Natural Speech Analysis Can Reveal Individual Differences in Executive Function Across the Adult Lifespan

Purpose: Automated analysis of naturalistic speech has emerged as an effective tool for detecting cognitive decline in dementia but has seldom been used to examine the ordinary cognitive decline occurring in normal aging. Executive function (EF) declines throughout the adult lifespan but is difficult to track longitudinally due to practice effects, making speech-based assessments particularly attractive. This study examined relationships between EF and speech characteristics. Method: We collected two audio picture descriptions from participants in two experiments that also included EF assessments, with 67 healthy older adults (aged 65–75 years) in Study 1 and 174 healthy adults (aged 18–90 years) in Study 2. Language composite scores were computed by aggregating relevant speech features indexing aspects of speech that have been reported to show changes in pathological aging. Principal components reflecting common covariation in speech features were extracted from a large training data set to compute speech domain scores. The relationships between language composites/speech principal components and EF were assessed while controlling for age, gender, and education. Results: In Study 1, older adults' word-finding difficulties, measured as speech disfluencies, showed significant associations with EF. Study 2 confirms that speech disfluencies can explain individual differences in EF not only for adults above the age of 65 years but also across the adult lifespan. Information units and coherence in speech showed weaker associations with EF and Montreal Cognitive Assessment scores that were not significant after correction for multiple comparisons. Conclusion: The findings revealed associations between word-finding ability in natural speech and general EF across the adult lifespan, supporting natural speech analysis as a convenient and sensitive assessment of general cognitive ability.