title: Combined transcranial Doppler and EEG recording in vasovagal syncope.
abstract: 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.
authors.affiliation: Department of Neurological Sciences, University of Rome, 'La Sapienza', Rome, Italy. edoardo.vicenzini@uniroma1.it
authors.forename: E
authors.initials: E
authors.lastname: Vicenzini
authors.forename: S
authors.initials: S
authors.lastname: Pro
authors.forename: S
authors.initials: S
authors.lastname: Strano
authors.forename: P
authors.initials: P
authors.lastname: Pulitano
authors.forename: M
authors.initials: M
authors.lastname: Altieri
authors.forename: V
authors.initials: V
authors.lastname: Di Piero
authors.forename: G L
authors.initials: GL
authors.lastname: Lenzi
authors.forename: N
authors.initials: N
authors.lastname: Accornero
authors.forename: O
authors.initials: O
authors.lastname: Mecarelli