Title:Structural Correlates of Overt Sentence Reading in Mild Cognitive
Impairment and Mild-to-Moderate Alzheimer’s Disease
Volume: 19
Issue: 8
Author(s): Céline De Looze*, Amir Dehsarvi, Narin Suleyman, Lisa Crosby, Belinda Hernández, Robert F. Coen, Brian A. Lawlor and Richard B. Reilly
Affiliation:
- Trinity Centre for Biomedical Engineering, School of Engineering, Trinity College Dublin, Dublin, Ireland
- Department of Gerontology, The Irish Longitudinal Study on Aging, Trinity College Dublin, Dublin, Ireland
Keywords:
Alzheimer disease, mild cognitive impairment, cognitive aging, functional neuroimaging, sentence reading, temporal speech features, genetic programming, machine learning.
Abstract:
Background: Overt sentence reading in mild cognitive impairment (MCI) and mild-tomoderate
Alzheimer’s disease (AD) has been associated with slowness of speech, characterized by a
higher number of pauses, shorter speech units and slower speech rate and attributed to reduced working
memory/ attention and language capacity.
Objective: This preliminary case-control study investigates whether the temporal organization of
speech is associated with the volume of brain regions involved in overt sentence reading and explores
the discriminative ability of temporal speech parameters and standard volumetric MRI measures for the
classification of MCI and AD.
Methods: Individuals with MCI, mild-to-moderate AD, and healthy controls (HC) had a structural MRI
scan and read aloud sentences varying in cognitive-linguistic demand (length). The association between
speech features and regional brain volumes was examined by linear mixed-effect modeling. Genetic
programming was used to explore the discriminative ability of temporal and MRI features.
Results: Longer sentences, slower speech rate, and a higher number of pauses and shorter interpausal
units were associated with reduced volumes of the reading network. Speech-based classifiers performed
similarly to the MRI-based classifiers for MCI-HC (67% vs. 68%) and slightly better for AD-HC (80%
vs. 64%) and AD-MCI (82% vs. 59%). Adding the speech features to the MRI features slightly improved
the performance of MRI-based classification for AD-HC and MCI-HC but not HC-MCI.
Conclusion: The temporal organization of speech in overt sentence reading reflects underlying volume
reductions. It may represent a sensitive marker for early assessment of structural changes and cognitive-
linguistic deficits associated with healthy aging, MCI, and AD.