NFFIS
Description
Background: Post-stroke fatigue (PSF) affects 40–70% of stroke survivors and significantly impairs functional recovery, rehabilitation participation, and quality of life. Existing fatigue instruments were developed for non-stroke populations and do not adequately capture stroke-specific functional limitations. There is a clear need for a psychometrically rigorous, stroke-specific, functionally oriented outcome measure. Objectives: To systematically develop and establish content validity of the Neuro Fatigue Functional Impact Scale (NFFIS), a patient-centred, multidimensional instrument measuring the functional impact of neuro-fatigue across physical, cognitive, emotional, and social domains in stroke survivors. Methods: A three-phase methodological design was employed, following Boateng et al. (2018) best-practice scale development guidelines and COSMIN recommendations. Phase I involved construct conceptualisation and item generation (50 items, 5 domains) via systematic literature review and inductive-deductive methods. Phase II applied a two-round Delphi expert consensus process (n=9 multidisciplinary experts) with quantitative content validity assessment using Item-level Content Validity Index (I-CVI) and Scale-level Content Validity Index (S-CVI), with adjusted Kappa statistics. Phase III comprised pre-testing with 30 stroke survivors, including item descriptive analysis and Cronbach's alpha internal consistency estimation. Results: Following two Delphi rounds, 24 of 50 items were retained across four domains: Physical Fatigue Impact (PFI, 6 items), Cognitive Fatigue Impact (CFI, 5 items), Emotional/Psychological Impact (EPI, 9 items), and Social Role Functioning Impact (SRFI, 4 items). The overall S-CVI/Ave was 0.823, meeting established adequacy criteria. Of 24 retained items, 14 achieved excellent Kappa agreement (κ≥0.74) and 9 achieved good agreement (κ=0.60–0.73). The total NFFIS Cronbach's α was 0.976 (95% CI: 0.96–0.99), with domain-level α ranging from 0.966 to 0.982. All corrected item-total correlations exceeded 0.93. Conclusion: The NFFIS demonstrates strong content validity and excellent preliminary internal consistency. It represents the first stroke-specific, functionally oriented, multidimensional neuro-fatigue impact scale developed within an Indian rehabilitation context. Formal large-scale psychometric validation including factor analysis, test-retest reliability, and criterion validity assessment is planned.
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Steps to reproduce
A panel of 7–10 subject-matter experts was recruited based on predefined eligibility criteria: Step 2: Delphi Round 1 Procedure Experts independently evaluated each item using the NFFIS Expert Review Form .Each item was rated on three parameters: •Relevance •Clarity •Representativeness using a 4-point Likert scale. Step 3: Delphi Round 2 Procedure Revised items were redistributed to the expert panel for re-evaluation. Consensus was defined as ≥80% agreement. This iterative refinement ensured convergence toward content adequacy. Outcomes of Delphi Process The Delphi process resulted in: •Improved linguistic clarity •Enhanced domain alignment •Elimination of ambiguous or redundant items The pre-testing process involved interviewer-assisted administration of the draft NFFIS. Each participant completed the scale in the presence of a trained assessor, followed by a structured cognitive debriefing session. Participants were encouraged to: •Paraphrase items in their own words •Describe how they chose their responses •Identify confusing terms or phrases •Comment on relevance to their daily life Field notes were maintained for each session, documenting: •Item-specific difficulties •Patterns of misunderstanding •Emotional reactions to item content Modifications Following Pre-Testing Based on pre-testing feedback: •Minor linguistic modifications were made to simplify phrasing •Medical jargon was replaced with lay terminology •Redundant wording was streamlined •Instructions were clarified to emphasize the reference period No items were removed at this stage, as all items were deemed conceptually essential following Delphi consensus. The pre-testing phase thus resulted in a refined, patient-friendly draft of the NFFIS
Institutions
- Chhatrapati Shahu Ji Maharaj UniversityUttar Pradesh, Kanpur