Modeling voice production and self-perception in noise: Understanding the Lombard effect in non-phonotraumatic vocal...

Area of Science:

• Speech Science
• Neuroscience
• Biomedical Engineering

Background:

• Sensorimotor adaptation is vital for clear speech.
• Non-phonotraumatic vocal hyperfunction (NPVH) impairs adaptation in noise (Lombard effect).
• The roles of auditory and somatosensory feedback in this adaptation remain unclear.

Purpose of the Study:

• To investigate sensorimotor adaptation dynamics in individuals with NPVH speaking in noise.
• To utilize the SimpleDIVA model to analyze adaptation in typical and NPVH voices.
• To elucidate the contributions of auditory and somatosensory feedback in NPVH.

Main Methods:

• A three-parameter mathematical model (SimpleDIVA) was adapted.
• Participants (typical voices and NPVH) uttered syllables in baseline, Lombard (noise), and recovery conditions.
• Speech adaptation was analyzed using the SimpleDIVA model.

Main Results:

• NPVH participants failed to return to baseline levels post-noise exposure.
• SimpleDIVA model indicated reduced feedforward learning rate in NPVH.
• NPVH subjects demonstrated diminished somatosensory feedback gain compared to controls.

Conclusions:

• NPVH may involve reduced reliance on somatosensory feedback during speech production in noise.
• Individuals with NPVH might need extended periods to adjust motor commands after noise exposure.
• Findings highlight potential therapeutic targets for improving speech adaptation in NPVH.