Development and validation of the dysarthria impact scale: a patient-reported outcome for motor speech disorders

TL;DR

Researchers created and tested a new tool to measure how speech disorders affect quality of life across different neurological conditions.

Contribution

The Dysarthria Impact Scale (DIS) is a novel patient-reported outcome measure for motor speech disorders.

Findings

The DIS showed strong validity and reliability when compared to existing tools like the Voice Handicap Index and SF-36.

Shorter versions of the DIS (DIS-17 and DIS-6) maintained high sensitivity and specificity for measuring dysarthria impact.

Participants with Parkinson’s disease and ataxia had significantly lower DIS scores compared to those with Huntington’s disease.

Abstract

Impaired speech due to dysarthria significantly impacts quality of life. Patient-reported outcomes (PROs) offer critical insight into the lived experience of communication disability and are central to regulatory frameworks for patient-focused drug development.

To develop and validate the Dysarthria Impact Scale (DIS), a brief PRO designed to assess the impact of motor speech disorders on quality of life across neurological conditions.

A multi-site, cross-sectional study was conducted with 244 participants, including individuals with Huntington’s disease, Parkinson’s disease, hereditary ataxias, and head and neck cancer, and healthy controls. The 22-item DIS was developed using expert input and patient feedback and evaluated alongside reference tools (Voice Handicap Index and SF-36). Item reduction procedures yielded two shorter versions (DIS-17 and DIS-6). Validity, reliability, and sensitivity/specificity analyses were performed, and minimal clinically important differences (MCIDs) were estimated using distribution-based methods.

All DIS versions showed strong convergent validity with the VHI (r = −0.85) and SF-36 (r = 0.72) and were correlated with blinded perceptual speech ratings. DIS-17 and DIS-6 achieved comparable sensitivity (0.93 and 0.88) and specificity (0.84 and 0.86, respectively). Test–retest reliability was high (r = 0.98), with estimated MCIDs and within-subject variability provided. Group differences were observed, with lower DIS scores in ataxia and Parkinson’s disease compared to Huntington’s disease.

The DIS is a valid, reliable, and practical PRO for quantifying the impact of dysarthria on quality of life. Longitudinal responsiveness remains to be established.

The online version of this article (10.1007/s00415-026-13740-1) contains supplementary material, which is available to authorized users.

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