The diagnostic value of EEGs in patients with syncope

Abubakr, Abuhuziefa; Wambacq, Ilse

doi:10.1016/j.yebeh.2005.01.003

Cited by 56 publications

(39 citation statements)

References 10 publications

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“…Published studies have found that the electroencephalogram (EEG) is of low diagnostic yield when the clinical diagnosis is syncope [2][3][4][5] . Reviews state that EEGs should not be performed routinely in cases of suspected syncope unless there has been a witnessed seizure 6 , there is a history of prior seizures 7,8 , or there are "symptoms suggestive of a seizure" 7,9 .…”

mentioning

confidence: 99%

EEG in Suspected Syncope: Do EEGs Ordered by Neurologists Give a Higher Yield?

Poliquin‐Lasnier

Moore

2009

Can. j. neurol. sci.

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Syncope is often difficult to distinguish from a seizure because both can present clinically with a transient loss of consciousness 1 . Published studies have found that the electroencephalogram (EEG) is of low diagnostic yield when the clinical diagnosis is syncope [2][3][4][5] . Reviews state that EEGs should not be performed routinely in cases of suspected syncope unless there has been a witnessed seizure 6 , there is a history of prior seizures 7,8 , or there are "symptoms suggestive of a seizure" 7,9 . Electroencephalograms ordered by a neurologist might be expected to have a higher diagnostic yield because most neurologists are experienced in evaluating patients with syncope and seizures, and presumably would only refer a patient with suspected syncope for an EEG if there was something ABSTRACT: Background: Prior studies have shown that the electroencephalogram (EEG) is of low diagnostic yield in the evaluation of syncope but have not looked at the yield according to referring physician specialty. The goals of this study were to determine if the yield of the EEG is higher when ordered by neurologists and whether EEGs with abnormal findings resulted in any significant change in patient management. Methods: We retrospectively reviewed the records of the EEGs requested for a clinical diagnosis of syncope, convulsive syncope, loss of consciousness, or falls from 2003 to 2007 at our institution. We obtained further information from the medical record of patients with an abnormal EEG. Results: Of 517 EEGs meeting our inclusion criteria, only 57 (11.0%) were read as abnormal. No EEG was positive for epileptiform activity and only 9 (1.6%) showed potentially epileptic activity. EEGs ordered by neurologists did not have a higher yield compared to non-neurologists. Five abnormal EEGs resulted in further investigations being ordered. One patient was ultimately started on phenytoin. Conclusions: EEGs requested for the evaluation of patients with suspected syncope have an extremely low diagnostic yield and do not significantly alter the management of the patients, regardless of the specialty of the referring physician. RÉSUMÉ: L'EEG chez les patients suspects de syncope : les EEG demandés par les neurologues donnent-ils un meilleur rendement? :Contexte : Des études antérieures ont montré que l'électroencéphalogramme (EEG) offre un rendement diagnostique faible dans l'évaluation de la syncope, mais ces études n'ont pas examiné le rendement selon la spécialité du médecin qui réfère le patient. Les buts de cette étude étaient de déterminer si le rendement de l'EEG est plus élevé quand il est demandé par un neurologue et si les EEG dont les résultats sont anormaux entraînaient des changements significatifs dans le traitement du patient. Méthodes :Nous avons revu de façon rétrospective les dossiers des EEG demandés de 2003 à 2007 dans notre institution à cause d'un diagnostic clinique de syncope, de syncope convulsive, de perte de conscience ou de chute. Nous avons tiré des informations complémentaires des dossiers médicaux...

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confidence: 99%

EEG in Suspected Syncope: Do EEGs Ordered by Neurologists Give a Higher Yield?

Poliquin‐Lasnier

Moore

2009

Can. j. neurol. sci.

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“…In 1957, Gastaut and Fischer-Williams [14] described normal EEG patterns between attacks, but with a high incidence of slow, high-voltage α-rhythm in patients with syncope. On the other hand, more recent papers have reported aspecific interictal EEG alterations in up to 30% of patients with syncope, generally consisting of diffuse or focal slowing, or even epileptic activity in a small percentage of patients [3]. ‘Paroxysmal dysrhythmias’ have also been reported in 15–20% of patients with nonepileptic seizures [13] and, in a recent paper, we described a ‘typical’ pseudoparoxysmal EEG pattern more evident during HV, consisting of mild slowing of baseline rhythm and rhythmic intermittent δ-activity, in young adults with neurally mediated syncope [4].…”

Section: Discussionmentioning

confidence: 99%

“…If the acute episode is prolonged, ‘convulsive’ phenomena occur frequently [2] and syncope may be misdiagnosed and treated as epilepsy, despite the observation of aspecific interictal EEG alterations in up to 30% of patients with syncope [3]. Generally, these abnormalities consist of diffuse or focal slowing, but in a small percentage of patients epileptic activity may be observed [3]. …”

Section: Introductionmentioning

confidence: 99%

Combined Transcranial Doppler and EEG Recording in Vasovagal Syncope

Vicenzini

Pro

Strano³

et al. 2008

Eur Neurol

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Background: In neurally mediated syncope a ‘typical’ EEG pattern during hyperventilation (HV) may be observed. This study aimed to investigate transcranial Doppler (TCD) and EEG variations in response to hyper- and hypocapnia using simultaneous recording. Methods: Syncope patients with a typical EEG pattern during HV (SEEG+, n = 15) and those without abnormalities (SEEG–, n = 16) were compared with healthy controls (n = 20). Simultaneous TCD and EEG recordings were performed at rest (baseline), during 2 apnea tests and during HV. Cerebrovascular vasoreactivity, index for hypocapnia, total vasomotor reserve and time to flow velocity normalization after HV (t-norm) were recorded. Results: With TCD, a reduction in Vasomotor reserve was observed in SEEG+ compared with the other 2 groups (control: 67 ± 8%; SEEG–: 67 ± 10%; SEEG+: 57 ± 8%; p < 0.0001). t-norm was longer in all syncopal patients and in particular in SEEG+ (control: 20.2 ± 3 s; SEEG–: 40 ± 7 s; SEEG+: 123 ± 45s; p < 0.0001). Quantitative EEG showed an increase in slow bands in all subjects during HV, small and nonsignificant in controls and SEEG–, higher and significant in SEEG+, related with flow reduction. Conclusions: Changes in the sympathetic modulation of cerebral vasoconstriction may explain both the pathophysiology of vasovagal syncope and the typical paroxysmal EEG findings.

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“…The annual incidence of syncope is evaluated at between 1.3 to 2.7 episodes for 1000 inhabitants and per year [136]. Since the clinical presentation of syncope can sometimes be similar to epileptic symptoms, EEG is often requested, even though studies have shown its low diagnostic value [8,26,43,124]. In 67% of cases the EEG is normal.…”

Section: Syncopementioning

confidence: 99%