Background: Speech and Language Impairments, generally attributed to lexico-semantic
deficits, have been documented in Mild Cognitive Impairment (MCI) and Alzheimer's disease (AD).
This study investigates the temporal organisation of speech (reflective of speech production planning) in
reading aloud in relation to cognitive impairment, particularly working memory and attention deficits in
MCI and AD. The discriminative ability of temporal features extracted from a newly designed read
speech task is also evaluated for the detection of MCI and AD.
Method: Sixteen patients with MCI, eighteen patients with mild-to-moderate AD and thirty-six healthy
controls (HC) underwent a battery of neuropsychological tests and read a set of sentences varying in
cognitive load, probed by manipulating sentence length and syntactic complexity.
Results: Our results show that Mild-to-Moderate AD is associated with a general slowness of speech,
attributed to a higher number of speech chunks, silent pauses and dysfluences, and slower speech and
articulation rates. Speech chunking in the context of high cognitive-linguistic demand appears to be an
informative marker of MCI, specifically related to early deficits in working memory and attention. In
addition, Linear Discriminant Analysis shows the ROC AUCs (Areas Under the Receiver Operating
Characteristic Curves) of identifying MCI vs. HC, MCI vs. AD and AD vs. HC using these speech characteristics
are 0.75, 0.90 and 0.94 respectively.
Conclusion: The implementation of connected speech-based technologies in clinical and community
settings may provide additional information for the early detection of MCI and AD.