Vestibular Balance Disorders (cont.)
What are the specific balance disorders and their treatments?
Meniere disease
Please read the main article on
Meniere disease for information about this
condition.
Motion sickness syndrome
Motion sickness syndrome
includes such conditions as seasickness,
airsickness, carsickness, and space sickness. Common to all of these is the
presence of a motion or visual stimulus to which a person has not adapted.
Symptoms include dizziness, increased perspiration, hyperventilation, nausea,
vomiting, decreased appetite, increased salivation, and vague discomfort
(malaise). Individual responses to the same situation are quite variable. In
severe situations, however, even the most seasoned sailor can and will get
seasick.
Motion sickness results from a conflict between the balance (vestibular) and
eye (visual) systems. For example, if a person sits in an enclosed cabin on a
ship at sea, the person will see a stationary environment but the vestibular
system will be measuring constant movement. In this case, the continued motion
of the head, as measured by the vestibular system, is not accompanied by a
commensurate motion of the visual scene. At this point, therefore, a conflict
exists between the two sensory structures, the eyes and the ears. If the person
goes outside and looks at the horizon, however, the match between the visual and
vestibular signals is in more alignment, and seasickness improves. Similarly,
when riding in a car, sitting in the front seat allows ample peripheral vision
of the surrounding stationary structures.
Motion sickness can also occur in the absence of movement. For example, an
amusement type motion simulator or cinema movies can induce symptoms of motion
sickness. In these situations, motion sickness occurs because the visual system
perceives motion but the vestibular system does not detect motion. Again, there
is a conflict between the vestibular and visual systems.
Space sickness is another kind of motion sickness, which is brought on by
active head movement in space. In fact, space sickness has been reported in 50%
of astronauts. It usually resolves within 2-3 days of space travel. As you might
expect, lack of gravity appears to be the activating force in space sickness.
The problem is thought to occur because the saccule and utricle in the vestibule
measure the effect of both linear acceleration and gravity. On earth, therefore,
a specific head movement will generate a well-defined response, while in space
(the absence of gravity), the same head movement will produce a different
response. After several days in space, however, most astronauts will recalibrate
their vestibular systems to account for the absence of gravity. But then, on
return to a gravity environment, astronauts often will develop transient motion
sickness until they can adjust back to functioning in gravity again.
Another important feature of motion sickness is the adaptation process.
Adaptation occurs with continual exposure to the motion that causes the motion
sickness. So, it is not unusual for someone to feel seasick the first day out at
sea. But then they adapt to the continued motion and no longer have symptoms of
motion sickness. On the other hand, the mal de debarquement syndrome is a
persistent sensation of motion after return to a stable environment. Thus, until
the vestibular system is able to readapt itself, individuals often report the
feeling of motion for several hours to days after disembarking from a sea
voyage.
Motion sickness can occur at any age, although its frequency increases after
age 40. Interestingly, children under two years of age appear to be highly
resistant to motion sickness. A resistance or particular response to one form of
motion sickness does not grant resistance or predict a response to other forms
of motion sickness. Psychological factors may also play a role in the
development of motion sickness.
How is motion sickness treated?
Multiple medications and home remedies have
been touted as a cure for motion sickness. Unfortunately, however, few
medications are effective, and none affords complete protection. Medications
that do not require a prescription include dramamine and meclizine (Bonine,
Antivert). Prescription medications include tranquilizers, anti-depressants, and
anti-nausea medications. Scopolamine is used as a patch
scopolamine (Transderm Scop) applied
to the skin behind the ear. Scopolamine patches are safe and effective and can
provide protection for up to three days. In the elderly, however, they can cause
psychological problems as side effects.
All motion sickness medications work by diminishing activity at the
vestibular center (nucleus) in the brain. They thereby diminish the potential
for eye-balance (visual-vestibular) conflict. Motion sickness is usually a
self-treatable problem. In severe and progressive cases, however, medical
evaluation should be undertaken.
Next: Vestibular migraines »
 |
 |
From the Doctors at MedicineNet.com  |
|
|
- promethazine, Phenergan - Explains the medication promethazine (Phenergan), a drug used to prevent motion sickness, nausea or vomiting, itching associated with allergies or for sedation. Source:MedicineNet
- CT Scan - CAT Scan / CT Scan (Computerized Axial Tomography) information. Learn what a CAT Scan is, why it is performed, risks, and how to prepare for a CAT scan Source:MedicineNet
- MRI (Magnetic Resonance Imaging Scan) - Medical information on magnetic resonance imaging (MRI) used in detecting structural abnormalities of the body. Learn uses, risks, and how to prepare for an MRI scan Source:MedicineNet
- Read 63 more Vestibular Balance Disorders related articles ...
|
| |
|
Specialty RSS
Slideshows