Functional Ambulation Categories (FAC)
Purpose
The Functional Ambulation
Categories (FAC) is a functional walking test that evaluates ambulation ability. This 6-point scale assesses ambulation status by determining how much human support the patient requires when walking, regardless of whether or not they use a personal assistive device (Teasdall, Foley & Salter, 2011). The FAC can be used with, but is not limited to, patients with stroke
In-Depth Review
Purpose of the measure
The Functional Ambulation
Categories (FAC) is a functional walking test that evaluates ambulation ability. This 6-point scale assesses ambulation status by determining how much human support the patient requires when walking, regardless of whether or not they use a personal assistive device (Teasell et al., 2011). The FAC does not evaluate endurance, as the patient is only required to walk approximately 10 ft (Holden, Gill, Magliozzi, Nathan & Piehl-Baker, 1984). The FAC can be used with, but is not limited to, patients with stroke
Available versions
The FAC was developed at Massachusetts General Hospital and first described by Holden et al. in 1984.
Features of the measure
Items:
There are no actual items to the FAC.
To use the FAC, an assessor asks the subject various questions (Mehrholz et al., 2007) and briefly observes their walking ability to provide a rating from 0 to 5 (Collen, Wade and Bradshaw, 1990).
- A score of 0 indicates that the patient is a non-functional ambulator (cannot walk);
- A score of 1, 2 or 3 denotes a dependent ambulator who requires assistance from another person in the form of continuous manual contact (1), continuous or intermittent manual contact (2), or verbal supervision/guarding (3)
- A score of 4 or 5 describes an independent ambulator who can walk freely on: level surfaces only (4) or any surface (5=maximum score) (Holden et al., 1984)
What to consider before beginning:
To prepare for the FAC, the client should be encouraged to:
- Wear comfortable clothing
- Wear appropriate footwear
- Use their usual walking aides during the test (cane, walker, etc.)
To prepare for the FAC, clinicians should be aware that provision of human support to the patient may be required.
Scoring and Score Interpretation:
| Score | Category | Interpretation |
| 0 | Nonfunctional ambulator | |
| 1 | Ambulator, dependent on physical assistance – level I | Indicates a patient who requires continuous manual contact to support body weight as well as to maintain balance or to assist coordination. |
| 2 | Ambulator, dependent on physical assistance – level II | Indicates a patient who requires intermittent or continuous light touch to assist balance or coordination. |
| 3 | Ambulator, dependent on supervision | Indicates a patient who can ambulate on level surface without manual contact of another person but requires standby guarding of one person either for safety or verbal cueing. |
| 4 | Ambulator, independent level surface only | Indicates a patient who can ambulate independently on level surface but requires supervision to negotiate (e.g. stairs, inclines, nonlevel surfaces). |
| 5 | Ambulator, independent | Indicates a patient who can walk everywhere independently, including stairs. |
(Mehrholz et al., 2007)
Time:
The average completion time has not been reported, however, it is estimated that the FAC takes approximately 1 to 5 minutes to complete.
Training requirements:
No special training is required to administer the FAC but the administrator should be familiar with the scale prior to its use.
Subscales:
None typically reported.
Equipment:
The FAC does not require any specialized equipment and can therefore be accomplished in community as well as institutional settings.
- Ten feet path free from obstruction
- Stairs and uneven terrain in order to evaluate category 5 (Ambulator, independent)
Alternative Forms of the assessment
Also known as Functional Ambulation
Classification.
There are no alternative forms of the FAC.
Client suitability
Can be 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./hemiplegia (acute, subacute, and chronic) (Holden et al., 1984, 1986; Hesse et al. 1994)
Other groups tested with this measure:
- Multiple Sclerosis (Holden et al., 1984, 1986)
- Cerebral Palsy (Schindl et al., 2000).
Should not be used with:
- A proxy – because the FAC is administered through direct observation, a proxy respondent cannot be used.
In what languages is the measure available?
No information available. As it is not a measure with specific items that are asked of the patient it is likely the scale can be used by any clinician who understands English sufficiently well to differentiate the coding structure.
