CSDS 131 - Final Exam

Auricle

is the visible part of the ear that projects from the side of the head

consists of cartilage covered by skin and includes various structures: helix, antihleix, lobule, tragus

Helix

outer rim of the ear

Antihelix

a curved prominence parallel to the helix

Lobule

the fleshy lower part, commonly known as the earlobe 

tragus

a small pointed eminence in front of the ear canal

Functions of the outer ear

sound collection

directionality

Sound collection

auricle gathers sound waves from the environment 

Directionality

its unique shape helps localize sound sources by altering the intensity and timing of sound waves entering the ear canal

External auditory canal (EAC)

A slightly curved tube about 2.5cm long in adults

extends from the auricle to the tympanic membrane

Functions of the EAC

resonance 

protections 

Resonance

responds to sound waves by vibrating

Protection

Lined with hair and ceruminous glands producing earwax (cerumen) to trap dust and foreign particles

Tympanic Membrane (Eardrum) 

a thin, semi-transparent membrane forming the boundary between the outer and middle ear

Composed of three layers—outer epithelial, middle fibrous, and inner mucosal.

Functions of the Tympanic Membrane

Vibration

Transmission

Vibration

responds to sound waves by vibrating

Transmission

transfers these vibrations to the ossicles in the middle ear, initiating auditory processing 

Common Disorders of the Outer Ear

Congenital Malformations

Microtia

Anotia

Skin Cancer

EAC Disorders

Atresia

Stenosis

Foreign Bodies

Infections: Otitis Externa, Necrotizing Otitis Externa

Congenital Malformations 

these are structural abnormalities present at birth 

Microtia

Characteristics: an underdeveloped auricle, ranging from slight deformities to significant abnormalities

Associations: Can occur with syndromes like Down Syndrome or Treacher Collings Syndrome

Hearing Impact: may cause conductive hearing loss if the EAC or middle ear structures are affected

Treatment: otopasty (surgical reconstruction of the auricle), prosthetic auricles (for cosmetic enhancement and improved social interaction)

Anotia

Definition: complete absence of the auricle

Challenges: difficulty with sound localization due to the missing structure

Management: Prosthetic auricles (to improve appearance), hearing devices (bone-conduction hearing aids may be used if inner ear function is intact)

Skin Cancer 

due to its exposure, the auricle is susceptible to skin cancers 

Basal Cell Carcinoma

Prevalence: most common type of skin cancer on the auricle

Cause: Prolonged exposure to ultraviolet (UV) radiation

Role of Audiologists: early detection by recognizing suspicious lesions during examinations

Treatment: Surgical excision, radiation therapy, or topical medications

Atresia 

Definition: Absence or closure of the EAC 

Impact: leads to conductive hearing loss by blocking sound transmission 

Treatment: Surgical Reconstruction (creating or opening the ear canal), Bone-conduction hearing aids (transmit sound directly to the inner ear)

Stenosis

Description: Narrowing of the EAC

Complications: can cause debris and cerumen buildup, increasing infection risk

Management: Regular cleaning (performed by healthcare professionals), surgical widening (in severe cases to restore normal canal size)

Foreign Bodies

Occurrence: commonly seen in children inserting objects into the ear

Symptoms: Pain, infection, or temporary hearing loss

Treatment: Professional removal to prevent damage to the ear canal or tympanic membrane

Otitis Externa (Swimmer’s Ear) 

Cause: Bacterial or fungal infection from prolonged moisture exposure 

Symptoms: itching, pain (especially when touching the ear), swelling, and discharge

Treatment: Topical Antibiotics/Antifungals (applied directly into the ear canal), Cleaning and Drying (keeping the ear cnaal dry to prevent recurrence)

Necrotizing Otitis Externa

Severity: a serious infection spreading to the skull base and surrounding bones

Risk factors: Diabetes, weakened immune system

Symptoms: Severe ear pain, especially at night, and possible cranial nerve involvement

Treatment: Systemic Antibiotics (often administered intravenously), hospitalizations (required for close monitoring and management)

Ossicular Chain

Components: malleus (hammer), incus (anvil), stapes (stirrup)

Function: amplify and transmit vibrations from the TM to the inner ear

Eustachian Tube 

Connection: Links the middle ear to the nasopharynx 

Functions: Pressure equalization (balances air pressure on both sides of the TM), protection (prevents retraction and damage to the TM)

Common middle ear disorders

eustachian tube dysfunction (ETD)

Otitis Media (Acute, Chronic, and Serous)

Cholesteatoma

Mastoiditis

Eustachian Tube Dysfunction (ETD)

