Chronic Fatigue Syndrome – Activities and Participation Questionnaire

Abstract

The Chronic Fatigue Syndrome – Activities and Participation Questionnaire (CFS-APQ) is a specialized psychological scale developed to assist clinicians in determining relevant treatment goals and identifying modifiable functional deficits in individuals diagnosed with Chronic Fatigue Syndrome (CFS). The instrument comprehensively inventories the patient’s level of activities and participation over the preceding seven days.

The questionnaire utilizes statements detailing specific situations where CFS symptoms impact daily life. A unique feature of the CFS-APQ is the dual scoring system: patients rate both the extent to which the statement applies to them (applicability) and the subjective importance they assign to that specific activity or domain (importance). Elevated total scores reflect a greater degree of impairment in functional skills and social participation.

Keywords

Chronic Fatigue Syndrome, CFS-APQ, Activities and Participation, Functional Assessment, Treatment Goals, Behavioral Measurement, Psychological Scale, Adults, Older Adults.

Authors

Nijs J, et al. (2002)

Purpose

The primary purpose of the CFS-APQ is to provide a structured, quantifiable measure of the impact of Chronic Fatigue Syndrome symptoms on daily functioning, encompassing both activities (task execution) and participation (involvement in life situations). This assessment is crucial for evidence-based practice and personalized patient care, particularly in rehabilitation and cognitive behavioral therapy settings.

By capturing both applicability and importance ratings, the instrument helps prioritize intervention targets. Clinicians can identify which impairments are most distressing or relevant to the patient, ensuring that treatment goals are patient-centered and clinically meaningful, thereby maximizing adherence and therapeutic outcomes. The scale is specifically oriented towards general tasks and demands.

Construct

The CFS-APQ measures the construct of functional impairment related to Chronic Fatigue Syndrome, specifically focusing on the domains of Activities and Participation. These domains are often conceptualized within the framework of the World Health Organization’s International Classification of Functioning, Disability and Health (ICF), emphasizing the external manifestations of the chronic illness.

The scale operationalizes this construct by examining how chronic symptoms hinder specific daily tasks and broader life involvement. The dual scoring system allows for a nuanced understanding of both objective limitation (applicability) and subjective burden (importance), which are key elements in chronic illness assessment and subsequent intervention planning.

Validity

Detailed psychometric validation studies for the CFS-APQ, including content, construct, and criterion validity, are documented in the primary publication by Nijs J, et al. (2002). The instrument is expected to demonstrate strong content validity, ensuring that the items adequately cover the necessary range of daily activities and participation challenges faced by CFS patients.

Construct validity is typically established through correlations with other established measures of fatigue severity, quality of life, and general functional status. Criterion validity is often assessed by comparing CFS-APQ scores against objective measures of physical performance or clinical diagnosis criteria.

Reliability

The reliability of the CFS-APQ is generally assessed using measures of internal consistency (e.g., Cronbach’s alpha) and test-retest reliability. High internal consistency is essential, confirming that the items within the scale measure a unified underlying construct of functional impairment related to CFS.

Test-retest reliability ensures that the scale provides stable scores over time, assuming the patient’s underlying clinical status remains unchanged between administrations. The instrument must demonstrate robust reliability to be used effectively for monitoring treatment progress and evaluating clinical outcomes.

Factor Analysis

The initial development and subsequent refinement of the CFS-APQ likely involved rigorous statistical procedures, including exploratory or confirmatory factor analysis. Such analyses are crucial for determining the underlying dimensional structure of the scale.

Factor analysis clarifies whether the items load onto a single, unitary factor representing general functional impairment, or if they distribute across multiple sub-domains (e.g., physical tasks, social engagement, cognitive function). The resultant factor structure dictates the appropriate scoring methodology and the clinical interpretability of potential subscale scores.

Instrument

Test Type: Psychological Scale / Self-Report Questionnaire

Format: Paper-and-pencil or digital self-administered questionnaire. The assessment covers the patient’s experience over the past 7 days, utilizing a dual response format (applicability and importance) for each item.

Language Available: Original development likely in Dutch. Availability in other languages depends on subsequent translation and validation studies.

Population Group: Clinical population diagnosed with Chronic Fatigue Syndrome (CFS) or related chronic fatigue conditions.

Age Group: Adults and Older Adults.

Population Details: Individuals capable of reading and self-reporting on their functional status and subjective importance of daily activities without significant cognitive impairment.

Test Methodology: Standardized self-report inventory. The items describe how symptoms affect daily activities. Scoring is summative, where higher scores reflect greater levels of impairment and difficulty in skills and participation.

Keywords

Impairment assessment, Functional status, Disability, Quality of life, Self-report measure, Nijs J, 2002, Psychometrics.

Authors

Author ORCID Identifier: Not specified in source material; refer to the original publication for author identification.

Affiliation Email addresses: Refer to primary publication (Nijs J, et al., 2002) for corresponding author details.

Correspondence Address: Refer to primary publication (Nijs J, et al., 2002).

Permissions & Fee and Test Year

Test Year: 2002 (Primary publication date).

Permissions and Fees: Information regarding licensing, reproduction permissions, and usage fees should be obtained directly from the copyright holders or primary researchers (Nijs J, et al.) or the institution associated with the scale’s development.

Reference’s

• Nijs J, et al. (2002). Primary publication detailing the development and psychometric properties of the Chronic Fatigue Syndrome – Activities and Participation Questionnaire (CFS-APQ).
• The original explanatory form (Toelichtingsformulier) can be downloaded here: CFS-APQ-form.pdf
• The original measurement instrument (Meetinstrument) can be downloaded here: CFS-APQ-meetinstr.pdf

Items of the Chronic Fatigue Syndrome – Activities and Participation Questionnaire

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

The source material does not provide the specific item content, but indicates that the items are statements describing situations detailing how symptoms of Chronic Fatigue Syndrome affect daily activities. Each statement is followed by two sub-questions regarding applicability (in hoeverre deze bewering op de patiënt van toepassing is) and importance (of hij/zij deze belangrijk vindt).