Hidden Hearing Loss: When You Have Good Hearing but Struggle To Hear in Background Noise
Do you feel like you can hear a pin drop from across the room, yet you struggle to hear in noisy restaurants? Well, I have good news and some not-so-good news for you.
The good news: you aren’t alone. Over 26 million people with “normal” hearing report having difficulty following conversations when the background noise is just too much to compete with.
The not-so-good news: you are probably suffering from hidden hearing loss. Please don’t shoot the messenger. And please don’t disregard my ‘from afar’ medical opinion. I typically don’t like to ‘Monday-morning diagnose’ patients, but with over 20 years in research, working with patients, and taking part in the lab where the ground-breaking studies first documented hidden hearing loss, I feel fairly confident in the diagnosis.
What is hidden hearing loss?
As we get in to our 30’s and beyond, having difficulty following a conversation in background noise is more common than you think; and is the most common complaint from patients. As the ear-to-brain connections deteriorate, this breakdown (referred to as cochlear synaptopathy) can wreak havoc in the ear and brain. The difficulty with separating what you want to listen to versus what you don’t want to hear can be very frustrating, embarrassing and devastating to you and your loved ones. Unfortunately, when someone is not able to follow along with the conversation happening around them, too many people eventually default to ‘then why bother even being there’.
If you have been told that your hearing is "normal" but you still struggle to hear in background noise, you might suffer from a common condition known as "hidden hearing loss".
The feelings of isolation, depression, fear, loneliness, embarrassment, frustration, and anxiety that are associated with hearing loss and tinnitus (sounds in the ear) are real; and are very well-documented. Perhaps you only need to look in the mirror, or at a loved one, to realize how real these emotions are. The ability to follow a conversation when multiple people are speaking, or with other competing sounds (i.e., the TV in the background, running water from the sink) is a natural cognitive (brain) ability that we take for granted until it begins to breakdown and interfere with communication with others.
As we age, (many first notice it in their 40’s and 50’s), subtle changes in the anatomy inside the ear yields significant differences and changes in the ability to hear in these ‘complex’ listening environments. And most often this difficulty is noticed long before the person’s hearing loss is detected by conventional hearing tests; hence the term ‘hidden hearing loss’. While hidden hearing loss is typically attributed to cochlear synaptopathy, some argue that central auditory processing disorder (CAPD) may be the most common cause.
Some speech cues appear to be lost on the way to the brain even though they were audibleDr. Mead Killion, 2002
Nearly all of us will experience hearing loss and/or tinnitus as we age, and most often there are tell-tale precursors to this process, although the reasons for hearing loss are complex and include several risk factors such as age, genetics, past exposure to loud sounds and medications. Regardless of the cause, it all begins with a breakdown of cellular activity in the ear that then extends deep into the brain.
Tiny ‘hair cells’ in our ears that process sound (much like the rods and cones in our eyes that perceive light, color and shape) become damaged and die off; and they do not grow back. As a result, our ears will have difficulty noticing fine differences in sounds. For example, the subtle differences between the ‘s’ and ‘sh’ sounds may become undetectable to the listener; making words like ‘see’ and ‘she’ harder to understand and distinguish. This difficulty with clarity is why so many people with hearing loss say, ‘can you repeat that’ and not ‘can you please say that louder’. Clarity and volume are not the same; and the loss of clarity impacts your life 5-10 years before you need sounds to be louder.
Once the ‘hair cells’ inside the ear are no longer working, the vast neural network that connects these cells to the brain begins to feel the impact. It is estimated that millions of neural connections from ear to brain breakdown and do not work properly at the earliest stages of hearing loss. Think of these connections as the ‘Neural Superhighway.’ Simply put, the ‘neural superhighway’ cannot manage all the ‘traffic’ of sound, e.g., the conversation you are trying to listen to versus the background sounds you do not want to listen to, if there are too many potholes!
Perhaps the scariest part about all the difficulty hearing in background noise is the silent (no pun intended!) damage that is happening from the loss of these neural connections. Hearing loss and resulting neural degeneration may lead to cerebral atrophy (aka brain shrinkage). Unfortunately, once the damage in the ears begins, the nerves will continue to be impacted and the damage becomes progressively worse with age. Therefore, most forms of hearing loss are medically defined as a progressive degenerative disorder.
With an intact auditory system (notice, I am no longer saying ‘normal hearing’), listening to others and following a conversation in background noise is otherwise simple and effortless with normal hearing. But as the system weakens, the brain will strain just to get by and hear bits and pieces of what others are saying.
The brain is responsible for many unique hearing capabilities, including:
- Selective Attention - segregating out what you want to hear from what you don’t want to hear.
- Emotional Reactions – the interaction of auditory input with the limbic/emotional portions of the brain.
- Auditory Memory – the interaction of auditory input with the hippocampal/memory portions of the brain.
- Descending Control – top-down feedback that can modulate information coming from inside the ear.
- Auditory Processing Tasks – the ability to determine where sounds are coming from (localization), locate sound in space (orientation), and recognize words and understand the conversation (recognition)
Each of these tasks relies on a vast and robust ‘neural superhighway’ of information coming from the ears. Thus, each of these tasks are adversely affected even at the earliest stages of dysfunction amongst the sensory cells in the ear.
The damage in your ears, and thereafter in your brain, is not reversible; however, treatment is designed to slow the progression and halt the impact that this damage has on your lifestyle. The medical treatment of hearing loss and tinnitus is custom prescribed to address the needs of each patient by restoring clarity, supporting the cognitive tasks mentioned above and, most importantly, allowing people to maintain high-quality communication with others – even in the noisiest situations.
If you or a loved one are feeling that ‘something has changed’ and that it is more difficult to hear and follow a conversation in noisy situations than it ‘used to be’, don’t wait. The prognosis for treatment is significantly improved when treatment starts early (said differently – the longer you wait for treatment, the worse the prognosis!).
Consult with a hearing healthcare specialist who understands that the impact of hearing loss goes far beyond the ears and impacts the brain and your life.
This was so informative! Thank you Dr. Darrow.