EEG - Electroencephalography Pediatric and Neonatal EEG Questions and Answers

Question 1

An EEG is performed on a 32-week conceptional age premature infant. During quiet sleep, the recording shows bursts of high-amplitude mixed frequencies lasting 3-10 seconds, separated by periods of marked attenuation (<25 µV) lasting 10-20 seconds. This pattern is best described as:

Accepted Answer

Tracé discontinu

Answer

Tracé discontinu is the characteristic EEG pattern of quiet sleep in premature infants between approximately 30 and 34 weeks conceptional age. It consists of bursts of mixed-frequency activity separated by interburst intervals of significant voltage attenuation, typically less than 25 µV. [1, 2, 3] Tracé alternant is seen in older infants (around 34-44 weeks) and has a higher interburst interval amplitude (>25 µV). Burst-suppression is a profoundly abnormal pattern associated with severe encephalopathy. Hypsarrhythmia is a chaotic, high-voltage, disorganized pattern seen in infants with West syndrome.

Question 2

A 7-year-old child with normal development presents with new-onset seizures, often occurring shortly after falling asleep. The seizures involve twitching on one side of the face and drooling. The interictal EEG shows high-amplitude, diphasic sharp-and-slow wave complexes that are most prominent over the left centrotemporal region and increase significantly during drowsiness. What is the most likely diagnosis?

Accepted Answer

Self-Limited Epilepsy with Centrotemporal Spikes (SeLECTS)

Answer

The clinical description of focal seizures involving the face and the specific EEG finding of high-amplitude sharp waves in the centrotemporal (rolandic) region, which are activated by sleep, are pathognomonic for Self-Limited Epilepsy with Centrotemporal Spikes (SeLECTS), formerly known as Benign Rolandic Epilepsy. [16, 18] Childhood Absence Epilepsy features generalized 3 Hz spike-wave discharges. [12] Lennox-Gastaut Syndrome and Juvenile Myoclonic Epilepsy have different clinical and EEG characteristics.

Question 3

Which of the following electrographic features is most characteristic of an ictal event (electrographic seizure) in a full-term neonate?

Accepted Answer

A sustained, rhythmic, evolving pattern of sharp waves or delta activity lasting more than 10 seconds.

Answer

The gold standard for identifying a neonatal electrographic seizure is the presence of a sustained, rhythmic discharge that shows clear evolution in frequency, morphology, or location and lasts for at least 10 seconds. [5, 26] Neonatal seizures are typically focal in onset and can consist of various morphologies, including rhythmic delta or sharp activity. [5] Generalized 3 Hz spike-and-wave is typical of absence seizures in older children, hypsarrhythmia is an interictal pattern, and sleep spindles are normal sleep architecture.

Question 4

A 6-month-old infant is brought in for evaluation of developmental regression and clusters of flexor spasms that occur upon waking. The EEG shows a continuous, chaotic, and disorganized pattern of very high-voltage, asynchronous slow waves with multifocal spikes and sharp waves. This EEG pattern is called:

Accepted Answer

Hypsarrhythmia

Answer

The described EEG pattern is the classic presentation of hypsarrhythmia. It is characterized by its chaotic, disorganized, and high-amplitude ('mountainous') appearance with asynchronous slow waves and multifocal spikes. [8, 9, 10] This pattern is the interictal hallmark of West Syndrome, which includes the clinical triad of infantile spasms, hypsarrhythmia on EEG, and developmental delay or regression. [10]

Question 5

In a healthy 3-year-old child, the posterior dominant rhythm (PDR) during relaxed wakefulness with eyes closed is expected to have a frequency of approximately:

Accepted Answer

8-9 Hz

Answer

The posterior dominant rhythm (PDR), or alpha rhythm, matures with age. It begins around 3-4 Hz at a few months of age and should reach the alpha frequency range of 8 Hz by approximately 3 years of age. [2] A PDR of 4-5 Hz would be too slow for a 3-year-old, while 10-12 Hz is more typical of an older child or adult. 6-7 Hz would be expected around 12 months of age.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Pediatric and Neonatal EEG Questions and Answers