Patient Specific Functional Scale (PSFS)

The Patient Specific Functional Scale (PSFS) was developed by Stratford et al. in 1995 as a self-reported outcome measure to individually assess a patient’s functional level. The goal was to provide clinicians with a valid, reliable, responsive, and efficient tool that is simple to use and applicable across a wide range of clinical conditions¹².

Application

PSFS is used to assess functional status in patients with:

• Low back pain (lumbar and cervical)

• Neck pain

• Knee dysfunction

• Upper extremity disorders³⁴

PSFS has shown high test-retest reliability in both nonspecific low back pain and knee dysfunction⁵¹, as well as responsiveness in detecting change in patients with chronic pain⁶.

Method of Use

The patient identifies up to five daily activities that they find difficult or cannot perform due to their condition (e.g., putting on socks, grocery shopping).

Each activity is rated on a 0–10 scale:

• 0 = unable to perform the activity

• 10 = able to perform the activity at pre-injury level

After intervention, the same activities are reassessed, with the option to add new problem areas if the condition has changed.This provides an individualized profile of functional status that can be tracked over time.

Advantages

• Promotes goal-oriented treatment by focusing on specific daily activities⁷

• Provides patients with positive feedback on treatment effect

• Quick and easy to administer, patient-friendly

• Applicable to a wide range of musculoskeletal and neurological conditions⁸

• Shifts focus from pain to function

Disadvantages

• Final PSFS score cannot always be obtained if the patient does not attend the last session⁷

• Some patients may struggle with numerical rating

• Not condition-specific; may require complementary instruments for certain diagnoses⁴

Evidence

Reliability

PSFS has shown:

• High test-retest reliability in cervical radiculopathy (ICC = 0.82; 95% CI = 0.54–0.93), compared with the Neck Disability Index⁹

• Moderate to good reliability in upper extremity disorders (ICC = 0.713)¹⁰

• Lower reliability in cervical radiculopathy in some studies¹¹

Validity

PSFS is a valid tool to identify patients with upper extremity functional limitations (p < 0.001)¹⁰.

Responsiveness

PSFS demonstrates adequate responsiveness in cervical radiculopathy, with a change score of 3.3 points, while the minimal clinically important difference (MCID) is 2.2 points¹¹.

Clinical Relevance

PSFS is a flexible, individualized outcome measure that provides valuable insight into how patients perceive functional impairment in daily life. It can be used to:

• Set targeted treatment goals

• Track progression in clinical practice

• Document treatment outcomes

• Increase patient engagement

Patient Specific Functional Scale (PSFS) – Scoring Sheet

Patient name: ___________________________Date: ___________________________

Instruction: Please list up to five daily activities that you have difficulty performing or cannot perform due to your current condition/problem. Then rate each activity from 0 to 10:

• 0 = Unable to perform the activity

• 10 = Able to perform the activity as before the problem began

Activity	Description of activity	Current score (0–10)
Activity 1	_________________________	_____
Activity 2	_________________________	_____
Activity 3	_________________________	_____
Activity 4	_________________________	_____
Activity 5	_________________________	_____

Total score: _____ / 50Average score: _____ / 10

Follow-up (date): Scores for the same activities:

Activity	New score (0–10)
Activity 1	_____
Activity 2	_____
Activity 3	_____
Activity 4	_____
Activity 5	_____

Therapist comments: ________________________________

Interpretation:

• A change of ≥2 points is considered clinically meaningful.

• Use this form as a basis for evaluating treatment effectiveness and patient progress.

References

1. Horn KK, Jennings S, Richardson G, Van Vliet D, Hefford C, Abbott JH. The patient-specific functional scale: psychometrics, clinimetrics, and application as a clinical outcome measure. journal of orthopaedic & sports physical therapy. 2012 Jan;42(1):30-D17.

2. Stratford P, Gill C, Westaway M, Binkley J. Assessing disability and change on individual patients: a report of a patient specific measure. Physiotherapy canada. 1995 Oct;47(4):258-63.

3. Hefford C, Abbott JH, Arnold R, Baxter GD. The patient-specific functional scale: validity, reliability, and responsiveness in patients with upper extremity musculoskeletal problems. journal of orthopaedic & sports physical therapy. 2012 Feb;42(2):56-65.

4. Westaway MD, Stratford PW, Binkley JM. The patient-specific functional scale: validation of its use in persons with neck dysfunction. Journal of Orthopaedic & Sports Physical Therapy. 1998 May;27(5):331-8.

5. Chatman AB, Hyams SP, Neel JM, Binkley JM, Stratford PW, Schomberg A, Stabler M. The Patient-Specific Functional Scale: measurement properties in patients with knee dysfunction. Physical therapy. 1997 Aug 1;77(8):820-9.

6. Maughan EF, Lewis JS. Outcome measures in chronic low back pain. European Spine Journal. 2010 Sep 1;19(9):1484-94.

7. Nicholas P, Hefford C, Tumilty S. The use of the Patient-Specific Functional Scale to measure rehabilitative progress in a physiotherapy setting. Journal of Manual & Manipulative Therapy. 2012 Aug 1;20(3):147-52.

8. Maughan EF, Lewis JS. Outcome measures in chronic low back pain. European Spine Journal. 2010 Sep 1;19(9):1484-94.

9. Cleland JA, Fritz JM, Whitman JM, Palmer JA. The reliability and construct validity of the Neck Disability Index and patient specific functional scale in patients with cervical radiculopathy. Spine. 2006 Mar 1;31(5):598-602.

10. The Patient-Specific Functional Scale: Validity, Reliability, and Responsiveness in Patients With Upper Extremity Musculoskeletal Problems

11. Reliability, Construct Validity, and Responsiveness of the Neck Disability Index, Patient-Specific Functional Scale, and Numeric Pain Rating Scale in Patients with Cervical Radiculopathy