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Abstract

Objective: To establish consensus recommendations among health care specialties for defining and establishing diagnostic criteria for the minimally conscious state (MCS).
Background: There is a subgroup of patients with severe alteration in consciousness who do not meet diagnostic criteria for coma or the vegetative state (VS). These patients demonstrate inconsistent but discernible evidence of consciousness. It is important to distinguish patients in MCS from those in coma and VS because preliminary findings suggest that there are meaningful differences in outcome.
Methods: An evidence-based literature review of disorders of consciousness was completed to define MCS, develop diagnostic criteria for entry into MCS, and identify markers for emergence to higher levels of cognitive function.
Results: There were insufficient data to establish evidence-based guidelines for diagnosis, prognosis, and management of MCS. Therefore, a consensus-based case definition with behaviorally referenced diagnostic criteria was formulated to facilitate future empirical investigation.
Conclusions: MCS is characterized by inconsistent but clearly discernible behavioral evidence of consciousness and can be distinguished from coma and VS by documenting the presence of specific behavioral features not found in either of these conditions. Patients may evolve to MCS from coma or VS after acute brain injury. MCS may also result from degenerative or congenital nervous system disorders. This condition is often transient but may also exist as a permanent outcome. Defining MCS should promote further research on its epidemiology, neuropathology, natural history, and management.
Precise estimates of the incidence and prevalence of severe disorders of consciousness are unavailable. In the United States, the number of individuals who sustain severe traumatic brain injury (i.e., brain injury caused by externally inflicted trauma1) with prolonged loss of consciousness each year is estimated to be between 56 and 170 per one million.2,3 The economic impact of the problem is enormous. Projected average per person lifetime costs of care alone for severe traumatic brain injury range from $600,000 to $1,875,000.4 A single case described by Paris5 reported in-hospital lifetime costs of $6,104,590. In the last 5 years, there have been some attempts to clarify and define diagnostic, prognostic, and treatment issues concerning patients with severe disturbances of consciousness.6-10 Disorders of consciousness include coma and the vegetative state (VS). Patients in coma have complete failure of the arousal system with no spontaneous eye opening and are unable to be awakened by application of vigorous sensory stimulation.11 VS is characterized by the complete absence of behavioral evidence for self or environmental awareness. There is preserved capacity for spontaneous or stimulus-induced arousal, evidenced by sleep–wake cycles.12 The locked-in syndrome, characterized by anarthria and quadriplegia with general preservation of cognition, must be distinguished from disorders of consciousness.11 The table outlines the clinical features of disorders of consciousness and the locked-in syndrome.
Table 1. Comparison of clinical features associated with coma, vegetative state, minimally conscious state, and locked-in syndrome
ConditionConsciousnessSleep/wakeMotor functionAuditory functionVisual functionCommunicationEmotion
ComaNoneAbsentReflex and postural responses onlyNoneNoneNoneNone
Vegetative stateNonePresentPostures or withdraws to noxious stimuliStartleStartleNoneNone
   Occasional nonpurposeful movementBrief orienting to soundBrief visual fixation Reflexive crying or smiling
Minimally conscious statePartialPresentLocalizes noxious stimuliLocalizes sound locationSustained visual fixationContingent vocalizationContingent smiling or crying
   Reaches for objectsInconsistent command followingSustained visual pursuitInconsistent but intelligible verbalization or gesture 
   Holds or touches objects in a manner that accommodates size and shape    
   Automatic movements (e.g., scratching)    
Locked-in syndromeFullPresentQuadriplegicPreservedPreservedAphonic/AnarthricPreserved
      Vertical eye movement and blinking usually intact 
Some patients with severe alteration in consciousness have neurologic findings that do not meet criteria for VS. These patients demonstrate discernible behavioral evidence of consciousness but remain unable to reproduce this behavior consistently. This condition is referred to here as the minimally conscious state (MCS). MCS is distinguished from VS by the partial preservation of conscious awareness.13 This distinction is important for prognosis, treatment decisions, resource allocation, and medicolegal judgements. Some studies suggest a high rate of misdiagnosis (false positives and false negatives) among disorders of consciousness.14,15 The prevalence of adult and pediatric cases of MCS is estimated to be between 112,000 to 280,000, based on operationally defined diagnostic criteria extracted from a large state registry.16
This article, prepared by the Aspen Neurobehavioral Conference Workgroup, proposes diagnostic criteria for MCS.

Methods.

Evidence review process.

