Disability Assessment Scale (DAS)

Purpose

The Disability Assessment Scale (DAS) evaluates upper limb functional disability in patients with spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
following strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain.

In-Depth Review

Purpose of the measure

The Disability Assessment Scale (DAS) evaluates upper-limb functional disability in patients with spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
following strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain.. The DAS was developed as a tool that objectively evaluates functional impairment resulting from spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
.

Available versions

None reported.

Features of the measure

Items:

• Hand hygiene
  • Extent of palm maceration, ulceration or infection.
  • Cleanliness of the palm, ease of cleaning, nail trimming.
  • Effect of hygiene-related disability on other areas of functioning.
• Dressing
  • Ability to dress.
  • Effect of dressing-related disability on other areas of functioning.
• Limb position abnormality.
  • Amount of abnormal limb position.
• Pain
  • Intensity of pain or discomfort related to upper-limb spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
    .
  • Interference with activitiesAs defined by the International Classification of Functioning, Disability and Health, activity is the performance of a task or action by an individual. Activity limitations are difficulties in performance of activities. These are also referred to as function.
    of daily living.

Description of tasks:

Patients are interviewed to determine the extent of functional impairment for the following 4 areas:

• Hygiene: The rater assesses the extent of palm maceration, ulceration, or infection; cleanliness of the palm, ease of cleaning, and nail trimming; and the effect of hygiene-related disability on other areas of functioning.
• Dressing: The rater assess the patient’s ability to dress and the effect of dressing-related disability on other areas of functioning.
• Limb position: The rater assesses the amount of abnormal position of the limb; and
• Pain: The rater assesses the intensity of pain or discomfort related to upper-limb spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
  and interference with activitiesAs defined by the International Classification of Functioning, Disability and Health, activity is the performance of a task or action by an individual. Activity limitations are difficulties in performance of activities. These are also referred to as function.
  of daily living.

Scoring and Score Interpretation:

The DAS Scale uses a 4-point rating scale according to the following criteria:

• 0 – no disability.
• 1 – mild disability (noticeable but does not interfere significantly with normal activitiesAs defined by the International Classification of Functioning, Disability and Health, activity is the performance of a task or action by an individual. Activity limitations are difficulties in performance of activities. These are also referred to as function.
  .
• 2 – moderate disability (normal activitiesAs defined by the International Classification of Functioning, Disability and Health, activity is the performance of a task or action by an individual. Activity limitations are difficulties in performance of activities. These are also referred to as function.
  require increased effort and/or assistance).
• 3 – severe disability (normal activitiesAs defined by the International Classification of Functioning, Disability and Health, activity is the performance of a task or action by an individual. Activity limitations are difficulties in performance of activities. These are also referred to as function.
  limited).

Time:

Not typically reported.

Training requirements:

None reported.

Subscales:

None

Equipment:

None reported.

Alternative Forms of the Disability Assessment Scale

None reported.

Client suitability

Can be used with:

• Clients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. with spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
  .

Should not be used with:

• Clients without spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
  .

Languages of the measure

None reported.

Summary

What does the tool measure?	Functional disability in patients with spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke. .
What types of clients can the tool be used for?	The Disability Assessment Scale can be used with, but is not limited to clients with post-strokespasticity.
Is this a screeningTesting for disease in people without symptoms. or assessment tool?	Assessment
Time to administer	Not reported
Versions	None
Other Languages	None
Measurement Properties
ReliabilityReliability can be defined in a variety of ways. It is generally understood to be the extent to which a measure is stable or consistent and produces similar results when administered repeatedly. A more technical definition of reliability is that it is the proportion of “true” variation in scores derived from a particular measure. The total variation in any given score may be thought of as consisting of true variation (the variation of interest) and error variation (which includes random error as well as systematic error). True variation is that variation which actually reflects differences in the construct under study, e.g., the actual severity of neurological impairment. Random error refers to “noise” in the scores due to chance factors, e.g., a loud noise distracts a patient thus affecting his performance, which, in turn, affects the score. Systematic error refers to bias that influences scores in a specific direction in a fairly consistent way, e.g., one neurologist in a group tends to rate all patients as being more disabled than do other neurologists in the group. There are many variations on the measurement of reliability including alternate-forms, internal consistency , inter-rater agreement , intra-rater agreement , and test-retest .	Intra-rater: One study examined the intra-rater reliabilityThis is a type of reliability assessment in which the same assessment is completed by the same rater on two or more occasions. These different ratings are then compared, generally by means of correlation. Since the same individual is completing both assessments, the rater’s subsequent ratings are contaminated by knowledge of earlier ratings. of the DAS in patients with spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke. following strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. and found adequate to excellent intra-rater reliabilityThis is a type of reliability assessment in which the same assessment is completed by the same rater on two or more occasions. These different ratings are then compared, generally by means of correlation. Since the same individual is completing both assessments, the rater’s subsequent ratings are contaminated by knowledge of earlier ratings. . Inter-rater: One study examined the inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept. of the DAS in patients with spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke. following strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. and found adequate to excellent inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept. .
ValidityThe degree to which an assessment measures what it is supposed to measure.	No studies have examined the validityThe degree to which an assessment measures what it is supposed to measure. of the DAS.
Floor/Ceiling Effects	No studies have examined the floor/ceiling effects of the DAS.
Does the tool detect change in patients?	The responsivenessThe ability of an instrument to detect clinically important change over time. of the DAS has not formally been studied, however the DAS has been used to measure change in spasiticity in a clinical trial with patients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain..
Acceptability	The DAS is one of the only tools available for evaluation of upper limb functional disability in patients with spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke. following strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain..
Feasibility	There is a lack of information about the DAS, affecting ease of administration.
How to obtain the tool?	See: Brashear, A., Zafonte, R., Corcoran, M., Galvez-Jimenez, N., Gracies, J-M., Gordon, M.F., et al. (2002). Inter- and Intrarater reliabilityReliability can be defined in a variety of ways. It is generally understood to be the extent to which a measure is stable or consistent and produces similar results when administered repeatedly. A more technical definition of reliability is that it is the proportion of “true” variation in scores derived from a particular measure. The total variation in any given score may be thought of as consisting of true variation (the variation of interest) and error variation (which includes random error as well as systematic error). True variation is that variation which actually reflects differences in the construct under study, e.g., the actual severity of neurological impairment. Random error refers to “noise” in the scores due to chance factors, e.g., a loud noise distracts a patient thus affecting his performance, which, in turn, affects the score. Systematic error refers to bias that influences scores in a specific direction in a fairly consistent way, e.g., one neurologist in a group tends to rate all patients as being more disabled than do other neurologists in the group. There are many variations on the measurement of reliability including alternate-forms, internal consistency , inter-rater agreement , intra-rater agreement , and test-retest . of the Ashworth Scale and the Disability Assessment Scale in patients with upper-limb poststroke spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke. . Archives of Physical Medicine Rehabilitation, 83, 1349-1351.

