The MFIS is a modified form of the Fatigue Impact Scale (Fisk et al, 1994) based on items derived from interviews with MS patients concerning how fatigue impacts their lives.

This instrument provides an assessment of the effects of fatigue in terms of physical, cognitive, and psychosocial functioning.

The full-length MFIS has 21 items while the abbreviated version has 5 items. The full-length version has the advantage of generating subscales.

The MFIS is a 21-item shortened version of the 40-item FIS and has been recommended for use by the Multiple Sclerosis Council for Clinical Practice Guidelines. It assesses the perceived impact of fatigue on the subscales physical, cognitive and psychosocial functioning during the past 4 weeks (Rietberg et al., 2010).

The MFIS is one of the components of the MSQLI.

Description of scoring: Likert scale. Participants rate on a 5-point Likert scale, with 0 = ‘Never’ to 4 = ‘Almost always’ their agreement with 21 statements.

Total score (0‐84) and subscales for physical (0‐36), cognitive (0‐40) and psychosocial functioning (0‐8). The 5 item version is scored (0‐20). Higher numbers indicate greater fatigue.

Rasch analysis revealed that the 21-item scale was found to contain a “physical” and a “cognitive” dimension (the original 2 social items were found to be part of the physical dimension).

Scoring for Standard 21-item version: either represented as a total score by summing the totals from each subscale or by each individual subscale (see below).

Physical subscale: range from 0-36

• Add raw scores on items: 4+6+7+10+13+14+17+20+21

Cognitive subscale: range from 0-40

• Add raw scores on items: 1+2+3+5+11+12+15+16+18+19

Psychosocial subscale: range from 0-8

• Add raw scores on items: 8+9

Scoring for 5-item version:

• Total score is the sum of items 1+9+10+17+19

Range from 0-20