EEG

EEG activity is the basis of the physiological function of the brain. The scope of application of EEG is no longer limited to neurological diseases, but has been widely used in the monitoring of critically ill patients in various departments, anesthesia monitoring and psychological and behavioral research. In addition to conventional EEG examinations, there are long-term monitoring of EEG, video EEG monitoring, sleep monitoring and digital computer analysis. Basic Information Specialist classification: neurological examination classification: neuroelectrophysiology Applicable gender: whether men and women apply fasting: not fasting Tips: Wash your hair with soapy water the day before the test. Stop taking sedatives, hypnotics and anti-epileptic drugs for 1-3 days. Should not be fasting, such as can not eat or vomiting should be given intravenous glucose. Do not wear nylon clothes. Patients should follow the instructions of closing eyes, blinking eyes or taking deep breaths during the examination. Normal value The normal EEG can be divided into the following four types of alpha-shaped EEG, beta-shaped EEG, low-voltage EEG, and irregular EEG. The EEG of a normal person can be divided into two types, α wave and β wave, depending on the frequency and amplitude. Clinical significance Abnormal EEG can be divided into mild, moderate and severe abnormalities. (1) The mild abnormal EEG α rhythm is very irregular or very unstable, and the blink inhibition reaction disappears or is not significant. High amplitude beta waves appear in the frontal area or in each zone. Q wave activity increased, Q activity was dominant in some parts, and Q waves were seen in each area. High amplitude Q waves appear after excessive ventilation. (2) Moderate abnormal EEG α section activity frequency slowed down and disappeared, there was obvious asymmetry. Diffuse Q activities predominate. Paroxysmal Q wave activity occurred. After hyperventilation, high amplitude delta waves appear in groups or in groups. (3) Severe abnormal EEG diffuse Q and δ activities predominate, and high voltage δ activity between slow waves. The alpha rhythm disappears or slows down. Paroxysmal delta waves appear. Spontaneous or induced high-amplitude spikes, spikes or slow-synchronized waves. There is an explosive suppression activity or a flat activity. Electroencephalogram abnormalities are helpful for the diagnosis of the following diseases: (1) Disorder-conscious diseases (sleepiness, coma, etc.). (2) Intracranial space-occupying lesions include brain tumors, brain abscesses, brain metastases, and chronic subdural hematomas. (3) Epilepsy. (4) Brain concussion, brain contusion, etc. (5) Cerebrovascular disease, cerebral hemorrhage. (6) Intracranial inflammation and encephalopathy viral encephalitis. Precautions Requirements for inspection: 1. Don't be nervous when checking, put the receiving electrode on the scalp, not energized. 2, the whole body muscles to relax to avoid interference with myoelectricity. 3. Blink, close your eyes or breathe as required by your doctor. Preparation before inspection: 1. Wash your hair with soapy water the day before the test. 2, the day before the test should stop taking sedatives, hypnotics and anti-epileptic drugs for 1-3 days. 3, should eat before the examination, should not be fasting, such as can not eat or vomiting should be given intravenous glucose. 4, if there is increased intracranial pressure and need to help locate, should use a dehydrating agent to reduce intracranial pressure about 1 hour before the test, such as intravenous drip or bolus injection of mannitol. 5. Explain to the patient before the examination, do not wear nylon clothes, avoid static interference, avoid tension, blink, bite, swallow, shake your head or body activity, sweat should be wiped out to avoid the effects of artifacts. Patients should follow the actions of closing their eyes, blinking or taking a deep breath during the examination. 6, for children and mental disorders who can not cooperate with sedatives, sleeping pills, do sleep chart check. Inspection process The routine EEG recording time should not be less than 30 minutes, sleep monitoring should include at least one complete sleep cycle, and video EEG monitoring should preferably monitor the same episode as the past episode. Any movements of the patient in the tracing should be recorded on the recording paper in time, especially in the case of seizures. (1) Reference leads, longitudinal bipolar leads, and lateral bipolar leads should be included. (2) Physiological and inducing tests should be performed in the reference lead. (3) Closed eyes: In the reference lead, when the baseline is stable, do 3 eyes closed, each time 3s, interval 10s. (4) Excessive ventilation: Excessive ventilation for 3 minutes in the reference lead, breathing 15 to 20 times per minute. A child or a collaborator can blow a feather or piece of paper in front of his mouth. At least 3 minutes after hyperventilation, if abnormal, it should be traced to abnormal disappearance. (5) Flash stimulation: Place 100,000 candlelight incandescent flashes 20 to 30 cm in front of the patient's eyes, and the patient closes the eyes. Flash stimulation with different frequencies, each frequency stimulated for 10s, interval 10s. Common frequencies are 1 Hz, 3 Hz, 9 Hz, 12 Hz, 15 Hz, 18 Hz, 20 Hz, 25 Hz, 30 Hz, 40 Hz and 50 Hz. (6) Before each tracing, 10s instrument calibration should be done. Each amplifier inputs 50μV voltage, observe its damping and sensitivity, and bio-calibration. Each channel will enter O1 into input 1, A1 enter input 2, trace 10s, observe frequency response. The instrument calibration and biocalibration are completely consistent in order to perform patient tracing, otherwise the instrument should be debugged first. Not suitable for the crowd Traumatic trauma and scalp rupture after craniocerebral surgery or when the surgical incision does not heal. Adverse reactions and risks Generally no adverse reactions.