Nine formal meetings of the Aspen Workgroup were held between March 1995 and October 2000. National and international delegates represented the fields of bioethics, neurology, neuropsychology, neurosurgery, physiatry, nursing, and allied health. Although it was not possible for each participant to attend all nine meetings, the current document was approved by all members of the workgroup. All delegates previously participated in the development of discipline-specific position statements on disorders of consciousness or made substantial contributions to the peer-reviewed literature. A list of the organizations represented by each author appears in the appendix, which also includes the names of all conference participants.
Selected members of the workgroup completed independent MEDLINE searches of published articles using the key words coma, vegetative state, minimally responsive state, stupor, slow-to-recover, severe disability, and Glasgow Coma Scale. These terms were then cross-indexed with brain injury, diagnosis, and outcome in eight different permutations to retrieve articles that included patients who did not meet diagnostic criteria for VS, but at the same time, were not considered fully conscious. A total of 260 abstracts containing one or more of the terms were retrieved. Only five reports8,17–20 differentiated patients in VS from those with inconsistent signs of consciousness, defined here as MCS. The workgroup concluded that there were insufficient data to establish evidence-based guidelines for diagnosis, prognosis, and management of MCS. Consequently, consensus-based recommendations were developed for the definition of MCS as well as criteria for entry into and emergence from this condition.

Results.

Definition of the minimally conscious state.

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.

Diagnostic criteria for the minimally conscious state.

MCS is distinguished from VS by the presence of behaviors associated with conscious awareness. In MCS, cognitively mediated behavior occurs inconsistently, but is reproducible or sustained long enough to be differentiated from reflexive behavior. The reproducibility of such evidence is affected by the consistency and complexity of the behavioral response. Extended assessment may be required to determine whether a simple response (e.g., a finger movement or eye blink) that is observed infrequently is occurring in response to a specific environmental event (e.g., command to move fingers or blink eyes) or on a coincidental basis. In contrast, a few observations of a complex response (e.g., intelligible verbalization) may be sufficient to determine the presence of consciousness.
To make the diagnosis of MCS, limited but clearly discernible evidence of self or environmental awareness must be demonstrated on a reproducible or sustained basis by one or more of the following behaviors:
1.
Following simple commands.
2.
Gestural or verbal yes/no responses (regardless of accuracy).
3.
Intelligible verbalization.
4.
Purposeful behavior, including movements or affective behaviors that occur in contingent relation to relevant environmental stimuli and are not due to reflexive activity. Some examples of qualifying purposeful behavior include: – appropriate smiling or crying in response to the linguistic or visual content of emotional but not to neutral topics or stimuli – vocalizations or gestures that occur in direct response to the linguistic content of questions – reaching for objects that demonstrates a clear relationship between object location and direction of reach – 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
Although it is not uncommon for individuals in MCS to demonstrate more than one of the above criteria, in some patients the evidence is limited to only one behavior that is indicative of consciousness. Clinical judgments concerning a patient’s level of consciousness depend on inferences drawn from observed behavior. Thus, sensory deficits, motor dysfunction, or diminished drive may result in underestimation of cognitive capacity.

Proposed criteria for emergence from the minimally conscious state.

Recovery from MCS to higher states of consciousness occurs along a continuum in which the upper boundary is necessarily arbitrary. Consequently, the diagnostic criteria for emergence from MCS are based on broad classes of functionally useful behaviors that are typically observed as such patients recover. Thus, emergence from MCS is characterized by reliable and consistent demonstration of one or both of the following:
1.
Functional interactive communication.
2.
Functional use of two different objects.
Functional interactive communication may occur through verbalization, writing, yes/no signals, or use of augmentative communication devices. Functional use of objects requires that the patient demonstrate behavioral evidence of object discrimination.
To facilitate consistent reporting of findings among clinicians and investigators working with patients in MCS, the following parameters for demonstrating response reliability and consistency should be used:
1.
Functional communication: accurate yes/no responses to six of six basic situational orientation questions on two consecutive evaluations. Situational orientation questions include items such as, “Are you sitting down?” and “Am I pointing to the ceiling?”
2.
Functional object use: generally appropriate use of at least two different objects on two consecutive evaluations. This criterion may be satisfied by behaviors such as bringing a comb to the head or a pencil to a sheet of paper.
To help ensure that the operational parameters for demonstrating functional communication and object use described above are equivalent in terms of difficulty, the neurobehavioral profiles of a convenience sample of patients in MCS (n = 24) extracted from a database maintained by one of the authors were reviewed (unpublished data). From this pool, 17 patients were identified who met criteria for either functional object use (FO) or functional communication (FC). The temporal course of recovery of FO and FC was investigated to determine whether the sequence of recovery could serve as an index of difficulty. For example, if most patients met criteria for FO before the criteria for FC were satisfied, it could be concluded that the criteria for FC were more stringent. Data were analyzed for 15 of the 17 available patients. Two patients were excluded because both FO and FC were intact on the admitting examination. Among the remaining 15 patients, seven recovered FO before FC; three recovered FC before FO; and five recovered FO and FC concurrently. The mean time between recovery of FO and FC (independent of sequence) was 8 days (range, 5 to 14 days). Based on these findings, it was concluded that the operational criteria for FO and FC are of equal difficulty.
It is necessary to exclude aphasia, agnosia, apraxia, or sensorimotor impairment as the basis for nonresponsiveness, as opposed to diminished level of consciousness. As noted previously, the criteria for emergence from MCS may underestimate the level of consciousness in some patients. For example, patients with some forms of akinetic mutism demonstrate limited behavioral initiation but are capable of occasional complex cognitively mediated behavior. When there is evidence to suggest that the assessment of level of consciousness is confounded by diminished behavioral initiation, further diagnostic investigation is indicated. Until these diagnostic ambiguities can be resolved by future research, the above definitions should be applied to all patients whose behavior fails to substantiate higher levels of consciousness. It is likely that studies investigating the neurologic substrate underlying subgroups of MCS patients will, in the future, allow the development of diagnostic criteria that are more reliably tied to the level of consciousness.

