by Neil Bauman, Ph.D.
January 24, 2016
A man wrote,
I am a 29 year old male. 11 days ago, I shot about 60 rounds from an AR-15 (.223) rifle, outdoors, with foam ear plugs in both ears. I might not have had the plugs in as deeply as they could go, but the sound was very much muffled, and I experienced no pain while shooting. I only fired the gun for a few minutes total.
After I took off my ear plugs, my hearing was horribly muffled and distorted in my left ear. It remained that way for several hours before mostly coming back. Tinnitus and a strange feeling remained a couple days later, so I made an appointment with my ENT. He gave me Prednisone and a hearing exam, which revealed ~30 dB hearing loss in my left ear at 4,000 Hz, but mostly normal everywhere else.
It’s been 11 days since I shot the gun. I still have some tinnitus, which is pretty quiet. My tinnitus seems to be low in frequency, maybe around 1,500 Hz. I was wondering if you might be able to explain some of these symptoms I’m having as they are very strange and hard to nail down.
1. A strange feeling of “difference” between my right and left ears, almost like my left ear has something in it, or the pressure is slightly different. Is this a side effect to the hearing loss?
2. My own voice, especially when speaking low, sounds different in my left ear, and seems to buzz or vibrate my left ear while I’m talking.
3. There is a strange, metal-like amplification or echo of sound that seems to occur in my left ear when touching my ear, rubbing my ear, or talking. It almost sounds like my tinnitus is being temporarily exacerbated in short bursts as something impacts my ears. Could this be a function of my low frequency tinnitus? Does low frequency tinnitus produce different sensations than high pitched tinnitus?
I’m really unhappy with the current state of things and can’t believe all this came about just from shooting a gun with ear plugs on. Can you explain what’s going on with my ears?
First, like you, I think you didn’t have your ear protectors inserted properly. Thus they didn’t do their job properly. Hence you had that muffled feeling when you took them out after shooting the rifle. Another possibility is that you didn’t have ear protectors with the correct protection factor.
Ear protectors come in various protection factors ranging from 10 to about 35 dB. For shooting rifles with their sudden sharp sound, you want a protection factor of 30 or so.
The fact that your left ear was damaged more than your right ear indicates to me that you are right handed and shoot right-handed. When you shoot right-handed, your left ear is facing forward and thus gets more of the muzzle blast than your right ear which is more facing back. That’s probably why your left ear got the worst of it. And it could have been acerbated if you did not have the ear protector properly seated in your left ear.
Your ears are most sensitive to sound at 4,000 Hz. Thus, it is not surprising that you now have the typical “noise notch” at 4,000 Hz indicating that you have damaged that ear from exposing it to excessive noise.
In answer to your question No. 1, when you have a sudden hearing loss like the one you experienced from a rifle blast, you have a feeling of pressure in that ear and /or a feeling that everything is muffled. Different people describe this same feeling differently. This is really a temporary hearing loss and is called a temporary threshold shift.
Typically, your hearing returns to normal in a matter of minutes, hours or days depending on the intensity of the sound and how robust your ears are. Sometimes, not all hearing returns and you are left with a permanent threshold shift, meaning you now have some degree of permanent hearing loss.
In answer to question No. 2, the sudden loud noise “bruised” your ear (to use a fancy medical term), and so all sorts of strange things may appear. And just like real bruises, it takes time for your ears to get back to normal. With ears it can be 2 or 3 months or longer, so you have to be patient. Again, the worse the damage, the longer it takes to heal.
Your question No. 3 is very interesting. You wonder why just touching or rubbing your outer ear generates various strange sensations.
Probably what is happening is that other nerves apart from your auditory nerves—called the non-classical pathways—have been super-stimulated and now are also sending messages to your brain.
Here is an excerpt from the 7th (soon to be published) edition of my tinnitus book that explains what is happening and why you get such sensations.
So what exactly are the non-classical auditory pathways? The auditory nervous system consists of two parallel pathways. The first is called the classical pathway and the second goes by the name of non-classical pathway (otherwise called the extra-lemniscal pathway). These two pathways process information differently and go to different parts of the brain.
The classical pathway is strictly for auditory information. It is narrowly tuned to sound frequencies. It processes auditory information as this information moves from the cochlea to the primary auditory areas in the brain.
In contrast, the non-classical pathway is more broadly tuned, is more diffusely organized and is more plastic as compared to the classical pathway. The non-classical pathway receives its information not only from the ear, but also from other sensory organs of the somatosensory system such as the tactile (sense of touch/feel) system and the visual system.
The association between the auditory and the non-classical (somatosensory) pathways occurs due to connections in the dorsal cochlear nucleus of the brain. There multitasking neurons receive signals from both the auditory and the somatosensory pathways.
Because there can be this association between the auditory pathways and the non-auditory pathways, when abnormal interactions occur between the various systems connected to these pathways, the result can be somatic tinnitus.
This explains the connection between various forms of “weird” tinnitus that affect the other senses. It also explains how involving another sense can change your existing tinnitus.
I think this is what you are experiencing, and will continue to experience while your ears are still “bruised”. During this time you want to protect your ears from overly-loud sounds. If you expose them to more loud sounds, you are just “whacking the bruise” and its going to take a lot longer for your ear problems to fade away.
The good news is that give it time and most likely your ears will return to normal, but you’ll probably be left with the noise notch hearing loss at 4,000 Hz.
You can get your own copy of the new, expanded 7th edition of “When Your Ears Ring” when it comes out for the same price as the current 6th edition—just $22.95 plus shipping if you act now. The day the new 7th edition comes out (sometime in February, 2016), the price will immediately go up. So save now. Click on “When Your Ears Ring 7th Edition” to order the new 7th edition and it will be shipped to you as soon as it is available.