ELECTRICAL WAVES OF BRAIN MEASURED

Manawatu Times, Volume 64, Issue 307, 29 December 1939, Page 2

ELECTRICAL WAVES OF BRAIN MEASURED

Tests By Delicate Instrument

QNE of the most recent experiments made by the Manchester Royal Infirmary, the new medical neurological department’s work on a delicate instrument for measuring electrical waves emitted by the human brain, is now passing out of the experimental -stage, and promises definite improvements in diagnosing and treat, ing diseases of the brain (states the Manchester Guardian). The instrument, the electro-encephalograph, is already in clinical use at the infirmary. The work has been made possible financially by a gift from Mr. Robert Turner. . In 1937 the infirmary’s medical board expressed its anxiety that a department should be established to give patients at the infirmary the benefit of recent advances in medical neurology. Lack of funds compelled the infirmary to postpone it, but last year Mr. Turner became interested in the project, and decided to give £4500 to found a fellowship in neurological research. The department was established, and the first research fellow was appointed to make research into the possibilities of the clectro-encephalo-graph. This elaborate and costly instrument was then built for the infirmary, and about four months ago the new research fellow, a young student of brain diseases, was able to begin tests with it. Two or three similar instruments already exist in London, and

one was used by a London neurologist not long ago to produce evidence for a trial for homicide, to demonstrate that the accused man was an epileptic. Its principle is based on a fact that is well known to the scientist, though not to the ordinary man—the electrical activity of the human brain. Electrical waves come from the normal brain at the rate of about ten a second—not, curiously enough, when the owner of the brain is actively using it, but when he relaxes and closes his eyes. If he opens his eyes to look at anything, or even if he concentrates with his eyes shut (for instance, if he attempts a sum in mental arithmetic), the waves stop almost completely. They are extremely small waves—about fiftymillionths of a volt in size. If they can be measured they will tell a good deal about the state the brain is !n, and will offer a way of diagnosing the disease of a mental suffered. The problem is to measure them.

The electro-encephalograph now being used in the Manchester Royal Infirmary senses these minute electrical changes of the brain and amplifies them 2,000,000 to 3,000,000 times. It then reproduces them as movements of a spot of light on the face of a glass tube. Actually, it has three points of contact with the patient's head and three moving lights; thus the electrical activity at three points of the cranium can be observed simultaneously.

Electrical waves in a normal brain are most active at the back of the head, and any variation from this rule is a guide to the doctor looking for the seat of a disease. By photographing the movements of the recording light on to a band of paper the infirmary gets a complete record of the patient’s cerebral electrical change*, which can then be analysed at leisure. The normal record—showing, when the brain is re. laxed, ten waves on the paper foi very second of time—can be distinguished from the abnormal at a glance. A diseased brain will probably show a much slower rate of electrical change, perhaps two or three waves a second. Certain diseases can be picked out at once by the characteristic lines the* make on the photographic record Epilepsy has a peculiar type of wave A cerebral tumor can be located by the encephalograph, for through its pres- ( sure on the brain the tumor displaces the electrical waves from their usual A seat at the back of the head. So by ' using its “feelers” or electrodes (which are merely pads of cotton wool soaked in salty water) to locate the waves the machine can locate the tumor.

All this is done without discomfort and without any risk whatever to the patient. The patient has merely to sit in a chair while the instrument record* the state of his brain. Some of the tests which the brain specialist is compelled to use to diagnose in grave cases are very serious, even hazardous, experience* for the patient. In many cases, when the use of the electroencephalograph becomes established, these test* wil be done away with. The doctor will have a more precise knowledge of the inside of his particular patient’s head, and 60 will to some cases not have to open the head surgi. cally to find the seat of the trouble. Some, perhaps many, brain sufferers will be spared risky operations; for others necessary operations will be carried out with a better chance of success, since the surgeon will know more precisely what he has to do.