Tests for diagnosis in neurology
It is recorded by placing a number (generally 21) of small disc like electrodes which are attached by means of wire to the main machine. These discs measure the small amount of electrical activity from the part of brain which is lying below that disc electrode. This electrical activity of brain is represented on the screen (or the paper in cae of a print) and is analysed. The most common indication for doing an EEG would be convulsions (=fits/ seizures/ epilepsy). Apart from that there are various other indications to do it. Generally it takes about 30-45 minutes to complete a test. Sometimes it may be done for a prolonged period ranging from few hours to a day or two. Video EEG is a modificatin of EEG in which a synchronized video is recorded along with the EEG.
CT scan :
It is a type of test which uses X-rays to capture anatomy of the internal structures of the body part. The X-rays are passed through the body part and are collected at the other end to gather information about the fraction of it which has been absorbed. This information is then analysed with the help of complicated computerized algorithms and final out put is the pictures that we see of the internal structures.
MRI scan :
Similar to CT scan it gives us information about the internal structures of the body part which is scanned. It is much more elaborate and gives more resolution. There is no risk of radiation exposure as in case of CT scan. However it is more expensive, time consuming and not easily available. Also patients with metallic implants can not undergo MRI scan.