Summary
| What does the tool measure? | It is a functional walking test that assesses ambulation status by determining how much human support the patient requires. |
| What types of clients can the tool be used for? | Clients with stroke |
| Is this a screening or assessment tool? |
Assessment |
| Time to administer | Approximately 1 to 5 minutes. |
| Versions | Also referred to as Functional Ambulation Classification. There are no alternative versions. |
| Other Languages | None reported. |
| Measurement Properties | |
| Reliability |
Test-retest: One study examined the test-retest reliability of the FAC and found the test to have excellent test-retest reliability (k=.950). Inter-rater: |
| Validity |
Criterion: Concurrent: One study examined the concurrent validity of the FAC and reported excellent correlations with Rivermead Mobility Index, 6 Minute Walk Test, walking velocity and stride length. Predictive: One study examined the predictive validity of the FAC in patients with stroke |
| Does the tool detect change in patients? | Earlier studies suggested that the FAC may lack responsiveness , especially if using it to distinguish between groups at lower levels of functioning (Teasdall et al., 2011), however, a recent study reported moderates to larges effect sizes when the FAC was used to evaluate change in ambulation over a period of 6-months (Mehrholz et al., 2007). Future research is required to determine the responsiveness of the FAC in assessing patients at various levels of functioning. |
| Acceptability | Administration of the FAC is simple, requiring only brief questioning and observation, thereby creating minimal patient burden. |
| Feasibility | The FAC is quick and easy to use and the scale can be obtained at no cost. Also, there is no equipment that needs to accompany administration of the scale. No formal training is required to administer the FAC but the user should be familiar with the scale prior to its use. |
| How to obtain the tool? | Please visit: http://www.rehabmeasures.org |
Psychometric Properties
Overview
We conducted a literature search to identify all relevant publications on the psychometric properties of the FAC in individuals with stroke
, validity
and responsiveness
of the FAC.
Floor/Ceiling Effects
No studies have reported on the floor/ceiling effects of the FAC with patients with stroke
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 reported on 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 FAC 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..
Test-retest:
Mehrholz et al. (2007) 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).
(one week apart) of the FAC by administering the measure to a sample of 55 clients with stroke (< 60 days since onset). The correlationThe extent to which two or more variables are associated with one another. A correlation can be positive (as one variable increases, the other also increases – for example height and weight typically represent a positive correlation) or negative (as one variable increases, the other decreases – for example as the cost of gasoline goes higher, the number of miles driven decreases. There are a wide variety of methods for measuring correlation including: intraclass correlation coefficients (ICC), the Pearson product-moment correlation coefficient, and the Spearman rank-order correlation.
between the two evaluations was excellent (k=.950), indicating that the FAC has excellent 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).
.
Intra-rater:
No studies have reported on 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 FAC in 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..
Inter-rater:
Collen, Wade and Bradshaw (1990) investigated the inter-rater reliability
of the FAC in 25 patients with chronic stroke
between examiners, as measured using kappa statistics was found to be be poor (k=0.36).
Mehrholz et al. (2007) examined the inter-rater reliability
of the FAC in 55 clients with subacute stroke
was found to be excellent (k.905). Researchers believe that the use of key questions, video recordings and experienced examiners improved the inter-rater reliability
in this study.
Validity
Content:
No studies have reported on 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 FAC with patients with stroke
Criterion:
No studies have reported on the criterion validityExamines the extent to which a measure provides results that are consistent with a gold standard . It is typically divided into concurrent validity and predictive validity .
of the FAC 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..
Concurrent:
Mehrholz et al. (2007) 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 FAC and commonly used measures of gaitThe pattern of walking, which is often characterized by elements of progression, efficiency, stability and safety.
performance, the Rivermead Mobility Index (RMI), 6 Minute Walk Test (6MWT), walking velocity and stride length in 55 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.. Evaluations were performed at admission, 2 and 4 weeks, and 6 months. 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.”
was measured using Spearman correlations. Correlations between the FAC and RMI, 6MWT, walking velocity and stride length from baseline to 6-months were excellent (k=.841; k=.795; k=767; k=.805 respectively).
Predictive:
Mehrholz et al. (2007) examined whether FAC scores assessed following a 4-week rehabilitation program could predict functional community ambulation at 6-month follow-up in 55 patients with subacute 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.. Community ambulation was defined as the ability to walk faster than 73m/min, longer than 332m, climb stairs and curbs; patients that met all three community ambulation criteria were deemed community ambulators. 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.
, as calculated using a Receiver Operating Characteristic (ROC) curve, was highest for ROC cut-off scores ≥ 4 (AUC = 0.89). Thus scoring ≥ 4 on the FAC following a 4-week rehabilitation program is predictive of community ambulation at 6-months.
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:
No studies have reported on 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.”
or the specificitySpecificity refers to the probability that a diagnostic technique will indicate a negative test result when the condition is absent (true negative).
of the FAC 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..
Construct:
Convergent/Discriminant:
No studies have reported on the convergent/discriminant validityThe degree to which an assessment measures what it is supposed to measure.
of the FAC 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..
