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The PFS is a patient rated scale that reflects the physical aspects of fatigue in patients with Parkinson’s Disease (PD) and measures both the presence of fatigue and its impact on daily function.

Acronym PFS-16

Area of Assessment

Activities of Daily Living

Assessment Type

Patient Reported Outcomes

Administration Mode

Paper & Pencil



Actual Cost



  • Parkinson's Disease & Movement Disorders

Key Descriptions

  • The PFS is a 16-item patient rated scale. Seven items tap the presence or absence of the subjective experience of fatigue with an emphasis on the physical effects of fatigue, (e.g. “I feel totally drained”) and nine items address the impact of fatigue on daily functioning and activities, including socialization and work but not exercise specifically (e.g. “I get more tired than other people I know”).
  • Neither severity nor frequency of fatigue symptoms is specifically measured.
  • The scale is designed to exclude the cognitive and emotional features of fatigue.
  • Ratings are based on feelings and experiences over the prior 2 weeks.
  • Scoring options range from 1 (“strongly disagree”) to 5 (“strongly agree”).
  • There are 3 scoring options:
    1) A total PFS score, the average item score across all 16 items ranging from 1-5.
    2) A binary scoring method yields scores from 0-16 with positive scores for each item generated by “agree,” and “strongly agree,” responses.
    3) A total ordinal PFS score ranging from 16-80 based on the sum of scores for the 16 individual items. This ordinal scale has been validated and is used more often.

Number of Items


Equipment Required

  • Pen/Paper

Time to Administer

5 minutes

Required Training

No Training

Age Ranges


18 - 64


Elderly Adult

65 +


Instrument Reviewers

Initially reviewed by Alicia Esposito, PT, DPT, NCS.

ICF Domain

Body Function

Measurement Domain

Activities of Daily Living

Professional Association Recommendation

Recommendations for use of the instrument from the Neurology Section of the American Physical Therapy Association’s Multiple Sclerosis Taskforce (MSEDGE), Parkinson’s Taskforce (PD EDGE), Spinal Cord Injury Taskforce (PD EDGE), Stroke Taskforce (StrokEDGE), Traumatic Brain Injury Taskforce (TBI EDGE), and Vestibular Taskforce (VEDGE) are listed below. These recommendations were developed by a panel of research and clinical experts using a modified Delphi process.


For detailed information about how recommendations were made, please visit:




Highly Recommend




Reasonable to use, but limited study in target group  / Unable to Recommend


Not Recommended


Recommendations Based on Parkinson Disease Hoehn and Yahr stage:














Recommendations for entry-level physical therapy education and use in research:


Students should learn to administer this tool? (Y/N)

Students should be exposed to tool? (Y/N)

Appropriate for use in intervention research studies? (Y/N)

Is additional research warranted for this tool (Y/N)





Not reported


Whether the PFS provides an advantage over generic fatigue scales is unclear. Because fatigue is multidimensional with physical emotional, cognitive and social features, the PFS may not adequately reflect clinically significant non-physical aspects of fatigue.


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Parkinson's Disease

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Cut-Off Scores

Parkinson’s Disease:

(Brown et al, 2005)

  • Using the full Likert scale, an average score of > 2.95 optimally distinguished those who experienced fatigue from those who did not with a sensitivity of 81.0% and specificity of 85.7.% (area under the curve 87.5%)
  • Using the full Liker scale, a higher cut off of > 3.30 identified those perceiving fatigue to be a problem with a sensitivity of 84.7% with a specificity of 82.1% (area beneath the curve: 93.2%)
  • Using the binary coding scoring a score of > 7 distinguished those who experienced fatigue from those who did not with a sensitivity of 73.8% and specificity of 76.9% (area under the curve: 87.1%)
  • Using the binary coding scoring, a score of > 8 identified those perceiving fatigue to be a problem with a sensitivity of 89.5% with a specificity of 83.3% (area beneath the curve: 93.4%)

Normative Data

Parkinson's Disease

(Brown et al, 2005)

Mean PFS-16 Scores:






n = 315

n = 180

n = 495

Age (years)

70.3 (10.2)

70.4 (9.1)

70.4 (9.5)

Time since onset (yrs)

7.2 (5.8)

9.2 (7.7)

7.9 (6.7)

Schwab and England ADL score

67.2 (22.7)

65.0 (23.4)

66.4 (23.0)

Mean PFS-16 scores

3.48 (0.81)

3.36 (0.84)

3.41 (0.82)

  • Mean score of the 16 item PFS score (average item score) = 3.50 (2.94)
  • Mean total score using binary scoring method = 8.51(4.98)

(Grace et al, 2007; n = 50, mean age = 71.66 (1.39); controls n = 16, mean age = 69.94 (2.42) years)

  • Mean total PFS score for patients with PD: 54.34(34.81)
  • Mean total PFS score for community elderly controls: 15.03(15.53)

Test/Retest Reliability

Parkinson’s Disease:

(Brown et al, 2005)

  • Excellent reliability using original mean 5 point score: ICC = 0.83
  • Excellent reliability using summed binary coded score: ICC = 0.82
  • Adequate to excellent reliability for individual items: ICC = 0.52-0.72 (mean 0.63(0.06) for actual scores)

Internal Consistency

Parkinson’s Disease:

(Brown et al, 2005)

  • Excellent internal consistency (Cronbach’s alpha = 0.98)
  • Excellent internal consistencies with split half analysis (Cronbach’s alpha = 0.90 and 0.92)

(Grace et al, 2007)

  • Excellent split half reliability (0.93 and 0.95)
  • Excellent internal consistency (Cronbach’s alpha = 0.97)
  • Inter-item correlations ranged from 0.44-0.87.
    • A few scale items were highly inter-correlated (> 0.85) with other items which suggests that some items my be redundant
    • Highly correlated items were 5 and 12 (r = 0.87); 7 and 9 (= 0.85) and 11 and 13 (= 0.85)

Construct Validity

Parkinson’s Disease:

(Brown et al, 2005)

  • Excellent correlation with Rhoten Fatigue Scale (RFS) (ICC = 0.68)


(Grace et al, 2007)

  • Excellent construct validity compared to the Fatigue Severity Scale (FSS) (= 0.84, < 0.001)
  • Excellent construct validity compared to the Fatigue Rating (FR) (= 0.78, < 0.001)
  • No significant correlations between the total scores on the PFS and disease severity as measured by the Hoehn and Yahr or the UPDRS motor subscale however specific statistics were not provided

Floor/Ceiling Effects

Parkinson’s Disease:

(Martinez-Martin et al, 2008)

  • Floor effect: < 4%
  • Ceiling effect: < 4%


Parkinson’s Disease:

(Grace et al, 2007)

  • Moderate effect size: n= 0.24


Brown, R. G., Dittner, A., et al. (2005). "The Parkinson fatigue scale." Parkinsonism Relat Disord 11(1): 49-55. Find it on PubMed

Friedman, J. H., Alves, G., et al. (2010). "Fatigue rating scales critique and recommendations by the Movement Disorders Society task force on rating scales for Parkinson's disease." Movement Disorders 25(7): 805-822. Find it on PubMed

Grace, J., Mendelsohn, A., et al. (2007). "A comparison of fatigue measures in Parkinson's disease." Parkinsonism Relat Disord 13(7): 443-445. Find it on PubMed

Martinez-Martin, P., Rodriguez-Blazquez, C., et al. (2008). "Specific patient-reported outcome measures for Parkinson's disease: analysis and applications."