CSD Exam 1 Study Guide

Page 1: Basic Ear Anatomy

• Transduction

  • The process of changing sound from one form to another.

  • Converts acoustic information to electrical signals for perception in the brain.

• Main Components of Sound

  • Loudness/Intensity: Height of sound waves (measured in dB), correlating with loudness.

  • Frequency/Pitch: Refers to how high or low a sound is (measured in Hz).

  • Location in Space:

    • Horizontal localization superior due to Interaural Time Difference (ITD) and Interaural Level Difference (ILD).

    • The shape and positioning of the pinna affect sound wave alteration before entering the ear canal.

• Peripheral Ear Components

  • Outer Ear:

    • Pinna: Collects sound waves.

    • Ear Canal: Directs sound to the eardrum.

    • Eardrum (Tympanic Membrane): Vibrates in response to sound.

  • Middle Ear:

    • Impedance Matching: Adjusts sound resistance from air to fluid of inner ear.

    • Ossicles:

      • Malleus (hammer), Incus (anvil), Stapes (stirrup).

    • Include muscles for protection.

    • Eustachian Tube: Equalizes pressure.

  • Inner Ear:

    • Cochlea: Spiral-shaped, fluid-filled structure that converts sound waves to electrical signals using hair cells.

    • Vestibular System: Maintains balance.

• Organ of Corti:

  • Receives sound wave vibrations in the cochlea.

  • Hair cells' stereocilia bend against the tectorial membrane, opening ion channels and generating electrical signals sent to the brain.

Page 2: Clinical Audiology

• Roles of AuD:

  1. Hearing Loss Prevention: Educating on NIHL; fitting hearing protection (earplugs, earmuffs).

  2. Hearing Screenings: Quick tests identifying individuals needing further hearing tests.

  3. Hearing Testing: Comprehensive evaluations measuring hearing ability and diagnosing types of hearing loss (sensorineural, conductive, mixed).

  4. Operating Room Monitoring: IONM protecting the auditory nerve during surgeries.

  5. Cochlear Implants: Evaluating candidates and managing post-surgery rehabilitation.

  6. Support Groups: Offering resources and education for patients and families regarding hearing loss.

• Path to AuD:

  • Complete an undergraduate degree (usually in CSD).

  • Enter a 4-year Doctorate (AuD) program.

  • Complete a clinical externship and pass national praxis exam for licensure.

Page 3: EHDI

• EHDI"1-3-6" Benchmarks:

  • 1 Month: All newborns should be screened for hearing.

  • 3 Months: Diagnostic evaluation for those who do not pass screening.

  • 6 Months: Early intervention for diagnosed infants (e.g., hearing aids, speech therapy).

• Newborn Hearing Screening:

  • A quick, non-invasive test to identify potential hearing loss in newborns before leaving the hospital.

  • Early detection supports better developmental outcomes.

  • Applies to all newborns regardless of risk factors; a failed screening indicates the need for further testing.

• Objective Tests for Infants:

  • Otoacoustic Emissions (OAE): Checks cochlea response via soft sounds; fast and non-invasive.

  • Auditory Brainstem Response (ABR): Measures electrical activity in the auditory pathway; more accurate but takes longer than OAE.

Page 4: Causes of Hearing Loss

• Types of Hearing Loss:

  • Sensorineural: Inner ear/auditory nerve damage, usually permanent.

    • Causes: Aging, noise damage.

  • Conductive: Issues with sound passage, often temporary.

    • Causes: Fluid, foreign objects, allergies, ruptured eardrum, impacted earwax.

• Impact of Untreated Hearing Loss in Adults:

  • Emotional, social, cognitive consequences:

    • Avoidance of social situations leads to isolation.

    • Strain on relationships due to communication barriers.

    • Increased risk of dementia linked to cognitive decline from untreated hearing loss.

Page 5: Psychological and Overall Health

• Consequences of Untreated Hearing Loss:

  • Emotional impacts include increased risk of depression, anxiety, stress, and diminished independence.

  • Quality of life significantly affected leading to higher risk of accidents from reduced spatial awareness.

Page 6: Hearing Conservation

• Audiogram:

  • Graph measuring hearing ability (frequency in Hz on x-axis, loudness in dB on y-axis).

  • Components include frequency, intensity, and hearing threshold.

• Importance of Outreach:

  • Promotes awareness, early detection, and safe listening habits.

• Sound Levels:

  • Sounds 85 dB or higher can cause hearing damage over time, while 120 dB causes immediate harm.

• Daily Dose of Sound:

  • Total exposure throughout the day defined by the 3 dB rule (every 3 dB increase halves the safe exposure time).

  • Defined by WHO, NIOSH, OSHA.

• Noise-Induced Hearing Loss (NIHL):

  • Hearing loss caused by loud sounds damaging cochlea hair cells.

  • Factors involved: sound level, exposure time, genetics, age.

  • Symptoms include difficulty hearing and tinnitus.

  • Audiogram typically shows a notch at 3,000-6,000 Hz.