Expressive prosody in behavioral variant frontotemporal degeneration and late-onset psychiatric disorders.

Objective: Neuropsychological assessment of social cognition has traditionally focused on mentalizing and emotions recognition. Recently developed digital measures allow clinicians to capture direct markers of abnormal social interactions, but they have not yet been used to distinguish neurological from psychiatric populations. This study examined prosodic alterations and explored structural neural correlates in behavioral variant frontotemporal degeneration (bvFTD) versus late-onset or atypical psychiatric disorders (LOAPD) and healthy controls (HCs).

Method: We analyzed audio recordings from 31 patients with bvFTD, 15 patients with LOAPD, and 39 HCs across two speech samples: an anamnestic interview and a narrative task. Fundamental frequency (f₀) metrics were extracted to assess between-group differences and to identify voxel-based morphometry correlates of prosodic alteration.

Results: Compared with HCs, patients with bvFTD showed a reduced f₀ range in both the anamnestic interview (p = .025, η² = .09, 95% CI [-23.83, -1.04]) and the narrative task (p = .002, η² = .14, 95% CI [-36.21, -4.74]). In the anamnestic interview, both bvFTD (p = .010, 95% CI [-36.59, -6.23]) and LOAPD (p = .012, 95% CI [-46.30, -8.81]) groups exhibited lower f₀ variability than HCs; no differences were observed during the narrative task. In bvFTD, reduced prosodic measures correlated with atrophy in the left superior frontal gyrus and the right middle and inferior temporal gyri (p < .05, family-wise error corrected).

Conclusions: Patients with bvFTD demonstrate a narrowed pitch span and reduced intonational variability, linked to disruptions in frontotemporal networks integrating emotional and semantic cues into speech. These findings highlight the relevance of prosodic alterations as a target for further research in bvFTD and assessment. (PsycInfo Database Record (c) 2025 APA, all rights reserved).