Acoustic analysis in stuttering: a machine-learning study

Francesco Asci; Luca Marsili; Antonio Suppa; Giovanni Saggio; Elena Michetti; Pietro Di Leo; Martina Patera; Lucia Longo; Giovanni Ruoppolo; Francesca Del Gado; Donatella Tomaiuoli; Giovanni Costantini

doi:10.3389/fneur.2023.1169707

Acoustic analysis in stuttering: a machine-learning study

Front Neurol. 2023 Jun 30:14:1169707. doi: 10.3389/fneur.2023.1169707. eCollection 2023.

Authors

Francesco Asci^{1

2}, Luca Marsili³, Antonio Suppa^{1

2}, Giovanni Saggio⁴, Elena Michetti⁵, Pietro Di Leo⁴, Martina Patera¹, Lucia Longo⁶, Giovanni Ruoppolo⁷, Francesca Del Gado⁵, Donatella Tomaiuoli⁵, Giovanni Costantini⁴

Affiliations

¹ Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy.
² IRCCS Neuromed Institute, Pozzilli, Italy.
³ Department of Neurology, James J. and Joan A. Gardner Center for Parkinson's Disease and Movement Disorders, University of Cincinnati, Cincinnati, OH, United States.
⁴ Department of Electronic Engineering, University of Rome Tor Vergata, Rome, Italy.
⁵ CRC - Centro Ricerca e Cura, Rome, Italy.
⁶ Department of Sense Organs, Otorhinolaryngology Section, Sapienza University of Rome, Rome, Italy.
⁷ IRCCS San Raffaele Pisana, Rome, Italy.

Abstract

Background: Stuttering is a childhood-onset neurodevelopmental disorder affecting speech fluency. The diagnosis and clinical management of stuttering is currently based on perceptual examination and clinical scales. Standardized techniques for acoustic analysis have prompted promising results for the objective assessment of dysfluency in people with stuttering (PWS).

Objective: We assessed objectively and automatically voice in stuttering, through artificial intelligence (i.e., the support vector machine - SVM classifier). We also investigated the age-related changes affecting voice in stutterers, and verified the relevance of specific speech tasks for the objective and automatic assessment of stuttering.

Methods: Fifty-three PWS (20 children, 33 younger adults) and 71 age-/gender-matched controls (31 children, 40 younger adults) were recruited. Clinical data were assessed through clinical scales. The voluntary and sustained emission of a vowel and two sentences were recorded through smartphones. Audio samples were analyzed using a dedicated machine-learning algorithm, the SVM to compare PWS and controls, both children and younger adults. The receiver operating characteristic (ROC) curves were calculated for a description of the accuracy, for all comparisons. The likelihood ratio (LR), was calculated for each PWS during all speech tasks, for clinical-instrumental correlations, by using an artificial neural network (ANN).

Results: Acoustic analysis based on machine-learning algorithm objectively and automatically discriminated between the overall cohort of PWS and controls with high accuracy (88%). Also, physiologic ageing crucially influenced stuttering as demonstrated by the high accuracy (92%) of machine-learning analysis when classifying children and younger adults PWS. The diagnostic accuracies achieved by machine-learning analysis were comparable for each speech task. The significant clinical-instrumental correlations between LRs and clinical scales supported the biological plausibility of our findings.

Conclusion: Acoustic analysis based on artificial intelligence (SVM) represents a reliable tool for the objective and automatic recognition of stuttering and its relationship with physiologic ageing. The accuracy of the automatic classification is high and independent of the speech task. Machine-learning analysis would help clinicians in the objective diagnosis and clinical management of stuttering. The digital collection of audio samples here achieved through smartphones would promote the future application of the technique in a telemedicine context (home environment).

Keywords: acoustic analysis; home environment; machine-learning; stuttering; telemedicine.