Introduction:
Neonatal EEG or neonatal electroencephalography is a technique that is used to analyze and record the electrical activity present in the brain of newborn infants. Electroencephalography includes a non-invasive procedure by placing electrodes on the head or scalp to detect and record the electrical signals given by the neurons present in the brain. Neonatal EEG helps in understanding the development and function of the brain in infants and newborns and can identify the neurological disorders which can cause risk for newborns. It gives information about the electrical activities and patterns in the brain, which help diagnose and treat different medical conditions that affect newborns.
What Are the Types of Electrodes Used in Neonatal EEG?
Neonatal EEGs need correct positioning and placement of the electrode to analyze brain activities. The electrodes present in the neonatal EEG are placed on the scalp of the baby. The electrodes will be positioned in specific areas present in the brain, which help in capturing the signals from different parts of the brain. The number can differ, but typically the number of electrons ranges between 8 to 21. There are mainly two types of electrodes, and they are disposable electrodes and disposable ring electrodes. In most cases, disposable adhesive electrodes are used. It contains an adhesive surface or a conducting gel which gives good electrical contact between the scalp. They are easy to use and will decrease the risk of developing infection. It can be easily disposable after usage. In some cases, apart from disposable electrodes, disposable ring electrodes are used, which contain a conductive gel-filled center. The EEG equipment contains amplifiers, filters, a recording system, and a display.
What Are the Normal Neonatal EEG Patterns?
The normal patterns of neonatal EEG can differ depending on the brain development stage and the age of the newborn. Some of the normal patterns seen in the neonatal EEG include the following:
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The background activity will be disorganized and slow rhythmic activity. In the case of premature babies, the background activity will be irregular and disorganized. It is more commonly seen in the early weeks of their birth. After the maturation of the newborn baby, rhythmic slow activities or delta brushes can be seen. High amplitude waveforms and rhythmic activities are called delta brushes that are seen commonly during the active sleep period.
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There are two transients seen in the normal neonatal EEG pattern. They are vertex waves and K-complexes. High amplitude waveforms that are in slow duration that are seen commonly in the vertex and central region of the brain are called vertex waves. They are seen in the active sleep period. High-amplitude waveforms which are sharp that contain a negative component after a positive component are called K-complexes. They are seen during quiet sleep and are seen in older infants.
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The sleep-wake cycle in normal infants is of two types. The active sleep, or REM (rapid eye movement), and the quiet sleep, or the non-REM. During the active sleep period, there will be a desynchronized EEG pattern that will resemble the pattern of adults during REM sleep. Irregular breathing and rapid eye movements are seen during this stage. During the quiet sleep period, there will be more synchronized EEG activity and will have a slower frequency along with higher amplitude.
What Are the Abnormal Neonatal EEG Patterns?
Abnormal patterns of neonatal EEG correspond to any neurological abnormalities or conditions. Some of the abnormal neonatal EEG patterns include the following:
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There will be electrographic seizure activity. This is characterized by abnormal electrical discharge with stereotyped waveforms that are repeated. The seizure activity can be subclinical or subtle that may not be associated with any clinical signs. It can be seen in different patterns like generalized focal or multi-focal. The duration and frequency of the seizure can also differ depending on the complexity.
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It can be seen as a burst suppression pattern that is characterized by alternate periods of low amplitude activity and high amplitude burst. It is seen commonly with severe brain injury or dysfunction, like severe metabolic disturbance and hypoxic-ischemic encephalopathy.
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There will be abnormal background activities like CSWS (continuous spike-wave discharge of slow sleep) or suppression burst pattern. In CSWS, there will be wave discharge and continuous spikes during the slow wave sleep. It is associated with different types of disorders or neurodevelopment issues and can have behavioral and cognitive impacts. In the suppression burst pattern, there will be alternate periods of burst activity and electrical silence, which is seen in encephalopathy and metabolic disorders.
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Sharp waves and interictal spikes can be seen, which are high-amplitude waveforms that are abnormal and brief.
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Excessive disorganization or abnormal sleep with transition can be seen in the abnormal development dysfunction of the brain.
What Are the Clinical Applications of Neonatal EEG?
Neonatal EEG has different clinical applications which help in assessing the condition of newborn infants. Some of the applications of neonatal EEG include the following:
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It helps in detecting and diagnosing seizures in neonates. By assessing the electrical activities of the brain, abnormal patterns can be identified, which help in diagnosing seizures. Early detection and immediate diagnosis help in giving timely intervention and treatment.
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Neonatal EEG helps in monitoring the severity of the disease. Conditions like hypoxic-ischemic encephalopathy can be identified using this neonatal EEG.
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The neonatal EEG helps in monitoring the development of the brain in newborns and infants. It helps in identifying the normal patterns of development and noticing any deviation from the normal pattern. It is useful for premature babies to identify any higher chance of developing neurological disorders and developmental delays.
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It helps in the evaluation of neonatal encephalopathy, which is a condition that has abnormal functioning of the brain and shows signs of neurological impairment.
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The neonatal EEG helps monitor treatment effects like therapeutic hypothermia and medication administration in infants and neonates with neurological conditions.
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The neonatal EEG helps in determining the prognosis in the neonatal intensive care unit (NICU).
Conclusion:
In conclusion, neonatal EEG is used to monitor and measure the electrical activity present in the brain of infants and newborns. With the help of neonatal EEG, the development and function of the brain can be monitored, and it helps in diagnosing and treating various neurological conditions in infants and newborns. The abnormal activity or patterns present in the brain can be analyzed, which helps in treating seizures and other types of neurological abnormalities. It helps in preventing complications and further damage to the brain.
