Auditory Processing, Tinnitus and Hyperacusis Flashcards
What is Auditory Neuropathy Spectrum Disorder (ANSD)? When does it typically present? What is its diagnostic criteria? What are the suspected causes/sources? What is the recommended management?
Poor speech understanding in the presence of normal to near normal outer hair cell function with evidence of absent or abnormal neural synchrony
Can develop at any time, but majority present before age 10.
Diagnostic Criteria:
1. Evidence of normal outer hair cell function (normal OAEs and cochlear microphonics)
2. Evidence of poor neural synchrony/function (absent/abnormal ABR, reflexes, OAE suppression)
3. Evidence of poor hearing function (audiogram showing SNHL with significantly depressed speech discrimination scores, out of keeping with hearing loss); poor HINT (hearing in noise test)
Etiologies (theories):
1. Inner hair cell problem
2. Issue with synapse between IHC and 8th nerve
3. Problem with cochlear nerve
Management:
1. Trial of hearing amplification (4% benefit only)
2. Cochlear implantation increasingly viewed as an option
What is central auditory processing disorder? What are the symptoms, how is it diagnosed and what are the test results on audiologic testing?
Definition: Central receptive language disorder of adults and children from difficulty in decoding and storing auditory information
Symptoms:
- Perceptual hearing loss (especially with background noise)
- Delayed communication abilities (speech issues, delayed responses, use of gestures instead of speech)
- Echolalia (repeating back words without comprehension)
- Easy distraction
- Behavioural problems
- Frequently asking for repitition
- Difficulty following directions
- Inconsistent academic performance
- Difficulty with telephone conversations, reading/spelling, noisy environments
Diagnostic tests/results:
- Normal audiogram
- Abnormal hearing in noise test
- Test by audiologist + child psychologist - rule out auditory neuropathy
Audiologic tests:
- Monoaural testing: hearing in noise test (HINT) (250 sentences in 25 lists, start at 55dB SPL, noise constant 65dB SPL - if sentence correctly identified, next sentence presented at lower speech; if wrong then next sentence at higher sound), filtered speech
- Binaural - competing sentence test (two sentences one quiet one loud; repeat the quiet sentence)
- Dichotic tasks - digit test (repeating a series of numbers), staggered spondaic words (one syllable of a word read in one ear, other syllable in the other ear)
What are the differences between central auditory processing disorder and auditory neuropathy spectrum disorder?
Pure tone thresholds:
- CAP normal, ANSD normal to profound loss
Quiet word discrimination
- CAP excellent, ANSD excellent to poor
Noise word discrimination:
- CAP fair to poor, ANSD poor
Tymps: Both normal
Acoustic reflexes:
- CAP normal/present
- ANSD absent/abnormal
ABR:
- CAP normal
- ANSD absent/abnormal
What are two models of types of CAPDs? What are their subcategories of central auditory processing disorders?
Buffalo Model (1992):
1. Decoding: impairment of breakdown of auditory processing at the phonemic level (individual sounds) - cannot listen to language at natural speed
2. Integration: difficulty integrating/combining auditory information with other functions, such as visual and non-verbal aspects of speech
3. Tolerance fading memory: poor auditory memory or difficulty understanding speech under adverse conditions/background noise
4. Organization: Reversals and sequencing errors; difficulty coordinating thoughts and actions for expressive language
Bellis-Ferre Model
A. 3 Primary Profiles (DIP)
- Decoding
- Integration
- Prosodic (relating to rhythm of language) - flat or monotonic speakers, cannot convey expression with language, difficulty with social judgement
B. 2 Secondary profiles
- Association: Literal thinkers, difficulties with semantics
- Output Organization: Difficulty coordinating thoughts/actions for expressive language
What is the management of central auditory disorders?
