Have you recently taken a hearing exam, believing you have hearing loss, only to have the results indicate that your hearing levels are normal? You may have hidden hearing loss. Hidden hearing loss, or HHL, is characterized by difficulty hearing, especially in noisy environments, despite normal results on standard hearing tests, i.e., the audiogram indicates no hearing loss is present.
Hearing Thresholds vs. Listening Ability
Traditional hearing loss is understood as a degradation of your hearing threshold. Your hearing threshold is a measurement of what the lowest and highest sound pitches your ears can hear. Pitches are picked up by sensory cells inside the cochlea, an organ in your inner ear. When these cells sustain damage, they can no longer transmit pitches and sound information to the brain.
Hidden hearing loss is believed to be a degradation of your listening ability, but not necessarily your hearing threshold. This means that the cells in your cochlea are functioning fine and transmitting sound information to the brain, but the brain struggles to process those sounds correctly. This effect is worsened in environments with lots of background noise, because there’s a greater quantity of sound information for your brain to work through.
The concept that people can have normal hearing thresholds but not normal listening ability is relatively new. More research is currently needed.
Causes of Hidden Hearing Loss
Research is still ongoing, but recent studies have pointed to aging, loud noise exposure and ototoxic drugs as potential causes of HHL. These can all damage the neural synapses that relay sound information from the ear to the brain, as opposed to the sensory cells in the cochlea.
How to Detect Hidden Hearing Loss
One of the primary characteristics of HHL is that it doesn’t show up on a standard hearing test, so you may be wondering how it’s diagnosed. In a classic hearing test, called a pure-tone test, the patient is given headphones and sits in a soundproof room. The audiologist will play the test audio, which will emit a series of beeps at various volumes and pitches, and the patient will indicate when they hear the beeps. Doing this shows what pitches they struggle to hear.
This doesn’t work as well for HHL, however, and that’s why HHL is a new topic of study. Thankfully, there’s another form of hearing test called a speech-in-noise test. These hearing tests also have the patient sit in a soundproof room with headphones on, but instead of playing beeps, the audio is recordings of speech over various types of background noise. The patient must repeat what was said in the recording. This mimics real-life listening conditions more accurately and is a better tool for catching HHL.
If you suspect you have hearing loss, whether it’s traditional hearing loss or HHL, make an appointment with our skilled audiologists today for a hearing test that will provide the information and diagnosis you need. Call Beneficial Hearing Aid Center to make an appointment.