, under investigation

30. Plasticity in central auditory
system
• Plasticity first proposed by Ramon y Cajal
( 1852 - 1934 )
The ability of the brain to re-organize itself
• Caused by
– Reorganization following an insult (sensory
deprivation as an example)
– Adaptation and change of functions

31. The role of sensory deprivation
• Tonotopic organization through the auditory system
means that certain frequency areas on the basilar
membrane supplies certain regions in the central
auditory system with afferent signals
• Damage to the cochlea, resulting in SNHL will lead to
loss of afferent information leaving this specific area
(frequency region)

32. Sensory deprivation theory
• Corresponding areas in the central auditory
system become starved (deprived) of sensory
stimulation
• This might lead to:
– Increased level of spontaneous activity
– Plastic rearrangement of neurones leading to
abnormal firing patterns
• This can be perceived as tinnitus and
hyperacusis

33. Recent PET scan findings
Seng-Ha Oh (2010)
• Pre and post cochlear implantation in pre lingual
and post lingual hearing loss
• PET looks at auditory cortical metabolism
• Wider pre-operative hypometabolism of the
auditory cortex is an indication of BETTER
speech abilities post implantation
• The more the duration of deafness the LESS the
extent of hypometabolism in the auditory cortex

34. Final thoughts
• Hyperacusis is a specific term and should not be
confused with other phenomena
• The theories of causation are still not proven,
though strong associations with cochlear
damage, tinnitus and migraine should provide a
connection to the pathophysiological
mechanisms of these conditions

35. Tinnitus
• Definition
• Classification
• Objective tinnitus – pulsatile
• Subjective tinnitus
• Theories
• Evaluation
• Treatment

36. • Tinnitus -“The perception of sound in the
absence of external stimuli.”
• Tinnere – means “ringing” in Latin
• Includes Buzzing, roaring, clicking, pulsatile
sounds

37. Prevalence
1- The hearing threshold is considered the single
most important factor affecting the prevalence of
tinnitus
2- Age: because it is associated with HL, 12.1% in 60-69
year olds compared to 4.7 % in 20-29 year Olds. Heller
(2003)
3-Not sex dependent? In groups over age 65, there is a
slight tendency for tinnitus to be more prevalent in men
over women (Heller 2003)
4- Race Caucasians report tinnitus more than do
African-Americans,
37

38. Tinnitus
• May be perceived as unilateral or bilateral
• Originating in the ears or around the head
• First or only symptom of a disease process or
auditory/psychological annoyance

39. Classification
• Objective tinnitus – sound produced by
paraauditory structures which may be heard by
an examiner
• Subjective tinnitus – sound is only perceived by
the patient (most common)

41. Tinnitus
• Pulsatile tinnitus – matches pulse or a rushing
sound
– Possible vascular etiology
– Either objective or subjective
– Increased or turbulent bloodflow through
paraauditory structures

42. Objective -Pulsatile tinnitus
• Arteriovenous • Cardiac murmurs
malformations • Pregnancy
• Vascular tumors
• Anemia
• Venous hum
• Thyrotoxicosis
• Atherosclerosis
• Ectopic carotid artery • Paget’s disease
• Persistent stapedial artery • Benign intracranial
• Dehiscent jugular bulb hypertension
• Vascular loops

43. Subjective Tinnitus
• Much more common than • Presbycusis
objective • Noise exposure
• Usually nonpulsatile • Meniere’s disease
• Otosclerosis
• Head trauma
• Acoustic neuroma
• Drugs
• Middle ear effusion
• TMJ problems
• Depression
• Hyperlipidemia
• Meningitis
• Syphilis

44. Evaluation - History
• Careful history
• Quality
• Pitch
• Loudness
• Constant/intermittent
• Onset
• Alleviating/aggravating factors

45. Evaluation - History
• Infection
• Trauma
• Noise exposure
• Medication usage
• Medical history
• Hearing loss
• Vertigo
• Pain
• Family history
• Impact on patient

