“the limits of consciousness are hard to define satisfactorily and we can only infer the...
TRANSCRIPT
“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
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
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: ?