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2 The function of the sense of balance and the development of the DSB

The task of the sense of balance is to keep the whole body in the right position. The hair-cells in the broader parts of the semi-circular canals respond to the accelerating or decelerating rotation movement. The hair cells in the utricle and saccule respond to the gravity field and to the acceleration of a rectilinear movement. The sense of balance is part of the sense of movement and position, which also includes receptors in muscles, tendons and joints. (Duodecim)

The sense of balance controls all muscles in the human body, both the voluntary and the involuntary ones all the time. When the sense of balance functions as it should, gravity takes the small calcium stones from the semi-circular canals to their jelly-like bed after the body has stopped moving or when other stimuli disappear. This makes the body and its muscles relax.

The DSB is caused by the small calcium stones, which remain in the semi-circular canals even after the body's motion or other stimuli have stopped. This is probably caused by differences in the specific weight of the stones or variation in the amount of salt in the fluid in the canals. If there is some malformation in the canals it may also hinder the movements of the calcium stones.

According to Doc. Rahko there isn't necessarily one factor that disturbs the sense of balance but a pile of different factors. Their total effect may exceed the adapting capacity of the body and thus develop into recognizable symptoms. One factor is enough when it's strong enough. On the other hand, a tiny additional factor may sometimes reveal a problem in the function of the body. Doc Rahko estimates that benign positional vertigo is the main cause for 80 % of all disturbances in balance. The effective correcting mechanism of the brains is able to compensate smaller disturbances of the sense of balance and thus there won't be any recognizable symptoms although the dysfunction influences the body in one way or another all our lives.

As I already mentioned the old concept of "Benign positional vertigo" became too narrow to be used with the symptoms presented on these pages. In addition, it's questionable to define any type of vertigo to be "benign". Otolith-canal-irritation is basically a precise concept, but I prefer "the dysfunction of the sense of balance" with the abbreviation "the DSB", because it's easier to understand.