Mechanism: failure of the eustachian tube to open properly

Causes: Allergies, upper respiratory infections, anatomical blockages

Symptoms: ear fullness, discomfort, mild conductive hearing loss

Diagnosis: Type C Tympanogram (indicates negative middle ear pressure)

Treatment: Autoinflation techniques (valsalva-exhaling with closed mouth and nose, Toynbee maneuvers-swallowing with nose pinched), Medications (decongestants and antihistamines to reduce inflammation)

Acute Suppurative Otitis Media

Description: Bacterial infection with pus in the middle ear

Symptoms: Severe ear pain, fever, possible purulent dischange if TM ruptures

Treatment: Antibiotics (to eliminate infection), Myringotomy with PE Tube Placement (drains fluid and ventilates the middle ear)

Chronic Otitis media 

Characteristics: persistent inflammation causing structural damage 

Complications: Tympanosclerosis (scarring), ossicular erosion leading to hearing loss 

Management: Surgical repair or reconstruction of the ossicles and TM 

Serous Otitis Media (SOM)

Also known as: otitis media with effusion

Cause: Non-infecious fluid due to prolonged ET dysfunction

Treatment: medications (decongestants to reduce fluid buildup), PE Tube Insertion (allows continuous drainage and ventilation)

Cholesteatoma

Definition: abnormal skin growth in the middle ear behind the TM

Risks: Can erode ossicles and mastoid bone, leading to serious complications

Treatment: Surgical removal (complete excision is necessary), follow-up (regular monitoring to prevent recurrence)

Mastoiditis

Description: Infection of the mastoid air cells in the temporal bone 

Complications: can lead to meningitis, brain abscess if untreated 

Treatment: Antibiotics (high-dose to combat infection), Mastoidectomy (surgical removal of infected bone 

Types of Hearing loss

Hypacusis

Dysacusis

Diplacusis

Hypacusis

Definition: General reduction in hearing sensitivity

Impact: sounds must be louder to be heard

Dysacusis

Description: Difficulty in processing sounds, especially speech 

Symptoms: Distortion or muffling of sounds, making comprehension challenging 

Diplacusis

Explanation: perception of a single sound as two different pitches

Causes: Often due to unilateral cochlear damage

Genetic Causes of Inner Ear Disorders

Autosomal Dominant: only one defective gene needed; often a family history

Autosomal Recessive: Two copies of the defective gene required; parents may be carriers

X-linked Conditions: Gene mutation on the X chromosome; more severe in males

Maternal Infection causes of Inner Ear Disorders

Rubella: can cause congenital hearing loss if contracted during pregnancy

Cytomegalovirus (CMV): leading cause of non-genetic hearing loss in infants

Zika Virus: associated with microcephaly and potential auditory deficits

Ototoxic Medications during Pregnancy 

Aminoglycosides: antibiotics like gentamicin can damage fetal inner ear structures 

Specific Disorders that cause inner ear disorders

Ménière’s Disease

Presbycusis

Noise-Induced Hearing Loss (NIHL)

Ménière’s Disease

Symptoms: Vertigo, fluctuating low-frequency hearing loss, tinnitus, aural fullness.

Pathophysiology: Excessive endolymph fluid causing inner ear pressure.

Management: Dietary Changes (Low-sodium diet to reduce fluid retention), Medications (Diuretics, anti-vertigo drugs), Surgical Options (Endolymphatic shunt, vestibular nerve section in severe cases)

Presbycusis 

Definition: Age-related sensorineural hearing loss.

Characteristics: Bilateral, gradual loss, especially of high-frequency sounds.

Management: Hearing Aids (Amplify sounds to aid hearing), Assistive Devices (Telephone amplifiers, alerting systems), Communication Strategies (Lip-reading, visual cues)

Noise-Induced Hearing Loss (NIHL)

Cause: Prolonged exposure to loud noises or sudden intense sounds.

Prevention: Use of ear protection like earplugs or earmuffs.

Audiogram Findings: “Acoustic trauma notch” at 3000–6000 Hz, indicating specific frequency loss

Central Auditory System

Functions: Processing complex auditory information—localization, discrimination, comprehension.

Components: Neural pathways from the cochlea to the auditory cortex in the brain.

Central Auditory Disorders

Auditory Neuropathy Spectrum Disorder (ANSD)

Auditory Processing Disorders (APD)

Acoustic Neuromas

Auditory Neuropathy Spectrum Disorder (ANSD) 

Definition: Normal outer hair cell function but impaired neural transmission.

