Measuring tongue motion from tagged cine-MRI using harmonic phase (HARP) processing

Area of Science:

• Biomedical Engineering
• Speech Science
• Medical Imaging

Background:

• Understanding tongue biomechanics during speech is crucial for diagnosing and treating speech disorders.
• Previous methods for measuring tongue motion had limitations in capturing internal deformation.
• Magnetic Resonance Imaging (MRI) offers a non-invasive way to visualize soft tissue dynamics.

Purpose of the Study:

• To develop and validate a novel MRI-based method for quantifying tongue motion and internal deformation during speech production.
• To assess the utility of harmonic phase MRI (HARP-MRI) in analyzing speech-related tongue kinematics.
• To provide detailed measurements of tissue displacement, velocity, and strain within the tongue.

Main Methods:

• Acquisition of cine tagged MRI data in sagittal, coronal, and axial planes during the utterance "disouk" (/disuk/).
• Application of harmonic phase MRI (HARP-MRI) processing to tagged MR images for calculating tissue motion and deformation.
• Pixel-level analysis of displacement, velocity, principal strains, and muscle line-of-action strains.

Main Results:

• HARP-MRI successfully quantified tongue motion and internal deformation with high spatial resolution.
• Measurements included displacement, velocity, and strain fields across the entire tongue volume.
• The technique allowed for detailed analysis of tongue kinematics during speech, extending beyond tag intersections.

Conclusions:

• HARP-MRI is a powerful tool for in vivo measurement of tongue biomechanics during speech.
• This method enhances our understanding of tongue kinematics and provides a basis for hypothesizing internal muscle activation patterns.
• The detailed deformation data can inform clinical assessments and therapeutic strategies for speech impairments.