The rocks in your head
As a physical therapist with a specialty in vestibular rehabilitation and vertigo, I frequently hear patients say that the doctor told them they have a problem with the “rocks” in their head or that their “crystals are out of whack.”
These may sound like strange complaints, but to me, it can be normal, everyday conversation. These “rocks” and “crystals” that people talk about do exist. They can cause a lot of problems if they are not settled where they are supposed to be within the vestibular system.
Before we discuss the problems they can create, and how physical therapy can help, let’s take a look at the vestibular system and what these crystals do.
The vestibular system is a sensory system located in the inner ear. It is situated close to the hearing system and shares a common nerve connection. You have one on the left and one on the right.
Each side includes the otolithic organs (utricle and saccule) and three semicircular canals. The role of the vestibular system is to tell you where your head is in space in the absence of any visual stimuli, as well as help coordinate eye movements and maintain balance. If you are in a car and close your eyes, you can tell if the car is moving forward or backward because of the input from the vestibular system. It also lets you know if you are turning, or moving up or down.
The three semicircular canals detect rotary or angular movements. They have fluid that moves through them in response to changing positions.
The otolithic organs detect linear movements and are gravity sensitive. Within these organs, the crystals come into play. In order for the utricle and saccule to detect motion, they contain crystals that sit in a gel matrix to make it heavier. This makes it more sensitive to small changes in position. The crystals are composed of calcium carbonite and are supposed to be there. The problem with the crystals is when they migrate outside of the gel matrix and float through the fluid in the canals.
Imagine fluid moving through a pipe. If that pipe is completely clean with no debris, the fluid moves smoothly with no interruption. Now imagine there is a pebble in the pipe. As the fluid moves over that pebble, it creates a ripple. This is similar to what happens in your vestibular system if one of your crystals gets into the semicircular canals. Instead of having a nice, fluid movement, the stray crystal causes a ripple. Because that ripple only happens in one vestibular system (left or right), the brain receives conflicting messages. One side is smooth, and the other side has a ripple. Your brain likes symmetry, so when it gets this mixed message, it creates the symptom of room-spinning dizziness. This symptom is commonly referred to as vertigo, and the specific condition from the above example is benign paroxysmal positional vertigo.
This is the most likely culprit when I hear people say, “If I turn my head too fast or roll over in bed, the room starts spinning.” In the most common type, the symptoms usually last less than 30 seconds. As long as the provocative position/maneuver is avoided, most people can keep their symptoms away.
A variety of things can cause the crystals to wander into the canal and cause BPPV. Head trauma or whiplash-type injuries can dislodge the crystals. People with diabetes seem to have a high prevalence of BPPV. Most occurrences do not have a specific known cause. What is known is that once someone has had BPPV, they are more likely to get it again. Sometimes the BPPV resolves on its own. The crystal may dissolve or find its way out of the canal and back into the otolithic organs through normal head movements. For people whose symptoms don’t dissipate on their own, there is another option.
Physical therapy is very successful at treating BPPV. Through a thorough assessment of symptoms and objective measures, BPPV can be diagnosed and treated with positioning maneuvers designed to move the crystal out of the canal and back to where it belongs. Once that crystal is out of the semicircular canal, the symptoms of vertigo are relieved. Physical therapy can also help address balance impairments that can often coincide with vertigo.
