Sometimes, difficulty understanding speech and sounds isn’t caused by hearing loss alone. It may be related to auditory neuropathy spectrum disorder (ANSD), a condition that affects how sound signals travel from the inner ear to the brain. Auditory neuropathy can be challenging to understand because it affects people differently. Some individuals have hearing thresholds within the normal range, while others experience mild to profound hearing loss.
Think of auditory neuropathy like a radio that isn’t quite tuned to the right station. You may hear that someone is speaking, but their words sound unclear or distorted, making it difficult to understand what they’re saying. This happens because hearing depends not only on detecting sound but also on transmitting and processing sound signals accurately.
Follow along as El Dorado Hearing takes a closer look at auditory neuropathy and explains how it can affect speech understanding and hearing.
What Is Auditory Neuropathy?
Auditory neuropathy, commonly referred to as auditory neuropathy spectrum disorder (ANSD), is a hearing disorder in which sound may be detected by the inner ear but the signals are not transmitted or synchronized properly as they travel along the auditory pathway to the brain. This can make speech difficult to understand, even when a person can hear sounds.
People of all ages can experience auditory neuropathy, and the condition may go undiagnosed for some time because hearing abilities vary widely. Some individuals have relatively normal hearing thresholds but struggle to understand speech, particularly in noisy environments. Others experience varying degrees of hearing loss.
Although the severity of hearing loss differs from person to person, difficulty understanding speech can be a key feature of auditory neuropathy. Possible symptoms include:
- Hearing loss that ranges from mild to profound
- Fluctuations in hearing ability
- Ringing in the ears (tinnitus)
- Difficulty understanding speech, especially in background noise
- Difficulty distinguishing or identifying certain sounds
Some individuals with auditory neuropathy may also have other neurological or developmental conditions that affect skills such as speech, language, or coordination. However, these symptoms are not present in everyone with auditory neuropathy and may have other causes.
Because auditory neuropathy can be difficult to identify through a standard hearing test alone, it’s important to consult an audiologist if you or a loved one is having persistent difficulty understanding speech or other concerns about hearing.
What Causes Auditory Neuropathy?
Auditory neuropathy can occur when different parts of the auditory system do not transmit sound information accurately. Researchers have identified several possible causes, including:
- Inner hair cell damage: Inner hair cells in the cochlea help convert sound vibrations into electrical signals that can be transmitted to the auditory nerve.
- Auditory nerve dysfunction: Problems affecting the auditory nerve can interfere with the transmission of sound information to the brain.
- Genetic factors: Certain genetic changes can affect the function of inner hair cells, auditory nerve fibers, or the connections between them.
- Damage to the auditory system: Some medical conditions or injuries may affect the structures involved in transmitting sound signals.
In some cases, auditory neuropathy is associated with complications around birth, certain illnesses, or other underlying conditions. The exact cause is not always identified, and the contributing factors can vary from one person to another.
How Is Auditory Neuropathy Diagnosed?
Diagnosing auditory neuropathy generally involves a combination of hearing tests. An audiologist may recommend several evaluations to assess how well the ear detects sound and how effectively sound signals travel through the auditory pathway. Common tests include:
- Tympanometry and acoustic reflex testing: These tests help assess middle-ear function and the reflexes associated with sound stimulation.
- Auditory brainstem response (ABR): This test measures electrical activity along the auditory nerve and brainstem in response to sound. It is particularly important when evaluating suspected auditory neuropathy.
- Otoacoustic emissions (OAEs): These tests measure sounds produced by the cochlea and help assess the function of outer hair cells. They can provide important information about inner-ear function.
- Behavioral audiometry: This evaluates hearing sensitivity by measuring responses to sounds at different pitches and volumes.
Auditory neuropathy is often identified when testing shows an abnormal or absent auditory brainstem response despite evidence of preserved outer hair cell function, such as otoacoustic emissions or a cochlear microphonic. Because test results can vary, an audiologist may recommend additional assessments to confirm the diagnosis and understand how the condition affects hearing and speech perception.
If you believe that you or a loved one may have auditory neuropathy, El Dorado Hearing offers comprehensive hearing evaluations. Our hearing specialists can assess your hearing, determine which tests may be appropriate, and help you understand your results and potential next steps.
For personalized hearing testing in Tucson, AZ, consider El Dorado Hearing. We strive to make our hearing clinics welcoming and comfortable places where patients can feel at ease while receiving care.
If you’re ready to take the next step toward better understanding your hearing, visit one of our hearing clinics. Contact us today to schedule an appointment with one of our hearing specialists!