APS Scale: Measuring the Impact of Chronic Pain on Daily Activities

New self-report measure includes 8 factors related to avoidance, persistence, and pacing.

Researchers from the University of Malaga, Spain, have developed a new tool to help clinicians assess the impact of chronic pain on daily activities, according to a study published in the April issue of The Journal of Pain.1

Known as the Activity Patterns Scale (APS), the self-report measure breaks down 3 general activities (avoidance, persistence, and pacing) into 8 more specific patterns: pain avoidance, activity avoidance, task-contingent persistence, excessive persistence, pain-contingent persistence, pacing to increase activity, pacing to conserve energy, and pacing to reduce pain.

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Patients with chronic pain often have to modify how they perform activities of daily living, which can impact their sense of wellbeing and quality of life.

Construction and Validation

The APS was constructed and validated in 2 studies. The first of these evaluated the internal structure of the APS in 291 patients (262 women, 29 men; mean age, 52 y) with chronic pain from rheumatic diseases. Three different factor structures were tested using confirmatory factor analyses via structural equation modeling.

Confirmatory factor analysis supported the validity of a 24-item APS with 8 subscales for related factors. The new version was found to be slightly superior to the 6-factor structure, indicating that avoidance, persistence, and pacing should be thought of as multidimensional constructs.

Researchers also examined correlations between each APS subscale, and also between their matched subscales on the ‘‘Patterns of Activity Measure-Pain (POAM-P).” The highest correlation was found between pain avoidance and pacing for pain reduction (r = .51), and the lowest between pacing for increasing activity level and both avoidance subscales (pain avoidance and task avoidance). As expected, high correlations were found when comparing APS subscales with their matched subscales on the POAM-P.

In the second study, researchers examined the association between the APS subscales and pain intensity, daily functioning, impairment, and positive and negative affect. The study included 111 patients with chronic pain (81 women, 30 men; mean age, 53 y) who completed the APS, a Positive and Negative Affect Schedule, a 10-point pain scale, and the Impairment and Functioning Inventory.

Results showed an association between activity avoidance and daily functioning and impairment. Negative affect was positively associated with activity avoidance and excessive persistence, and negatively associated with task-contingent persistence; the latter was also positively associated with positive affect.