A 9-year-old boy with normal development and cognition is referred for EEG after two nocturnal seizures with oropharyngeal symptoms and secondary generalization. Neuroimaging is normal. During sleep-deprived EEG, the recording shows frequent high-amplitude diphasic sharp waves with maximum negativity at centrotemporal electrodes (C3/C4, T3/T4), demonstrating a characteristic horizontal dipole pattern. These discharges are unilateral but shift between hemispheres and are dramatically potentiated during sleep. The structure marked **A** in the diagram represents the characteristic EEG finding in this clinical context. Which of the following best describes the relationship between this EEG pattern and the clinical presentation?
A. Generalized 3 Hz spike-and-wave discharges indicate primary generalized epilepsy requiring immediate antiepileptic drug therapy
B. Centrotemporal sharp waves activated by sleep are the hallmark of benign epilepsy with centrotemporal spikes and typically remit by age 16, with observation often preferred over treatment
C. Frontal intermittent rhythmic delta activity suggests a focal structural lesion requiring neurosurgical evaluation
D. Triphasic waves are characteristic of metabolic encephalopathy and warrant urgent investigation for hepatic dysfunction
Explanation
Why option 1 is correct
The structure marked A — centrotemporal sharp waves activated by sleep — is the pathognomonic EEG hallmark of benign epilepsy with centrotemporal spikes (Rolandic epilepsy). The clinical vignette presents the classic triad: (1) oropharyngeal semiology with secondary generalization, (2) seizures occurring from sleep, (3) normal cognition, development, and neuroimaging. The EEG shows the characteristic high-amplitude diphasic sharp waves with centrotemporal maximum and horizontal dipole, dramatically potentiated by sleep—exactly as described in Wirrell EC (1998). The benign nature, sleep activation of discharges, and excellent prognosis with remission by age 16 are defining features. Observation is often preferred; if treatment is needed, levetiracetam or oxcarbazepine are first-line agents.
Why each distractor is wrong
Option 2 (Generalized 3 Hz spike-and-wave): This pattern is characteristic of childhood absence epilepsy or primary generalized epilepsy, not Rolandic epilepsy. The patient's semiology (focal oropharyngeal symptoms with secondary generalization) and focal EEG findings exclude generalized epilepsy. Additionally, absence seizures present with behavioral arrest and staring, not oropharyngeal twitching.
Option 3 (Frontal intermittent rhythmic delta activity): This pattern suggests focal structural pathology or metabolic disturbance. The patient's normal brain MRI, normal neurologic examination, and normal background EEG between discharges exclude structural disease. This finding is not associated with Rolandic epilepsy.
Option 4 (Triphasic waves): Triphasic waves are associated with hepatic encephalopathy, uremia, and other metabolic derangements—not primary epilepsy. The patient has no clinical or biochemical evidence of metabolic disease and normal cognition, making this diagnosis inappropriate.
High-YieldNEET PG
Centrotemporal sharp waves potentiated by sleep in a child with oropharyngeal seizures, normal cognition, and normal imaging = Rolandic epilepsy; prognosis is excellent with remission by age 16.
Wirrell EC. Benign epilepsy of childhood with centrotemporal spikes. Epilepsia. 1998;39 Suppl 4:S32-S41.
Practice similar questions
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.
