Atypical SREDA During Wakefulness, NREM and REM Sleep in a Young Teenager: A Diagnostic Challenge

Subclinical rhythmic electrographic discharges of adult (SREDA) is a rare variant considered to be normal in EEG. It consists of sharp-contoured or sinusoidal waveforms in the theta frequency range (usually 5-7 Hz), occurring in a widespread distribution, often maximal over the parietotemporal regions. SREDA is usually bilateral but could be unilateral (atypical SREDA). Compared with true ictal activities, SREDA has little change in frequency, morphology, and distribution. It has been described in adults and is extremely rare in children/adolescents. There are only 5 cases published in children. We report a case of atypical SREDA in a child that may have occurred in wakefulness, non-rapid eye movement (NREM) sleep, and REM sleep. This finding was initially misdiagnosed as epilepsy. Inpatient video-EEG demonstrated that during periods of SREDA in quiet wakefulness the patient did not have any signs or symptoms with the SREDA pattern; SREDA abated whenever the patient was alerted or if he spontaneously initiated some activities. SREDA with same morphology was noted in NREM and REM sleep. The patient had no true epileptogenic abnormalities and hence antiepileptic medication was discontinued and stopped uneventfully. This case illustrates the importance of recognizing this rare variant, avoiding a misdiagnosis of epilepsy as it occurred in our case.