Identification of neural structures involved in stuttering using vibrotactile feedback

Area of Science:

• Neuroscience
• Speech and Hearing Sciences
• Biomedical Engineering

Background:

• Auditory and vibratory feedback impact speech fluency differently in people who stutter (PWS).
• Understanding these differences can elucidate the neural underpinnings of stuttering.
• Previous research highlights the role of auditory feedback, particularly its delay, in modulating fluency.

Purpose of the Study:

• To investigate the neural mechanisms underlying the fluency-enhancing effects of vibrotactile feedback (VTF) in PWS.
• To compare the effects of VTF with those of auditory feedback on stuttering.
• To identify potential alternative fluency-enhancing pathways beyond those affected by auditory feedback delay.

Main Methods:

• Eleven people who stutter (PWS) read passages under vibrotactile feedback (VTF) and control (no-VTF) conditions.
• VTF involved vibrating body locations (hand, sternum, forehead) with varying amplitudes and synchronous or delayed delivery.
• Stuttering and speaking rates were measured and compared across conditions.

Main Results:

• Stuttering rate significantly differed between VTF and control conditions, indicating a fluency-enhancing effect of VTF.
• Speaking rate did not change when VTF was delayed versus synchronous, unlike with auditory feedback.
• This dissociation suggests that cerebellar mechanisms, implicated in delayed auditory feedback, are not involved in VTF's fluency enhancement.

Conclusions:

• Vibrotactile feedback (VTF) offers a distinct mechanism for enhancing speech fluency in people who stutter (PWS).
• The findings suggest the involvement of a neural pathway separate from the one modulated by delayed auditory feedback.
• This opens new avenues for understanding and treating stuttering by targeting alternative neural systems.