Dizziness Health Article

Definition

Dizziness is a general term that describes sensations of imbalance and unsteadiness, such as vertigo, mild turning, imbalance, and near fainting or fainting. Feelings of dizziness stem from the vestibular system, which includes the brain and the parts of the inner ear that sense position and motion, coupled with sensory information from the eyes, skin, and muscle tension.

Description

Because dizziness is a general term for a variety of feelings of instability, it spans a large range of symptoms. These symptoms range from the most dramatic, vertigo, to the least severe, imbalance. Included in these feelings is fainting, which results in a loss of consciousness.

Vertigo is an acute feeling of violent rotation. People with vertigo often feel as if they are tilting or falling through space. Vertigo is most often caused by problems with the vestibular system of the inner ear. Symptoms can be brief, or may last for extended periods of time and may be accompanied by changes in pulse and blood pressure, perspiration, nausea, and a type of rapid eye movement called nystagmus.

Mild turning is a less violent type of vertigo. People with mild turning are still able to function in normal daily routines. However, a feeling of turning may continue for weeks. Mild turning is usually a symptom of inner ear dysfunction. It may also result from transient ischemic attack, or a lack of blood flow to the brain. People who have suffered from strokes may feel mild turning for periods of time. Mild turning may also be associated with multiple sclerosis, AIDS, or head trauma.

Imbalance is a feeling of instability or floating. It is associated with many general medical problems such as the flu or infection. Imbalance can also be associated with arthritis, especially in the neck, or another neurological problem.

Fainting is a sudden loss of consciousness and near fainting is a feeling of extreme light-headedness with a sinking or falling feeling. Vision usually becomes hazy or dimmed and the extremities become weak. Both fainting and near fainting are caused by lack of blood flow to the brain. Anything that causes a rapid drop in blood pressure, such as a heart attack or an insulin reaction in a diabetic, can result in fainting or near fainting. Panic attacks that cause a person to exhale a lot of carbon dioxide can cause fainting or near fainting.

Vestibular system

The vestibular system is the sensory system located in the inner ear that helps the body to maintain balance. Balance in the human body is coordinated by the brainstem, which, with speed and precision, collects information from other parts of the brain and sensory organs throughout the body. It is the brainstem that sends neurological instructions to the muscles and joints. The sensory organs that play critical roles relaying information to the brain-stem include the skin, eyes, muscles and joints, and the vestibular system in the inner ear. Dizziness may result with dysfunction in any of these components or in the nerves that connect them.

Brain

The cerebellum, which is responsible for coordination and the cerebral cortex, provides neurological information to the brainstem. For example, the cerebellum is the organ that informs the body how to shift weight when going down a flight of stairs and how to balance on a bicycle. These processes are accomplished without conscious thinking.

In order to maintain balance, the brainstem depends on input from sensory organs including the eyes, muscles, joints, skin and ears. This information is relayed to the brainstem via the spinal cord. The combined neurological receptor system, which involves the brainstem, spinal cord, and sensory organs, is called the proprioceptive system. Proprioceptive dysfunction may result in dizziness, and people with problems with their proprioceptive system may fall often. Additionally, as people age, problems with proprioception become more common.