Considerations on Effective Feedback in Computerized Speech Training for Dysarthric Speakers

In this article, we consider the role of feedback in computerized speech training for patients with dysarthric speech due to acquired neurological disorders such as Parkinson's disease and stroke. Based on literature from different fields, we review several issues that play a role when designing feedback for computerized speech training, including serious games. Which speech dimensions (e.g., articulation, loudness) to target in computerized speech feedback, and at what level of detail to provide the feedback, depend on the focus of the specific speech therapy and the technical feasibility of providing reliable speech feedback. Furthermore, feedback that provides knowledge of results generally appears equally effective as knowledge of performance feedback, and is more easily provided in computerized speech training systems. Implicit feedback can be more motivating than explicit feedback (e.g., in serious games), but may be harder to understand. Multimodal feedback is preferred over unimodal feedback to ensure that the feedback message is optimally perceived. Mild negative task-oriented feedback can enhance effort but should be balanced with positive feedback, such as feedback referring to patients' progress. Finally, a balance should be found between the motivational advantages of high-frequency immediate feedback (e.g., in serious games) and the advantages of low-frequency and delayed feedback in preventing patients from becoming dependent on augmented feedback. Several aspects play a role in designing feedback for computerized speech training for dysarthric speakers. Decisions on these aspects should be made carefully, accounting for the specific characteristics of the patient group that is targeted, the focus of the specific speech therapy, and the technological possibilities that are available.