Psychometric Properties

Overview

A literature search was conducted to identify all relevant publications on the psychometric properties of the Disability Assessment Scale when used with patients with strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain.. Only one study was identified. Further studies are required before definitive conclusions can be drawn regarding the reliabilityReliability can be defined in a variety of ways. It is generally understood to be the extent to which a measure is stable or consistent and produces similar results when administered repeatedly. A more technical definition of reliability is that it is the proportion of "true" variation in scores derived from a particular measure. The total variation in any given score may be thought of as consisting of true variation (the variation of interest) and error variation (which includes random error as well as systematic error). True variation is that variation which actually reflects differences in the construct under study, e.g., the actual severity of neurological impairment. Random error refers to "noise" in the scores due to chance factors, e.g., a loud noise distracts a patient thus affecting his performance, which, in turn, affects the score. Systematic error refers to bias that influences scores in a specific direction in a fairly consistent way, e.g., one neurologist in a group tends to rate all patients as being more disabled than do other neurologists in the group. There are many variations on the measurement of reliability including alternate-forms, internal consistency , inter-rater agreement , intra-rater agreement , and test-retest .
and validityThe degree to which an assessment measures what it is supposed to measure.
of the DAS for use with patients following strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain..

Floor/Ceiling Effects

No studies were identified examining the floor/ceiling effects of the DAS.

Reliability

Internal consistencyA method of measuring reliability . Internal consistency reflects the extent to which items of a test measure various aspects of the same characteristic and nothing else. Internal consistency coefficients can take on values from 0 to 1. Higher values represent higher levels of internal consistency.:
No studies have examined the internal consistencyA method of measuring reliability . Internal consistency reflects the extent to which items of a test measure various aspects of the same characteristic and nothing else. Internal consistency coefficients can take on values from 0 to 1. Higher values represent higher levels of internal consistency. of the DAS.

Test-retest:
No studies have examined the test-retest reliabilityA way of estimating the reliability of a scale in which individuals are administered the same scale on two different occasions and then the two scores are assessed for consistency. This method of evaluating reliability is appropriate only if the phenomenon that the scale measures is known to be stable over the interval between assessments. If the phenomenon being measured fluctuates substantially over time, then the test-retest paradigm may significantly underestimate reliability. In using test-retest reliability, the investigator needs to take into account the possibility of practice effects, which can artificially inflate the estimate of reliability (National Multiple Sclerosis Society).
of the DAS.

Intra-rater:
Brashear et al. (2002) investigated the intra-rater reliabilityThis is a type of reliability assessment in which the same assessment is completed by the same rater on two or more occasions. These different ratings are then compared, generally by means of correlation. Since the same individual is completing both assessments, the rater’s subsequent ratings are contaminated by knowledge of earlier ratings.
of the DAS in nine patients with spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
following strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain.. All patients were evaluated twice on the same day by 10 trained evaluators. Inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept.
, as calculated using overall weighted kappa scores, was adequate to excellent (k=0.520, 0.530, 0.775 and 0.776 for hygiene, dressing, limb position and pain respectively).

