1. MAS develop atonia immediately after a single or a series of 2–3 myoclonic seizures (MS). A sudden loss of tone causes either a drop attack or slight myatonia, head nodding, or sagging at the knees (post-myoclonic myatonia or epileptic negative myoclonus).41,42 Ictal EEG during MS is similar to a pure atonic seizure (AS) and characterized by a generalized (poly)spike-and-wave discharges that can be isolated or repeated rhythmically at 2–4 Hz, lasting 2–6 sec. MS are time-locked to a spike-and-wave complex. The EMG correlation of each jerk is a burst lasting around 100 msec, followed by a longer (200–500 msec) post-myoclonic myatonia. The atonic component of seizures is characterized by a rhythmic discharge of (poly)spike-and-slow-wave complexes at 2–4 Hz, accompanied by EMG inhibition lasting 60–400 msec, synchronous in the recorded muscles and time-locked to the onset of the slow wave. This generalized post-myoclonic myatonia has caused the fall. The number of spikes in the individual complexes are associated with the severity of MS. AS is usually associated with the slow wave of a (poly)spike-wave complex, and the intensity of atonia is proportionate to the amplitude of the slow wave.14,41,43
Source: Generalized Epilepsy, Atlas of Pediatric EEG
Citation: Laoprasert P. Atlas of Pediatric EEG; 2011 Available at: Accessed: October 31, 2017
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