Diagnosis: ABR-Auditory Brainstem Response (Absent or abnormal responses), OAEs-Otoacoustic Emissions (Present, indicating normal cochlear outer hair cells)

Management: Hearing Aids/Cochlear Implants (May improve hearing by enhancing neural synchrony), Auditory Training (To improve processing skills)

Auditory Processing Disorder (APD)

Symptoms: Difficulty understanding speech, especially in noisy environments.

Diagnosis: Specialized auditory tests assessing different processing skills.

Management: Auditory Training Programs (Exercises to improve specific auditory abilities), Classroom Accommodations (Preferential seating, use of FM systems), Therapy (Speech-language therapy to develop compensatory strategies)

Acoustic Neuromas or vestibular schwannomas

Symptoms: Progressive unilateral hearing loss, tinnitus, balance problems.

Diagnosis: MRI (Imaging to detect tumors), ABR Testing (May show delayed neural responses)

Treatment: Surgical Removal (Via microsurgery), Radiation Therapy (For smaller tumors or when surgery isn’t an option)

Importance of Early Detection

Prevention of Delays: Early identification prevents speech, language, and cognitive delays.

Critical Development Window: The first three years are essential for auditory development

Newborn Screening Process

Universal Newborn Hearing Screening (UNHS):

Methods: Otoacoustic Emissions-OAEs (Tests cochlear function), Automated Auditory Brainstem Response-AABR (Assesses neural pathways up to the brainstem)

Follow-up Protocols:

By 1 Month: Initial screening completed.

By 3 Months: Diagnostic confirmation if screening is not passed.

By 6 Months: Intervention services initiated

Intervention

Hearing Aids: Fitted as early as possible for infants with hearing loss.

Cochlear Implants: Considered for severe to profound losses unresponsive to hearing aids.

Speech-Language Therapy: To support communication development.

Family Education: Involving parents in the intervention process enhances outcomes

Types of Hearing Aids 

Behind-the-Ear (BTE): Components housed in a case behind the ear; suitable for most types of hearing loss.

Receiver-in-Canal (RIC): Similar to BTE but with the receiver placed in the ear canal.

In-the-Ear (ITE): Custom-made to fit the outer ear; less visible than BTE.

Completely-in-Canal (CIC): Fits deep inside the ear canal; nearly invisible

Advanced Features of Hearing Aids

Bluetooth Connectivity: Allows pairing with smartphones and other devices.

Noise Reduction: Reduces background noise for clearer hearing.

Tinnitus Masking: Provides relief by generating white noise or soothing sounds

Cochlear Implants (CIs)

Suitable For: Individuals with severe to profound sensorineural hearing loss.

Components:

External Processor: Captures and processes sound.

Internal Electrode Array: Surgically implanted to stimulate the auditory nerve.

Post-Surgical Needs:

Mapping: Customizing settings for optimal hearing.

Rehabilitation: Auditory training to interpret new sounds

Bone Anchored Hearing Aids (BAHA) 

Indications: For conductive or mixed hearing loss and single-sided deafness.

Advantages: Bypasses Middle Ear-Directly stimulates the cochlea through bone conduction, Improved Clarity-Reduces distortion from middle ear pathology

Tinnitus Management

Sound Therapy: Uses background noise to mask tinnitus.

Tinnitus Retraining Therapy (TRT): Combines sound therapy with counseling to habituate the patient to tinnitus.

Cognitive-Behavioral Therapy (CBT): Addresses the emotional response to tinnitus

Vestibular Disorders Rehabilitation Techniques

Balance Retraining: Exercises to improve balance and coordination.

Gaze Stabilization: Enhances control of eye movements during head motion.

Specific Maneuvers:

Epley Maneuver: Repositions displaced ear crystals in BPPV patients.

Brandt-Daroff Exercises: Performed at home to reduce vertigo symptoms

Hearing conservation 

Purpose: Prevent Noise-Induced Hearing Loss (NIHL) in hazardous noise environments.

California Regulations: Governed by Cal/OSHA to enforce workplace safety standards

Hearing Conservation Regulatory Framework

Key Cal/OSHA Sections (Title 8, Sections 5096–5100):

5096: Noise exposure limits (5 dBA exchange rate halves exposure time).

5097–5100: Cover Hearing Conservation Programs, Hearing Protectors, Training, and Recordkeeping.

Exposure Limits:

Permissible Exposure Limit (PEL): 90 dBA over 8 hours.

Action Level (AL): ≥85 dBA requires conservation measures.

California standards exceed federal OSHA enforcement rigor.

Components of Hearing Conservation Program

Noise Monitoring: Regular assessments; results must be communicated to employees.

Audiometric Testing: Baseline within six months; annual tests to track hearing thresholds.

Hearing Protection Devices (HPDs): Provided for noise above AL; training on proper use required.

Training and Education: Annual instruction on noise effects, HPDs, and audiometric testing.

