The limits of consciousness are hard to define satisfactorily and we can only infer the self-awareness of others by their appearance the their acts.

Plum and Posner, 1982The Diagnosis of Stupor and Coma

The Facts

Incidence of Diagnostic Inaccuracy___________________________One out of five healthcare workers were mistaken when asked to make judgements as to whether patients were conscious or unconscious. (Teasdale and Jennett, 1976)

Incidence of Diagnostic Inaccuracy_______________________________15% of patients (n=60) in long term acare diagnosed w/PVS found to have self or environmental awareness

(Tresch et. Al, Arch Int Med 1991; 151:930-2)

Incidence of Diagnostic Inaccuracy__________________________37% of patients (n=49) admitted to inpatient rehab diagnosed incorrectly according to AMA criteria (Childs, et al, Neurol 1993; 43:1465-7)Rate of misdiagnosis significantly higher for traumatic vs non-traumatic injuries

Incidence of Diagnostic Inaccuracy______________________________43% of patients (n=40) admitted to rehab unit for profound BI incorrectly diagnosed with VS (Andrews, et al, BMJ 1996; 313:1306)

The majority of misdiagnosed patients had severe sensory and motor deficits believed to have masked behavioral evidence of consciousness

Why does Diagnosis Matter?_____________________________

Important differences exist among patients with disorders of consciousness re:Course of recoveryPrognosisTreatment needsOutcome

Implications of Diagnostic Non-Specificity and Inaccuracy_______________________________Inappropriate treatment decisionsFamily adjustment complicationsMisleading research finds

_______________________Definitions and Diagnostic Criteria

Coma: Definition (MSTF, 1994)____________________________Coma is a state of sustained pathologic unconsciousness in which the eyes remain closed and the patient cannot be aroused.

Clinical Criteria for Diagnosis of Coma(Plum and Posner 1982)____________________________________Absence of sleep/wake cycles on EEGContinuous eye closureNo evidence of awareness of self or environment; incapable of interacting with othersNo purposeful motor activityNo behavioral response to commandNo evidence of language comprehension or expressionInability to discretely localize noxious stimuli

Vegetative State: Definition (Aspen Workgroup, 2001)_____________________________The vegetative state is a condition in which there is complete absence of behavioral evidence for awarenessof self and environment, with preserved capacity for spontaneous or stimulus-induced arousal.

Clinical Criteria for Diagnosis of the Vegetative State (Multi-Society Task Force on PVS 1994)_____________________________________________No Evidence of awareness of self or environment; incapable of interacting with othersNo evidence of sustained or reproducible, purposeful or voluntary behavioral responses to visual, auditory, tactile or noxious stimuliNo evidence of language comprehension or expressionIntermittent wakefulness manifested by sleep-wake cycles

Clinical Criteria for Diagnosis of the Vegetative State (Multi-Society Task Force on PVS 1994)___________________________________Sufficient preservation of hypothalamic and brain stem autonomic functions for survival with medical and nursing careBowel and bladder incontinenceVariable preservation of cranial nerve function (pupillary, oculocephalic, corneal, vestibulo-ocular, gag, spinal reflexes)

Persistent Vegetative State (AAN 1995)________________________________A diagnostic term that denotes a vegetative state present 1 month after a traumatic or non-traumatic brain injury

PVS (Aspen Workgroup 1997)______________________________Use of the term persistent vegetative state (PVS) should be avoided. In place of PVS, the term vegetative state should be used, accompanied by a description of the cause of injury and the length of time since onset.

Permanent Vegetative State (AAN 1995)____________________________A prognostic term that denotes an irreversiblestate which can be applied 12 months after a traumatic injury and after 3 months following non-traumatic injury in adults and children

Probabilities for Recovery of Consciousness and Function at 12 months after Traumatic and Non-Traumatic Brain Injury for Patients in the Vegetative State at 3 and 6 Months after Injury._______________________________________Outcome Probabilities for Adults in PVS 3 Months After InjuryOutcomeTraumatic PVS (n=434)Non-Traumatic PVS (n=169)Dead (%)35 (27-43)%46 (31-61)%PVS (%)30 (22-38)%47 (32-62)%Severe (%)19 (12-26)% 6 (0-13)%Moderate/Good (%)16 (10-22)% 1 (0-4)%Outcome Probabilities for Adults in PVS 6 Months After InjuryDead (%)32 (21-43)%28 (12-44)%PVS (%)52 (40-64)%72 (56-88)%Severe (%)12 (4-20)% 0Moderate/Good (%) 4 (0-9)% 0____________________________________________________________________________

Prognostic Guideline for Patients in the Vegetative State (AAN, 1995)___________________________________Criteria for PermanenceAfter 12 months following traumatic brain injury in adults and childrenAfter 3 months following non-traumatic brain injury in adults and childrenAfter 1 to 3 months following metabolic and degenerative diseasesAt birth in infants with anencephaly and after 3 to 6 months following congenital malformations of the brain

Minimally Conscious State (MCS)(Giacino, et al., Neurology, 2002)_______________________________The minimally conscious state is a condition of severely altered consciousness in which minimalbut definite behavioral evidence of self or environmental awareness is demonstrated.

Minimally Conscious State: Course_________________________________Usually exists as transitional state reflecting improvement (as in coma/VS) or decline (as in neurodegenerative conditions) in consciousnessNot clear if MCS can occur immediately upon injury to the brainMay represent permanent outcomeNatural history and long term outcome not yet adequately investigated

Diagnostic Criteria for MCS (Giacino, et al., 2002)_________________________________One or more of the following must be clearly discernible and occur on a reproducible or sustained basis:Follows simple commandsGestural or verbal yes/no responsesIntelligible verbalizationMovements or affective behaviors that occur in contingent relation to relevant environmental stimuli and are not attributable to reflexive activity

Diagnostic Criteria for MCS (continued)______________________________Any of the following behavioral examples provide sufficient evidence for criterion 4:Smiling or crying in response to the linguistic or visual content of emotional but not neutral topics or stimuli;Vocalizations or gestures that occur in direct response to the linguistic content of comments or questions;Reaching for objects that demonstrates a clear relationship between object location and direction of reach

Diagnostic Criteria for MCS (continued)______________________________Touching or holding objects in a manner that accommodates the size and shape of the object;Pursuit eye movement or sustained fixation that occurs in direct response to moving or salient stimuli

MCS: Course/Prognosis__________________________________CourseUsually a transitional state reflecting improvement (as in coma/VS) or decline (as in neurodegenerative disease).May be permanent.

Outcome at 12MLevel of Disability 1-3 MTBI: 50% with none to moderateNTBI: 12 MTBI: ?NTBI: ?

Comparison of Outcome: VS v. MCS_________________________________Some evidence that pts in MCS show:More rapid rate of improvementLonger course of recoverySignificantly better functional outcome by 12 months