Neuropsychological Findings about Brain Waves with Special Reference to Epilepsy

Neuropsychologists record brain-wave activity using electroencephalograph or EEG. It is found that depending upon the activity done by an individual, the shape and pattern of the brain waves used to vary. Using EEG, investigators have uncovered a number of different types of brain waves. Alpha waves are commonly associated with a state of relaxation. Alphas change to higher frequency beta waves when a person is awake and still, but with eyes open. High-frequency gamma waves are characteristic of being awake and in a highly excited state. At the other extreme are the low-frequency delta waves that occur during deepest sleep. Also the site of origin in the brain varies with the type of wave. Alpha waves, for instance, are usually recorded in the occipital and parietal lobes. Delta waves are much more variable in location.

Other patterns of waves arise when the brain is exposed to stimuli such as sound or light or when it enters certain psychological states. Findings from different studies suggest that subtle psychological process such as a state of expectancy, can affect brain waves. Thus, brain waves shall be considered as indicators of an individual’s psycho-physiological states. However, they do not provide information about a person’s actual thoughts.

Recently, it is discovered that epilepsy is associated with highly unusual patterns of electrical activity in the brain. During each seizure, the brain is swept by sudden and dramatic changes that have been compared to electrical storms. During these disruptions, the height of the EEG can reach 5 to 20 times that of normal brain waves. In grand mal seizures, the EEG pattern in large areas of the brain reflects bursts of unusually rapid firing by individual neurons. The effect of these abnormalities on the behaviour of the victim is striking. The person loses consciousness and the body stiffens for one or two minutes before entering a phase marked by a sequence of sudden jerks and relaxation.

However, studies regarding the reason behind these uncontrolled burst of firing yet hooks more on speculations. Head injuries, exposure to chemicals, problems with metabolism etc are some of the known reasons. Still, why this happens in such cases, remains a mystery. Drugs are developed to inhibit unauthorized transmission of the nerve impulses that mark epilepsy. Drugs can reduce the attacks. In extreme cases, it is also possible to reduce epileptic seizures through brain surgery.