Smaller and Denser Speech Graphs in Nondemented Patients with Progressive Supranuclear Palsy

Abstract

The well-established semantic fluency test measures the ability to produce a sequence of spoken words from a particular category within a limited period of time. Like patients with Parkinson’s disease (PD), patients with progressive supranuclear palsy (PSP) tend to produce fewer correct words than age-matched healthy adults. This study further examined the difference between patients with PSP and PD in their semantic fluency performance using a graph theory-based approach. Twenty-nine patients with PSP Richardson’s syndrome (PSP-RS), thirty-eight patients with PD, and fifty-one healthy controls (HC) were recruited. All participants completed a standard semantic fluency test (animals). Their verbal responses were recorded, transcripted, and transformed into directed speech graphs. The speech graphs of the PSP-RS group showed higher density, shorter diameter, and shorter average shortest path than those of the PD and HC groups. It indicates that the PSP-RS group produced smaller and denser speech graphs than the PD and HC groups. In the PSP-RS group, moreover, the average shortest paths of the speech graphs correlated with the severity of motor symptoms. This study shows the potential of the graph theory-based approach in distinguishing the semantic fluency performance of nondemented patients with PSP-RS and PD.

Levodopa modulates semantic fluency and uniqueness in non‐demented patients with progressive supranuclear palsy

“…The methods of this study are similar to our previous study (Ma et al., 2023 ). Our previous study aimed to assess the PSP‐RS patients’ speechgraph, but this study aimed to assess the PSP‐RS patients’ semantic fluency and uniqueness.…”

“…The methods of this study are similar to our previous study (Ma et al, 2023). Our previous study aimed to assess the PSP-RS patients'…”

“…Patients with PSP or Parkinson's disease (PD) produced fewer correct words than healthy adults in this test (Azuma et al., 1997 ; Rosser & Hodges, 1994 ). Semantic disfluency occurs even at the early stages of PSP and PD (Ma et al., 2023 ; Zhang et al., 2022 ). Therefore, the semantic fluency test may be a sensitive tool for early detection of disease.…”

“…The PSP and PD patients showed a trend toward a smaller cluster size and produced fewer switches than healthy adults in verbal fluency tests (Chowdhury, 2018 ; Tröster et al., 1998 ). Our recent studies used the Speechgraph software based on the graph theory and found that the PSP and PD patients generated denser and smaller speech graphs than healthy adults (Ma et al., 2023 ; Zhang et al., 2022 ). Moreover, the graph parameters reflected the severity of motor and non‐motor symptoms of patients.…”

Impaired sequence manipulation in non‐demented patients with progressive supranuclear palsy

“…The methods of this study are similar to our recent study (Ma et al, 2023). Our recent study aimed to assess the PSP-RS patients' semantic fluency, but this study aimed to assess the PSP-RS patients' sequential working memory.…”