Compensatory strategies:
- Active listening
- Memory techniques
- Situational awareness
- Rules of language
- Rephrasing
Environmental modifications:
- Preferential seating
- Note taker
- Gaining attention before speaking
- Acoustic modifications
Auditory perceptual training:
- Target areas of processing where patient is struggling both formally and informally (e.g. software programs - LACE, Earobics, Fastforward; DIID training)
- SLP
Technology:
- FM system
- Sound field system
Define subjective vs. objective tinnitus
Subjective tinnitus: Perception of soudn without true external stimuli
Objective tinnitus: True organic cause of tinnitus - body sound, or vibration
List a differential for subjective tinnitus
- Hearing loss (Otologic) - 75% have > 30dB >3kHz
- Presbycusis
- Autoimmune hearing loss
- Retrocochlear lesions (vestibular schwannoma)
- Meniere’s disease
- Noise induced hearing loss - Medications
- ASA/NSAID
- AntiHTN
- Aminoglycosides
- Heterocyclic antidepressants
- Caffeine
- Heavy metals - Trauma
- Head injury
- Loud noise
- Barotrauma - Systemic diseases
- HTN
- Depression/Anxiety - Neurologic
- Whiplash (7-10d post injury)
- MS
- Meningitis
- Brainstem stroke - Metabolic
- Hyperthyroidism/hypothyroidism
- Hyperlipidemia
- Vitamin A, B/thiamine, zinc deficiency - Dental
- TMJ disorders
What is the differential diagnosis of objective non-pulsatile tinnitus?
- Patulous eustachian tube
- Spontaneous otoacoustic emission
What is the differential diagnosis of objective pulsatile tinnitus?
ASYNCHRONOUS WITH PULSE:
A. Muscular Myoclonus
1. Palatal myoclonus
2. Tensor tympani myoclonus
3. Stapedius muscle myoclonus
B. Otologic - middle ear
1. Patulous eustachian tube
2. Ossicular or TM abnormality
3. Otosclerosis
4. Semicircular canal dehiscence
5. Middle ear effusion
SYNCHRONOUS WITH PULSE:
A. Arterial
1. Cardiovascular: HTN, Valvular Heart Disease
2. Intraosseous (Paget’s disease, otosclerosis)
3. Neoplasm: Paraganglioma (glomus tympanicum or jugulare); Vestibular schwannoma; Endolymphatic sac tumor; Hemangiopericytoma; TB hemangioma; Meningioma; Vascular metastases to skull base
4. Vascular Stenosis: Carotid artery stenosis; Other atherosclerotic disease (subclavian, external carotid); Fibromuscular dysplasia of the carotid artery, Extracranial carotid web
5. Skull base variant: AV fistula/malformation, aneurysm, Arterial dissection (Carotid, vertebral), Persistent stapedial artery, aberrant/Intratympanic carotid artery, Vascular compression of VIII, hyperdynamic states of Increased cardiac output (pregnancy, thyrotoxicosis)
B. Arterio-venous
1. Dural arterio-venous fistula (dAVF)
2. Arterio-venous malformations (AVM)
C. Venous
1. Pseutotumor cerebri (ie. Idiopathic intracranial hypertension)
2. Venous hum
3. Sigmoid sinus and jugular bulb abnormalities (or high-riding jugular bulb)
4. Dilated mastoid or condylar emissary veins
5. Idiopathic tinnitus or essential tinnitus
6. Dural sinus stenosis (Transverse or sigmoid sinus)
7. Sinus Diverticulum
Robert Fahed Pulsatile tinnitus clinic
Discuss how you would perform the initial evaluations of tinnitus
Persistent tinnitus = > 6 months
Primary = identified cause
Secondary = from a disease process
HISTORY:
- Pitch, loudness, minimum masking level
- Tinnitus handicap index
PHYSICAL EXAM:
- Auscultate the mastoid and neck
- BP check both arms
- Otoscopy/pneumatic otoscopy –> masses, Brown’s sign (air pressure on TM causes blanching of tumor)
- Hennebert’s sign (pressure induced vertigo/nystagmus)
- Tulio’s sign (vertigo induced by sound)
- Compress IJV - is tinnitus extinguished (arterial vs. venous)
- Vestibular exam
BLOOD WORK:
1. CBC
2. Lytes/extended lytes
3. Thyroid function tests
4. Lipid profile
5. FTA-ABS (syphillis)
AUDIOMETRY (indications):
1. Unilateral
2. More than 6 months
3. Associated hearing loss
IMAGING:
1. MRI (work-up similar to asymmetric HL)
Describe the diagnostic imaging algorithm for pulsatile tinnitus
Pulsatile tinnitus, synchronous with pulse, and normal otoscopy
Step 1: Determine if tinnitus extinguishes with light ipsilateral IJV compression
- If yes - likely venous pulsatile tinnitus
- If No - likely arterial pulsatile tinnitus
SUSPECTED VENOUS:
Step 2: Is patient obese?
