Stroke
remains one of the major public health problems in the United States
today, with approximately 500 000 new or recurrent cases occurring
each year.1 About 4 000 000 persons alive today
have survived a stroke and have some neurological deficits. Although
the magnitude of healthcare resources used to treat and rehabilitate
stroke survivors is considerable, to date a standardized, comprehensive
classification system to document the resultant impairments and
disability has not been developed.
Successful management of any disabling disease, including stroke,
should benefit from the use of a classification system to judge the
impact of treatment, particularly emerging therapies. Participants in
the Methodologic Issues in Stroke Outcome
Symposium2 determined that the complex nature of
stroke recovery demands clarification of its natural history and
classification of the variable patterns of functional recovery. For
stroke survivors to receive the best care, a comprehensive stroke
outcome classification system is needed to direct appropriate
therapeutic interventions.3 Building on the work
and recommendations of the Stroke Outcome Symposium, the American Heart
Association Classification of Stroke Outcome Task Force has worked to
develop a valid and reliable global classification system that
accurately summarizes the neurological impairments, disabilities, and
handicaps that occur after stroke.
The development of a stroke outcome classification system is predicated
on the belief that neurological deficits often lead to permanent
impairments, disabilities, and compromised quality of
life.4 5 6 Although a person's ability to
complete daily functional tasks is thought to be largely dependent on
and often limited by the type and degree of impairment, additional
factors are often relevant in the ultimate determination of functional
outcome.7 8 9 Thus, a classification of stroke
outcome should include the broad range of disabilities and impairments
as well as the relationship of disability and impairment to independent
function.
It is important to underscore that impairment alone does not
define level of disability. In a study of stroke
survivors10 it was determined that although a
disability is most directly influenced by impairments, current stroke
scales that measure impairments only partially explained the level of
disability, handicap, or quality of life for those surviving at least 6
months. Some persons adapt well to many and/or severe impairments
caused by stroke. Others with only minimal neurological impairments can
be severely disabled. Many factors determine function, including the
influence of poststroke rehabilitation training and the physical and
social environments.
Approach to Stroke Assessment
The schema for the stroke outcome classification score
presented here is conceptually similar to the New York Heart
Association functional and therapeutic classification of patients with
diseases of the heart framework.11 However,
unlike heart disease, in which the primary limitation is impairment of
physical activity due to chest pain, shortness of breath, and fatigue,
stroke impairs many critical neurological functions, resulting in a
greater number and broader range of physical and social disabilities.
The AHA Stroke Outcome Classification (AHA.SOC) score
(Figure
Components of the AHA Stroke Outcome Classification Score
Classification of Neurological Impairments
Potentially affected neurological domains are
The domains of stroke impairments are documented both in the
number and severity of the neurological deficits observed. When >1
domain is affected, severity is defined by the most impaired domain.
The categories for the number of domains involved after stroke are
Level 0, no domains impaired; Level 1, 1 domain impaired; Level 2, 2
domains impaired; and Level 3, >2 domains impaired. For stroke
severity, impairment is classified as being either Level A, minimal or
no neurological deficit due to stroke in the above domains; Level B,
mild/moderate deficit due to stroke; or Level C, severe deficit due to
stroke.
The neurological examination is the basis for determining
neurological impairments in the AHA.SOC score. However, the task force
recommends that clinicians support their rating decisions by using
standardized assessment measures whenever possible. The Appendix
describes several available, well-documented assessment instruments
that have been tested in stroke populations. This listing is suggestive
and not all-inclusive of other available measures.
Classification of Functional Disabilities and
Handicap
Application of the AHA Stroke Outcome Classification Score to
Sample Cases
The following cases illustrate the decision-making process and use
of the AHA.SOC in assessments of 3 stroke patients.
Case 1: A 62-year-old man has an ischemic
infarct in the left hemisphere. Neurologically he is cognitively
intact, not depressed, and able to communicate. He has no residual
weakness or sensory loss. Three months after the stroke he is living
independently at home without healthcare assistance for basic daily
activities. He manages routine household maintenance and needs
assistance only with community activities such as shopping and banking.
The stroke classification score for this patient is number of
domains impaired=0; stroke severity=A; functional classification=Level
II. AHA.SOC score=0.A.II.
Case 2 is a 74-year-old woman with a large-vessel infarct in
the right hemisphere. Neurologically she has the following residual
impairments: partial hemianopia, facial palsy, and sensory loss and
weakness in the upper and lower left extremities. She is not depressed
and is cognitively intact. She lives at home with professional home
healthcare assistance. She requires the assistance of another person to
access the community. She is unable to do housekeeping tasks or prepare
meals. She can take her own medications and use a telephone; however,
she cannot bathe independently or climb stairs. The stroke
classification score for this patient is number of domains
impaired=3; stroke severity=B; functional classification level=lll.
