case_images: PMC7675853_01
case_images: 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.
case_images: 10.1177_2324709620969498-fig1.jpg
case_images: PMC7675853_01_10.1177_2324709620969498-fig1.jpg
case_images: fig1-2324709620969498
case_images: 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).
case_images: 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.
case_images: 10.1177_2324709620969498-fig2.jpg
case_images: PMC7675853_01_10.1177_2324709620969498-fig2.jpg
case_images: fig2-2324709620969498
case_images: 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.