Recommendations for behavioral assessment of neurocognitive responsiveness.

Differential diagnosis among states of impaired consciousness is often difficult. The following steps should be taken to detect conscious awareness and to establish an accurate diagnosis:
1.
Adequate stimulation should be administered to ensure that arousal level is maximized.
2.
Factors adversely affecting arousal should be addressed (e.g., sedating medications and occurrence of seizures).
3.
Attempts to elicit behavioral responses through verbal instruction should not involve behaviors that frequently occur on a reflexive basis.
4.
Command-following trials should incorporate motor behaviors that are within the patient’s capability.
5.
A variety of different behavioral responses should be investigated using a broad range of eliciting stimuli.
6.
Examination procedures should be conducted in a distraction-free environment.
7.
Serial reassessment incorporating systematic observation and reliable measurement strategies should be used to confirm the validity of the initial assessment. Specialized tools and procedures designed for quantitative assessment may be useful.17,19,21-25
8.
Observations of family members, caregivers, and professional staff participating in daily care should be considered in designing assessment procedures.
Special care must be taken when evaluating infants and children younger than 3 years of age who have sustained severe brain injury. In this age group, assessment of cognitive function is constrained by immature language and motor development. This limits the degree to which command following, verbal expression, and purposeful movement can be relied on to determine whether the diagnostic criteria for MCS have been met.

Prognosis.

The natural history and long-term outcome of MCS have not yet been adequately investigated. It is essential to recognize that MCS may occur in a variety of neurologic conditions, such as traumatic brain injury, stroke, progressive degenerative disorders, tumors, neurometabolic diseases, and congenital or developmental disorders. Clinical experience indicates that MCS after an acute injury can exist as a transitional or permanent state. Few studies of the natural history of MCS have been reported.22,26,27 Giacino and Kalmar22 followed 104 patients diagnosed with VS (n = 55) or MCS (n = 49) on admission to rehabilitation during the first 12 months after injury. The diagnosis of MCS was made retrospectively using clinical criteria that approximate the current definition. The MCS group showed more continuous improvement and attained significantly more favorable outcomes on the Disability Rating Scale28 by 1 year than did the VS group. These differences were more pronounced in patients diagnosed with MCS after traumatic brain injury. Fifty percent of patients in the MCS group with traumatic brain injury were found to have none to moderate disability at 12 months, whereas none of the patients in the MCS group without traumatic brain injury were classified in these outcome categories. Although it is not known how many patients will emerge from MCS after 12 months after injury, most patients in MCS for this length of time remain severely disabled according to the Glasgow Outcome Scale.29 As with VS, the likelihood of significant functional improvement diminishes over time.

Consensus-based general approaches to care.

There are no existing guidelines regarding the care of patients in MCS. Until sufficient empirical data become available, the following general consensus-based approaches to care are recommended. Evaluation and management decisions will differ depending on the prognosis and the needs of the patient. In all circumstances, the patient should be treated with dignity, and caregivers should be cognizant of the patient’s potential for understanding and perception of pain. In early MCS, prevention of complications and maintenance of bodily integrity should be emphasized because of the likelihood of further improvement. Efforts should be made to establish functional communication and environmental interaction when possible. A person with experience in neurologic assessment of patients with impaired consciousness should be primarily responsible for establishing the diagnosis and prognosis and for coordinating clinical management. An additional opinion of a physician or other professional with particular expertise in the evaluation, diagnosis, and prognosis of patients in VS and MCS is recommended when the assessment will impact critical management decisions. Such decisions include, but are not limited to, those regarding changes in level of care, disputed treatment decisions, and withdrawal of life-sustaining treatment.

