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Review
. 2014 Aug;55(8):1145-50.
doi: 10.1111/epi.12588. Epub 2014 Jun 30.

Consciousness as a useful concept in epilepsy classification

Hal Blumenfeld  1 , Kimford J Meador
Affiliations
Review

Consciousness as a useful concept in epilepsy classification

Hal Blumenfeld et al. Epilepsia. 2014 Aug.

Abstract

Impaired consciousness has important practical consequences for people living with epilepsy. Recent pathophysiologic studies show that seizures with impaired level of consciousness always affect widespread cortical networks and subcortical arousal systems. In light of these findings and their clinical significance, efforts are underway to revise the International League Against Epilepsy (ILAE) 2010 report to include impaired consciousness in the classification of seizures. Lüders and colleagues have presented one such effort, which we discuss here. We then propose an alternative classification of impaired consciousness in epilepsy based on functional neuroanatomy. Some seizures involve focal cortical regions and cause selective deficits in the content of consciousness but without impaired overall level of consciousness or awareness. These include focal aware conscious seizures (FACS) with lower order cortical deficits such as somatosensory or visual impairment as well as FACS with higher cognitive deficits including ictal aphasia or isolated epileptic amnesia. Another category applies to seizures with impaired level of consciousness leading to deficits in multiple cognitive domains. For this category, we believe the terms "dyscognitive" or "dialeptic" should be avoided because they may create confusion. Instead we propose that seizures with impaired level of consciousness be described based on underlying pathophysiology. Widespread moderately severe deficits in corticothalamic function are seen in absence seizures and in focal impaired consciousness seizures (FICS), including many temporal lobe seizures and other focal seizures with impaired consciousness. Some simple responses or automatisms may be preserved in these seizures. In contrast, generalized tonic-clonic seizures usually produce widespread severe deficits in corticothalamic function causing loss of all meaningful responses. Further work is needed to understand and prevent impaired consciousness in epilepsy, but the first step is to keep this crucial practical and physiologic aspect of seizures front-and-center in our discussions.

Keywords: Absence seizures; Classification; Complex partial seizures; Consciousness; Epilepsy; Generalized tonic-clonic seizures; Simple partial seizures.

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Conflict of interest statement

Disclosure: None of the authors has any conflict of interest to disclose. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

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References

    1. Lüders H, et al. Proposal: different types of alteration and loss of consciousness in epilepsy. Epilepsia. 2014 forthcoming. - PubMed
    1. Blume WT, Lüders HO, Mizrahi E, et al. Glossary of descriptive terminology for ictal semiology: report of the ILAE task force on classification and terminology. Epilepsia. 2001;42:1212–1218. - PubMed
    1. Berg AT, Berkovic SF, Brodie MJ, et al. Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, 2005–2009. Epilepsia. 2010;51:676–685. - PubMed
    1. Gloor P. Consciousness as a neurological concept in epileptology: a critical review. Epilepsia. 1986;27(Suppl. 2):S14–S26. - PubMed
    1. Cavanna AE, Monaco F. Brain mechanisms of altered conscious states during epileptic seizures. Nat Rev Neurosci. 2009;5:267–276. - PubMed

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