Patient Specific Functional Scale

Chronic Pain:

(Stratford et al, 1995; n = 63 with mechanical low back pain; mean age = 47 (12) years, Chronic Pain)

• SEM = 0.41

Chronic Pain: (Stratford et al 1995)

• MDC = 2 points

Chronic Pain:

(Stratford et al, 1995, Chronic Pain)

• Excellent test-retest reliability (ICC = 0.97)

Neck Pain:

(Westaway et al, 1998, Neck Pain)

• Excellent test-retest reliability on a modified three activity version of the scale (ICC = 0.92)

Chronic Pain:

(Stratford et al, 1995, Chronic Pain)

• Excellent concurrent validity with Roland-Morris - average across 5 activities scores (r = -0.67)

Neck Pain:

(Westaway et al, 1998, Neck Pain)

• Excellent concurrent validity for a modified three activity version of the scale with:
  • Neck Dysfunction Index (r = 0.73 - 0.83)
  • Clinical prognosis rating (r = 0.64)

Low Back Pain: (Maughan and Lewis, 2010)

• MDC = 1.4 points

Lower Back Pain:

(Maughan and Lewis, 2010, Lower Back Pain)

Knee Dysfunction:

(Chatman et al, 1997; n = 38 patients with knee dysfunction; mean age = 47 (18) years, Knee Dysfunction)

• SEM for individual activity analysis = 1.0
• SEM for average of 5 activity items = 0.62

Neck Dysfunction:

(Westaway et al, 1998; n = 31 patients with neck pain; mean age = 40.4 (14.1) years, Neck Dysfunction)

• SEM for a modified three activity version of the scale = 0.43

Hand Osteoarthritis (Wright et al., 2017; n= 35; Mean age= 63.8 (8.7))

• SEM for entire group (n = 35): 0.56

Total knee arthroplasty (Berghmans et al., 2015; n=150; Mean age= 65 (8); “calculated from SD & ICC given in article”)

• SEM for Complaint 1, 3 months post-surgery (n = 33): 1.82
• SEM for Complaint 2, 3 months post-surgery (n= 33): 1.85
• SEM for Complaint 3, 3 months post-surgery (n= 33): 1.38

Knee Dysfunction: (Chatman et al, 1997)

• MDC = 1.5 points

Neck Dysfunction: (Westaway et al, 1998)

• MDC = 2 points

Hand Osteoarthritis: (Wright et al., 2017; n= 35; Mean age= 63.8 (8.7))

• MDC90 for entire group (n = 35): 1.30
• MDC95 for entire group (n= 35): 1.56

Hand Osteoarthritis: (Wright et al., 2017; n= 35; Mean age= 63.8 (8.7))

• MCID for PSFS= 2.2-point change

Proximal humeral fracture (Backman et al., 2016; n= 53)

• MCID= 2 or more points

Total knee arthroplasty (Berghmans et al., 2015; n=150; Mean age= 65 (8); “calculated from SEM (calculated from SDs & ICCs given in article))

• MDC for Complaint 1, 3 months post-surgery (n=33): 5.04
• MDC for Complaint 2, 3 months post-surgery (n=33): 5.13
• MDC for Complaint 3, 3 months post-surgery (n=33): 3.83

Knee Dysfunction:

(Chatman et al, 1997, Knee Dysfunction)

• Excellent test-retest reliability (ICC = 0.84)

Hand Osteoarthritis (Wright et al., 2017)

• Excellent test-retest reliability: (ICC = .81)

Total knee arthroplasty (Berghmans et al., 2015)

• Adequate reliability: ICC= 0.73 complaint 1; ICC= 0.75 complaint 2; 0.86 complaint 3

Concurrent Validity:

Proximal humeral fracture (Backman et al., 2016)

• Poor correlations between the PSFS with:
  • Patient Global Score (r = -0.03)
  • Grip Strength (r = 0.25)
  • Pain (r = -0.14)
• Adequate correlations between the PSFS with:
  • Shoulder Function Assessment (r = -0.32)
  • WOOS (r = -0.32)
  • Physical Symptoms (r = -0.33)
  • Sports/Recreation/Work (r = -0.34)

A comparison of correlation coefficients determined good convergent validity of the Patient Specific Functional Scale (PSFS) with Global Rating of Change Scale (GRC), better than with the generic 36-item Short Form Health Survey (36-SF), possibly because both PSFS and GRC ask patients to self-identify areas of disability while a more generic measure would include items not relevant to the patient (Chatman et al, 1997).

Joint Replacement:

(Dill et al, 2012; n = 82 patients awaiting joint replacement; mean age = 70.3 (9.8), Joint Replacement)

• Poor convergent validity with SF-36 Physical function scale (r = 0.22), SF-36 Physical Component Summary scale (r = 0.11)
• Adequate convergent validity with the Western Ontario and McMasters University Arthritis Index (r = -0.37)
• Poor discriminant validity with SF-36 Mental Health scale (r = 0.11)

Convergent Validity:

Hand Osteoarthritis: (Wright et al., 2017; n= 35; Mean age= 63.8 (8.7))

• Adequate correlation with PSFS scores to left hand grip strength and right hand grip strength posttreatment (r = 0.39, 0.36 respectively)
• Adequate correlation with PSFS scores to DASH posttreatment (r = - 0.58)

• Poor correlation with change in PSFS scores to changes in left and right hand grip strength scores and DASH (r = 0.06, 0.08, 0.13 respectively)

Total knee arthroplasty: (Berghmans et al., 2015)

• Adequate correlation between the mean PSFS and total WOMAC score at 3 months (r = 0.41)
• Adequate correlation between the mean PSFS score and GPE score at 3 months (r = -0.37)
• Adequate correlation between the mean PSFS score and total WOMAC score at 1 year (r = 0.48)
• Adequate correlation between the mean PSFS score and total GPE score at 1 year (r = -0.55)

Proximal humeral fracture (Backman et al., 2016; n= 53)

“Content validity was described based on the 47 activities stated in the PSFS, and thereafter coded according to the ICF coding rules into different components by the authors. 45 (96%) of the activities were coded into activity levels according to the ICF, and 29 (62%) of them could be found in the WOOS. From the results of this study, Backman et al. (2016) concluded that the PSFS has very good content validity as 96% of the stated activities could be classified in the ICF activity component and 62% were found in the WOOS.”

