Impaired consciousness in epilepsy investigated by a prospective responsiveness in epilepsy scale (RES)

Abstract

Purpose Impaired consciousness in epileptic seizures has a major negative impact on patient quality of life. Prior work on epileptic unconsciousness has mainly used retrospective and nonstandardized methods. Our goal was to validate and to obtain initial data using a standardized prospective testing battery. Methods The responsiveness in epilepsy scale (RES) was used on 52 patients during continuous video/EEG monitoring. RES begins with higher-level questions and commands, and switches adaptively to more basic sensorimotor responses depending on patient performance. RES continues after seizures and includes postictal memory testing. Scoring was conducted based on video review. Key Findings Testing on standardized seizure simulations yielded good intra-rater and inter-rater reliability. We captured 59 seizures from 18 patients (35% of participants) during 1420 hours of RES monitoring. RES impairment was greatest during and after tonic-clonic seizures, less in partial seizures, and minimal in auras and subclinical seizures. In partial seizures, ictal RES impairment was significantly greater if EEG changes were present. Maximum RES impairment (lowest ictal score) was also significantly correlated with long postictal recovery time, and poor postictal memory. Significance We found that prospective testing of responsiveness during seizures is feasible and reliable. RES impairment was related to EEG changes during seizures, as well as to postictal memory deficits and recovery time. With a larger patient sample it is hoped that this approach can identify brain networks underlying specific components of impaired consciousness in seizures. This may allow the development of improved treatments targeted at preventing dysfunction in these networks.

Impaired consciousness in partial seizures is bimodally distributed

“…The RES is a standardized prospective battery used to assess responsiveness during epileptic seizures. 17,18 Test items evaluate orientation, receptive and expressive language, visual processing, and sensorimotor function (table e-2). RES test items were derived from the JFK CRS-R, a comprehensive, validated tool for the evaluation of patients with chronic disorders of consciousness.…”

“…17,18 CRS-R items were also administered by a trained examiner, and patients with TBI were similarly allowed up to 10 seconds to respond to each item. In both RES and JFK CRS-R, subject responses are graded and assigned a score based on level of responsiveness.…”

“…Of note, the current cohort included 60 seizures from 26 patients that were previously analyzed through similar but distinct methods. [17][18][19] Patients with structural brain abnormalities were included in the seizure cohort, including 8 patients with hippocampal atrophy or increased signal, 7 with cortical gliosis or poststroke encephalomalacia, 5 malformations of cortical development, 4 previous resections, and 1 brain tumor (table e-1).…”

“…The original RES 18 was used during the period from June 2009 to September 2011; RES-II 17 was used from September 2011 to September 2012. The 2 versions are generally similar, including many of the same test items, but are administered in a different order to improve efficiency of testing and minimize administration errors.…”

“…Data analysis. As described previously, 17,18 all seizures were scored within 24 hours of testing based on video review and agreement of 2 reviewers. In the original RES, a few items (Memory encoding, Name, Place, Year) were scored from 0 to 5, others (Ball, Mirror) were scored from 0 to 3, and the remainder, as with RES-II, were scored from 0 to 4.…”