Future directions for research.

The care of patients with severe disturbances of consciousness remains a complex challenge partly because of an inadequate foundation of scientific evidence. There are a number of critical areas in which scientific evidence is lacking and additional research is indicated. These areas include:
1.
1. Incidence and prevalence of MCS.
2.
2. Natural history, recovery course, and outcome.
3.
3. Interrater and test–retest reliability of the diagnostic criteria for MCS.
4.
4. Validation of diagnostic criteria for MCS with respect to pathophysiologic mechanisms and outcome.
5.
5. Differences in rate of recovery and outcome between adults and children.
6.
6. Interactions among cause of the injury (e.g., trauma vs anoxia vs dementia), length of time after onset, and recovery of consciousness.
7.
7. Predictors and patterns of emergence from VS and MCS.
8.
8. Utility of existing assessment methods and scales for monitoring recovery and predicting outcome.
9.
9. Treatment efficacy.
10.
Efficacy and cost analysis of different care settings.
11.
Issues related to family beliefs and their relation to functional outcome, service use, and evaluative decisions regarding quality of life.
12.
Cross-cultural differences in evaluation and management practices.
These recommendations are intended to serve as a reference for clinicians involved in the examination and treatment of patients with severe alterations in consciousness. They are based on the current state of knowledge and are expected to be revised and refined as additional empirical data become available. The primary purpose of these recommendations is to facilitate future scientific investigation and multidisciplinary discussion by providing a common frame of reference for the examination and treatment of patients in MCS.

Appendix

Author list with organizational affiliations: Joseph T. Giacino, PhD, American Congress of Rehabilitation Medicine,* Brain Injury Association, Inc.; Stephen Ashwal, MD, Child Neurology Society,* American Academy of Neurology*; Nancy Childs, MD, American Academy of Neurology, American Congress of Rehabilitation Medicine; Ronald Cranford, MD, American Academy of Neurology; Bryan Jennett, CBE, MD, FRCS, International Working Party on the Vegetative State and Profound Brain Damage*; Douglas I. Katz, MD, American Academy of Neurology, American Congress of Rehabilitation Medicine, Brain Injury Association, Inc.; James P. Kelly, MD, American Academy of Neurology, Brain Injury Association; Jay H. Rosenberg, MD, American Academy of Neurology, Brain Injury Association, Inc.; John Whyte, MD, PhD, American Academy of Physical Medicine and Rehabilitation, American Congress of Rehabilitation Medicine, Brain Injury Association, Inc.; Ross Zafonte, DO, American Academy of Physical Medicine and Rehabilitation,* Brain Injury Association, Inc.; Nathan D. Zasler, MD, Brain Injury Association, Inc.,* American Academy of Physical Medicine and Rehabilitation, American Congress of Rehabilitation Medicine. Note: Beverly Walters, MD, Chairperson of the Guidelines Committee of the American Association of Neurological Surgeons, served as the primary reviewer and ex-officio representative of AANS. *Denotes official organizational appointment. Aspen Neurobehavioral Consensus Conference Participants:Christopher M. Filley, MD (conference Co-Chair), University of Colorado Health Sciences Center, Denver, CO; James P. Kelly, MD (conference Co-Chair), Chicago Neurological Institute, Chicago, IL; Joseph T. Giacino, PhD, (workgroup Co-Chair), JFK Medical Center, Edison, NJ; Jay H. Rosenberg, MD (workgroup Co-Chair), Southern California Permanente Medical Group, San Diego, CA; H. Richard Adams, MD, Private Practice, Long Beach, CA; Keith Andrews, MD, Royal Hospital for Neuro-Disability, London, United Kingdom; Stephen Ashwal, MD, Loma Linda University Medical Center, Loma Linda, CA; Nancy Childs, MD, Brown Schools Rehabilitation Center, Austin, TX; Ronald Cranford, MD, Hennepin County Medical Center, Minneapolis, MN; Elie Elovic, MD, Kessler Medical Research and Rehabilitation Center, West Orange, NJ; Candace Gustafson, RN, Brain Injury Association, Inc., Alexandria, VA; Bryan Jennett, CBE, MD, FRCS, University of Glasgow, Glasgow, Scotland; Douglas I. Katz, MD, Boston University School of Medicine, Boston, MA, HealthSouth Braintree Rehabilitation Hospital, Braintree, MA; Theresa Louise-Bender Pape, PhD, CCC-SLP, Hines VAH HSR&D Service/MCHSPR, Maywood, IL; Fred Plum, MD, New York Hospital–Cornell Medical Center, New York, NY; Nicholas Schiff, MD, New York Hospital–Cornell Medical Center, New York, NY; Henry Stonnington, MD, 15419 Village Drive, Biloxi, MS; James Tulsky, MD, VA Medical Center, Durham, NC; John Whyte, MD, PhD, MossRehab Hospital, Philadelphia, PA; Jonathan Woodcock, MD, Mediplex Rehab–Denver, Thorton, CO; Stuart A. Yablon, MD, Mississippi Methodist Rehabilitation Center, Jackson, MS; Ross Zafonte, DO, University of Pittsburgh, Pittsburgh, PA; and Nathan D. Zasler, MD, Concussion Care Center of Virginia, Glen Allen, VA.

