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of everyone affected by epilepsy

Study reveals cause of consciousness loss during seizures

28 Apr 2004

Even small
epileptic seizures can trigger widespread abnormal signals in brain
networks leading to loss of consciousness, according to new findings by
a Yale University researcher.

Dr Hal Blumenfeld, assistant professor of neurology and neurobiology at Yale School of Medicine and lead author of the study, commented:

known for a long time that the temporal lobe misfires during seizures
but we were amazed to discover that the temporal lobe also causes the
rest of the brain to malfunction. That's why patients lose
consciousness. This often
causes serious motor vehicle accidents, injuries, and falls in patients
with epilepsy. The hope is that we can interrupt the process and
prevent unconsciousness."

focused his study on patients with seizures in the temporal lobe, the
most common form of epilepsy. He and his colleagues used single photon
emission computed tomography (SPECT) to view changes in brain activity
during seizures. He also analysed videotapes of patients during
seizures to determine how their behaviour was related to imaging

study found that in patients who lost consciousness during seizures,
there were abnormal signals scattered across brain images. In contrast,
patients who had seizures but did not lose consciousness had localized
increases confined to the temporal lobe.

Dr Blumenfeld added:

results may help us target new treatments, such as brain stimulation,
to prevent spread of abnormal activity outside the temporal lobe.
Understanding the network abnormalities leading to loss of
consciousness during seizures could also help solve an even more
fundamental question - what is the relationship between normal brain
activity and conscious thought?"