- If yes, MRI, MRA/V, Fundoscopic exam, lumbar puncture –> evaluate for IIH syndrome
- If no, MRI and MRA/V, or CTA/V (ideally 4D dynamic)
SUSPECTED ARTERIAL:
Step 2: Carotid duplex ultrasonography
- If positive, likely atherosclerotic coronary artery disease
- If negative, MRI and MRA/V or CTA/V (ideally 4D dynamic)
GOLD STANDARD: CEREBRAL ANGIOGRAM - especially if non-invasive imaging is negative or non-contributive. Multiple purposes:
1. Confirms the presence of an underlying vascular cause
2. Rules out other possible mechanisms (association between transverse sinus stenosis and dAVF)
3. Balloon occlusion test in case of doubt
4. Treatment planning
Figure 153.2 Cummings
In the audiologic workup of a patient with unilateral tinnitus, what are 5 findings suggestive of retrocochlear pathology?
- Asymmetric SNHL
- Disproportionate decrease in SDS
- Loss of acoustic reflexes of positive reflex decay
- Roll over effect
- Abnormal and delayed wave V on ABR
Discuss a complete management strategy for subjective tinnitus
A. Patient Education
- Tinnitus is real, has a physical basis, may be permanent
- Our reaction to tinnitus, rather than tinnitus itself, creates a problem; reaction is manageable and can be modified
B. Patient Counselling
- Emotional support
- Realistic understanding of tinnitus
- Attitude to pursue helpful activities
- Battery of tactics & strategies
C. Lifestyle Changes
- Stop Caffeine, chocolate, smoking, drugs (especially ASA)
D. Masking
- Amplification (25% success) –> 90% of patients with tinnitus have HL
- Hearing aid masker (33% success, for normal hearing patients)
- Tinnitus instrument: Hearing aid and masker (55% success)
E. Behavioural
- Stress management
- Habituation/tinnitus retraining
- Cognitive behavioural therapy
NOT RECOMMENDED:
- Medications: Alprazolam, Nortriptyline, Gabapentin, Melatonin, or transcranial magnetic stimulation
SURGERY:
- When associated with a condition (otosclerosis, Meniere’s disease, Vestibular schwannoma, glomus), tinnitus improves in ~50%
- Auditory nerve section specifically for tinnitus will make it worse in 50%
- CI not considered for debilitating tinnitus (however there seems to be some new research on this use now!)
Discuss masking or sound therapy for tinnitus
- Avoid silence using e.g. hearing aids, tinnitus combination instruments (hearing aids with sound generators built in so they emit a sound - e.g. shhhh - and environmental sounds)
- Masking of about 2-3dB indicates a good prognosis
Describe Tinnitus retraining therapy (TRT)
- Based on Jastreboff’s neurophysiological model of tinnitus, delivered through structured protocol
- Involves individualized educational counselling and sound therapy
- Goal is habituation (the diminishing of a physiological or emotional response to a frequently repeated stimulus)
- 18 months on average to complete
- Provider is trained in TRT
