“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, 1982 The 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 recovery Prognosis Treatment needs Outcome

Implications of Diagnostic Non- Specificity and Inaccuracy _______________________________ Inappropriate treatment decisions Family adjustment complications Misleading 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 EEG Continuous eye closure No evidence of awareness of self or environment; incapable of interacting with others –No purposeful motor activity –No behavioral response to command –No evidence of language comprehension or expression –Inability 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 awareness of 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 others –No evidence of sustained or reproducible, purposeful or voluntary behavioral responses to visual, auditory, tactile or noxious stimuli –No evidence of language comprehension or expression –Intermittent 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 care Bowel and bladder incontinence Variable 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 irreversible state 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 Injury OutcomeTraumatic 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 Injury Dead (%)32 (21-43)%28 (12-44)% PVS (%)52 (40-64)%72 (56-88)% Severe (%)12 (4-20)% 0 Moderate/Good (%) 4 (0-9)% 0 ____________________________________________________________________________

Prognostic Guideline for Patients in the Vegetative State (AAN, 1995) ___________________________________ Criteria for Permanence After 12 months following traumatic brain injury in adults and children After 3 months following non-traumatic brain injury in adults and children After 1 to 3 months following metabolic and degenerative diseases At 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 minimal but 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 consciousness Not clear if MCS can occur immediately upon injury to the brain May represent permanent outcome Natural 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 commands Gestural or verbal “yes/no” responses Intelligible verbalization Movements 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 moderate NTBI: <5% with none to moderate 6 MTBI: Mean = moderate NTBI: Mean = severe >12 MTBI: ? NTBI: ?

Comparison of Outcome: VS v. MCS _________________________________ Some evidence that pts in MCS show: –More rapid rate of improvement –Longer course of recovery –Significantly better functional outcome by 12 months