Response – The concept of consciousness and its relevance to the classification of seizures and epilepsies


The definition of consciousness is a crucial issue in the neurosciences but meets so many difficulties to induce many prominent neuroscientists to deny the possibility of grasping its essence by a scientific approach.

According to Alvarez-Rodriques et al. (2013) the problem arises from the pretention of including in a comprehensive definition both the self-awareness in a particular moment and the self-awareness as a unifying experience along life. Indeed the description of the subjective external and inner experience “here and now” is both possible from a neuroscientific perspective and workable for the epileptologist. Its continuous modulations in terms of intensity and focused field confer to consciousness its dynamic fluidity along the longitudinal dimension.

Blumenfeld and Jackson's (2013) article is a pleasantly written dialog among the two authors during a car journey in an exotic landscape that creates a metaphoric counterpart to their arguments. According to the authors, the evidence of the involvement of specific brain systems in seizures with impaired consciousness is a crucial argument to advocate for the maintenance of two different categories of focal seizures with or without impaired consciousness previously defined as simple and complex partial seizures.

The arguments raised in the two articles are certainly interesting to clinicians or investigators involved in epilepsy, as a clear description of the state of consciousness during a seizure is mandatory to understand its pathophysiology and has important practical consequences. What is not clear is why the ictal impairment of consciousness should be used as a main criterion for seizure classification. Back in the 1970s the international epilepsy community had been involved in a strong discussion about the definition of simple and complex partial seizures based on the state of consciousness during the seizure. Since then some of us continue to believe that the impairment of consciousness, although relevant to correctly describe a seizure has no more value than other ictal symptoms to its definition. Therefore, unlike Blumenfeld and Jackson, I agree with the decision of the International League Against Epilepsy (ILAE) Commission to consider a single category of focal seizures and to include the consciousness dysfunction among the main descriptors of seizure phenomenology.

As a general comment I think it important that the ILAE journal Epilepsia publishes papers and debates that may provide the Commission of Classification with valuable input from the epilepsy community. In addition to the matter of simple versus complex focal seizures on which I agree with the Commission's work, there are other controversial issues in the Commission's proposal—namely referring to the Classification of Epilepsies—that in my opinion need to be discussed further. As I argued in a previous commentary (Avanzini, 2010), the new proposal does not introduce the required changes in the conceptual framework of the Classification of Epilepsies, and the new terminology confuses even more the matter that it is intended to clarify. I hope that Epilepsia will continue to be a forum for the exchange of opinions and discussion of data, a substantial prerequisite to keep alive the process of developing a new classification.


The author has no conflict of interest to declare in relation to this paper. The author confirms that he has read the Journal's position on issues involved in ethical publication and affirms that this report is consistent with those guidelines.