Delayed Phonological Encoding in Stuttering: Evidence from Eye Tracking

Abstract

Stuttering is a multifactorial disorder that is characterized by disruptions in the forward flow of speech believed to be caused by differences in the motor and linguistic systems. Several psycholinguistic theories of stuttering suggest that delayed or disrupted phonological encoding contributes to stuttered speech. However, phonological encoding remains difficult to measure without controlling for the involvement of the speech-motor system. Eye-tracking is proposed to be a reliable approach for measuring phonological encoding duration while controlling for the influence of speech production. Eighteen adults who stutter and 18 adults who do not stutter read nonwords under silent and overt conditions. Eye-tracking was used to measure dwell time, number of fixations, and response time. Adults who stutter demonstrated significantly more fixations and longer dwell times during overt reading than adults who do not stutter. In the silent condition, the adults who stutter produced more fixations on the nonwords than adults who do not stutter, but dwell-time differences were not found. Overt production may have resulted in additional requirements at the phonological and phonetic levels of encoding for adults who stutter. Direct measurement of eye-gaze fixation and dwell time suggests that adults who stutter require additional processing that could potentially delay or interfere with phonological-to-motor encoding.

The Scope of Phonological Encoding Plans for Stutterers

“…The results showed that there was no difference in phonological encoding between the stuttering group and the control group, which may be due to multiple factors such as speech pressure or cognitive load leading to stuttering. The stuttering participants in this study were all mild stutterers, and a mild degree of stuttering may result in no difference in results (Byrd et al, 2012;Pelczarski et al, 2019). Korzeczek et al (2022) found differences in brain nerves between severe and mild stutterers.…”

Linguistic Aspects of Stuttering

“…Phonological awareness and phonological manipulation ability, rather than speech articulation skills, have also been found to be relatively depressed in CWS by a number of studies (Anderson et al, 2019; Ghorbani et al, 2020; Pelczarski & Yaruss, 2014; Sasisekaran & Byrd, 2013; Zohreh Ghaffari et al, 2012). There is also evidence that AWS likewise show relatively lower levels of performance, typically in rapidity of response, when asked to perform a variety of phonological processing tasks (Coalson & Byrd, 2015; Pelczarski et al, 2019; Vincent, 2017). Interestingly, a recent review found overlap in the profiles of AWS and adults with dyslexia (Elsherif et al, 2021).…”

Motivation for stuttering therapy and its concept and other determinants

“…Psychological theories look for the main cause of stuttering among negative emotions and particularly point to anxiety [6,7]. Moreover, linguistic theories are focused on speech disfluency and causes of the disfluency are to be found within the speech act [8].…”