Inner ear problems are one source of vertigo.
Vertigo is sense of motion that doesn’t actually exist. Often it’s a spinning sensation, but it can also be a sense of bobbing, rocking, tilting, swaying, tumbling, etc – a sense of motion. This may happen suddenly, gradually, randomly, or be provoked by something as simple as rolling in bed.
Often people understand the inner ear as it relates to hearing.
But, the inner ear actually has two divisions:
One side for hearing – called the cochlea
The other side for sensing head motion and head position. This side is called the peripheral vestibular apparatus.
In terms of vertigo, we need to look at the part involved in sensing head motion and head position
The Inner Ear and Vertigo
The inner ear is located within the temporal bone of the skull. It has its own little hollowed out section within the bone so it’s not visible from the outside. If a physician looks in your ear with a special scope, the ear drum can be seen, and the space behind the ear drum can be somewhat seen as well. This space behind the ear drum is the middle ear, not the inner ear. If you know someone that has had an ear infection, it’s probably the middle ear that was affected.
The portion of the inner ear devoted to sensing head motion and head position – the peripheral vestibular apparatus – is made up of 5 sensors that provide information about the direction of head motion, as well as information about the position of the head compared to vertical.
Because we have 2 ears, this means we have 10 sensors providing a constant stream of information about our head position and head motion. The sensors are finely tuned and work together in pairs – each sensor in the left inner ear is paired with a sensor in the right inner ear. This means that normally the left and right inner ears are sending the same messages to the brain – left inner ear signals “Head tilting to the left!” and the right ear signals “Head tilting to the left!”
The brain compares the signals and if they are equal to each other, then where you are in the world begins to makes sense.
The brain will also compare the information to the visual signals – “does the world look tilted?” And it’ll compare the information to signals coming from the legs – “is weight being shifted toward the left leg?” And it will also compare the incoming signals to “did I initiate this movement or did something happen to me that is causing this sensation.”
If all the signals match then the world makes sense, and your next movement and reaction can be planned.
Your emotional reaction will also be dictated by your brain’s understanding of the situation – “should I freak out and scream, or smile and laugh because it’s fun.”
During an episode of vertigo, the brain is often receiving information from the inner ears that do not match each other. This will often be experienced as a spinning sensation. Sometimes this is a result of one sensor of an inner ear signaling too much, and in other problems there’s too little signaling. This mismatch becomes a major issue. The brain experiences an extremely difficult time understanding what is real and what is not. It’s an illusion. An illusion of movement. Just like a great magician can confuse your sense of reality, your inner ear system can warp your sense of reality as well and inside you might scream, “Where am I???!!! What’s going on???!!!!”
Let’s think of an analogy -- like a vehicle driving on the road. If all the wheels are balanced and in alignment, then you have a smooth drive. But if there’s an alignment problem the smoothness of the drive becomes affected. A small alignment problem becomes an annoyance, but a major alignment problem can create a significant issue with keeping the car driving in a straight line. And it becomes dangerous. This is a good comparison to how the information from the inner ear can become a problem in terms of vertigo – sometimes it’s merely an annoyance, but sometimes if can create significant difficulties with standing and walking. And sometimes it becomes a danger that can result in falls and injury.
Although it’s a common cause, the inner ear is not the only thing that can cause vertigo:
The information from the inner ear about head position and head motion travels along a nerve from each ear, and that nerve connects to places in the brain stem, then the next nerve signals travel up to several areas within the brain. Problems with vertigo and dizziness can arise from anywhere along this complicated web of connections.
So the sensation of vertigo is pretty straight forward: usually a spinning sensation.
But the assessment of vertigo can be quite complicated and involved due to the number of areas that can be a problem.
When we look at how the vestibular apparatus of the inner ear is working, we can’t just peak inside the skull. We need to test how the sensors are working. Sometimes that testing is enough, but sometimes we need to look at how other parts of the whole system are working together in order to find the culprit.
The results of the assessment provide evidence about what the problem is, as well as, what the problem is not. From this information, a rehabilitation plan can be developed. Sometimes that’s going to be specialized head maneuvers, and sometimes it’s going to be a rehabilitation exercise program, and sometimes a little of both. At a basic level, the goal is to either equalize the information coming from the vestibular apparatus of each ear so they match each other, or train the brain to reinterpret the mismatched signals so that it can better understand the meaning of the signals. This is called Vestibular Rehabilitation.
The good news: Vertigo is often treatable.