Recordkeeping: Noise data retained for two years; audiometric results for the duration of employment.

Engineering Controls: Noise barriers, quieter machinery.

Administrative Controls: Shift rotations to reduce exposure

Implementation Challenges 

Diverse Workforce: Multilingual and multi-ethnic workplaces require tailored outreach.

Enforcement: Cal/OSHA inspections ensure compliance; non-compliance risks fines or restrictions.

Innovative Solutions: Adoption of advanced noise control technologies prioritizes employee wellness

Benefits of Hearing Conservation

Prevents Hearing Loss: Reduces risks of NIHL, tinnitus, and related stress.

Economic Impact: Saves workers’ compensation costs and improves productivity.

Legal and Ethical Compliance: Protects employers from lawsuits and demonstrates commitment to safety

Case Study: Construction Site Compliance

Scenario: Noise levels exceeded 95 dBA.

Actions Taken: Engineering controls (quieter machinery) and audiometric testing detected hearing loss in 10% of employees, enabling early interventions.

Outcome: Improved compliance and employee safety.

Normal Hearing dB HL

-10 dB HL to 25 dB HL

Mild Hearing Loss dB HL

30 dB HL to 40 dB HL

Moderate Hearing Loss dB HL

45 dB HL to 55 dB HL

Moderately-Severe Hearing Loss dB HL

60 dB HL to 70 dB HL 

Severe Hearing Loss dB HL

75 dB HL to 90 dB HL

Profound Hearing Loss dB HL

90 dB HL+

Tympanogram A_S

Shallow peak → stiff system (otosclerosis) 

Tympanogram A

Normal compliance and pressure

Tympanogram A_D

Deep peak → hypermobile membrane or ossicular discontinuity

Tympanogram B

Flat → fluid, perforation, or wax occlusion

Tympanogram C

Negative pressure → eustachian tube dysfunction

How to straighten the ear canal in Otoscopy for adults 

Pull ear back and up 

How to straighten the ear canal in Otoscopy for kids 

downward and back 

Impedance (Z)

resistance to sound flow caused by stiffness (S), mass (M), and friction (R)

Determine stiffness

Admittance (Y)

ease of sound flow; inverse of impedance

Determine flaccidity 

Compliance

mobility of the tympanic membrane and ossicular chain

Acoustic Reflex

a loud sound trigger stapedius muscle contraction, which stiffens the ossicular chain and protects the cochlea from overexposure

Absent or reflexes may suggest neural lesions or middle ear pathology

Acoustic Reflex Thresholds Ipsilateral Reflex

A sound in one ear triggers a reflex in the same ear

Acoustic Reflex Thresholds Contralateral Reflex

A sound in one ear triggers a reflex in the opposite ear, crossing over in the brainstem via the superior olivary complex

False Negatives in Pure Tone Audiometry

These occur when the patient fails to response to a sound they actually heard. This can be due to misunderstanding instructions, poor attention, or deliberate feigning (faking) 

False Positives in Pure Tone Audiometry

These happen when the patient responds to a sound that wasn’t presented. Highly motivated patients or those with tinnitus may inadvertently give false-positive responses (trigger happy patients) 

Stenger Principle

If I play the same tone in both ears you are only going to perceive the louder one

Audiogram Symbols 

Air-bone gap (ABG)

is the difference in decibels (dB) between air and bone conduction thresholds. A significant ABG (≥ 15 dB) indicates a conductive component. No gap indicates sensorineural loss

Interaural Attenuation

loss of sound energy between ears 

Supra-aural earphones have a minimum IA of 40 dB

Insert earphones: 60-75 dB

Bone conduction: 0 dB

Overview of Otoscopy

The process of visually examining the ear canal and tympanic membrane (eardrum) using an otoscope. It is one of the most fundamental diagnostic techniques in audiology and otolaryngology, used to assess ear health before any audiometric testing

Why does otoscopy matter?

The outer and middle ear are often the first places where pathologies can interfere with sound conduction.

Performing accurate otoscopy ensures that earwax impaction, infection, or perforation is identified before misinterpreting an audiogram or tympanogram.

Otoscope parts:

handle (power source), light source, magnifying lens, and speculum (disposable tip)

Traditional otoscope

handheld, commonly used in clinics

Video otoscope

projects a magnified image onto a screen for documentation or patient education

Speculum size

choose small for children, larger for adults to visualize the canal walls 

Otoscopy Procedure Steps

1. Inspect the external ear for deformities, swelling, or discharge.

2. Straighten the ear canal

3. Gently insert the speculum and view the tympanic membrane.

4. Note color, cone of light, and any abnormalities