Functional Ambulation Categories (FAC)

Evidence Reviewed as of before: 23-06-2011
Author(s): Katie Marvin, MSc. (Candidate)
Editor(s): Nicol Korner-Bitensky, PhD OT; Annabel McDermott, OT

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 stroke/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, Multiple Sclerosis and Cerebral Palsy.

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:
Two studies examined the inter-rater reliability of the FAC and found the test to have poor to excellent inter-rater reliabilities (k=.36 and k=.905).

Validity

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 and found it to be an adequate predictor of functional community ambulation 6 months after 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. We identified four studies. More studies are required before definitive conclusions can be drawn regarding the reliability, 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. However given that it measures the full range of functional walking floor/ceiling effects are not expected.

Reliability

Internal Consistency:
No studies have reported on the internal consistency of the FAC with patients with stroke.

Intra-rater:
No studies have reported on the intra-rater reliability of the FAC in patients with stroke.

Inter-rater:
Collen, Wade and Bradshaw (1990) investigated the inter-rater reliability of the FAC in 25 patients with chronic stroke (2 to 6 years of stroke with residual impaired mobility). Inter-rater reliability 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 admitted to a rehabilitation hospital. Clients were within 2-months post stroke. Inter-rater reliability 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.

Test-retest:
Mehrholz et al. (2007) examined the test-retest reliability (one week apart) of the FAC by administering the measure to a sample of 55 clients with stroke (< 60 days since onset). The correlation between the two evaluations was excellent (k=.950), indicating that the FAC has excellent test-retest reliability.

Validity

Content:
No studies have reported on the content validity of the FAC with patients with stroke.

Criterion:
No studies have reported on the criterion validity of the FAC with patients with stroke.

Concurrent:
Mehrholz et al. (2007) examined the concurrent validity of the FAC and commonly used measures of gait performance, the Rivermead Mobility Index (RMI), 6 Minute Walk Test (6MWT), walking velocity and stride length in 55 patients with stroke. Evaluations were performed at admission, 2 and 4 weeks, and 6 months. Concurrent validity 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 stroke. 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 validity, 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.

Sensitivity/Specificity:
No studies have reported on the sensitivity or the specificity of the FAC with patients with stroke.

Construct:
Convergent/Discriminant:
No studies have reported on the convergent/discriminant validity of the FAC with patients with stroke.

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 responsiveness, 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 responsiveness of the FAC in assessing patients at various levels of functioning.

Mehrholz et al. (2007) assessed the responsiveness of the FAC in evaluating recovery of walking ability in 55 patients with stroke 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 responsiveness 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 gait performance in patients with stroke.

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 Ambulation Categories?

Please visit: http://www.rehabmeasures.org and search “Functional Ambulation Classification” or “Functional Ambulation Categories”.

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