MOS Pain Effects Scale (PES)
The PES is a modified form of the pain scale contained in the Medical Outcomes Study Functioning and Well-Being Profile. This instrument provides an assessment of the ways in which pain and unpleasant sensations interfere with mood, ability to walk or move, sleep, work, recreation, and enjoyment of life. The PES consists of 6 items and is one of the components of the MSQLI.
Administration time is approximately 2-3 minutes.
The PES is a structured, self-report questionnaire that the patient can generally complete with little or no intervention from an interviewer. However, patients with visual or upper extremity impairments may need to have the PES administered as an interview. Interviewers should be trained in basic interviewing skills and in the use of this instrument.
The total score for the PES is the sum of the scores for the 6 items.
The PES is easy to administer and focuses on the ways in which pain and disturbing sensations affect everyday life, an issue for more than 50% of patients with MS. (Archibald, et al, 1994) It is particularly suitable to MS since it encompasses not just pain per se but other disturbing sensations often associated with MS such as burning, tingling, etc.
The PES has a Cronbach's alpha of .86. The straightforward nature of the items making up the PES give it good face validity for patients. In the original field testing of the MSQLI of which it is a part, the PES showed high correlations with two other pain scales and modest but significant correlations with other factors that are often related to pain such as emotional well-being and fatigue.