Vocal Outcomes in Vagus Nerve Stimulation: A Laryngeal Pattern-Based Objective Analysis.

Area of Science:

• Neurology
• Otolaryngology
• Speech-Language Pathology

Background:

• Vagus nerve stimulation (VNS) is an established treatment for drug-resistant epilepsy.
• VNS is known to induce laryngeal dysmotility.
• The impact of VNS on vocal outcomes requires further objective and subjective evaluation.

Purpose of the Study:

• To evaluate objective and subjective vocal outcomes in patients with VNS therapy for drug-resistant epilepsy.
• To assess vocal changes related to VNS-induced laryngeal dysmotility patterns.

Main Methods:

• Flexible fibreoptic laryngeal examination.
• Acoustic and perceptual voice analysis (at rest and during VNS activation).
• Voice Handicap Index (VHI) questionnaire administration in 16 adult epilepsy patients.

Main Results:

• VNS consistently caused laryngeal motility alterations, affecting voice quality in all patients.
• VNS activation significantly worsened perceptual (hoarseness, breathiness) and acoustic (jitter, shimmer) voice parameters.
• Patients with initially intact vocal folds showed greater voice impairment during VNS.

Conclusions:

• VNS therapy significantly impairs vocal outcomes, with objective and perceptual voice changes observed in all patients.
• Despite measurable vocal impairment, the subjective impact on Voice Handicap Index scores was mild.
• Vocal impairment is more pronounced in patients with pre-existing normal vocal fold function.