Electrocephalogram (eeg)

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The nervous system is unique in the vast complexity of thought processes and control actions it can perform.

It receives each minute literally millions of bits of information from the different sensory nerves and sensory organs and then integrates all these to determine responses to be made by the body.


The Basic Functional Unit of the brain is NEURONS..The central nervous system contains more than 100 billion neurons.Incoming signals enter this neuron through synapses located mostly on the neuronal dendrites, but also on the cell body.A special feature of most synapses is that the signal normally passes only in the forward directionNEURONSSYNAPSES

The ELECTROENCEPHALOGRAM (EEG) is recording of the electrical activity of the brain from the scalp.Another name for EEG is brain wave testThe first recordings were made by Hans Berger in 1929.But similar studies have been done at earlier years around 1870s in animals.The wave forms recorded are thought to reflect the activity of the surface of the brain and cortex.


The brain's cellsproduce tiny electrical signals when they send messages to each other. During an EEG test, small electrodes are placed on to scalp.They pick up brain's electrical signals and send them to a machine called an electroencephalograph.They records the signals as wavy lines on to a computer screen or paper.CONTINUEBrain cellscommunicatewith each other by producing tiny electrical signals,calledimpulsesAn EEGmeasures this activity. The test is done by a EEG specialist in doctor's office or at a hospital or laboratory.They will be asked to lie on back on a bed or in a reclining chair.Flat metal disks called electrodes are placed all over scalp.HOW THE TEST IS PERFORMED


The disks are held in place with a sticky paste.The electrodes are connected by wires to a speaker and recording machine.The recording machine changes the electrical signals into patterns that can be seen on a computer. It looks like wavy lines.The patient will need to lie still during the test with their eyes closed because movement can change the results.HOW THE TEST IS PERFORMED

Wash hair at night before the test going to perform.Do not use any oils, sprays, or conditioner on hair before this test.Avoid all food and drinkscontaining caffeine for 8 hours before the test.Patient may need to sleep during the test.If so, patient may be asked to reduce their sleep time the night before.But to reduce the sleep do not drink any caffeine containing material, energy drinks etc..HOW TO PREPARE FOR THE TESTThe electrodes may feel sticky and strange on scalp but should not cause any other discomfort.Patient should not feel any discomfortduring the test.HOW THE TEST WILL FEEL

This procedure is completely painless and can be performed without shaving any of patients hair.EEG can help diagnose a number of conditions, including epilepsy, sleep disorders and brain tumors.Normal brain waves occur at a rate of up to 30 per second, but in someone with epilepsy - the EEG may show bursts of abnormal discharges in the form of spikes and sharp wave patterns.CONDITIONS SHOULD BE DIAGNOSEDOTHER CONDITIONSSleep disorders (such as narcolepsy)Head injuriesBrain infectionBrain hemorrhageAlzheimer's diseaseDegeneration of brain tissueMetabolic conditions that affect brain tissueHormonal conditions that affect brain tissueCertain disorders of the central nervous systemStrokeBrain tumorBrain death.

Dementiaa group of symptoms that are responsible for thedecline of brain function.Vertigo the sensation that you are moving even when you are standing still.Brain abscessa pus-filled swelling in the brain that is caused by an infection.Encephalitis inflammation of the brain tissue thatis sometimes caused by an infection.Cerebral infarct brain tissue that has dieddue toa blockage inblood flow.

OTHER CONDITIONSAn abnormal EEG doesn't automatically mean that patient have epilepsy.The EEGs of babies and young children can often record irregular patterns that don't mean anything, or the irregularities may flag previously diagnosed neurological conditions such as cerebral palsy.


How EEG can interpreted with diseases ????????

RESULTSAbnormal results on an EEG test may be due to:Abnormal bleeding (hemorrhage)An abnormal structure in the brain (such as abrain tumor)Attention problemsTissue death due to a blockage in blood flow (cerebral infarction)Drug or alcohol abuseHead injuryMigraines (in some cases)Seizure disorder (such as epilepsy orconvulsions)Sleep disorder (such asnarcolepsy)Swelling of the brain (encephalitis)

ABNORMAL RESULTSThe procedure is very safe. The flashing lights or fast breathing (hyperventilation) required during the test may trigger seizures in those with seizure disorders. The health care provider performing the EEG is trained to take care of patient if this happens.