For millions in the deaf and hard of hearing community, early detection and intervention are critical to effective treatment options in both young and older communities. But what happens if your hearing loss cannot be detected? That is the reality for those struggling with “Hidden hearing loss”, a condition in which many may experience trouble hearing when background noise is present even though their audiograms document hearing limits well within normal levels. For audiologists and patients, there is still much to learn about this emerging condition. With similar auditory processing disorders such as Obscure Auditory Dysfunction (OAD) and King-Kopetzky Syndrome, more information is required to make detection and treatment of cochlear synaptopathy more precise for those struggling with the condition.
Cochlear Synaptopathy is referred to as “hidden hearing loss” due to patients suffering from difficulty hearing or communicating, especially when background noise is present, and often having normal audiograms showing healthy hearing thresholds with no obvious cause for their hearing difficulty. This is especially frustrating with older patients who can still hear conversations in quiet surroundings easily and have shown a modest deficit in hearing thresholds, but at a rate that is not agreeable with their hearing complaints.
As Dr. James Hall, an audiologist and professor in the Osborne College of Audiology at Salus University, explains “Based solely on the results of pure tone audiometry and probably a few simple speech recognition tests, the audiologist may confidently tell the patient and indicate in a formal report that ‘our testing shows that you have normal hearing.’ However, in most cases, this statement is inaccurate, misleading, and of no comfort to patients and their families who are convinced that they have a real and serious hearing problem.”
The correct response Hall contends is for audiologists to suggest a comprehensive evaluation of a patient’s hearing, including tests that measure how their ears and brain process sound. This is due to the root cause of Hidden Hearing Loss: the neural degeneration of synaptic connections between hair cells and sensory neurons while hair cells within the ear survive. Previously believed that these hair cells were the most fragile, new studies within animal models have found that their peripheral synaptic connections are the most vulnerable, and that cochlear nerve synapses can be destroyed by age or induced noise causing hearing loss and tinnitus even when the hair cell survives.
Due to recent and exciting discoveries regarding Cochlear Synaptopathy, there is still much to be learned about the condition before concrete plans to address the dysfunction are available. Dr. Hall is hopeful that further studies can chart a path forward in the future, stating they are “clearly warranted to provide clinically valuable information about the disorder’s prevalence, prevention, and management. Audiologists must play a leading role in learning more about the diagnosis of and intervention for hidden hearing loss.”
If you believe you are suffering from Hidden Hearing Loss, seek out the medical advice of a hearing health professional to have a comprehensive hearing evaluation, especially if symptoms persist after a basic hearing test has come back with healthy hearing thresholds.