Table of contents:
1- What are neurophysiological studies under sedation?
2- What do they consist of?
3- Why are they performed?
4- How is the preparation?
5- What does it feel like during the tests?
6- Meaning of the results
What are neurophysiological studies under sedation?
They are studies that allow a thorough evaluation of nerve responses, without causing pain or discomfort to the patient.
What do they consist of?
Neurophysiological studies can be Neurography, evoked potentials or electromyography.
– Neurography: electrical stimuli that study the functioning of a nerve.
– Evoked potentials: repetitive electrical stimuli (in batches of 500 stimuli) to determine the functioning of a nerve, its entry into the medulla and its response in the cerebral cortex.
– Electromyography: this is a study of muscle contractions using a needle-shaped electrode.
Why are they performed?
There are tests used to study the sacral roots, the pudendal nerves or the pelvic floor. To do so, they require multiple electrical stimuli, either on the genitals or on the sphincters.
These tests can be uncomfortable, painful and generate some modesty in the patient. For this reason, it is advisable to perform them under sedation, either conscious or deeper, depending on the case.
On the other hand, in addition to the patient’s pain, sedation allows more reliable results to be obtained, since the muscular contractions produced by the lack of relaxation make subsequent interpretation of the results very difficult.
In other words, they are performed under sedation in order to obtain the maximum performance of tests that can be, in many cases, uncomfortable and painful.
A common example is colonoscopy. The first ones were performed without sedation but, by changing this aspect, it was possible to complete all endoscopies and increase their diagnostic efficacy.
What is the preparation like?
As in any sedation process, the ideal is to fast for at least 6 hours for solid food and 2 hours for water.
Before starting the treatment, a vein in the hand or arm is cannulated and a drug is administered to sedate the patient. The ideal is to perform a conscious sedation, since the patient does not feel discomfort or pain but at all times remains breathing spontaneously.
These tests are used to study the sacral roots, the pudendal nerves or the pelvic floor.
What does it feel like during the tests?
If the study of sphincter and genital alterations is done without sedation, the patient will feel anxiety, fear, embarrassment. If the study is performed under adequate sedation, the patient will not feel any discomfort, or in any case, he/she will be able to tolerate it perfectly.
Meaning of the results
The result of these tests determines whether or not there are lesions at the level of the nerves, the nerve roots of the medulla or the muscles. That is to say, when normal results are obtained, it means that the conduction of the nervous stimulus, and its reception in the medulla and the brain, is normal.
However, it should be noted that, even if the results are normal, the patient’s pain may persist, as there are multiple causes beyond nerve damage.