“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 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

Outcome Traumatic 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__________________________________

Course Usually a transitional state reflecting improvement (as in

coma/VS) or decline (as in neurodegenerative disease).

May be permanent.

Outcome at 12M Level of Disability 1-3 M TBI: 50% with none to moderate

NTBI: <5% with none to moderate 6 M TBI: Mean = moderate

NTBI: Mean = severe >12 M TBI: ?

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