Dizziness

Our sensation of balance is derived from three major inputs to the brain. Visual input from the eyes gives the brain information regarding body position relative to the external environment. The inner ears are composed of the semicircular canals and the otolith organs. The semicircular canals detect angular acceleration of the head and the otolith organs detect linear acceleration of the head. The semicircular canals are oriented in the x, y and z planes so that head motion occurring within those planes will stimulate or inhibit electrical impulses along nerves leading from the semicircular canals toward the brain. The muscles in our legs, back and neck are always contracting and relaxing depending on the earth’s gravitational field and the contour of the terrain we find ourselves in. The constant change in the state of the contraction of these muscles is reported back to the brain. This kind of input is referred to as proprioceptive input. The brain uses the visual, inner ear and proprioceptive inputs to allow us to perceive a sense of balance.

Generally speaking, dizziness can be divided into two broad types, vertigo and dysequilibrium. Vertigo is the sensation that objects are spinning around. Dysequilibrium is a sensation such as lightheadedness, wooziness, or a feeling as though the body is being pulled toward one side. Nausea and vomiting can also occur with both sensations.

Dysequilibrium and other forms of dizziness can occur from disorders of other body systems as well.