Acknowledgments

Acknowledgment
The workgroup participants thank Judith Neisser of Chicago, IL, George Zitnay, PhD, of the International Brain Injury Association, Mary Reitter, MS, formerly of the Brain Injury Association, Inc. and the Pharmacia and Upjohn Company, for providing the vision and resources to launch this project and for their ongoing support. They also thank the outside reviewer panel: David Burke, MD (Australia), Jose Leon-Carrion, PhD (Spain), Randall Chestnut, MD (United States), Miklos Feher, MD (Hungary), Jam Ghajar, MD, PhD (United States), Andrew Maas, MD (the Netherlands), Claudio Perino, MD (Italy), Alexander Potapov, MD (Russia), and Paul Shoenle, PhD (Germany).

Footnote

See also pages 337 and 506

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National Consensus Development Panel on Rehabilitation of Persons with Traumatic Brain Injury. Rehabilitation of persons with traumatic brain injury. JAMA . 1999; 282: 974–983.
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Giacino JT, Zasler ND. Outcome after severe traumatic brain injury: coma, the vegetative state, and the minimally responsive state. J Head Trauma Rehabil . 1995; 10: 40–56.
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Tresch DD, Sims FH, Duthie EH, et al. Clinical characteristics of patients in the persistent vegetative state. Arch Intern Med . 1991; 151: 930–932.
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NIH Consensus Development Panel on Rehabilitation of Persons with Traumatic Brain Injury. JAMA . 1999; 282: 974–983.
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Paris JJ. The six million dollar woman. Conn Med . 1981; 45: 720–721.
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The Multi-Society Task Force Report on PVS. Medical aspects of the persistent vegetative state. N Engl J Med . 1994; 330: 1499–1508
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The Quality Standards Subcommittee of the American Academy of Neurology. Practice parameter: assessment and management of persons in the persistent vegetative state. Neurology . 1995; 45: 1015–1018.
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American Congress of Rehabilitation Medicine. Recommendations for use of uniform nomenclature pertinent to persons with severe alterations in consciousness. Arch Phys Med Rehabil . 1995; 76: 205–209.
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Andrews K. International working party on the management of the vegetative state: summary report. Brain Inj . 1996; 10: 797–806.
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Royal College of Physicians Working Group. The permanent vegetative state. J R College Physicians Lond . 1996; 30: 119–121.
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Plum F, Posner J. The diagnosis of stupor and coma, 3rd ed. Philadelphia: FA Davis, 1982.
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Jennett B, Plum F. Persistent vegetative state after brain damage: A syndrome in search of a name. Lancet . 1972; 1: 734–737.
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Giacino JT, Zasler ND, Katz DI, et al. Development of practice guidelines for assessment and management of the vegetative and minimally conscious states. J Head Trauma Rehabil . 1997; 12: 79–89.
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Andrews K, Murphy L, Munday R, et al. Misdiagnosis of the vegetative state: retrospective study in a rehabilitation unit. BMJ . 1996; 313: 13–16.
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Childs NL, Mercer WN, Childs HW. Accuracy of diagnosis of persistent vegetative state. Neurology . 1993; 43: 1465–1467.
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Strauss DJ, Ashwal S, Day SM, et al. Life expectancy of children in vegetative and minimally conscious states. Pediatric Neurol . 2000; 23: 1–8.
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Giacino JT, Kezmarsky MA, DeLuca J, et al. Monitoring rate of recovery to predict outcome in minimally responsive patients. Arch Phys Med Rehabil . 1991; 72: 897–901.
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Whitlock JA Jr. Functional outcome of low-level traumatically brain-injured admitted to an acute rehabilitation programme. Brain Inj . 1992; 6: 447–459.
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Rappaport M, Dougherty AM, Kelting DL. Evaluation of coma and vegetative states. Arch Phys Med Rehabil . 1992; 73: 628–634.
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Ansell BJ. Slow-to-recover patients. Improvement to rehabilitation readiness. J Head Trauma Rehabil . 1993; 8: 88–98.
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Whyte J, DiPasquale MC. Assessment of vision and visual attention in minimally responsive brain injury patients. Arch Phys Med Rehabil . 1995; 765: 804–810.
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Giacino JT, Kalmar K. The vegetative and minimally conscious states: a comparison of clinical features and functional outcome. J Head Trauma Rehabil . 1997; 12: 36–51.
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Ansell BJ, Keenan JE. The Western Neuro Sensory Stimulation Profile: a tool for assessing slow-to-recover head-injured patients. Arch Phys Med Rehabil . 1989; 70: 104–108.
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DiPasquale MC, Whyte J. The use of quantitative data in treatment planning for minimally conscious patients. J Head Trauma Rehabil . 1996; 11: 9–17.
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Whyte J, Laborde A, DiPasquale MC. Assessment and treatment of the vegetative and minimally conscious patient. In: Rosenthal M, Griffith ER, Kreutzer J, Pentland B, eds. Rehabilitation of the adult and child with traumatic brain injury, 3rd ed. Philadelphia: FA Davis, 1999: 435–452.
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Kalmar K, Giacino JT. Comparison of rates of recovery and outcome in vegetative and minimally responsive persons following traumatic vs. non-traumatic brain injury. Arch Phys Med Rehabil . 1995; 76: 597.Abstract.
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Francisco GE, Yablon SA, Ivanhoe CB, et al. Outcome among vegetative and minimally responsive patients with severe acquired brain injury. Am J Phys Med Rehabil . 1996; 75: 158.Abstract.
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Letters to the Editor
24 June 2002
The minimally conscious state: Definition and diagnostic criteria
Joseph J Fins
Nicholas D. Schiff

