30/03/2025
Objective
The Patient- Specific Functional Scale was developed by Stratford et al 1995 as a self-report outcome measure of function that could be used in patients with varying levels ofindependence. .[1] The aim of PSFS is to provide clinicians with a valid, reliable, responsive and efficient outcome measure that would be easy to use and applicable to a large number of clinical presentations.[2]
Intended Population
The PSFS is a self-reported valid, reliable, and responsive outcome measure for patients with back, neck, knee and upper extremity problems[3][4]. It has also been shown to have a high test-retest reliability in both generic lower back pain and knee dysfunction issues.[5][1] It is also clinically responsive to changes over time with chronic pain patients[6]
Method of Use
Patients are asked to identify up to five important activities they are unable to perform or are having difficulty with as a result of their problem eg putting socks on, shopping.
Patients are asked to rate (on an 11-point scale) the current level of difficulty associated with each activity.
Following the intervention, patients are asked again to rate the activities previously identified (and are given the chance to nominate new problematic activities that might have arisen during that time).
"0" represents “unable to perform” and "10" represents “able to perform at prior level”
Patients select a value that best describes their current level of ability on each activity assessed.
Advantages
Gives the patient positive re-enforcement that the intervention is effective[7]
Keeps therapy goal orientated
Quick to complete
Relatively easy for patients to complete
Helpful to redirect subjective assessment to function as opposed to pain
Can be used on a wide variety of musculoskeletal and neurological conditions[8]
Disadvantages
Not obtaining a final PSFS score. For example if a patient cancels their final appointment it is not always possible to ask for the score completion.[7]
Some patients can find rating their activities on a numerical scale difficult
Not specific to condition
May require further outcome measures specific to condition to be completed[4]
Evidence
The PSFS is a valid, reliable, and responsive outcome measure for patients with back, neck, knee and upper extremity problems[3][4]. It has also been shown to have a high test-retest reliability in both generic lower back pain and knee dysfunction issues.[5]
Reliability
A study into cervical radiculopathy found the test-retest reliability of the PSFS to be high (Intraclass correlation coefficient = 0.82; 95% Confidence interval= 0.54–0.93) in comparison with the Neck Disability Index.[9]
Moderate to good reliability for patient with upper extremity musculoskeletal problems ICC = 0,713.[10]
Poor reliability exhibited in patient with cervical radiculopathy.[11]
Validity
PSFS is a valid tool (p
