The Facts

1. “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

2. The Facts

3. 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)

4. 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)

5. 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

6. 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

7. Why does Diagnosis Matter?_____________________________ Important differences exist among patients with disorders of consciousness re: • Course of recovery • Prognosis • Treatment needs • Outcome

8. Implications of Diagnostic Non-Specificity and Inaccuracy_______________________________ • Inappropriate treatment decisions • Family adjustment complications • Misleading research finds

9. _______________________ Definitions and Diagnostic Criteria

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

11. 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

12. 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.

13. 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

14. 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)

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

16. 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.

17. 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

18. 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 ____________________________________________________________________________

19. 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

20. 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.

21. 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

22. 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

23. 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

24. 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

25. 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: ?

26. 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