46. Evaluation – Physical Exam
• Complete head & neck exam
• General physical exam
• Otoscopy (glomus tympanicum, dehiscent
jugular bulb)
• Search for audible bruit in pulsatile tinnitus
– Auscultate over orbit, mastoid process, skull, neck,
heart using bell and diaphragm of stethoscope
– Toynbee tube to auscultate EAC

47. Evaluation – Physical Exam
• Light exercise to increase pulsatile tinnitus
• Light pressure on the neck (decreases venous
hum)
• Valsalva maneuver (decrease venous hum)
• Turning the head (decrease venous hum)

48. Evaluation - Audiometry
• PTA, speech descrimination scores,
tympanometry, acoustic reflexes
• Pitch matching
• Loudness matching
• Masking level

49. Evaluation - Audiometry
• Vascular or palatomyoclonus induced tinnitus –
graph of compliance vs. time
• Patulous Eustachian tube – changes in
compliance with respiration
• Asymmetric sensorineural hearing loss or speech
discrimination, unilateral tinnitus suggests
possible acoustic neuroma - MRI

50. Laboratory studies
• As indicated by history and physical exam
• Possibilities include:
– Hematocrit
– FTA absorption test
– Blood chemistries
– Thyroid studies
– Lipid battery

51. Imaging
• Pulsatile tinnitus
• Reviewed by Weissman and Hirsch (2000)
• Contrast enhanced CT of temporal bones, skull
base, brain, calvaria as first-line study
• Sismanis and Smoker (1994) recommended CT
for retrotympanic mass, MRI/MRA if normal
otoscopy

52. • Glomus tympanicum – bone algorithm CT scan
best shows extent of mass
• May not be able to see enhancement of small
tumor
• Tumor enhances on T1-weighted images with
gadolinium or on T2-weighted images

53. Glomus Tympanicum
From: Weissman JL, Hirsch BE. Imaging of tinnitus: a review.
Radiology 2000;216:343.

54. Glomus Tympanicum
From: Weissman JL, Hirsch BE. Imaging of tinnitus: a review.
Radiology 2000;216:343.

55. Imaging
• Glomus jugulare
– Erosion of osseous jugular fossa
– Enhance with contrast, may not be able to
differentiate jugular vein and tumor
– Enhance with T1-weighted MRI with gadolinium
and on T2-weighted images
– Characteristic “salt and pepper” appearance on MRI

56. Glomus jugulare
From: Weissman JL, Hirsch BE. Imaging of tinnitus: a review.
Radiology 2000;216:344.

57. Glomus jugulare
“salt and pepper appearance”
From: Weissman JL, Hirsch BE. Imaging of tinnitus: a review.
Radiology 2000;216:344.

58. Imaging
• Arteriovenous malformations – readily apparent
on contrasted CT and MRI
• Normal otoscopic exam and pulsatile tinnitus
may be dural arteriovenous fistula
– Often invisible on contrasted CT and MRI/MRA
– Angiography may be only diagnostic test

59. Imagining
• Shin et al (2000)
– MRI/MRA initially if subjective pulsatile tinnitus
– Angiography if objective with audible bruit in order
to identify dural arteriovenous fistula

60. Imaging
• Other contrast enhanced CT diagnoses
• Aberrant carotid artery
• Dehiscent carotid artery
• Dehiscent jugular bulb
• Persistent stapedial artery
– Soft tissue on promontory
– Enlargement of facial nerve canal
– Absence of foramen spinosum

61. Persistent Stapedial Artery
From: Araujo MF et al. Radiology quiz case I: persistent stapedial artery. Arch
Otolaryngol Head Neck Surg 2002;128:456.