Known Groups:
No studies have reported on the known groups validity
of the FAC with patients with stroke
Responsiveness
Earlier studies have suggested that the FAC may lack responsivenessThe ability of an instrument to detect clinically important change over time.
, especially when being used to differentiate between groups at lower levels of functioning (Teasdall et al., 2011). However, a recent study reported moderates to larges effect sizes when the FAC was used to evaluate change in ambulation over a period of 6-months (Mehrholz et al., 2007). Future research is required to determine the responsivenessThe ability of an instrument to detect clinically important change over time.
of the FAC in assessing patients at various levels of functioning.
Mehrholz et al. (2007) assessed the responsivenessThe ability of an instrument to detect clinically important change over time.
of the FAC in evaluating recovery of walking ability in 55 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. who could not walk without assistance prior to initiating inpatient rehabilitation. The mean score at baseline was 0.44 +/- 0.69 and the mean score at discharge was 2.79 +/- 2.12. The responsivenessThe ability of an instrument to detect clinically important change over time.
to change as measured by the standard response mean (SRM) was was moderate to large: FAC scores changed significantly within the first 2 weeks of the study (SRM=1.016) and between week 4 and study end date at 6 months (SRM=.699); and adequately within weeks 2 and 4 (SRM=.842). The results of this study suggest that the FAC can be used to measure change and outcome in gaitThe pattern of walking, which is often characterized by elements of progression, efficiency, stability and safety.
performance in 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..
References
- Brock, J.A., Goldie, P.A. & Greenwood, K.M. (2002). Evaluating the effectiveness of stroke rehabilitation: Choosing a discriminative measure. Archives of Physical Medicine Rehabilitation, 83, 92-99.
- Collen, F.M., Wade, D.T. & Bradshaw, C.M. (1990). Mobility after stroke: Reliability of measures of impairment and disability. International Disability Studies, 12, 6-9.
- Cunha, I.T., Lim, P.A., Henson, H., Monga, T., Qureshy, H. & Protas, E.J. (2002). Performance-based gait tests for acute stroke patients. American Journal of Physical Medicine Rehabilitation, 81, 848-856.
- Hesse, S., Bertelt, C., Schaffrin, A., Malezic, M. & Mauritz, K.H. (1994). Restoration of gait in nonambulatory hemiparetic patients by treadmill training with partial body-weight support. Archives of Physical Medicine Rehabilitation, 75, 1087-1093.
- Holden, M.K., Gill, K.M., Magliozzi, M.R., Nathan, J. & Piehl-Baker, L. (1984). Clinical gait assessment in the neurologically impaired. Reliability and meaningfulness. Physical Therapy, 64, 35-40.
- Holden, M.K., Gill, M.K. & Magliozzi, M.R. (1986). Gait and assessment for neurologically impaired patients. Standards for outcome assessment. Physical Therapy, 66, 1530-1539.
- Lord, S.E., McPherson, K., McNaughton, H.K., Rochester, L., Weatherall, M. (2004). Community ambulation after stroke: How important and obtainable is it and what measures appear predictive? Archives of Physical Medicine Rehabilitation, 85, 234-239.
- Mehrholz, J., Wagner, K., Rutte, K., Meiner, D. and Pohl, M. (2007). Predictive validity and responsiveness of the Functional Ambulation Category in hemiparetic patients after stroke. Archives of Physical Medicine Rehabilitation, 88, 1314-1319.
- Schindl, M.R., Forstner, C., Kern, H. & Hesse, S. (2000). Treadmill training with partial body weight support in nonambulatory patients with cerebral palsy. Archives of Physical Medicine Rehabilitation, 81, 301-306.
- Simondson, J.A., Goldie, P., Greenwood, K.M. (2003). The Mobility Scale for Acute Stroke Patients: Concurrent validity. Clinical Rehabilitation, 17, 558-564.
- Stevenson, T.J. (1999). Using impairment inventory scores to determine ambulation status in individuals with stroke. Physiotherapy Canada, 51, 168-174.
- Teasell, R., Foley, N. C., & Salter K. (2011). EBRSR: Evidence-Based Review of Stroke Rehabilitation. 13th ed. London (ON): EBRSR.
See the measure
How to obtain the Functional AmbulationThe ability to walk, with or without the aid of appropriate assistive devices (such as canes or walkers), safely and sufficiently to carry out mobility-related activities of daily living (ADLs). From Perry et al (1995), functional ambulation is referred to as walking in parallell bars for exercise at a speed of about 10/cm per second.
Categories?
Please visit: http://www.rehabmeasures.org and search “Functional Ambulation
Classification” or “Functional Ambulation
Categories”.