Researchers have long sought accessible methods to detect early changes in brain health before noticeable symptoms appear. Recent investigations have begun exploring everyday behaviors and subtle markers that might reveal cognitive shifts. Traits and patterns in speech are emerging as a focus of emerging scientific interest.
Everyday Speech May Uncover Risk of Cognitive Decline or Presence of Early Cognitive Decline
Researchers are uncovering early warning signs of cognitive decline in the most familiar place imaginable: everyday speech. Subtle shifts in timing, vocabulary, and sound are emerging as reliable indicators of changes in brain function that may appear long before formal symptoms arise.
Frequent and Longer Pause Patterns and Slower Overall Speech Rate
The tip-of-the-tongue phenomenon, also known as lethologica, is a common experience regardless of age. However, word-finding difficulty and speech timing patterns are different phenomena. A study published in 2024 and led by cognitive scientist Jed A. Meltzer noted that both could be considered important measures of executive function decline.
Meltzer and his team analyzed speech samples from 125 volunteers aged 18 to 90 who completed standardized tasks requiring scene descriptions and picture responses. Computational tools showed that a slower speech rate and increased pause frequency correlated with lower executive function scores. This indicates slower neurological processing speed.
Note that participants with reduced verbal pace specifically demonstrated diminished processing speed. The findings align with theories suggesting cognitive slowing, and not isolated and specific memory failure, represents a primary marker of early neurological change among aging adults that affects overall executive function and processing efficiency.
Individuals with early cognitive decline often produce fewer words per minute because the brain requires more time to retrieve information, organize thoughts, and coordinate verbal output. More frequent silent pauses or extended pauses beyond conversational timing reflect difficulty retrieving words and further indicate slower cognitive coordination.
Reduced Lexical or Vocabulary Richness and Shorter Narratives
A team of linguists led by Bao Zhiming of the National University of Singapore obtained natural speech data from 148 Singaporeans in their 60s and 70s. Half of them were cognitively healthy. The other half had mild cognitive impairment. Of these participants with impairment, 38 had amnestic impairment, and 36 had non-amnestic impairment.
Those with amnestic mild cognitive impairment spoke less, demonstrated reduced lexical richness or a narrower range of vocabulary, used short descriptions, and produced fewer and more abstract nouns. These speech traits and patterns, the researchers explained, reflected weakening semantic networks and difficulty managing multi-step verbal structures.
Neurologist Eloy Rodríguez-Rodríguez and his team examined individuals using clinical tests and cognitive assessments to determine if speech biomarkers predict amyloid status or levels in cases of cognitive impairment. Note that amyloids are abnormal proteins that can clump together in organs. These clumps are one of the hallmarks of Alzheimer’s disease.
Machine learning methods were used to develop amyloid status predictions. Results revealed that lexical-semantic features could be an indicator of amyloid levels. This indicates that changes in the manner of speech might reflect early and preclinical brain pathology even before clinical signs of cognitive impairment or issues become more pronounced.
Notable Acoustic Changes Such as Increased Jitter and Reduced Shimmer
The same research by E. Rodríguez-Rodríguez et al. also showed that acoustic changes in speech could be a strong predictor of amyloid levels. Note that acoustic features have been investigated in relation to cognitive assessment. The 2021 review of J. J. G. Meilán et al. showed that acoustic and rhythmic features have a diagnostic accuracy of 80 percent.
Furthermore, in a longitudinal acoustic study, researchers Elizabeth Mahon and Margie Lachman tracked middle-aged and older adults for over 10 years to determine if voice biomarkers or acoustic features can predict cognitive changes in later life. This involved using and evaluating data from the longstanding national Midlife in the United States study.
Acoustic markers, including jitter or frequency variation and shimmer or amplitude variations, were measured. Cognitive assessments recorded changes over time. Results revealed that subtle changes in voice predicted cognitive decline a decade later. Instabilities in jitter and shimmer may reflect early neurological shifts affecting motor control of speech.
Note that jitter in speech is the cycle-to-cycle variation in the fundamental frequency of the voice or the small and short-term changes in pitch. Shimmer is the cycle-to-cycle variation or changes in the amplitude or loudness of the voice. More pitch variation and less loudness variation were linked to greater declines in episodic and working memory.
FURTHER READINGS AND REFERENCES
- Cao, L., Han, K., Lin, L., Hing, J., Ooi, V., Huang, N., Yu, J., Ng, T. K. S., Feng, L., Mahendran, R., Kua, E. H., and Bao, Z. 2024. “Reversal of the Concreteness Effect Can Be Detected in the Natural Speech of Older Adults with Amnestic, but Not Non‐amnestic, Mild Cognitive Impairment.” Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring. 16(2). DOI: 1002/dad2.12588
- Gabirondo, P., García-Martínez, M., Pozueta-Cantudo, A., Maran, P. L., Dias, P., Rojo, T., Jiménez-Raboso, J., Lage, C., Martínez-Dubarbie, F., López-García, S., Fernández-Matarrubia, M., Corrales-Pardo, A., Bravo, M., Irure-Ventura, J., López-Hoyos, M., Sánchez-Juan, P., Zaldua, C., and Rodríguez-Rodríguez, E. 2025. “Speech Biomarkers Predict Amyloid Status in Cognitively Unimpaired Adults.” Intelligence-Based Medicine. 12: 100306. DOI: 1016/j.ibmed.2025.100306
- Mahon, E., and Lachman, M. E. 2024. “Voice Biomarkers in Middle and Later Adulthood as Predictors of Cognitive Changes.” Frontiers in Psychology. 15. DOI: 3389/fpsyg.2024.1422376
- Martínez-Nicolás, I., Llorente, T. E., Martínez-Sánchez, F., and Meilán, J. J. G. 2021. “Ten Years of Research on Automatic Voice and Speech Analysis of People With Alzheimer’s Disease and Mild Cognitive Impairment: A Systematic Review Article.” Frontiers in Psychology. 12. DOI: 3389/fpsyg.2021.620251
- Wei, H. T., Kulzhabayeva, D., Erceg, L., Robin, J., Hu, Y. Z., Chignell, M., and Meltzer, J. A. 2024. “Cognitive Components of Aging-Related Increase in Word-Finding Difficulty.” Aging, Neuropsychology, and Cognition. 31(6): 987-1019. DOI: 1080/13825585.2024.2315774