The vagus nerve is actually two nerves, both of which run from the brain stem and branch out separately, down the body, across the abdomen and to the main organs such as the heart and stomach. Disorders of the vagus nerve are often also called 10th cranial nerve disorders and they can have a variety of different effects upon the human body.
The vagus nerve is directly responsible for a number of bodily functions, such as breathing, maintaining digestive function, keeping the brain up to date with what we have eaten and/or digested and monitoring the heart beat to keep it regular. Any disorders of the vagus nerve can affect these functions, but some effects are more common than others. For example, if there is pressure upon the vagus nerve, or it is stimulated for any reason then the result is usually unconsciousness, clammy, cool skin and nausea. This is because when stimulated, the vagus nerve causes the heart to slow down and blood pressure levels to drop considerably. While this might appear to be a negative, the vagus nerve is sometimes stimulated to treat people with severe depression or epilepsy conditions.
Vagus nerve disorders are tested for using the same measures as disorders of the 9th cranial nerve are too. Both these nerves affect swallowing, language and the gag reflex. A medical professional will usually touch the back of the tongue to see if the gag reflex is present as well as observe the uvula and the back of the throat when the person talks. If there is anything unusual with these processes then this poses further evidence for a 9th or 10th cranial (vagus) nerve disorder.
Those suffering from congenital (present from birth) vagus nerve disorders may require breathing apparatus, pacemakers to help with maintaining a regular heart beat and gastronomy feeding tube insertion, so that they can bypass having to swallow. They may also need to follow very rigid feeding time schedules because the vagus nerve is unable to relay to the brain whether digestion has finished and the person is hungry again. As you can see, vagus nerve disorders can be particularly devastating and patients often require a lot of specialist care.
There are some vagus nerve disorders that come about during mid to later life, or are brought on by trauma to the 10th cranial nerve. In this case the individual may need to readjust to life with a pacemaker or whatever other equipment is required. Of course, if the disorder is caused by temporary pressure on a part of the vagus nerve then a full recovery is possible. Anyone experiencing regular fainting spells, a difficulty eating, swallowing or talking and low blood pressure should see a specialist for a definitive diagnosis. Once this has been sought the patient will work with a specialist to get the treatment that they need and maintain a good quality of life.