0896-2960/18/$35.00 © 2018 by Begell House, Inc. www.begellhouse.com 77 Critical Reviews™ in Physical and Rehabilitation Medicine, 30(1):77–92 (2018) Content Comparison among Commonly Used Self-Reported Fatigue Instruments in Post-Polio Syndrome Surajo Kamilu Sulaiman,* Marcia Finlayson, Kathleen Norman, Heather Michelle Aldersey, & Vincent G. DePaul School of Rehabilitation Therapy, Louise D. Acton Building, 31 George Street, Queen’s University, Kingston, Ontario K7L 3N6 Canada *Address all correspondence to: Surajo Kamilu Sulaiman, PhD Candidate, School of Rehabilitation Therapy, Louise D. Acton Building, 31 George Street, Queen’s University, Kingston, Ontario K7L 3N6 Canada. Tel.613-539-6940.e-mail: surajo.sulaiman@queensu.ca. Twitter:@sks4rufy ABSTRACT: Various self-reported fatigue instruments are commonly used to assess fatigue in post-polio syndrome. It is unclear whether these instruments are conceptually multidi- mensional based on the biopsychosocial model of disability. In this review, we identify the commonly used fatigue instruments in post-polio syndrome and analyze their contents based on the International Classifcation of Functioning, Disability, and Health (ICF). A literature search was conducted to identify commonly used fatigue instruments in post-polio syndrome. Items from the instruments were extracted, and concepts therein were identifed and linked to the ICF categories based on the standardized ICF linking rules. Content density, content diver- sity, and measure of ICF linkage were analyzed for these instruments. Our fndings revealed that the Fatigue Severity Scale (FSS), the Modifed Fatigue Impact Scale (MFIS), and the Multidimensional Fatigue Inventory (MFI) are the most commonly used fatigue instruments in post-polio syndrome. The FSS, MFIS, and MFI have a content densities of 2.2, 1.6 and 1.3, respectively; content diversities of 0.4, 0.5, and 0.5, respectively; and ICF linkages of 90%, 85%, and 85%, respectively. The FSS, MFIS, and MFI are generally consistent with the ICF domains of body function, activities, and participation. The FSS assesses mainly physical and mental fatigue, whereas the MFIS and MFI mainly assess the dimension of mental fatigue. Therefore, these scales cannot be used interchangeably. Key woRdS: fatigue, post-polio syndrome, ICF, content analysis ABBReVIATIoNS: FSS, Fatigue Severity Scale; ICF, International Classifcation of Functioning, Disability, and Health; MC, meaningful concept; MFIS, Modifed Fatigue Impact Scale; MFI, Multidimensional Fatigue Inventory; MSQLI, Multiple Sclerosis Quality of Life Inventory; PSI, Person Separation Index; wHo, World Health Organization I. INTRODUCTION Post-polio syndrome is a common disabling disorder among polio survivors. 1,2 It is characterized by late-onset neuromuscular symptoms and decreased functional abil- ity, often decades following primary polio infection. The classic symptoms of post- polio syndrome include fatigue, increased muscle weakness, muscle ache, joint pain,