Functional Ambulation Categories (FAC)

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 between examiners, as measured using kappa statistics was found to be poor (k=0.36).

Mehrholz et al. (2007) examined the inter-rater reliability in this study.

Test-retest
Mehrholz et al. (2007) examined the 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 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 RAC 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/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 adequate to significant 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 to change as measured by the standard response mean (SRM) 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.