Evaluation of Speech-Based Digital Biomarkers: Review and Recommendations

Abstract

Speech represents a promising novel biomarker by providing a window into brain health, as shown by its disruption in various neurological and psychiatric diseases. As with many novel digital biomarkers, however, rigorous evaluation is currently lacking and is required for these measures to be used effectively and safely. This paper outlines and provides examples from the literature of evaluation steps for speech-based digital biomarkers, based on the recent V3 framework (Goldsack et al., 2020). The V3 framework describes 3 components of evaluation for digital biomarkers: verification, analytical validation, and clinical validation. Verification includes assessing the quality of speech recordings and comparing the effects of hardware and recording conditions on the integrity of the recordings. Analytical validation includes checking the accuracy and reliability of data processing and computed measures, including understanding test-retest reliability, demographic variability, and comparing measures to reference standards. Clinical validity involves verifying the correspondence of a measure to clinical outcomes which can include diagnosis, disease progression, or response to treatment. For each of these sections, we provide recommendations for the types of evaluation necessary for speech-based biomarkers and review published examples. The examples in this paper focus on speech-based biomarkers, but they can be used as a template for digital biomarker development more generally.

The Dawn of the Human-Machine Era: A forecast of new and emerging language technologies

“…Linguistic analysis may characterize cognitive impairments or Alzheimer's disease, which are manifested by decreased lexical diversity and grammatical complexity, loss of semantic skills, word finding difficulties and frequent use of filler sounds (Nguyen et al 2020;Robin et al 2020). Because linguistic disabilities have different reasons (Antaki & Wilkinson 2012) and different effects (traumata, autism, dementia and others), different types of technology are needed to support speakers suffering from those disorders, and speakers who communicate with people with interactional disabilities.…”

Voice for Health: The Use of Vocal Biomarkers from Research to Clinical Practice

“…Besides, given the technical constraints, we suspect that the first vocal biomarkers to be validated will be restricted to a specific language or a specific sub-group of the population. A relevant template to help standardizing and evaluating speech-based digital biomarkers has recently been proposed [4]. Health check-ups could one day be performed directly on an everyday device such as a smart mirror to track digital biomarkers, including vocal biomarkers, activity, healthcare status, and body movement [52].…”

“…If current voice searches are mostly restricted to basic questions, perspectives for rapid expansion in the healthcare sector are numerous. The evolution of voice technology, audio signal analysis, and natural language processing/understanding methods have opened the way to numerous potential applications of voice, such as the identification of vocal biomarkers for diagnosis, classification, or patient remote monitoring, or to enhance clinical practice [4].…”

Rationale and study-design of a randomized, placebo-controlled, double-blind phase 2b trial to Evaluate Efficacy, Safety and Tolerability of an oral glutaminyl cyclase inhibitor Varoglutamstat (PQ912) in Study participants With MCI and Mild AD -  VIVIAD

“…To assess AD-speci c speech changes the Winterlight speech assessment (WLA) will be employed regularly to assess any change from baseline in the study participants (36). Also, blood will be drawn for hematology, blood biochemistry and assessment of blood biomarkers.…”