Kinematic Correlates of Early Speech Motor Changes in Cognitively Intact APOE-ε4 Carriers: A Preliminary Study Using...

Area of Science:

• Neuroscience
• Speech Science
• Biomarker Discovery

Background:

• Alzheimer's disease (AD) is a leading cause of dementia, necessitating early diagnostic tools for effective management.
• Current diagnostic methods often identify AD after significant cognitive decline, highlighting the need for pre-symptomatic risk detection.

Purpose of the Study:

• To investigate if speech kinematic features can identify individuals at elevated risk for Alzheimer's disease before cognitive impairment.
• To determine if lip movement patterns during a cognitive task differ between cognitively normal APOE-ε4 carriers (E4+) and non-carriers (E4-).

Main Methods:

• Speech kinematic data, specifically lip movement properties (duration, speed, range), were collected during a color-word interference task.
• Independent t-tests were used for group-level analysis, and a support vector machine (SVM) model was employed for classification.
• Lip movements were analyzed in pre-, during-, and post-interference speech segments.

Main Results:

• While no statistically significant group differences were found in descriptive statistics, moderate effect sizes suggested potential neuromotor variations.
• An SVM model achieved 87.5% accuracy in classifying APOE-ε4 status using three key lip kinematic features.
• The model demonstrated high precision (88.90%), sensitivity (88.90%), and specificity (85.70%).

Conclusions:

• Speech kinematics, particularly lip movement patterns, show potential as a digital biomarker for early Alzheimer's disease risk identification in cognitively intact individuals.
• These findings support the use of non-invasive speech analysis for scalable, remote screening and longitudinal monitoring of AD risk.
• Subtle differences in motor planning and cognitive-motor interference susceptibility are reflected in speech kinematics, indicating potential for early detection.