CSD 673 HA I - severe/profound HL

Severe HL range

70–90 dB HL

Profound HL

>90 dB HL

Auditory Impacts of Severe and Profound HL

• Reduced dynamic range

• Limited speech perception, even with amplification

• Poor frequency and temporal resolution

Functional Challenges of Severe and Profound HL

• Reliance on visual cues for communication

• Difficulty in listening in background noise

• Increased likelihood of auditory/listening fatigue.

• Difficulty on the phone.

Challenges in Fitting Hearing Aids for Severe and Profound Loss

Main Challenge: Need maximum power without causing discomfort or feedback.

• Power & Gain: Need very high gain w/o feedback and high output (safe to prevent loudness discomfort)

• Dynamic range compression: reduced dynamic range

• High Frequencies info is often degree of loss; limited benefit in"dead regions"

• Feedback: High amplification increases acoustic feedback. Needs strong feedback cancellation.

• Battery: Drains quickly due to high power needs.

Goal: Make loud sounds comfortable and soft sounds audible, all while preventing feedback.

Hearing Aid Technologies for Severe and Profound Loss — HA TYPE?

Behind-the-Ear (BTE): higher output capacity and larger battery size

Key Features of BTE for Severe and Profound HL

• High-Power Amplification: Designed specifically for severe/profound losses

• Wide Dynamic Range Compression (WDRC): sound within the user’s residual dynamic range

• Frequency Lowering:  Compresses high-frequency sounds into lower frequencies where hearing is better

• Directional Microphones: Improves speech perception in noise

• Telecoil and Connectivity:  Useful for assistive listening systems (loop systems and Bluetooth devices)

• Feedback Suppression: Advanced algorithms minimize feedback without compromising audibility.

Assessment and Pre-Fitting for Severe and Profound HL

•Comprehensive audiological evaluation (pure-tone thresholds, speech audiometry, loudness discomfort levels).

•Determine candidacy for hearing aids versus cochlear implants.

•Evaluate real-world needs (e.g., listening environments, communication goals).

When to refer for a cochlear implant evaluation?

“60/60”

PTA (500, 1k, 2k Hz) ≥ 60 dB in better ear

Unaided WRS 60% ≤ in better ear

• TRADITIONAL CI Candidacy, NOT SSD

Threshold Equalizing Noise Test (TEN TEST)

• Purpose: Quick clinical test to identify cochlear dead regions.

• Stimulus: Uses a special masking noise (TEN).

• Concept/Method: In a dead region, a tone is detected by neighboring healthy areas. The TEN noise is used to mask these healthy regions.
  Result: If the tone is not heard over the masker = DEAD REGION

• Administration: Done via software; tone in Channel 1, TEN noise in Channel 2.

Interpreting TEN Results

• Normal Hearing:

  • Pure-tone threshold is the same as the presentation level of the TEN noise.

• Hearing Loss WITHOUT a Dead Region:

  • Pure-tone threshold is slightly above the presentation level of the TEN noise.

• Hearing Loss WITH a Dead Region:

  • Pure-tone threshold is 10 dB or more above the presentation level of the TEN noise.

• If a cochlear dead region is present, traditional amplification may not provide benefit in that region. Patients may report the amplified signal sounds distorted

HA Verification

•Real-Ear Measurements (REM) are crucial!

•Ensure prescribed gain is delivered across frequencies. 

•Assess audibility of speech signals

•Measure improvement in speech perception with aids.

•Can do aided speech recognition testing in the booth.

Counseling and Aural Rehabilitation

1. Realistic Expectations:

• Explain limits of amplification (e.g., speech in noise).

• Discuss benefit of ALDs or CIs if aids aren't enough.

2. Communication Strategies:

• Encourage use of visual cues and speechreading.

• Train caregivers in effective communication techniques.

3. Device Management:

• Teach proper care and maintenance of high-powered hearing aids.

4. Aural Rehabilitation:

• Encourage programs for auditory training and speech perception.

• Recommend group/individual therapy to practice using residual hearing.

Hybrid Hearing Solutions

combination of HAs and CIs for those w/ residual low-freq hearing (after surgery) but severe to profound high freq thresholds

• pt hears high freqs via CI

• low freqs amplified and presented acoustically via receiver

• Challenge: Balancing the sound of CI and HA simultaneously 

Bimodal Users (definition)

A cochlear implant (CI) in one ear and a hearing aid (HA) in the other.

Benefits of Bimodal Users

• Provides low-frequency acoustic information that a CI lacks.

• Improves speech perception in quiet and noise.

• Improves localization cues.

• Provides more natural sound quality.

Limitation of Bimodal Users

Binaural integration (combining the electric and acoustic signals) is difficult.

Manufacturer Partnerships for Bimodal Users

• Cochlear Americas & ReSound

• Med-El & Starkey

• Advanced Bionics & Phonak

Partnership Benefits for Bimodal Users

• Bimodal streaming 

• Single app to control both devices

• Programmed together to better match two incoming signals (e.g., match time delays)