Investigating Perceptions of Speech Intelligibility & Communication Effectiveness: views of people with Parkinson’s Disease, their primary caregivers and unfamiliar participants
study explored the relationship between speech intelligibility and communication effectiveness as rated by people with Parkinson’s Disease (PWP) and familiar listeners (PCs). Additionally, this study compared the ability of familiar and unfamiliar listeners to decode the speech of PWP. Background: A distinction can be made between research where participants are asked how well they think they understand the speech of others and research testing how well participants correctly identify utterances. While many studies in the past have compared measures of intelligibly in people with PWP to other listener’s perspectives, very few have done so while using the PWP primary caregiver’s (PC) perception of both speech intelligibility and communication effectiveness. In addition, few studies have examined familiar vs. unfamiliar judgements of speech intelligibility in PWP, as well as the correlation between speech intelligibility tasks and self-rating scales. Overall Aims, Questions, and Hypotheses: The current study covers 2 aims, 3 questions and 3 hypotheses in regard to the perceptions of speech intelligibility and communication effectiveness as rated by PWP, their PCs, and unfamiliar listeners. Method and Procedures: Two procedures took places during the current study. Procedure (1) included 20 data collection sessions with a total of 40 participants (20 PWP and one of their PCs). During the session, each participant completed two rating scales (i.e.- the Speech Intelligibility Rating (SIR)1 and Communication Effectiveness Survey (CES)2), and one speech identification task (using a set of 20 Semantically Unpredictable Sentences (SUS)3). Procedure (2) included a smaller group of 4 unfamiliar participants, who listened to a total of 10 audio-recordings each from the PWP’s data collection session. Each recording from a PWP was transcribed by 2 unfamiliar participants for comparison. Results: The key findings were that (a) PWP’s subjective ratings of their own intelligibility are significantly lower than ratings by their PCs, (b) familiar and unfamiliar listeners were equally good at identifying unpredictable sentences spoken by PWP, and (c) there is a good alignment between subjective ratings of everyday intelligibility and the actual intelligibility in PWP. Conclusion: The present research hopes to aid future clinicians in the management of PWP and their PCs’ related speech, language, and communication needs by providing more information on the value of speech intelligibility and communication effectiveness measurements in PWP, as rated by the speaker, familiar listeners, and unfamiliar listeners.