The response engendered by the proposed criteria for the minimally conscious state by Giacino et. al. is at once predictable and paradoxical. [1, 2, 3] It is predictable in voicing concern that a new diagnostic category could be used to undermine the care of the severely disabled. Opponents contend that in the absence of an evidence base for these criteria, the consensus model used to generate these guidelines represents the consolidation of an ideological stance about the worth of these individuals. But is also paradoxical. This categorization could be a helpful tool in better understanding the continuum of brain states and designing research and therapies to improve and augment cognitive function. [1]

By further distinguishing those in PVS from those who we suspect have elements of consciousness; we can collectively make a stronger distributive justice claim for enhanced services and more research to address the needs of patients and families with brain injury. Practically, this regard should translate into better diagnostic precision. The staggering public health need posed by traumatic brain injury, coupled with society's marginalization of the disabled, makes this an ethical imperative as medicine seeks to provide the benefits of science to these historically under-served individuals. [1] In this we disagree with Dr. Shewmon's assertion that, "there is no clinical or research need for, and strong reasons against, inventing a new diagnostic 'entity' that inherently cannot not be meaningfully demarcated from 'severe disability."

While the concerns of Ms. Coleman are understandable and laudable, it would be more productive if she broadened her advocacy to bring therapeutic or palliative care advances to those with brain injury. Similarly, researchers and clinicians should seek out the diverse views of the disability community. While we applaud advocacy for the disabled, it is important that it does not pre-empt the prerogative of properly authorized surrogates to make decisions to withdraw life-sustaining therapies in accord with the patient's previously expressed preferences.

References:

1. Giacino JT, Ashwal S, Childs N et al. The minimally conscious state: Definition and diagnostic criteria. Neurology 2002;58:349-353.

2. Coleman D. The minimally conscious state: Definition and diagnostic criteria. Neurology 2002;58:506-507.

3. Shewmon DA. The minimally conscious state: Definition and diagnostic criteria. Neurology 2002;58:506-507.

4. Fins JJ. A proposed ethical framework for interventional cognitive neuroscience: A consideration of deep brain stimulation in impaired consciousness. Neurological Research 2000;22:273-278.

24 June 2002
Reply to Letters to the Editor by Burke and Machado
Douglas Katz
JT Giacino, S Ashwal, N Childs, R Cranford, B Jennett, JP Kelly, JH Rosenberg, J Whyte, R Zafonte and ND Zasler

In response to Dr. Burke's letter, we reiterate that the primary objective of the Aspen Group was to distinguish individuals who demonstrate discernible, albeit limited, behavioral evidence of consciousness (i.e. minimally conscious state) from those who are clinically unconscious (i.e. vegetative state). This project's impetus grew out of concern that clinical management of patients in acute MCS was often no different than for patients in VS. Consequently, some individuals with at least partial preservation of consciousness were not afforded the opportunity to receive aggressive rehabilitative treatment--a situation we believe that prevails. Our motivation was further bolstered by preliminary empirical evidence showing that although VS and MCS patients have similar degrees of neurobehavioral disability early after injury, functional outcome at one year is significantly more favorable in some MCS subgroups. [2, 3]

