doi:10.1093/brain/awu088
Brain 2014: 137; 1
| e285
BRAIN A JOURNAL OF NEUROLOGY
LETTER TO THE EDITOR Reply: Syncope and electroencephalography J. Gert van Dijk,1 Roland D. Thijs,1,2 Erik van Zwet,3 Martijn R. Tannemaat,1,4 Julius van Niekerk,1 David G. Benditt5 and Wouter Wieling6 Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands SEIN-Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands Department of Medical Statistics, Leiden University Medical Centre, Leiden, The Netherlands Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, The Netherlands Cardiac Arrhythmia and Syncope Centre, Department of Medicine (Cardiovascular Division), University of Minnesota Medical School, Minneapolis, Minnesota, USA 6 Department of Internal Medicine, Academic Medical Centre, Amsterdam, The Netherlands Correspondence to: J. Gert van Dijk E-mail: [email protected]
Sir, We thank Dr Stephenson for his favourable opinion of our work and agree that the slow-flat-slow pattern is probably independent of age, although we did not study this formally. We think that the clinical expression of syncope in any age group depends on the speed and depth of cerebral hypoperfusion, and suspect that such expressions may differ between children and adults. Our study cannot prove whether the appearance of some symptoms depends on yet other factors. It is possible that the execution of some movements depends on body position: in our study the subjects’ heads rested on a pillow, which would have prevented the appearance of weak opisthotonus, but not a strong one. Our hypothesis that myoclonic jerks require cortical activity was based on a statistical analysis of 69 cases in whom synchronized clinical and EEG data were analysed with a 1 s resolution. Our conclusion indeed contrasts with earlier observations stating that myoclonic jerks could occur during flat phases of the EEG. However, our experience has made us wary to establish the relative time of fleeting clinical and EEG phenomena without recourse to repeated analysis of well-synchronized video and EEG signals.
We are aware that syncope in children can evoke an epileptic seizure on rare occasions, but know of no reliable reports in adults, and have not seen epileptiform EEG abnormalities evoked by syncope in the present series. As Dr Stephenson mentions, oral automatisms have been mentioned in at least two earlier reports; our quantification suggests that they are much more common than this limited number of reports would suggest. We assume that their subtle nature has caused most people to miss them, except for a few astute observers. Finally, We thank Dr Stephenson for noting the typographical error in a reference.
Funding Dr Benditt was supported in part by the Earl E Bakken Family philanthropic grant in support of Heart-Brain Research.
Advance Access publication April 15, 2014 ß The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: [email protected]
Downloaded from http://brain.oxfordjournals.org/ by guest on January 19, 2016
1 2 3 4 5
Brain 2014: 137; 1
| e285
BRAIN A JOURNAL OF NEUROLOGY
LETTER TO THE EDITOR Reply: Syncope and electroencephalography J. Gert van Dijk,1 Roland D. Thijs,1,2 Erik van Zwet,3 Martijn R. Tannemaat,1,4 Julius van Niekerk,1 David G. Benditt5 and Wouter Wieling6 Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands SEIN-Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands Department of Medical Statistics, Leiden University Medical Centre, Leiden, The Netherlands Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, The Netherlands Cardiac Arrhythmia and Syncope Centre, Department of Medicine (Cardiovascular Division), University of Minnesota Medical School, Minneapolis, Minnesota, USA 6 Department of Internal Medicine, Academic Medical Centre, Amsterdam, The Netherlands Correspondence to: J. Gert van Dijk E-mail: [email protected]
Sir, We thank Dr Stephenson for his favourable opinion of our work and agree that the slow-flat-slow pattern is probably independent of age, although we did not study this formally. We think that the clinical expression of syncope in any age group depends on the speed and depth of cerebral hypoperfusion, and suspect that such expressions may differ between children and adults. Our study cannot prove whether the appearance of some symptoms depends on yet other factors. It is possible that the execution of some movements depends on body position: in our study the subjects’ heads rested on a pillow, which would have prevented the appearance of weak opisthotonus, but not a strong one. Our hypothesis that myoclonic jerks require cortical activity was based on a statistical analysis of 69 cases in whom synchronized clinical and EEG data were analysed with a 1 s resolution. Our conclusion indeed contrasts with earlier observations stating that myoclonic jerks could occur during flat phases of the EEG. However, our experience has made us wary to establish the relative time of fleeting clinical and EEG phenomena without recourse to repeated analysis of well-synchronized video and EEG signals.
We are aware that syncope in children can evoke an epileptic seizure on rare occasions, but know of no reliable reports in adults, and have not seen epileptiform EEG abnormalities evoked by syncope in the present series. As Dr Stephenson mentions, oral automatisms have been mentioned in at least two earlier reports; our quantification suggests that they are much more common than this limited number of reports would suggest. We assume that their subtle nature has caused most people to miss them, except for a few astute observers. Finally, We thank Dr Stephenson for noting the typographical error in a reference.
Funding Dr Benditt was supported in part by the Earl E Bakken Family philanthropic grant in support of Heart-Brain Research.
Advance Access publication April 15, 2014 ß The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: [email protected]
Downloaded from http://brain.oxfordjournals.org/ by guest on January 19, 2016
1 2 3 4 5
