Reliability of a procedure for segmenting extemporaneous speech produced by speakers with Parkinson disease

Gravelin et al. (2023) developed a segmentation procedure informed by Systemic Functional Linguistics (SFL) for parsing extemporaneous speech samples. The purpose of the current study is to investigate the reliability, utility, and application of this system when it is applied to samples produced by 10 participants with Parkinson Disease (PD). Two expert analysts and one clinician analyst utilised an SFL-based segmentation procedure to identify clauses and clause complexes. We calculated intra- and inter-rater reliability for each analyst and pair of analysts. We also measured speech acoustics, including duration, inter-complex pause durations, and speech rate for each clause complex. Both intra- and inter-rater reliability for SFL segmentation procedures within and between analysts revealed high percent agreement that was significantly greater than chance (κ = 0.661-0.855; p < 0.001) for speakers with PD. Acoustic analyses revealed expected variation in number and duration of spoken syllables of clause complexes between and within speakers. The clause-focused segmentation approach operationalised in Gravelin et al. (2023) and the current study is a reliable method for segmenting extemporaneous speech produced by individuals with PD. Moreover, this method allows for acoustic examination of speech and prosody production.