From a scientific standpoint, we are at a loss to understand Dr. Burke's portrayal of the MCS diagnosis as a mechanism for achieving "eugenics." The Aspen Group is comprised largely of clinicians who have been providing acute and long-term care for individuals with catastrophic brain injury for many years. The affiliations and experience of the authors of the MCS article [1] should be considered when judging Dr. Burke's allegations. We acknowledge that the definition and recommendations that we have proposed for MCS represent little more than a starting point, but one we hope will direct attention to this condition and facilitate further scientific inquiry.

We appreciate Dr. Machado's comments. He raises some issues that get at some key problems in understanding and defining consciousness and disorders of consciousness. One problem is semantics and how various terms are used in describing consciousness. He points out that consciousness is composed of two components, arousal and awareness and suggests that the term 'minimally aware state' be used in place of 'minimally conscious state', since awareness, but not arousal is the relevant component in this condition.

Different authors use the terms, arousal, awareness and consciousness differently in relation to each other. Some emphasize the distinctness of arousal or wakefulness and consciousness. [4] Some use the terms awareness and consciousness almost synonymously (e.g., consciousness = awareness of self and environment). Some consider awareness subordinate to consciousness. Others define awareness as a state in which information is available for the individual to report on and act on. [5] Even others note that using this definition; computers may demonstrate awareness, but not consciousness. [6] Therefore, the appropriateness of one term over another may depend on the semantic nuances intended by the author. In order to avoid this problem, diagnostic terms, such as vegetative state and minimally conscious state (MCS), require well-defined criteria so that there is some uniformity in their use for clinical and research purposes. The main goal of our paper was to propose such criteria for MCS. [1]

References :

1. Giacino JT, Ashwal S, Childs N et al. The minimally conscious state: definition and diagnostic criteria. Neurology 2002;58;349-353.

2. Giacino JT, Kalmar K. The vegetative and minimally conscious states: a comparison of clinical features and functional outcome. Journal of Head Trauma Rehabilitation 1997;12:36-51.

3. Francisco GE, Yablon SA, Ivanhoe CB, et al. Outcome among vegetative and minimally responsive patients with severe acquired brain injury. American Journal of Physical Medicine and Rehabilitation 1996;75:158. Abstract.

4. Damasio A. The feeling of what happens. San Diego: Harcourt, 1999.

5. Chalmers DJ. The conscious mind. Oxford: Oxford University Press, 1996.

6. Zeman A. Consciousness. Brain 2001;124:1263-1289.

24 June 2002
The minimally conscious state: Definition and diagnostic criteria
Calixto Machado

Normal conscious behavior requires arousal that depends on the function of the ascending reticular activating system (ARAS) and, awareness or content of consciousness that represents the sum of the cognitive, affective, and other higher brain functions, related to "complex physical and psychologic mechanisms by which limbic systems and the cerebrum enrich and individualize human consciousness". [1]

Nonetheless, arousal cannot simply be related to the function of the ARAS, and awareness related to the function of the cerebral cortex, because substantial interconnections among the brainstem, subcortical structures and the neocortex are indispensable for both components of human consciousness. Hence, consciousness does not bear a simple one-to- one relationship with higher or lower brain structures.[1,2]

Giacino et al. stated that the vegetative state (VS) is "characterized by complete absence of behavioral evidence for self or environmental awareness…", and described the minimally conscious state as patients with "inconsistence but discernible evidence of consciousness." [3] Most authors mention human consciousness, without considering its two components. For example, higher brain theorists of death habitually describe the persistent or permanent vegetative state (VS) as patients with "irreversible loss of consciousness" or "permanent unconscious", but in these patients arousal is preserved, while awareness is apparently lost. [2,4]

VS patients reflect the only situation in which an apparent dissociation of both components of consciousness is found. [2] I used the adjective "apparent" because of the following reflection. Can we deny the existence of internal awareness in VS, because these patients apparently seem to be disconnected from the external world? The subjective dimension of awareness is philosophically impossible to test, but physiologically it seems conceivable that subjective awareness might continue. [2]

Karen Ann Quinlan's brain showed severe damage of the thalamus, with the cerebral hemispheres relatively spared. [5] We can ask ourselves if, in a case like this, other activating pathways, projecting to the cerebral cortex without relaying through the thalamus, could stimulate the cerebral cortex to provide internal awareness, even if physicians are unable to detect its manifestations. [2]

Hence, the paper of Giacino et al. represents a remarkable effort to identify and diagnose a new syndrome of consciousness impairment, along a continuum of brain damage. Nonetheless, I would use the term minimally aware state instead of minimally conscious state.

