Development of a Speech-based Composite Score for Remotely Quantifying Language Changes in Frontotemporal Dementia

Abstract

Background: Changes to speech and language are common symptoms across different subtypes of frontotemporal dementia (FTD). These changes affect the ability to communicate, impacting everyday functions. Accurately assessing these changes may help clinicians to track disease progression and detect response to treatment. Objective: To determine which aspects of speech show significant change over time and to develop a novel composite score for tracking speech and language decline in individuals with FTD. Method: We recruited individuals with FTD to complete remote digital speech assessments based on a picture description task. Speech samples were analyzed to derive acoustic and linguistic measures of speech and language, which were tested for longitudinal change over the course of the study and were used to compute a novel composite score. Results: Thirty-six (16 F, 20 M; Mage = 61.3 years) individuals were enrolled in the study, with 27 completing a follow-up assessment 12 months later. We identified eight variables reflecting different aspects of language that showed longitudinal decline in the FTD clinical syndrome subtypes and developed a novel composite score based on these variables. The resulting composite score demonstrated a significant effect of change over time, high test–retest reliability, and a correlation with standard scores on various other speech tasks. Conclusion: Remote digital speech assessments have the potential to characterize speech and language abilities in individuals with FTD, reducing the burden of clinical assessments while providing a novel measure of speech and language abilities that is sensitive to disease and relevant to everyday function.

Linguistic changes in neurodegenerative diseases relate to clinical symptoms

“…While a healthy older adult might describe a picnic scene as “A lady is sitting on the grass and pouring a beverage next to a gentleman by the lake,” a patient with dementia might only say “She is sitting and pouring something. There is a man.” Building on our previous work looking at longitudinal linguistic changes in AD and FTD ( 30 , 40 ), the link between linguistic changes and cognition across diagnoses highlights the importance of these language properties beyond the neurodegenerative disease categories.…”

“…Since the earlier work, naming difficulty has been linked to word frequency and familiarity in dementia ( 63 , 64 ). Noun frequency and familiarity are two related linguistic features reflecting vocabulary complexity, and have been previously shown to be impacted in semantic dementia and, more generally, in FTD ( 30 , 65 ). These features could even distinguish semantic dementia from healthy controls and patients with progressive non-fluent aphasia ( 9 ).…”

“…Typical AD and the logopenic variant of PPA produce fewer prepositions than healthy controls ( 20 ). Similarly, patients with FTD use fewer and fewer prepositional phrases over time ( 30 ). Prepositional phrases in AD were associated with performance on BNT, relating to the difficulty in efficiently retrieving semantic information ( 20 ).…”

“…Linguistic impairments measured with WAB were associated with the severity of dementia across diagnoses such as behavioral variant of FTD, primary progressive aphasia and AD ( 70 ). Patients with typical AD or the logopenic variant of PPA produce fewer nouns ( 20 ), and the use of nouns in AD and FTD decreases over time ( 30 , 40 ). Semantic dementia also presents with decreased noun use, specifically in connected speech ( 9 ).…”

“…There is an added benefit of the feasibility of collecting speech samples remotely and with high frequency. We recently demonstrated the importance of high frequency speech assessments in understanding the individual symptom fluctuations relating to depression and cognitive impairment ( 30 , 39 , 40 ). In neurodegenerative diseases, there are no standardized speech and language assessments to be utilized.…”