title: Impaired consciousness in partial seizures is bimodally distributed.
abstract: OBJECTIVE
  To investigate whether impaired consciousness in partial seizures can usually be attributed to specific deficits in the content of consciousness or to a more general decrease in the overall level of consciousness.
  
  
  METHODS
  Prospective testing during partial seizures was performed in patients with epilepsy using the Responsiveness in Epilepsy Scale (n = 83 partial seizures, 30 patients). Results were compared with responsiveness scores in a cohort of patients with severe traumatic brain injury evaluated with the JFK Coma Recovery Scale-Revised (n = 552 test administrations, 184 patients).
  
  
  RESULTS
  Standardized testing during partial seizures reveals a bimodal scoring distribution, such that most patients were either fully impaired or relatively spared in their ability to respond on multiple cognitive tests. Seizures with impaired performance on initial test items remained consistently impaired on subsequent items, while other seizures showed spared performance throughout. In the comparison group, we found that scores of patients with brain injury were more evenly distributed across the full range in severity of impairment.
  
  
  CONCLUSIONS
  Partial seizures can often be cleanly separated into those with vs without overall impaired responsiveness. Results from similar testing in a comparison group of patients with brain injury suggest that the bimodal nature of Responsiveness in Epilepsy Scale scores is not a result of scale bias but may be a finding unique to partial seizures. These findings support a model in which seizures either propagate or do not propagate to key structures that regulate overall arousal and thalamocortical function. Future investigations are needed to relate these behavioral findings to the physiology underlying impaired consciousness in partial seizures.
authors.affiliation: From the Departments of Neurology (C.C., W.C.C., A.S., M.M., T.C., C.P.S., V.C., A.B., C.B., M.C., M.F., K.D., H.B.), Neurobiology (H.B.), and Neurosurgery (H.B.), Yale University School of Medicine, New Haven, CT; and Department of Physical Medicine and Rehabilitation (J.T.G.), Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA.
authors.forename: Courtney
authors.initials: C
authors.lastname: Cunningham
authors.forename: William C
authors.initials: WC
authors.lastname: Chen
authors.forename: Andrew
authors.initials: A
authors.lastname: Shorten
authors.forename: Michael
authors.initials: M
authors.lastname: McClurkin
authors.forename: Tenzin
authors.initials: T
authors.lastname: Choezom
authors.forename: Christian P
authors.initials: CP
authors.lastname: Schmidt
authors.forename: Victoria
authors.initials: V
authors.lastname: Chu
authors.forename: Anne
authors.initials: A
authors.lastname: Bozik
authors.forename: Cameron
authors.initials: C
authors.lastname: Best
authors.forename: Melissa
authors.initials: M
authors.lastname: Chapman
authors.forename: Moran
authors.initials: M
authors.lastname: Furman
authors.forename: Kamil
authors.initials: K
authors.lastname: Detyniecki
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Giacino
authors.forename: Hal
authors.initials: H
authors.lastname: Blumenfeld
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000503:physiopathology* / Q000523:psychology*; D003244:Consciousness Disorders / Q000150:complications / Q000503:physiopathology* / Q000523:psychology*; D004828:Epilepsies, Partial / Q000150:complications / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D055815:Young Adult
references.citation: Ann N Y Acad Sci. 2009 Mar;1157:ix-xi
references.pmid: 19351349
references.citation: Epilepsia. 2001 Sep;42(9):1212-8
references.pmid: 11580774
references.citation: Cereb Cortex. 2004 Aug;14(8):892-902
references.pmid: 15084494
references.citation: Neurology. 2004 Sep 28;63(6):1015-21
references.pmid: 15452292
references.citation: Epilepsia. 2012 Oct;53(10):e180-3
references.pmid: 22931210
references.citation: Epilepsy Behav. 2012 Feb;23(2):98-102
references.pmid: 22236572
references.citation: Brain. 2010 Dec;133(Pt 12):3764-77
references.pmid: 21081551
references.citation: Lancet Neurol. 2012 Sep;11(9):814-26
references.pmid: 22898735
references.citation: Ann Neurol. 1982 Mar;11(3):292-300
references.pmid: 7092181
references.citation: Epilepsy Behav. 2011 Dec;22(4):651-8
references.pmid: 22079438
references.citation: J Head Trauma Rehabil. 2010 Sep-Oct;25(5):349-56
references.pmid: 20142758
references.citation: Behav Neurol. 2011;24(1):11-20
references.pmid: 21447893
references.citation: Neurology. 2003 Nov 11;61(9):1262-4
references.pmid: 14610133
references.citation: Neuropsychol Rehabil. 2005 Jul-Sep;15(3-4):454-60
references.pmid: 16350986
references.citation: Nature. 2006 Jun 1;441(7093):589-94
references.pmid: 16688184
references.citation: Brain. 2006 Jul;129(Pt 7):1917-28
references.pmid: 16760199
references.citation: Brain. 2009 Aug;132(Pt 8):2091-101
references.pmid: 19416952
references.citation: Neurology. 2002 Sep 24;59(6):841-6
references.pmid: 12297563
references.citation: Epilepsy Behav. 2002 Jun;3(3):219-231
references.pmid: 12662601
references.citation: J Neurosci. 2008 Sep 3;28(36):9066-81
references.pmid: 18768701
references.citation: Lancet Neurol. 2004 Sep;3(9):537-46
references.pmid: 15324722
references.citation: Epilepsia. 1981 Aug;22(4):489-501
references.pmid: 6790275
references.citation: J Neurosci. 2009 Oct 14;29(41):13006-18
references.pmid: 19828814
references.citation: Neurology. 2002 Feb 12;58(3):349-53
references.pmid: 11839831
references.citation: Epilepsia. 2012 Dec;53(12):2104-10
references.pmid: 23016829
references.citation: Neurol Clin. 2011 Nov;29(4):801-23
references.pmid: 22032662
references.citation: Epilepsy Behav. 2013 Jan;26(1):25-8
references.pmid: 23201609
references.citation: Epilepsia. 2012 Mar;53(3):437-47
references.pmid: 22150524
references.citation: Epilepsia. 2013 Jun;54(6):1125-30
references.pmid: 23731397
references.citation: Epilepsia. 2010 Apr;51(4):676-85
references.pmid: 20196795
references.citation: N Engl J Med. 2012 Mar 1;366(9):819-26
references.pmid: 22375973
references.citation: Arch Phys Med Rehabil. 2004 Dec;85(12):2020-9
references.pmid: 15605342
references.citation: J Clin Neurosci. 2012 Nov;19(11):1605-6
references.pmid: 22925412
references.citation: Epilepsy Behav. 2008 Jul;13(1):184-8
references.pmid: 18353730