What types of hearing aids are suitable for different levels of hearing loss?

Hearing Aid Selection by Hearing Loss Severity

Conventional hearing aids are appropriate for mild to moderate hearing loss (20-70 dB HL), while severe to profound hearing loss (>70 dB HL) requires more powerful amplification or alternative technologies like cochlear implants, with specific device selection depending on whether the loss is unilateral or bilateral. 1

Mild Hearing Loss (20-40 dB HL)

Conventional hearing aids provide significant benefit for mild sensorineural hearing loss, with evidence supporting small-to-medium effect sizes (0.85) for quality of life improvements. 2

• Modern digital hearing aids with multiple microphones and digital noise reduction are suitable for patients with mild hearing loss, allowing precise control for the patient's dynamic range 1
• Personal sound amplification devices may serve as an initial, less expensive option for mild or intermittent hearing loss, though they lack the sophisticated components of conventional hearing aids 1
• For mild low-frequency hearing loss (>40 dB HL in low frequencies), gain compensation is necessary when using directional microphones 3

Moderate Hearing Loss (40-70 dB HL)

Conventional hearing aids remain the primary treatment option for moderate hearing loss, with patients experiencing difficulty following conversations without amplification. 1

• Custom-fitted digital hearing aids based on audiometric testing are recommended, with programming adjusted as hearing fluctuates or progresses 1
• These patients benefit from hearing aids that address their narrow dynamic range and provide optimal hearing across various listening environments 1
• Hearing assistive technology systems (infrared, FM systems) can supplement hearing aids in specific listening conditions 1

Severe Hearing Loss (70-95 dB HL)

When hearing loss progresses to severe levels with compromised word recognition scores or narrow dynamic range, conventional hearing aids may worsen hearing, necessitating alternative technologies. 1

For Unilateral Severe Loss:

• CROS (Contralateral Routing of Signal) hearing aids are recommended, using a microphone on the affected ear to transmit sound to the better-hearing ear 1
• BiCROS hearing aids are indicated when both ears have hearing loss, placing microphones on both ears 1
• Bone-anchored hearing devices (BAHA) provide an alternative for single-sided deafness, particularly when patients cannot tolerate devices on the normal-hearing ear 1, 4

For Bilateral Severe Loss:

• Powerful behind-the-ear (BTE) hearing aids with receiver-in-aid (RIA) placement offer greater maximum power output capabilities than receiver-in-canal (RIC) devices 5
• Patients often rely heavily on lip-reading even when using hearing aids 1

Profound Hearing Loss (>95 dB HL)

Cochlear implants are the definitive treatment when amplification provides limited benefit, offering direct electrical stimulation of the cochlea. 1, 6

• Cochlear implantation achieves 96% tinnitus improvement rates when tinnitus is present preoperatively, along with significant improvements in sound localization and speech discrimination 1, 6
• These devices restore substantial hearing even in patients who have undergone ablative labyrinthectomy 1
• For single-sided profound deafness, cochlear implants provide superior outcomes compared to CROS or bone-anchored devices for sound localization and speech understanding 1, 6

Special Considerations for Conductive and Mixed Hearing Loss

For hearing losses with a conductive component, the 75% air-bone gap + bone conduction approach is more appropriate than the 25% air-bone gap + air conduction approach because it correctly determines compression ratios based on sensorineural hearing loss rather than air conduction thresholds. 5

• Hearing aids can address conductive, sensorineural, or mixed hearing loss across a wide severity range 7
• RIA BTE products generally have greater output capabilities than RIC BTE products for fitting large conductive components combined with significant sensorineural loss 5

Critical Pitfalls to Avoid

• Do not delay amplification for mild hearing loss—evidence supports benefit even at this early stage, and patients often wait 10+ years before seeking treatment 2
• Do not fit conventional hearing aids for severe loss with poor word recognition—this may worsen hearing rather than improve it 1
• Do not overlook the distortion component of hearing loss—approximately one-third of total hearing loss represents distortion (class D) that hearing aids cannot compensate for, explaining limited benefit in noisy environments 8
• Ensure adequate maximum power output capabilities when fitting conductive or mixed losses, as not all devices can support the required output 5