Affiliations: Academic Neurology Unit, University of Sheffield,
Royal Hallamshire Hospital, Sheffield, UK | Swiss Epilepsy Centre, Zürich, Switzerland
Note: [] Corresponding author: Dr. Markus Reuber FRCP MD PhD, Senior
Clinical Lecturer, Academic Neurology Unit, University of Sheffield, Royal
Hallamshire Hospital, Glossop Road, Sheffield, UK. Tel.: +44 114 2268763; Fax:
+44 114 2713158; E-mail: markus.reuber@sth.nhs.uk
Abstract: Non-epileptic attack disorder (NEAD) is one of the most important
differential diagnoses of epilepsy. Impairment of consciousness is the key
feature of non-epileptic attacks (NEAs). The first half of this review
summarises the clinical research literature featuring observations relating to
consciousness in NEAD. The second half places this evidence in the wider
context of the recent discourse on consciousness in neuroscience and the
philosophy of mind. We argue that studies of consciousness should not only
distinguish between the 'level' and `content' of consciousness but also between
'phenomenal consciousness' (consciousness of states it somehow "feels to be
like") and 'access consciousness' (having certain 'higher' cognitive processes
at one's disposal). The existing evidence shows that there is a great intra-
and interindividual variability of NEA experience. However, in most NEAs
phenomenal experience – and, as a precondition for that experience, vigilance
or wakefulness – is reduced to a lesser degree than in those epileptic
seizures involving impairment of consciousness. In fact, complete loss of
"consciousness" is the exception rather than the rule in NEAs. Patients, as
well as external observers, may have a tendency to overestimate impairments of
consciousness during the seizures.