AHA.SOC score=3.B.III.
Case 3 is an 85-year-old woman with a right-hemisphere
infarct who lives in a skilled-nursing facility. She has paralysis of
the left upper and lower extremities, partial hemianopia, cognitive
impairment, and depression. She eats independently but is incontinent
and needs help with dressing, bathing, toileting, and mobility-related
activities. She cannot manage her medications, prepare her meals, use
the telephone, or access the community without special transportation
arrangements. The stroke classification score for this patient is
number of domains impaired=3; stroke severity score=C; functional
classification level=V. AHA.SOC score=3.C.V.
Conclusion
New therapies and improved survival after stroke provide an
opportune time to develop a stroke outcome classification system that
measures the full range of domains affected by stroke. The AHA.SOC
score provides a mechanism to comprehensively document stroke
impairments and disabilities in a single summary stroke score. The
system can be used by healthcare providers to reliably assess recovery,
measure responses to treatment, and describe the long-term impact of
stroke on survivors.
Acknowledgments
We thank Sue Min Lai, PhD, for her statistical assistance with
this project.
Footnotes
"The American Heart Association Stroke Outcome Classification" was approved by the American Heart Association Science Advisory and Coordinating Committee in December 1997. The full text version is being published simultaneously in Stroke.
A single reprint is available by calling 800-242-8721 (US only) or writing the American Heart Association, Public Information, 7272 Greenville Avenue, Dallas, TX 75231-4596. Ask for reprint No. 71–0144. To purchase additional reprints: up to 999 copies, call 800-611-6083 (US only) or fax 413-665-2671; 1000 or more copies, call 214-706-1466, fax 214-691-6342, or
References
© 1998 American Heart Association, Inc.
AHA Scientific Statement
The American Heart Association Stroke Outcome Classification: Executive Summary
Key Words: AHA Medical/Scientific Statements • stroke • prognosis • stroke outcome • disability evaluation
) classifies the severity and
extent of neurological impairments that are the basis for disability.
The classification also identifies the level of independence of stroke
patients according to basic and more complex activities of daily living
both at home and in the community. The classification score is meant to
describe the limitations resulting from the current stroke. It is not
an evaluation of disabilities caused by other neurological events.
Furthermore, it is a summary score. The task force recommends that
clinicians support their rating decisions with standardized assessment
instruments whenever possible.
View larger version (45K):
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Figure 1. American Heart Association Stroke Outcome Classification
(AHA.SOC). BADL indicates Basic Activities of Daily Living:
feeding and swallowing, grooming, dressing, bathing, continence,
toileting, and mobility; and IADL, Instrumental Activities of
Daily Living: using the telephone, handling money, shopping, using
transportation, maintaining a household, working, participating in
leisure activities, etc.
The first area of assessment in the AHA.SOC score is the
evaluation of neurological impairment. A complete clinical examination
is the basis for documenting the major domains of neurological
impairment.12 In this classification schema the
number of affected domains is recorded as well as severity of
impairments.
The second major area of assessment in determining the stroke
outcome classification score is the evaluation of function in terms of
resultant disability. Disability is defined as "any restriction or
lack of ability to perform an activity in a manner or within the range
considered normal for a human being."4 The
basic self-care tasks are feeding; grooming; dressing; bathing;
toileting, including sphincter control; and mobility, including
transferring from place to place. These are called basic
activities of daily living (BADL). Independence in BADL
could enable the stroke patient to live at home with help from family
or community providers for meals and other household tasks as needed.
More complex activities of daily living are called instrumental
activities of daily living (IADL). These tasks are
performed to maintain independence in the home and community and
include shopping, using transportation, telephoning, preparing meals,
handling finances, and maintaining a household. Independence in these
activities enables the stroke patient to be discharged to home without
being dependent on others. Other instrumental activities of daily
living that affect quality of life are work skills, religious
activities, and leisure-time and recreational activities (see
Appendix).
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Table 1. Appendix: Stroke Deficit Scales
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Table 2. Appendix: Stroke Deficit Scales
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Table 3. Appendix: Language Scales
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Table 4. Appendix: Depression
Scales
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Table 5. Appendix: BADL Scales
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Table 6. Appendix: IADL Scales
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