The nervous system is a set of organs and structures, made up of nervous tissue, that are responsible for collecting and processing signals and then controlling and organizing the rest of the organs, and thus achieving correct interaction between the person and their environment.
The science in charge of studying this complex structure is neurology. Which tries to evaluate, diagnose and treat all types of disorders of the nervous system. For evaluation and diagnosis tasks, a series of neurological tests have been developed that allow medical personnel to observe the operation of said system.
Neurological tests or examinations are performed with the purpose of examining whether the patient’s nervous system is functioning correctly. These tests can be more or less exhaustive depending on what the doctor is trying to evaluate, in addition to the age or condition of the patient.
The importance of these tests lies in their usefulness in detecting possible alterations early and thus eliminate or reduce, as far as possible, possible complications that may appear in the long term.
The first tests that the clinician performs are physical tests, in which, through the use of hammers, tuning forks, flashlights, etc. the nervous system is tested.
The aspects that are evaluated during this type of neurological examination are:
However, in the event that there is suspicion of a possible alteration in any of these aspects, The medical professional has at his disposal a large number of specific and very revealing clinical tests when diagnosing any type of neurological problem.
Types of neurological tests
There are more than a dozen tests to evaluate the state of the nervous system, any of them will be more or less useful depending on what the clinician wants to look for.
Cerebral angiography, also known as arteriography, is a procedure to locate possible vascular singularities in the brain These irregularities range from possible brain aneurysms, blood vessel blockages or strokes, to brain inflammation or malformations in the veins of the brain.
To detect any of these abnormalities, the doctor injects a radiopaque substance into one of the cerebral arteries, thus making any vascular problem in the brain visible on x-rays.
2. Electroencephalogram (EEG)
If what the doctor needs is to monitor brain activity, the electroencephalogram can be their reference test. During this test, a series of electrodes are placed on the patient’s head. These small electrodes transport the electrical activity of the brain to a device that reads said activity and converts it into an electrical recording trace.
In addition, The patient may be subjected to different tests in which a series of stimuli such as lights, noises or even medications are presented In this way the EEG can detect changes in brain wave patterns.
If the medical professional sees it necessary to narrow down the search or make it more exhaustive, he or she can place these electrodes directly in the patient’s brain through a surgical incision in the patient’s skull.
The electroencephalogram is very interesting when diagnosing diseases or disorders such as
3. Lumbar puncture
Lumbar punctures are performed to obtain samples of cerebrospinal fluid This fluid is analyzed to check for bleeding or cerebral hemorrhages, as well as to measure intracranial pressure. The purpose is to diagnose a possible brain or spinal infection such as those that occur in some neurological diseases such as multiple sclerosis or meningitis.
Commonly, the procedure to follow in this test begins by lying the patient on one of his sides, asking him to place his knees next to his chest. Next, the doctor locates the position between the vertebrae in the middle of which the puncture will be performed. After administering a local anesthetic, the doctor inserts a special needle and withdraws a small sample of fluid.
4. Computed tomography (CT)
This test is part of the so-called brain ultrasounds, which also include magnetic resonance imaging and positron emission tomography. The advantage of all of them is that they are painless and non-invasive processes.
Thanks to computed tomography, quick and clear images of organs such as the brain, as well as tissues and bones, are obtained.
Neurological CT can help make differential diagnoses in neurological disorders with several similar properties. In addition, it is especially effective in detecting, among others:
The test lasts about 20 minutes, during which the patient must remain lying down inside the CT chamber. For this exam, the person must remain very still while the X-rays scan their body from different angles.
The final result is several cross-sectional images of the internal structure, in this case of the internal structure of the brain. Occasionally, a contrast liquid may be introduced into the bloodstream to facilitate the differentiation of different brain tissues.
5. Magnetic resonance imaging (MRI)
Radio waves are used to obtain images obtained by magnetic resonance imaging that are generated in a device and a large magnetic field that reveal the details of organs, tissues, nerves and bones.
As in CT, the patient must remain lying down and motionless and is placed inside a hollow duct surrounded by a large magnet.
During the test, a large magnetic field is created around the patient and through a series of reactions a resonance signal is produced from various angles of the patient’s body. A specialized computer processes this resonance by converting it into a three-dimensional image or a two-dimensional cross-sectional image.
Likewise, there is also functional magnetic resonance imaging, in which images of blood flow in different areas of the brain are obtained thanks to the magnetic properties of blood.
6. Positron emission tomography (PET)
In positron emission tomography, the clinician can obtain images, in two or three dimensions, of brain activity This image is achieved through the measurement of radioactive isotopes injected into the patient’s bloodstream.
These radioactive isotopes bound to chemicals that flow through the brain are tracked as the brain performs different tasks. Meanwhile, gamma ray sensors scan the patient and a computer processes all the information, displaying it on a screen. Different compounds can be injected so that more than one brain function can be examined at a time.
PETs are especially useful when:
7. Evoked potentials
Possible sensory nerve problems can be evaluated in the evoked potential test as well as corroborating certain neurological conditions such as brain tumors, spinal injuries or multiple sclerosis.
These potentials or evoked responses calibrate the electrical signals that visual, auditory or tactile stimuli send to the brain.
By using electrode needles, nerve damage is evaluated. One pair of these electrodes measures the electrophysiological response to stimuli on the patient’s scalp, and the other pair is placed in the area of the body to be examined. The clinician then notes the time it takes for the generated impulse to reach the brain.
Other tests frequently used for the evaluation and diagnosis of neuronal disorders are:
