If you’ve ever noticed a hollow or echo-like sound while wearing earplugs or headphones, you’ve experienced the occlusion effect. This phenomenon can also affect hearing aid users, where sounds like their own voice seem distorted, muffled, or booming.
What is the Occlusion Effect?
The occlusion effect occurs when an object, such as a hearing aid or earplug, blocks the ear canal. This blockage traps sound, especially low-frequency noises (200-400 Hz), causing them to echo within the ear. This leads to sounds like the user’s voice, chewing, or swallowing sounding louder or distorted. Though external noises are less affected, they may still seem lifeless or unclear.
How the Occlusion Effect Affects Perception
The insertion of a hearing aid alters ear canal acoustics, amplifying low-frequency sounds while dampening high-frequency ones, which are critical for speech clarity. This leads to the perception of one’s voice sounding muffled or hollow and external voices being difficult to understand.
The occlusion effect is more noticeable in individuals with mild to moderate hearing loss or those with narrow ear canals. It’s also more pronounced with custom hearing aids compared to receiver-in-canal (RIC) styles.
Implications for Hearing Aid Users
Hearing aid users often complain of hearing their own voice reverberating in their head. The degree of occlusion depends on hearing aid type, ear canal shape, and degree of hearing loss. Completely-in-canal (CIC) hearing aids, which sit deeper in the ear, tend to cause more occlusion than RIC models.
Hearing aids with open-fit designs or venting can help alleviate occlusion by allowing more natural sound to enter the ear, reducing the stuffed-up sensation.
Solutions to Reduce the Occlusion Effect
To minimize the occlusion effect, users can:
- Opt for hearing aids with larger vents or open-fit designs.
- Choose receiver-in-canal (RIC) models that prevent ear canal blockage.
- Ask for adjustments to gain settings to reduce amplification of low frequencies.
- Use thin tube or open-fit domes for a more natural sound.
- Ensure proper hearing aid insertion and fit to avoid unnecessary occlusion.
The occlusion effect can be frustrating for hearing aid users, but understanding its causes and solutions can help reduce its impact. Styles like RICs and open-fit hearing aids are designed to minimize occlusion, and with the right adjustments, most users can experience clearer and more comfortable hearing. If you’re experiencing occlusion, consult your audiologist for a better fit and potential adjustments.