Evaluation of manual ability in stroke patients in Benin: cultural adaptation and Rasch validation of the ABILHAND-Stroke questionnaire.

BACKGROUND: ABILHAND is a self-reported questionnaire assessing manual ability. It was validated and calibrated using the Rasch analysis for European stroke patients. After a stroke, performing upper limb activities of daily living is influenced by personal and environmental contextual factors. It is thus important to conduct a contextual validation to use this questionnaire outside of Europe. AIM: The aim of this study was to perform a cross cultural validation of the ABILHAND-Stroke questionnaire for post-stroke patients living in Benin, a West-African country. DESIGN: Observational cross-sectional study. SETTING: Outpatient rehabilitation centres. POPULATION: 223 Beninese chronic stroke patients. METHODS: The experimental questionnaire was made of 59 items evaluating manual activities. Patients had to estimate their difficulty of performing each activity according to four response categories: impossible, very difficult, difficult and easy. For construct validity analysis, patients were also evaluated with other assessment tools: Box and Block Test, the motor subscale of the Functional Independence Measure, the Stroke Impairment Assessment Set, and ACTIVLIM-Stroke. Data were analysed with the Rasch partial credit model. RESULTS: The response categories very difficult and difficult were merged and the number of response categories was reduced from 4 to 3 (impossible, difficult and easy). The Rasch analyses selected 16 bimanual activities that fit the Rasch model (chi square=42.35; P=0.10). The item location ranged from -1.10 to 2.24 logits. The standard error ranged from 0.15 to 0.22 logits. There is no differential item functioning between subgroups (age, sex, dexterity, affected side, time since stroke). The person separation index is 0.82. The questionnaire can measure 3 levels of manual ability, similarly to the occidental version. CONCLUSIONS: The ABILHAND-stroke is a Rasch validated, unidimensional and invariant questionnaire to assess manual ability among Beninese patients. The ordinal score can be transformed into linear score using a conversion table. CLINICAL REHABILITATION IMPACT: This assessment tool is clinically relevant in Benin, a developing country, since it requires no specific equipment or training. It should promote and standardize assessments for stroke patients in clinical practice and research in this African country