The part of the inner ear dedicated to balance is primarily made up of the three semicircular canals which are positioned on differing angles as well as structures called the utricle and the saccule.
The three semicircular canals are filled with fluid and when head movement occurs movement of the fluid stimulates sensory hair cells. Long story short, the brain makes sense of this information and allows us to sense movements up and down, side to side as well as tilting and combinations of these.
The ends of the semicircular canals connect to a structure called the utricle and the utricle is then connected to the saccule.
Whilst the semicircular canals give the brain information about head movement, it is the sensory hair cells within the utricle and saccule that give the brain information about head position when it is not actually moving. The utricle provides information about movement in the horizontal plane such as acceleration in a car and the saccule gives information on vertical acceleration such as going up in an elevator.
The brain of course is constantly processing all of these varying sources of information to give a unified sense of our position and movement of our body. Our brain also will add into this mix sensory information from the eyes (vision) as well as sensory information from the joints and muscles of the body. Interestingly from a chiropractic perspective there is a dense supply of these “joint position sensors” located in the upper cervical spine (neck). It is in this way that sometimes joint problems in the upper neck can have a negative impact on balance.
When the brain processes the information it is receiving from the inner ears, the eyes as well as joint position sensors in the body, and when this information all “agrees and make sense” to the brain, everything is perceived in the world to be as it should be. Dysfunction however can occur in either of these sources and problems can arise.
Seasickness is a classic example where the rocking of the boat is not making sense with visualising a stable horizon. Imbalance and nausea are the result.
Dysfunction in the balance system can range from a mild sense of imbalance or giddiness through to a completely debilitating case of vertigo where all the patient can do is close the eyes and lie still until the sense that the world is spinning stops.
When the source of dysfunction causing a loss of balance is primarily in the cervical spine because of joint stiffness and altered joint movement leading to an aberrant
sensory input, a short course of treatment to improve mobility and reduce inflammation is often sufficient to gain relief. Sometimes however the problem is more severe and is related to issues in the middle ear. One of the most interesting of these conditions I feel is that of Benign paroxysmal positional vertigo or BPPV for short.
BPPV is one of those rare conditions where there is thankfully a simple test to confirm its diagnosis (called the Dix-Hallpike test) and then a series of head and body movements (called the Epley manoeuvre) which will reposition debris in the posterior semicircular canal to remove the source of irritation causing the vertigo.
The Epley manoeuvre has a high success rate in treating BPPV.