Floor effect observed in knee dysfunction patients: patients generally identify activities where substantial disability exists, and because score of “0” on activity means “unable to perform”  there is no space on the scale for the patient to demonstrate deteriorating abilities (Chatman et al, 1997)

No floor or ceiling effects observed for Lower Limb Amputees (Resnik and Borgia, 2011)

Proximal humeral fracture

(Backman et al., 2016; n= 53; Mean age= 60; time post trauma or operation= 6 weeks (1))

• Poor floor effect of 28% found for the PSFS in activity limitation at baseline
• Poor ceiling effect of 48% found for the PSFS  in activity limitation at follow up.

Joint Replacement:

• Moderate responsiveness (Standardized Response Mean (SRM) = 0.55; Guyatt’s Responsiveness Index(GRI) = 1.18)

Hand fractures and dislocations (Novak et al., 2014; n = 63; assessed from baseline (initial hand therapy assessment) to final (discharge from hand therapy)

• Statistically significant improvement in overall PSFS scores from the initial (mean score of 3.2) to final (mean score of 8.1) assessment (p < 0.001)
• Poor correlation between the

Proximal humeral fracture (Backman et al., 2016; n= 53)

“The outcome in all variables was statistically significant and improved after shoulder rehabilitation, as was the PSFS (Table 4). There was total agreement (100%) between patients’ and physical therapists’ ratings of direction of outcome of rehabilitation in the GRC (better/worse/no change) and no systematic deviation could be detected between patients’ and physical therapists’ rating of level ( ± 0–7) of improvement (Sign test p - 0.34).

Sensitivity to Change 22 participants measured before (median 1) and after 2 months of shoulder rehabilitation (median 2).

Western Ontario Osteoarthritis of the shoulder Index (WOOS)

Total knee arthroplasty: (Berghmans et al., 2015)

Large change in effect size at 3 months and 1 year: between 1.71 and 2.89 respectively.

Responsiveness of the PSFS after 3 months

Responsiveness of the PSFS after 12 months

Multiple Sclerosis:

(Hammer et al, 2005; n = 13; mean age = 47.9 years (8.4); 10 week Hippotherapy intervention; Swedish sample, Multiple Sclerosis)

• Evidence of concurrent validity with the SF-36- Role Emotional (RE) Dimension

Lower Limb Amputees:

(Resnik and Borgia, 2011; n = 44 patients with unilateral lower limb amputation, current prosthesis users with limb loss at least 2 years prior to the study, mean age = 66 (13) years, Lower Limb Amputees)

Lower Limb Amputees: (Resnik and Borgia, 2011)

Lower Limb Amputees:

(Resnik and Borgia, 2011, Lower Limb Amputees)

• Excellent interrater reliability (ICC = 0.83)

Spinal Stenosis:

(Cleland et al, 2012; n = 55 patients with lumbar stenosis; mean age = 69.2 (8); mean duration of low back pain = 13.1 (16.2) years, Spinal Stenosis)

• SEM = 1.03

Spinal Stenosis: (Cleland et al, 2012)

• MDC = 2.4 points

Spinal Stenosis:

(Cleland et al, 2012, Spinal Stenosis)

• MCID = 1.34 points

UE Musculoskeletal:

(Hefford et al., 2012, UE Musculoskeletal)

• MCID = 1.2 points

Spinal Stenosis:

(Cleland et al, 2012, Spinal Stenosis)

• Adequate test-retest reliability (ICC = 0.59)

UE Musculoskeletal:

(Hefford et al., 2012, UE Musculoskeletal)

• Excellent interrater reliability (ICC2,1 = 0.713)

*Note a small positive change in the stable (as opposed to improved) group

Spinal Stenosis:

(Cleland et al, 2012, Spinal Stenosis)

• Excellent convergent validity with the Global Rating of Change (r = 0.69)

Spinal Stenosis:

• Large responsiveness (SRM = 0.91, GRI = 1.75)

Community-Dwelling Older Adults (Mathis, et. al, 2019; n=31; mean age= 81.1 years (8.3); mean body mass= 70.6 kg (15.0); mean height= 164.5 cm (9.8))

• SEM for entire group (n=31): 1.0

Community-Dwelling Older Adults (Mathis, et. al, 2019)

• MDC for entire group (n=31): 2.8

Community-Dwelling Older Adults: (Mathis et al., 2019; n= 31; Mean age= 81.1 (8.3))

• Excellent test-retest reliability: (ICC = .82)

Convergent Validity:

Community-Dwelling Older Adults: (Mathis et al., 2019; n = 31);

• Excellent correlation with the Activity-specific Balance Confidence Scale (r=0.68)
• Excellent correlation with the Lower Extremity Functional Scale (r=0.81)
• Adequate correlation with the Short Physical Performance Battery assessment (r=.37)
• Poor correlation with the Berg Balance Scale (r=.17)
• Poor correlation with Timed Up and Go assessment (r= - 0.26)