Relationships Among Auditory Discrimination, Adaptive Vocal Learning, and Perilaryngeal Muscle Activation in People...

Area of Science:

• Speech and Hearing Sciences
• Neuroscience
• Biomechanics

Background:

• Hyperfunctional voice disorders (HVDs) are characterized by abnormal vocal fold function, often linked to motor control deficits.
• Auditory-motor integration is crucial for voice regulation, but its specificity in HVDs remains unclear.
• Perilaryngeal muscle activity patterns during voicing may reflect underlying control strategies in HVDs.

Purpose of the Study:

• To investigate the specificity of auditory-motor impairment in HVDs.
• To explore the relationship between HVDs, perilaryngeal muscle activation, and adaptive vocal learning.
• To measure muscle activity during adaptive vocal learning for intensity and fundamental frequency (f₀).

Main Methods:

• Fifty-two participants (26 HVDs, 26 controls) performed auditory discrimination and adaptive vocal learning tasks for intensity and f₀.
• Surface electromyography (sEMG) recorded activity from suprahyoid and infrahyoid muscles.
• Co-contraction index (CCI) was analyzed, along with mediation models examining relationships between variables.

Main Results:

• No significant differences in discrimination thresholds between HVDs and controls.
• HVDs showed greater adaptation to intensity perturbations; singers adapted less.
• More individuals with HVDs exhibited large following responses for f₀ adaptation compared to controls.
• No significant effects of HVD status on CCI, but moderate relationships found between discrimination, CCI, and f₀ adaptation.

Conclusions:

• HVDs exhibit distinct auditory feedback integration deficits for f₀ versus intensity, suggesting independent control mechanisms.
• Preliminary evidence indicates a laryngeal stabilization response to perceived external feedback mismatch.
• Findings highlight the complexity of auditory-motor control in voice disorders.