References:

1. Plum F. Coma and related global disturbances of the human conscious state. New York, Plenum Publishing Corporation. Cerebral Cortex. A. Peters. Ref Type: Serial (Book, Monograph) 1991;[9]:359-425.

2. Machado C. Consciousness as a definition of death: its appeal and complexity. Clin Electroencephalogr 1999; 30:156-164.

3. Giacino JT, Ashwal S, Childs N et al. The minimally conscious state: definition and diagnostic criteria. Neurology 2002; 58:349-353.

4. Truog RD, Fackler JC. Rethinking brain death. Crit Care Med 1992; 20:1705-1713.

5. Kinney HC, Korein J, Panigrahy A, Dikkes P, Goode R. Neuropathological findings in the brain of Karen Ann Quinlan. The role of the thalamus in the persistent vegetative state. N Engl J Med 1994; 330:1469-1475.

24 June 2002
The minimally conscious state: Definition and diagnostic criteria
William J Burke

The definition of yet another dubious diagnosis, the minimally conscious state (MCS). [1] makes it apparent that a few members are hijacking the Academy to promote their own eugenic social agenda. The MCS diagnosis attempts to extend beyond the persistent vegetative state (PVS) justification for terminating the brain-injured disabled. [2, 3, 4] In the process, these social engineers are transforming neurologists into IQ police whose job it will be to interrogate their patients for the exact intelligence information required to avoid the death penalty. The warning of our fellow neurologist, Dr. Leo Alexander, who served on the staff of the Office of Chief Counsel for War Crimes at Nuremberg, holds true now as ever. Writing about the Holocaust, he states:

"Whatever proportions these crimes [the Nazi war crimes] finally assumed, it became evident to all who investigated them that they had started from small beginnings. The beginnings at first were merely a subtle shift in emphasis in the basic attitude of the physicians. It started with the acceptance of the attitude, basic in the euthanasia movement, that there is such a thing as life not worthy to be lived. Gradually, the sphere of those to be included in this category was enlarged…but it is important to realize that the infinitely small wedged- in lever from which this entire trend of mind received its impetus was the attitude toward the nonrehabilitable sick." [5]

References:

1. Giacino JT, Ashwal S, Childs N et al. The minimally conscious state: Definition and diagnostic criteria. Neurology 2002;58:349-353.

2. In re the Conservatorship of Robert Wendland, Superior Court of California, County of San Joaquin, Case No. 65669.

3. Coleman D. The minimally conscious state: Definition and diagnostic criteria. Neurology 2002;58:506-507.

4. Ibid, Shewmon DA.

5. Alexander L. Medical science under a dictatorship N Engl J Med 1949;241:44-49.

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Neurology®
Volume 58Number 3February 12, 2002
Pages: 349-353
PubMed: 11839831

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Published online: February 12, 2002
Published in print: February 12, 2002

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Affiliations & Disclosures

J.T. Giacino, PhD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
S. Ashwal, MD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
N. Childs, MD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
R. Cranford, MD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
B. Jennett, MD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
D.I. Katz, MD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
J.P. Kelly, MD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
J.H. Rosenberg, MD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
J. Whyte, MD PhD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
R.D. Zafonte, DO
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.
N.D. Zasler, MD
The American Academy of Neurology has reviewed this document and recommends it to Academy membership as an educational tool. This document has been endorsed by the American Academy of Physical Medicine and Rehabilitation, the American Association of Neurological Surgeons, the American Congress of Rehabilitation Medicine, the Brain Injury Association, Inc., and the Child Neurology Society., From the JFK Medical Center (Dr. Giacino), Edison, NJ; Loma Linda University Medical Center (Dr. Ashwal), CA; Brown Schools Rehabilitation Center (Dr. Childs), Austin, TX; Hennepin County Medical Center (Dr. Cranford), Minneapolis, MN; University of Glasgow (Dr. Jennett), United Kingdom; Boston University School of Medicine (Dr. Katz), MA; Chicago Neurological Institute (Dr. Kelly), IL; Southern California Permanente Medical Group (Dr. Rosenberg), San Diego; Moss Rehabilitation Research Institute (Dr. Whyte), MossRehab Hospital, Philadelphia, PA; University of Pittsburgh (Dr. Zafonte), PA; and the Concussion Care Center of Virginia (Dr. Zasler), Glen Allen.

Notes

Address correspondence and reprint requests to Dr. Joseph T. Giacino, JFK Johnson Rehabilitation Institute, 2048 Oak Tree Road, Edison, NJ 08820; e-mail: [email protected]

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