Psychometric evaluation of the disabilities of the arm, shoulder and hand (DASH) in patients with orthopedic shoulder impairments seeking outpatient rehabilitation

Psychometric properties of the Disability of Arm Shoulder and Hand (DASH) in subjects with frozen shoulder: a reliability and validity study

BACKGROUND

Frozen Shoulder (FS) is a painful condition characterized by severe pain and progressive restriction of shoulder movement, leading to functional impairment and reduced quality of life. While different Patient Reported Outcome Measurements (PROMs) tools exist for assessing shoulder diseases, few specific PROMs are validated for FS patients.

PURPOSE

This study aims to assess the psychometric properties of the Disability of Arm, Shoulder, and Hand (DASH) questionnaire in FS patients.

METHODS

One hundred and twenty-four subjects (mean ± SD age = 55.4 ± 7.9 years; 55.6% female) diagnosed with FS were included and completed the DASH questionnaire, the Numerical Pain Rating Scale (NPRS), the Shoulder Pain and Disability Index (SPADI), and the Short-Form Health Survey 36 (SF-36). Floor or ceiling effects were investigated. Structural validity was analysed through a unidimensional Confirmatory Factor Analysis (CFA), internal consistency through Cronbach's alpha, test-retest reliability through the Intraclass Correlation coefficient (ICC), measurement error through the Standard Error of Measurement (SEM), and the Minimum Detectable Change (MDC), and construct validity through the hypothesis testing with the correlation with the other outcome measures used.

RESULTS

No floor or ceiling effects were observed. CFA confirmed a one-factor structure after addressing local item dependency (Root Mean Square Error of Approximation = 0.055; Standardized Root Mean Square Residual = 0.077; Comparative Fit Index = 0.970; Tucker-Lewis Index = 0.968). Cronbach's alpha was high (= 0.951), and test-retest reliability was excellent (ICC = 0.999; 95% CI: 0.998-1.000). SEM was equal to 0.5 points, and MDC to 1.5 points. Construct validity was considered satisfactory as 80% of the a-priori hypotheses were met.

CONCLUSION

The DASH questionnaire demonstrated good psychometric properties in FS patients, supporting its use as a valuable tool for assessing the impact of FS in clinical and research settings.

Structural validity of the Arabic version of the disabilities of the Arm, Shoulder and Hand (DASH) using Rasch measurement model

Background

The disabilities of the arm, shoulder and hand (DASH) is a commonly used region-specific patient-reported outcome measure (PROM) that quantify upper extremity function (activity limitation) and symptoms. Current evidence suggests that measurement properties of the adapted versions of the DASH are not sufficiently examined. The Arabic DASH has evidence supporting its internal consistency, test–retest reliability, construct validity and responsiveness. On the other hand, the validity of the assumed unidimensionality of the Arabic DASH has not been examined previously. The aim of this study was to examine the structural validity of the Arabic DASH in patients with upper extremity musculoskeletal disorders using Rasch measurement model.

Methods

Patients with upper extremity musculoskeletal disorders were recruited and were asked to complete the Arabic DASH at their initial visit to physical therapy departments. The overall fit of the Arabic DASH to the requirement of the Rasch measurement model was examined using chi-square statistics for item-trait interaction, mean item and person fit residuals. The fit of individual items, thresholds ordering, local dependency, differential item functioning (DIF), and unidimensionality using the t-test approach were also examined.

Results

The Arabic DASH did not fit the Rasch measurement model initially (χ² = 179.04, p < 0.001) with major breach of local item independence and a pattern of high residual correlations among the activity-related items and among the impairment-related items. Combining items into activity-limitation and impairment testlets accommodated the local dependency and led to satisfactory fit of the Arabic DASH to the requirement of the Rasch measurement model (χ² = 3.99, p = 0.41).

Conclusions

Rasch measurement model supports the structural validity of the Arabic DASH as a unidimensional measure after the accommodation of local dependency.

Shoulder-Specific Patient-Reported Outcome Measures for Use in Patients With Head and Neck Cancer: An Assessment of Reliability, Construct Validity, and Overall Appropriateness of Test Score Interpretation Using Rasch Analysis

OBJECTIVES

The purpose of this study was to investigate the construct validity and overall appropriateness of test score interpretation of 4 shoulder-related patient-reported outcome (PRO) measures for use in a population of patients with head and neck cancer using Rasch analysis.

METHODS

One hundred eighty-two individuals who had received a neck dissection procedure within the past 2 weeks to 18 months were recruited for this cross-sectional psychometric study. Rasch methodologies were used to investigate scale dimensionality, scale hierarchy, response scale structure, and reliability of Disabilities of the Arm, Shoulder and Hand (DASH), QuickDASH, Shoulder Pain and Disability Index (SPADI), and Neck Dissection Impairment Index (NDII).

RESULTS

DASH did not meet criteria for unidimensionality and was deemed inappropriate for use in this sample. The QuickDASH, SPADI, and NDII were all determined to be unidimensional. All scales had varying issues with person and item misfit, differential item functioning, coverage of ability levels, and optimal rating scale requirements. The NDII met most requirements. All measures were found to meet thresholds for person and item separation as well as reliability statistics.

CONCLUSIONS

Rasch analysis indicates the NDII is the most appropriate measure studied for this population. The QuickDASH and SPADI are recommended with reservation, whereas the DASH is not recommended.

IMPACT

This study demonstrates the use of objective methodologies, using Rasch analysis, to validate PRO recommendations provided by clinical experts in forums such as the Evaluation Database to Guide Effectiveness (EDGE) TaskForce, which are based upon a comprehensive literature review, consideration of published psychometric properties, and expert consensus. Use of Rasch methodologies demonstrates weaknesses in this model and provides opportunities to strengthen recommendations for clinicians.

Is the Disabilities of the Arm, Shoulder and Hand (DASH) Questionnaire Adequate to Assess Individuals With Subacromial Pain Syndrome? Rasch Model and International Classification of Functioning, Disability and Health

OBJECTIVE

The Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire is widely used to assess patients with symptoms of subacromial pain syndrome (SPS). No study has analyzed the DASH by using the Rasch model in these patients and related the level of difficulty of the items with the International Classification of Functioning Disability and Health (ICF) domains. The purpose of this study was to evaluate the measurement properties of the DASH in individuals with SPS and to describe which ICF components are influenced by SPS based on the DASH.

METHODS

The full version of the DASH was used to assess upper limb pain and function in individuals with SPS. Responses were assessed using the Rasch model. DASH items were grouped according to the level of difficulty and associated with the ICF domains to identify the most compromised aspect in these individuals.

RESULTS

Reliability and internal consistency for the DASH were shown to be 0.93 and 0.95, respectively. Item 3 ("Turn a key") was the easiest and 25 ("Pain during specific activity") the most difficult. Only item 30 ("Less capable/confident/useful") was as an erratic item. Item 15 ("Put on a sweater") showed differential functioning by age and item 11 ("Carry a heavy object") by sex. Seven items showed differential functioning related to the angular onset of pain during arm elevation. Sixty percent of the most difficult items belonged to the "Body function" domain of the ICF.

CONCLUSION

Although some psychometric properties of the DASH are adequate according to the Rasch model, adjustments to some items are necessary for individuals with SPS. Clinicians should be cautious when interpreting the DASH, especially in patients with angular onset of pain above 120 degrees of arm elevation.

IMPACT

The information contained in this study should be used by clinicians to interpret the results of the DASH when assessing individuals with SPS. The DASH may not be adequate to assess those with shoulder pain above 120 degrees of arm elevation. These results are not generalizable to other shoulder pathologies.