Overreliance on auditory feedback may lead to sound/syllable repetitions: Simulations of stuttering and fluency-inducing conditions with a neural model of speech production

Abstract

This paper investigates the hypothesis that stuttering may result in part from impaired readout of feedforward control of speech, which forces persons who stutter (PWS) to produce speech with a motor strategy that is weighted too much toward auditory feedback control. Over-reliance on feedback control leads to production errors which, if they grow large enough, can cause the motor system to "reset" and repeat the current syllable. This hypothesis is investigated using computer simulations of a "neurally impaired" version of the DIVA model, a neural network model of speech acquisition and production. The model's outputs are compared to published acoustic data from PWS' fluent speech, and to combined acoustic and articulatory movement data collected from the dysfluent speech of one PWS. The simulations mimic the errors observed in the PWS subject's speech, as well as the repairs of these errors. Additional simulations were able to account for enhancements of fluency gained by slowed/prolonged speech and masking noise. Together these results support the hypothesis that many dysfluencies in stuttering are due to a bias away from feedforward control and toward feedback control. EDUCATIONAL OBJECTIVES The reader will be able to (a) describe the contribution of auditory feedback control and feedforward control to normal and stuttered speech production, (b) understand the neural modeling approach to speech production and its application to stuttering, and (c) explain how the DIVA model accounts for enhancements of fluency gained by slowed/prolonged speech and masking noise.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers

Increased Response to Altered Auditory Feedback in Dyslexia: A Weaker Sensorimotor Magnet Implied in the Phonological Deficit

“…The stronger response to altered auditory feedback in the ramp phase is at least partially consistent with an overreliance on auditory feedback, another model discussed earlier. This interpretation corresponds to neurocomputational models showing that stuttering, reported to share characteristics with DD (Malek et al, 2013), is characterized by a bias toward feedback control (Civier et al, 2010). This overreliance, however, on auditory feedback could also not explain the weak de-adaptation in DD in the aftereffect phase.…”

“…Studies on these formant adaptation effects in clinical disorders are scarce. Using simulations, Civier, Tasko, and Guenther (2010) showed that stuttering may be caused by deficits in speech feed-forward and feedback mechanisms (as explicated in the Directions Into Velocities of Articulators model). Their study suggests that stutterers rely too heavily on the auditory feedback trace to control speech and hence are more sensitive to changes in auditory feedback.…”

“…The hypothesized overreliance on auditory feedback in stuttering (Civier et al, 2010) as well as the stronger response to altered feedback in SLI (Holmes, 2012) led us to expect a stronger response to altered auditory feedback in adults with DD during the ramp and hold phase. This would also be in line with the allophonic mode of perception in DD proposed by Serniclaes and colleagues (2004).…”

A Lag in Speech Motor Coordination During Sentence Production Is Associated With Stuttering Persistence in Young Children

“…The central nervous system of CWS-Per, on average, may exhibit increased levels of neuromotor noise compared to CWS-Rec and CWNS, resulting in difficulty using sensory information to optimally execute a motor plan (Wolpert, 2007). Stuttering has been associated with limitations in sensorimotor integration (Hickok, Houde, & Rong, 2011;Max, 2004;Max, Guenther, Gracco, Ghosh, & Wallace, 2004;Namasivayam & van Lieshout, 2011), including a deficit in the use of feedforward processing during speech (Cai et al, 2012;Civier, Tasko, & Guenther, 2010).…”

Speech-Language Dissociations, Distractibility, and Childhood Stuttering

“…267-268). Likewise, results of a computer simulation study suggest that increased stuttering is associated with overmonitoring or "too much attention" (Civier, Tasko, & Guenther, 2010). Although several investigators have studied the relation between attention and stuttering behaviors (e.g., frequency of disfluencies) in adults who do and do not stutter (e.g., Arends, Povel, & Kolk, 1988;Bosshardt, 2002;Bosshardt, Ballmer, & de Nil, 2002;Oomen & Postma, 2001;Vasiç & Wijnen, 2001), to our knowledge only two studies have empirically assessed the relation between attention and stuttering behaviors in preschool-age children (Kraft et al, 2014;Ntourou et al, 2013).…”