Subclinical rhythmic electrographic discharge in adults: an atypical evolution

Abstract

SUMMARY -The subclinical rhythmic electrographic discharge in adults (SREDA) has been rarely reported. We describe the case of a 71 year-old man with transient ischemic attack, whose EEG showed an atypical evolution of this uncommon pattern. The computed tomography scan and cerebrospinal fluid were normal. We are not aware of any other report in the literature with this atypical evolution of SREDA.KEY WORDS: subclinical rhythmic electrographic discharge in adults (SREDA), EEG. Descarga eletrográfica rítmica subclínica do adulto: uma evolução atípicaRESUMO -A descarga eletrográfica rítmica subclínica do adulto tem sido raramente referida na literatura. Relatamos o caso de um homem de 71 anos com ataque isquêmico transitório, cujo EEG mostrou evolução atípica deste padrão incomum. A tomografia computadorizada de crânio e o liquido cefalorraquidiano foram normais. Na literatura por nós pesquisada, não achamos outra publicação com evolução atípica do SREDA. PALAVRAS-CHAVE: descarga eletrográfica rítmica subclínica do adulto (DERSA) (SREDA), EEG.The subclinical rhythmic electrographic discharge in adults (SREDA) 10 was first described as "décharges paroxystiques du carrefour" by Naquet et al. (1961,1965) 6,7 and it is considered a benign EEG pattern of uncertain significance 11 . It may closely resemble an EEG seizure pattern and it is an unusual EEG finding 5 -9 -w with an incidence of 0.02-0.045% 2 .Our aim in this paper is to report a case of this rare situation on EEG. CASE REPORTJTN, a 71-year-old man with a story of hypertension and ischemic attack was referred to the neurological emergency room. At the first neurologic examination he was conscient, disphasic and without other neurological signs. The disphasy (Wernicke's type) lasted 20h and then disappeared. ECG, echocardiography, CSF and CT scan were normal. His neurologic status remained stable, and at hospital day 2 an EEG was recorded.The first EEG (EEG1) was performed 24 h after the onset of symptoms and lasted 45 min. The patient was resting quietly with eyes closed and exposed to minimal background noise. EEG tracings were obtained on

Subclinical rhythmic EEG discharge of adults: “SREDA in a child”

“…Few others have also reported SREDA in patients who had transient ischemic attack (TIA), transient global amnesia (TGA), and cerebellar degeneration. 7,8,12 These anecdotal reports shed some light on the possible pathogenesis of SREDA, but it still needs to be ascertained prospectively in a larger sample of patients.…”

Subclinical rhythmic electrographic discharge of adults (SREDA) in a case with spinocerebellar degeneration improved clinically by thyrotropin‐releasing hormone

“…The causative mechanism of SREDA remains to be elucidated. Previous reports have suggested that the generation of SREDA is related to cerebrovascular disorders, ischemia, and transient hypoxia 1,4,9 . However, other reports do not supported these hypotheses 2,5 .…”

“…It is usually predominant over the parietal and temporal regions and lasts between a few seconds and a minute without any clinical manifestations or symptoms 2 . The prevalence of SREDA has been reported to be extremely small (0.002–0.045) 3 and SREDA is sometimes described as ‘subclinical’, 2,3 with some reports indicating that there is no correlation between SREDA and any specific clinical symptoms 4–6 . In addition, SREDA has been described most commonly in middle‐aged and elderly adults (over 40 years of age), 2,3,5,7 although SREDA has also been reported in children 8 .…”

Aspectos Gerais e Práticos do EEG

“…Temos também as pontas positivas 6/ 14 Hz, o "SREDA" (Fig. 12) 30 , que pode ser confundido com crise eletrográfica, a descarga rítmica temporal média, a pseudo-ponta-onda (hipersincronia hipnagógica), o ritmo da fenda em pacientes craniotomizados e mais recentemente o potencial "N" 31 . No caso de dúvida entre a atividade epileptiforme e a VB, a primeira geralmente fica mais freqüente conforme o sono vai aprofundando, enquanto a VB só aparece durante a sonolência 32 .…”