An APD is a disorder of how the brain receives, encodes and interprets the information it receives. These disorders occur at the level of the brain versus the ear. It is important to remember, we detect sound with our ears, but we hear with our brains.
Causes for APD
Head trauma, strokes, diseases and medications may also contribute to auditory processing disorders. In these cases, APDs can occur suddenly and are obvious; other times, they can be more subtle. It is possible that an APD can indicate that there is an underlying medical condition that may warrant further attention.
Untreated hearing loss, or inappropriately treated hearing loss, is another cause for APD. The lack of auditory input, or distorted input, will reduce or distort the input the brain receives, which may result in neural atrophy or neural reorganization (the neurons necessary for hearing disappear or do not respond appropriately to input). This ultimately leads to reduced ability to hear sounds or process language, especially in complex situations.
Signs or Symptoms of APD
Symptoms of APD may range from mild to severe. Common difficulties include, but are not limited to, difficulty hearing in the following situations:
- Hearing in noisy environments
- Following conversations
- Understanding speech when spoken quickly
- Following complex or multi-step directions
- Remembering spoken information
- Maintaining focus and attention
- Processing nonverbal information
- Issues organizing at home or work
Diagnosing an Auditory Processing Disorder
APDs can create subtle difficulties with hearing and communication. This can lead to frustration, social withdrawal, isolation, safety concerns, anxiety, and depression. However, these same conditions can also be seen with untreated hearing loss. For this reason, a thorough assessment is important to determine if an APD may be contributing to hearing and communication difficulties.
Speech-in-Noise Testing
Speech-in-noise testing assesses a patient’s ability to understand speech in a real-world setting, such as when there’s background noise. Traditional pure-tone hearing tests (where you respond to beeps) provide information about hearing sensitivity but don’t reflect how well you function in noisy environments. Speech-in-noise (SIN) tests help audiologists understand how loud speech needs to be compared to noise for it to be intelligible.
One commonly used SIN test is the QuickSIN. It consists of a series of sentences, starting with minimal background noise (the control sentence). With each repetition, the background noise increases. The test takes just two minutes to administer.
Cognitive Screening
Cognitive screening is an essential aspect of audiology practice, especially when considering the relationship between cognitive function and hearing. Cognition refers to the ability to reason, plan, remember and direct tasks. Research has shown that hearing loss is associated with a greater likelihood of cognitive decline.
While our ears collect and convert sound waves, it’s the brain that truly allows us to ‘hear’ by interpreting and giving context to the sounds. Here’s a simplified explanation of how it works:
- Sound Wave Conversion:
- Sound waves enter the ear and cause the eardrum to vibrate.
- These vibrations are transferred to the three tiny bones in the middle ear, which amplify them and send them to the cochlea in the inner ear.
- Cochlear Processing:
- Inside the cochlea, the vibrations cause fluid to ripple, creating a traveling wave along the basilar membrane.
- Hair cells on top of the basilar membrane ride this wave. Different hair cells are tuned to different frequencies of sound.
- Electrical Signal Generation:
- As the hair cells move, their microscopic hair-like projections, called stereocilia, bend against an overlying structure.
- This bending opens pore-like channels at the tips of the stereocilia, allowing chemicals to rush in and create an electrical signal.
- Auditory Nerve Transmission:
- The electrical signals are picked up by the auditory nerve.
- The auditory nerve carries these signals to the brain, specifically to the auditory cortex.
- Brain Processing:
- The brain translates the electrical signals into sounds that we recognize and understand.
- It also discriminates relevant sounds from background noise and helps us determine the direction from which the sound is coming.
- Cognitive Interpretation:
Cognivue Thrive Cognitive Screening System
The Cognivue Thrive system is an innovative cognitive screening tool designed for use in healthcare settings.
It’s a 5-minute self-administered test based on FDA-cleared technology that adapts dynamically as the test progresses. Patients interact with the system through the CogniWheel, a simple and intuitive interface designed to make the screening process straightforward.
After completion, it generates an easy-to-understand report that assesses domains of memory, visuospatial, and executive function, along with two speed performance parameters.
Cognivue Thrive is not a stand-alone diagnostic tool, and the results should be assessed and interpreted by a licensed clinician.
Call Audiology Center of Maine at (207) 664-2123 for more information or to schedule an appointment.