Current Case: Winter 2024

Contributed by: Fatai Akemokwe, MBBS, Patricia Bacus, MD, Divya Menghani, MBBS, Meriem Bensalem-Owen, MD, FACNS, Zahra Haghighat, MD, Gulam Khan, MD, Kimberly Jones, MD, Zabeen Mahuwala, MD, University of Kentucky College of Medicine, Lexington, KY, USA

Case Presentation

A 9-year-old boy was transferred to our hospital after a spell described as an angry outburst followed by transient headache, abdominal pain, and unsteady gait. He had a history of in-utero drug exposure, autism spectrum disorder, and attention deficit hyperactivity disorder. His paternal uncle and grandmother had epilepsy. He was evaluated 2 years earlier for staring episodes, head and body movements and angry outbursts. His awake routine EEG at that time was normal, and those spells were deemed behavioral. During his current hospitalization, his neurological examination was unremarkable. Routine EEG showed a 11 Hz posterior dominant rhythm and runs of 5-Hz sharply contoured theta rhythm over the left temporal electrodes (F7/T7/P7) during drowsiness. These lasted up to 8 seconds without any evolution (Figure 1). There was no change in concomitant clinical behavior. Intravenous levetiracetam was administered due to the initial concern that this pattern was ictal. However, continuous video-EEG still showed runs of notched monomorphic 5Hz theta predominantly over F7/T7/P7 and independently over F8/T8/ P8 lasting up to 47 seconds during drowsiness and these did not persist into stage N2 of sleep (Figure 2). Similar rhythms were provoked by hyperventilation.

Figure 1

Figure 1. Scalp EEG tracing showing sharply contoured monomorphic theta over F7/T7/P7 electrodes. Sensitivity 7 µV/mm, time base 30 mm/sec, HFF 70 Hz, LFF 1 Hz, Notch filter 60 Hz

Figure 1

Figure 2. Scalp EEG tracing (average referential montage) showing notched monomorphic theta over F7/T7/P7 electrodes with onset of similar activity on F8/T8/P8 near the end of the tracing. Sensitivity 10 µV/mm, time base 30 mm/sec, HFF 70 Hz, LFF 1 Hz, Notch filter 60 Hz

Question 1: Given the patient’s history and EEG findings, what is the most likely diagnosis?

  1. Rhythmic mid-temporal theta of drowsiness
  2. Wicket rhythms
  3. Benign epileptiform transients of sleep
  4. Runs of epileptiform discharges
Answer: (click here)

 

Question 2: Which of the following statements is incorrect regarding the above EEG findings?

  1. These discharges may originate from fissural cortex of the posterior-inferior temporal region
  2. This diagnosis is more common in children compared to older people
  3. Younger children have higher amplitude spikes compared to adolescents
  4. They have the lowest epileptogenic potential compared to other temporal discharges
Answer: (click here)

References:

Reference 1: Mari-Acevedo J, Yelvington K, Tatum WO. Normal EEG variants. Handb Clin Neurol. 2019;160:143-60.

Reference 2: Kang JY, Krauss GL. Normal Variants Are Commonly Overread as Interictal Epileptiform Abnormalities. J Clin Neurophysiol. 2019;36(4):257-63.

Reference 3: Asadi-Pooya AA, Sperling MR. Normal Awake, Drowsy, and Sleep EEG Patterns That Might Be Overinterpreted as Abnormal. J Clin Neurophysiol. 2019;36(4):250-6.

Reference 4: Fawaz A, Nasreddine W, Bustros S, Kayed DM, Beydoun A. A prolonged rhythmic midtemporal discharge in a child without seizures. Clin EEG Neurosci. 2015;46(2):126-9.

Reference 5: Hughes JR. The continuous rhythmic mid-temporal discharge. Clin Electroencephalogr. 2001;32(1):10-3.

Reference 6: Jain P, Whitney R, Cortez MA. Prolonged rhythmic mid-temporal discharges (RMTD) in a 5-year old child. Journal of Clinical Neuroscience. 2018;48:81-2.

Reference 7: Hughes JR, Olson SF. An investigation of eight different types of temporal lobe discharges. Epilepsia. 1981;22(4):421-35.

Reference 8: Lin YY, Wu ZA, Hsieh JC, Yu HY, Kwan SY, Yen DJ, et al. Magnetoencephalographic study of rhythmic mid-temporal discharges in non-epileptic and epileptic patients. Seizure. 2003;12(4):220-5.

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