Assistive Technology Usability Questionnaire for people with Neurological diseases Questionnaire (NATU Quest)

Abstract

The Assistive Technology Usability Questionnaire for people with Neurological diseases (NATU Quest) is a 10-item instrument developed in 2023 by Masbernat-Almenara and colleagues. Its primary function is to rigorously evaluate the usability and subsequent user satisfaction concerning Assistive Technology products utilized by patients diagnosed with neurological conditions. The scale’s construction relied on a rigorous Delphi study methodology to ensure content relevance. Comprehensive psychometric testing, including analyses of validity, reliability, and Item Response Theory, was performed using a Spanish sample of both experts and end-users, affirming its appropriateness for clinical and research settings.

Keywords

Assistive Technology, Usability, Neurological Diseases, NATU Quest, Psychometric Validation, Delphi Study, Rasch Model

Authors

Masbernat-Almenara, Maria, Rubi-Carnacea, Francesc, Opisso, Eloy, Duarte-Oller, Esther, Medina-Casanovas, Josep, Valenzuela-Pascual, Fran

Purpose

The central objective of the NATU Quest is to provide a standardized, robust method for assessing the usability of various Assistive Technology (AT) devices and software specifically tailored for individuals managing neurological diseases. This focus addresses the critical need for tools that measure how effectively and satisfactorily these technologies function in real-world contexts.

By measuring user perception and experience, the questionnaire generates actionable insights for developers, clinicians, and researchers regarding the quality of interaction between the user and the AT product, ultimately aiming to improve adherence to technology use and enhance rehabilitation outcomes for this specialized population.

Construct

The primary construct measured by the NATU Quest is the Usability of Assistive Technology specifically applied within the context of Neurological diseases. Usability, in this context, is defined broadly to include aspects of effectiveness, efficiency, and user satisfaction, ensuring that the technology not only performs its intended function but is also accessible, easy, and pleasant for the target population to operate.

The 10 items of the scale are designed to capture the user’s subjective experience, providing a quantitative measure of how well the AT integrates into their daily life and supports their functional goals, taking into account the unique motor and cognitive challenges faced by individuals with neurological conditions.

Validity

The validity of the NATU Quest was established through multiple rigorous psychometric methods.

Content Validity: Content validity was ensured via a structured Delphi process involving experts. This procedure resulted in the identification of nine highly relevant items (exceeding a threshold of 0.58), leading to the final selection of the ten items included in the questionnaire. This methodology confirms that the scale items adequately cover the necessary domain of AT usability for this specific population.

Concurrent Validity: The instrument demonstrated strong concurrent validity, showing significant correlations with scores from other established and validated questionnaires. A Spearman’s coefficient of ρ = 0.756 (p<0.001) confirmed that the NATU Quest measures the same underlying construct as existing, recognized usability instruments.

Item Response Theory: Analysis using Item Response Theory (IRT) further supported the scale’s quality. All ten items showed a satisfactory fit to the Rasch model, indicating that the items function optimally within a modern measurement framework and reliably allow for the differentiation of individuals based on their perceived level of AT usability.

Reliability

The reliability analyses confirm the internal consistency and temporal stability of the NATU Quest.

Internal Consistency: The scale exhibits a high degree of internal consistency, as measured by Cronbach’s Alpha, which yielded a coefficient of α = 0.895. This value strongly suggests that the ten items are highly cohesive and measure a singular, common underlying dimension related to AT usability and satisfaction.

Test-Retest Reliability: Stability over time was assessed using test-retest procedures. Results indicated moderate to considerable concordance across items (measured by the Kappa coefficient). Furthermore, a strong association between repeated administrations was found with a Spearman’s coefficient of ρ = 0.818 (p<0.001). The Intraclass Correlation Coefficient (ICC) was calculated at 0.869 (95% CI: 0.781 to 0.923), collectively affirming the stability and consistency of the NATU Quest scores across different measurement occasions.

Factor Analysis

The provided developmental literature primarily focused on establishing the unidimensionality of the measure through Item Response Theory, specifically demonstrating a satisfactory fit to the Rasch model. Traditional Exploratory or Confirmatory Factor Analysis results were not explicitly reported in the source material regarding the scale’s internal structure.

Instrument

Test Type: Original Inventory/Questionnaire

Format: The NATU Quest is a brief, 10-item questionnaire. Responses are collected via a 6-point Likert-type scale, anchored from 0 (Strongly Disagree) to 5 (Strongly Agree). The instrument utilizes an electronic administration method and incorporates visual enhancements, such as a traffic light color scheme and expressive faces, corresponding to the numerical ratings, to improve accessibility and clarity for users with neurological impairments.

Language Available: Spanish. Data concerning translation or validation in other languages is not currently available.

Population Group: Human (Male and Female)

Age Group: Adulthood (18 years and older)

Population Details: The validation study recruited a specialized sample from Spain, consisting of both end-users of Assistive Technology living with neurological conditions and subject matter experts in the field.

Test Methodology: The development and validation process employed advanced psychometric techniques, including the assessment of Content Validity, Concurrent Validity, Internal Consistency, Test-Retest Reliability, and sophisticated analyses derived from Item Response Theory.

Keywords

Assistive Technology, Usability, Neurological diseases, Psychometrics, Rasch Analysis, User Satisfaction, Rehabilitation

Authors

Author ORCID Identifier:

• Masbernat-Almenara, Maria: orcid.org/0000-0002-5822-239X (Affiliation: Department of Nursing and Physiotherapy, University of Lleida)

• Opisso, Eloy: orcid.org/0000-0002-6868-6737 (Affiliation: Institut Guttmann, Neurorehabilitation Institute)

• Valenzuela-Pascual, Fran: orcid.org/0000-0002-1945-629X (Affiliation: Department of Nursing and Physiotherapy, University of Lleida)

Affiliation Email addresses:

• Rubi-Carnacea, Francesc: [email protected] (Affiliation: Department of Nursing and Physiotherapy, University of Lleida)

• Duarte-Oller, Esther (Affiliation: Physical Medicine and Rehabilitation Department Parc de Salut Mar)

• Medina-Casanovas, Josep (Affiliation: Institut Guttmann, Neurorehabilitation Institute)

Correspondence Address: [email protected]

Permissions & Fee and Test Year

The NATU Questionnaire is made available under a Creative Commons Attribution 4.0 International License, granting permission for use in Research and Teaching purposes. Further details on permissions can be found at creativecommons.org/licenses/by/4.0/deed.en. There is No fee associated with the use of this instrument. The scale was developed and validated in 2023.

Reference’s

Masbernat-Almenara, M., Rubi-Carnacea, F., Opisso, E., Duarte-Oller, E., Medina-Casanovas, J., & Valenzuela-Pascual, F. (2023). Developing an assistive technology usability questionnaire for people with neurological diseases. PLoS ONE, 18(1), Article e0281197. doi.org/10.1371/journal.pone.0281197

Items of the Assistive Technology Usability Questionnaire for people with Neurological diseases Questionnaire (NATU Quest)

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

The NATU Questionnaire is composed of 10 distinct items. Specific details regarding the phrasing of these items are available in the supplemental material referenced in the primary publication (Test Location: 2023-43869-001).

The original PDF of the NATU Questionnaire can be downloaded here: NATU Questionnaire