Inter-rater:
Brashear et al. (2002) investigated the inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept.
of the DAS in nine patients with spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
following strokeAlso called a "brain attack" and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a "schemic stroke", or the formation of a blood clot in a vessel supplying blood to the brain.. All patients were evaluated twice on the same day (at least an hour apart) by 10 trained evaluators. Inter-rater reliabilityA method of measuring reliability . Inter-rater reliability determines the extent to which two or more raters obtain the same result when using the same instrument to measure a concept.
, as calculated using Kendall’s W, was adequate to excellent (Kendall’s W=0.494, 0.557, 0.626 and 0.772 for dressing, limb position, hygiene, and pain respectively).

Validity

Content:

No studies have examined the content validityRefers to the extent to which a measure represents all aspects of a given social concept. Example: A depression scale may lack content validity if it only assesses the affective dimension of depression but fails to take into account the behavioral dimension.
of the DAS.

Criterion:

Concurrent:
No studies have examined the concurrent validityTo validate a new measure, the results of the measure are compared to the results of the gold standard obtained at approximately the same point in time (concurrently), so they both reflect the same construct. This approach is useful in situations when a new or untested tool is potentially more efficient, easier to administer, more practical, or safer than another more established method and is being proposed as an alternative instrument. See also “gold standard.”
of the DAS.

Predictive:
No studies have examined the predictive validityA form of criterion validity that examines a measure's ability to predict some subsequent event. Example: can the Berg Balance Scale predict falls over the following 6 weeks? The criterion standard in this example would be whether the patient fell over the next 6 weeks.
of the DAS.

Construct:

Convergent/Discriminant:
No studies have examined the convergent/discriminant validityThe degree to which an assessment measures what it is supposed to measure.
of the DAS.

Known Groups:
No studies have examined the known groups validityKnown groups validity is a form of construct validation in which the validity is determined by the degree to which an instrument can demonstate different scores for groups know to vary on the variables being measured.
of the DAS.

Sensitivity/ Specificity:

No studies have examined the sensitivitySensitivity refers to the probability that a diagnostic technique will detect a particular disease or condition when it does indeed exist in a patient (National Multiple Sclerosis Society). See also "Specificity."
/specificity of the DAS.

Responsiveness

Brashear et al. (2002) investigated the effect of Botulinum Toxin A on arm flexor spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
in 126 patients with strokeAlso called a “brain attack” and happens when brain cells die because of inadequate blood flow. 20% of cases are a hemorrhage in the brain caused by a rupture or leakage from a blood vessel. 80% of cases are also know as a “schemic stroke”, or the formation of a blood clot in a vessel supplying blood to the brain. over a 12-week period. The DAS was administered at baseline 4, 6, 8 and 12-weeks. Although the responsivenessThe ability of an instrument to detect clinically important change over time.
of the DAS was not formally assessed in this study, the scale was sensitive enough to detect an improvement in function following botox treatment.

References

• Brashear, A., Gordon, M.F., Elovic, E., Kassicieh, V.D., Marciniak, C., Do, M., Lee, C-H, Jenkins, S. et al. (2002). Intramuscular injection of botulinum toxin for the treatment of wrist and finger spasticity after a stroke. New England Journal of Medicine, 347(6), 395-400.
• Brashear, A., Zafonte, R., Corcoran, M., Galvez-Jimenez, N., Gracies, J-M., Gordon, M.F., et al. (2002). Inter- and Intrarater reliability of the Ashworth Scale and the Disability Assessment Scale in patients with upper-limb poststroke spasticity. Archives of Physical Medicine Rehabilitation, 83, 1349-1351.

See the measure

Further information on the DAS can be found in the following publication

Brashear, A., Zafonte, R., Corcoran, M., Galvez-Jimenez, N., Gracies, J-M., Gordon, M.F., et al. (2002). Inter- and Intrarater reliabilityReliability can be defined in a variety of ways. It is generally understood to be the extent to which a measure is stable or consistent and produces similar results when administered repeatedly. A more technical definition of reliability is that it is the proportion of “true” variation in scores derived from a particular measure. The total variation in any given score may be thought of as consisting of true variation (the variation of interest) and error variation (which includes random error as well as systematic error). True variation is that variation which actually reflects differences in the construct under study, e.g., the actual severity of neurological impairment. Random error refers to “noise” in the scores due to chance factors, e.g., a loud noise distracts a patient thus affecting his performance, which, in turn, affects the score. Systematic error refers to bias that influences scores in a specific direction in a fairly consistent way, e.g., one neurologist in a group tends to rate all patients as being more disabled than do other neurologists in the group. There are many variations on the measurement of reliability including alternate-forms, internal consistency , inter-rater agreement , intra-rater agreement , and test-retest .
of the Ashworth Scale and the Disability Assessment Scale in patients with upper-limb poststroke spasticityInvoluntary muscle tightness and stiffness that can occur after a stroke. It is characterized by exaggerated deep tendon reflexes that interfere with muscular activity, gait, movement, or speech. Spasticity can increase initially but wane down later on, after stroke.
. Archives of Physical Medicine Rehabilitation, 83, 1349-1351.