Thursday, October 21, 2010

The faithful Christian seizure

When I sit down to use my computer, the first thing I usually do is double-click the icon that opens up an internet browser. I do this so often, that even when I need to use the computer for purposes other than internet-browsing, I mindlessly open up the internet browser anyway. This action is an example of a learned automatism -- an unconscious behaviour that is generated as a result of trained associations in previous experiences.

Learned automatisms can last a long time, and the contexts in which they are acquired and retained can vary substantially. A couple of bizarre reports suggest that Christian individuals who learned to make the sign-of-the-cross hand gesture (also known as Signum Crucis) after having epileptic seizures may exemplify a form of long-lasting, deeply-engrained learned automatism.

In one of the reports, 4 out 530 epileptic patients at a clinic in Brazil displayed sign-of-the-cross gestures as automatic movements during seizures. None of the patients were aware of their own movements. The researchers evaluated these patients with electroencephalography (EEG) to measure electrical brain activity while seizures were experienced.

The figure above shows what the electrical brain activity of one of the four patients looked like at the time of seizure onset (first arrow), seizure duration, and sign-of-the-cross gesture onset (second arrow). The activity was measured at the right temporal lobe, the area in which all four patients regularly experienced seizures. All four patients were Christian and were raised in a religious manner, but it was not reported whether the patients learned the sign-of-the-cross gesture at a young age nor if they had a history of intentionally making these gestures at the time of seizures.

However, a second case report of an epileptic patient in Toronto demonstrates that the sign-of-the-cross gesture during seizures may be a learned automatism. The patient wasn't aware that she was making the cross gesture during her seizures, but when told that she was doing it, she explained that during childhood her mother used to teach her to cross herself at the end of her seizures. The authors of this study speculate that the patient was trained to make the cross gesture during seizures, and somehow a neural memory circuit for making the gesture gets recruited by spontaneous brain activity during her seizures.

This patient also had seizures in the right temporal lobe -- the same area as the four patients in the first study. Areas of the temporal lobe have been implicated in religious cognitive-emotional experience, although these findings are controversial. The association between epilepsy and religion has a rich history, with early Greeks referring to epilepsy as the "sacred disease."

However, although these cases provide an interesting insight to consciousness, it is unlikely that there is something special or miraculous about the sign-of-the-cross gesture during seizures. If the movement is due to a learned automatism, or some other mechanism, other gestures can likely be trained to be associated with seizures too. Maybe even single-clicking to close internet browsers.


Lin K, Marx C, Caboclo LO, Centeno RS, Sakamoto AC, & Yacubian EM (2009). Sign of the Cross (Signum Crucis): observation of an uncommon ictal manifestation of mesial temporal lobe epilepsy. Epilepsy & behavior : E&B, 14 (2), 400-3 PMID: 19059360

Wennberg R, McAndrews MP, Zumsteg D, & Velazquez JL (2009). The sign of the cross as a learned ictal automatism? Epilepsy & behavior : E&B, 15 (3), 394-8 PMID: 19393765

1 comment:

  1. Good post.

    Interestingly this kind of thing is a bit of a trope in zombie movies - the zombies lose their intelligence but are still able to "remember" things they did automatically when alive... often to comic effect.