PMC7675853_01
Electroencephalography (EEG) recorded in the emergency room. Catatonia did
not correlate with EEG findings. (A) Waxy flexibility (posture maintained
after left arm was raised) was detected, while high-voltage generalized
rhythmic delta activity (GRDA) was present in the EEG. (B) Waxy flexibility
was also detected in the absence of GRDA with the EEG showing low-voltage
beta, alpha, and theta rhythms with rare delta waves. (C) Waxy flexibility
and GRDA resolved completely and the patient started answering simple
questions within 10 minutes of lorazepam injection.
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PMC7675853_01_10.1177_2324709620969498-fig1.jpg
fig1-2324709620969498
Electroencephalography (EEG) was performed in the ER (Figure 1). When his arm was raised against gravity, he maintained the posture, consistent with waxy flexibility (Figure 1A and B). Lorazepam 2 mg was injected IV, and within 10 minutes, GRDA was replaced by low-voltage semirhythmic theta and intermittent rhythmic beta activity (Figure 1C).
Continuous electroencephalography (EEG) monitoring in the intensive care
unit. EEG is shown with compressed spectral array trend map. (A) GRDA onset
was usually not associated with clinical change. (B) GRDA onset coincided
with onset of right lower limb jerking (focal motor seizure) on 5 occasions.
(B) GRDA can last as long as 30 minutes with minor fluctuations in
amplitude, sharpness, and frequency from 1.5 Hz to 2.5 Hz. When present,
right lower limb jerking lasted only 10 to 20 seconds. (D) Non-GRDA epochs
were initially shorter than GRDA epochs. (E) GRDA epoch length progressively
decreased and non-GRDA epoch length progressively increased with
up-titration of antiepileptic drug dosage. GRDA eventually disappeared.
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Continuous EEG monitoring with video and compressed spectral array trending initially showed long periods of GRDA (2-42 minutes) punctuated by shorter non-GRDA periods (0.5-11 minutes; Figure 2). As a rule, GRDA was not associated with any clinical change (Figure 2A). However, the onset of a few GRDA episodes coincided with right lower limb jerking or focal motor seizure (Figure 2B). GRDA was seen whether the patient was not moving or his leg was jerking. GRDA showed some fluctuation in amplitude, sharpness, and frequency from 1.5 to 2.5 Hz (Figure 2A-C). GRDA and non-GRDA episodes progressively increased and decreased, respectively (Figure 2D). GRDA completely disappeared after 4 days of levetiracetam, lacosamide, and propofol therapy.