The Inner Ear

The Inner Ear

The inner ear which contains the a very important part of the hearing mechanism. This fluid-filled, snail-shaped cochlea purpose is to translate incoming sound waves into electrical signals so that the brain can understand its surroundings. The cochlea which is a Latin word for snailed-shell is a coiled, tapered tube containing the auditory branch of the inner ear. Its core component is the Organ of Corti, that is a cellular layer sitting on top of the basilar membrane for the sensory organ of hearing. The tube of the cochlea is divided into three chambers (upper, middle, and lower) that spiral around a bony core, the scala vestibuli the upper chamber, scala media the middle chamber or cochlear duct and the scala thmpani the lower chamber. The inner ear also contain a structure

called the vestibular labyrinth, which assists your sense

of balance (Olsen, W, Ph. D, 2003).

The vestibular labyrinth is used by the brain to determine where the head is in poportion to gravity and if the head or body is turning. By doing so, this keeps objects in focus when the head is moving. Joint and muscle receptors also are important in maintaining balance. The brain receives, interprets, and processes the information from these systems that control our balance. In order for you brain to maintain a sense

of balance, it must coordinate information from the eyes, musculoskeletal nerves and inner ear. The brain sends signals to the muscles all through the skeletal system on how to react and keep the body positioned upright and balanced. But if the central nervous system signals are not being processed and the messages are sending mixed messages, than the body can experience a loss of balance.

Balance problems can occur from anywhere in this complex system that is made up of the eyes, musculoskeletal nerves and vestibular labyrinth. Head injury, disorders of blood circulation affecting the inner ear or brain, certain medications, and aging may change our balance system and result in a balance problem. Individuals who have illnesses, brain disorders, or injuries of the visual or skeletal systems, such as eye muscle imbalance and arthritis, may also experience balance difficulties. When balance is impaired, difficulty with maintaining orientation will set in. Some of the symptoms a person with a balance disorder may experience are a sensation of dizziness and/or vertigo (Wilipedia, 2006).

The vertigo usually refers to the sensation of spinning or whirling that occurs as a result of a disturbance in balance (equilibrium). It also may be used to describe feelings of dizziness, lightheadedness, faintness, unsteadiness and is often used, incorrectly, to describe a fear of height. Vertigo should not be confused with dizziness. Dizziness is an unpleasant feeling of light-headedness, giddiness or fuzziness often accompanied by nausea. The sensation of movement is called subjective vertigo and the perception of movement in surrounding objects is called objective vertigo. Vertigo is one of the most common health problems in adults. According to the National Institutes of Health (NIH), about 40% of people in the United States experience feeling dizzy at least once during their lifetime. Prevalence is slightly higher in women and increases with age.

Vertigo

Vertigo, sometimes being called a headrush effects may be slight. symptom of an underlying harmless cause, such as in benign positional vertigo (BPPV) or it can suggest a more serious problem. These include drug toxicities, strokes or tumors (though these are much less common than BPPV). Benign positional vertigo is a condition caused by problems in the inner ear. Although its cause is not certain, it is most likely due to a build up ofcalcium in the semicircular canals of the inner ear (Housner, L, 1997). Vertigo is a symptom that can be associates with different diseases. It is classified into one of two categories depending on the location of the damaged vestibular pathway. These two categories are peripheral vertigo (can be caused by BPPV) and central vertigo. The peripheral vertigo orgins is felt by physicans to be more severe than central vertigo, by having affect the inner ear or the vestibular division of the acoustic nerve, always associated with nystagmus, which is a rapid involuntary rhythmic eye movement and occasionally hearing loss or tinnitus (ringing of the ears). Other disorders affect the peripheral labyrinth, including acute otitis media, chronic ear infection, hereditary degenerative disorders of the end organ, and local tumors. Conditions such as a vertebrobasilar transient ischemic attack (TIA) or focal ischemic stroke of the end organ, particularly in an elderly patient, are often cited as a cause of vertigo. Such isolated involvement is difficult to document, and vertebrobasilar insufficiency should not be diagnosed without associated brainstem symptoms and signs (iVertigo.net, 2006).

Peripheral Vertigo

Peripheral vertigo is characterized by sudden onset, episodic and objective feeling of swaying. Cochlear symptoms, nausea and vomiting are characteristics of peripheral vertigo. Vertigo with abnormal caloric response together with hearing loss signifies a peripheral pathology. "It is an unpleasant truth that patients with vertigo get little justice from a clinician" says, Dr. Debasish Burman. The underlying cause is not that we do not know the subject, but we presume that little can be done to these distressed patients and we have nothing in our hand but a vague assurance and consolation to offer.

Meniere's Disease also known as "Meniere's Syndrome" was first described by French physician "Prosper Meniere" in 1861. The symptoms of Meniere's are variable; not all sufferers experience the same symptoms. However, "classic Meniere's" is considered to consist of four symptom: Periodic episodes of rotary vertigo; Fluctuating, progressive, unilateral (in one ear) or bilateral (in both ears) hearing loss, often in the lower frequency ranges; Unilateral or bilateral tinnitus (the perception of noises, often ringing, roaring, or whooshing), sometimes variable; A sensation of fullness or pressure in one or both ears (Wilikepia, 2006).

Some of the symptoms of Meniere's disease are having a feeling of fullness of the ear; symptoms may come and go with changes in hearing, occur during or just before attacks, or be constant. There may also be an intermittent hearing loss early in the disease, especially in the low pitches, but a fixed hearing loss involving tones of all pitches commonly develops in time. Loud sounds may be uncomfortable and seem distorted in the affected