62. Imaging
• Acoustic Neuroma
– Unilateral tinnitus, asymmetric sensorineural hearing
loss or speech descrimination scores
– T1-weighted MRI with gadolinium enhancement of
CP angle is study of choice
– Thin section T2-weighted MRI of temporal bones
and IACs may be acceptable screening test

63. Acoustic Neuroma
From: Weissman JL, Hirsch BE. Imaging of tinnitus: a
review. Radiology 2000;216:348.

64. Acoustic Neuroma
From: Weissman JL, Hirsch BE. Imaging of tinnitus: a review.
Radiology 2000;216:348.

65. Imaging
• Benign intracranial hypertension
– MRI
– Small ventricles
– Empty sella

66. BIH – Empty Sella
Sismanis A, Smoker W. Pulsatile tinnitus: recent advances in
diagnosis. Laryngoscope 1994;104:685.

67. Treatments
• Multiple treatments • Reassurance
• Avoidance of dietary • White noise from radio
stimulants: coffee, tea, or home masking
cola, etc. machine
• Smoking cessation
• Avoid medications
known to cause tinnitus

68. Treatments - Medicines
• Many medications have been researched for the
treatment of tinnitus:
– Intravenous lidocaine suppresses tinnitus but is
impractical to use clinically
– Tocainide is oral analog which is ineffective
– Carbamazepine ineffective and may cause bone
marrow suppression

69. Treatments - Medicines
• Alprazolam (Xanax)
– Johnson et al (1993) found 76% of 17 patients had
reduction in the loudness of their tinnitus using both
a tinnitus synthesizer and VAS (dose 0.5mg-1.5
mg/day)
– Dependence problem, long-term use is not
recommended

70. Treatments - Medicines
• Nortriptyline and amitriptyline
– May have some benefit
– Dobie et al reported on 92 patients
– 67% nortriptlyine benefit, 40%placebo
• Ginko biloba
– Extract at doses of 120-160mg per day
– Shown to be effective in some trials and not in
others
– Needs further study

71. Treatments
• Hearing aids – amplification of background
noise can decrease tinnitus
• Maskers – produce sound to mask tinnitus
• Tinnitus instrument – combination of hearing
aid and masker
• Noise generator as a part of TRT

72. Treatments
• Tinnitus Retraining Therapy
– Based on neurophysiologic model
– Combination of masking with low level broadband
noise for several hours per day and counseling to
achieve habituation of the reaction to tinnitus and
perception of the tinnitus itself

73. Treatments
• Electrical stimulation of the cochlea
– Transcutaneous, round window, promontory
stimulation have all been tried
– Direct current can cause permanent damage
– Steenersen and Cronin have used transcutaneous
stimulation of the auricle and tragus decreasing
tinnitus in 53% of 500 patients

74. Treatments
• Cochlear implants
– Have shown some promise in relief of tinnitus
– Ito and Sakakihara (1994) reported that in 26
patients implanted who had tinnitus 77% reported
either tinnitus was abolished or suppressed, 8%
reported worsening

75. Treatments
• Surgery
– Used for treatment of arteriovenous malformations,
glomus tumors, otosclerosis, acoustic neuroma
– Some authors have reported success with cochlear
nerve section in patients who have intractable
tinnitus and have failed all other treatments, this is
not widely accepted

76. A Trial of Low Level Laser
Therapy for Reduction of Tinnitus
Symptoms

77. Treatments
• Biofeedback
• Hypnosis
• Magnetic stimulation
• Acupuncture
• Conflicting reports of benefit

78. Repetitive Transcranial Magnetic
stimulation

79. Repetitive Transcranial Magnetic
stimulation
• Rationale
Tinnitus is associated with
increase neuronal activity,
increase synchronicity, re-
organization in Aud. Cortex

80. Repetitive Transcranial Magnetic
stimulation
• Targeted modulation of aud. Cortex ?? New
therapy
• TMS is a non invasive electro-magnetic tool to
stimulate the primary motor cortex. Repetitive
stimulation produce neuro-stimulation of
specific regions potentially involved in the
patho-physiology of tinnitus. So the treatment
called rep. trans-cranial Magnetic stimulation
rTMS.

81. Conclusions
• Tinnitus is a common problem with an extensive
differential
• Need to identify medical process if involved
• Pulsatile/Nonpulsatile is important distinction
• Research into mechanism and treatments is
needed to better help our patients

82. Thank you