Research

Stuttering in daily life

Stuttering varies from situation to situation and from day to day. This variability is often reported in the clinical settings, but prior research hasn't investigated it in depth due to methodological limits. I send text messages to participants using SurveySignal to have them record their stuttering rate, their emotions, and the social settings for specific social situations and at the end of the day. The study aims to provide insights on how stuttering is actually experienced and coped with in daily life.

How stuttering fluctuates for an adult who stutter over 3 weeks (Permission has been granted to display the de-identified data).

Accuracy in recalling sequences of made-up words

The phonological working memory is closely intertwined with the speech production system. Researchers were interested in the involvement of working memory in producing fluent speech. Adults who stutter were found to have lower recall when recalling long multisyllabic made-up words. We did not find that adults who stutter were more negatively impacted by the increase in linguistic complexity, in terms of phonotactic probability and phonological similarity, compared to fluent adults. However, the occurrence of stuttering is associated with lower recall accuracy among adults who stutter.

Utterance to utterance variability in producing a single phoneme /s/

Children relative to adults were often found to show greater trial to trial variation when asked to perform the same task again and again. The evidence was used to suggest that children's motor control system was less mature relative to adults. Similarly, adults who stutter were often found to show higher articulatory variability relative to fluent adults, even when they were both producing fluent speech. The less mature speech motor control system was hypothesized to give rise to stuttering.

I investigated whether a similar group difference exists when producing a single phoneme /s/. Adults who stutter were not found to show greater variability relative to fluent adults. The acoustic data was collected remotely during the COVID pandemic. Studies in a controlled lab environment are needed to further investigate the hypothesis.

The development in the ability to allocate cognitive resources

We often need to perform multiple tasks at the same time. The current study simulate that daily demand of multi-tasking with a dual task of rhyme monitoring and tone decision tasks. The ability to perform dual task was found to be refined over time. The ability to allocate cognitive resources was indexed with reaction time and performance accuracy.

Publications

  • Lei, X., & Munson, B. (2021). Variability in the production of /s/ by adults who do and do not stutter. Proceedings of Meetings on Acoustics. Manuscript in preparation.

  • Lei, X. & Sasisekaran, J., & (2021). The influence of phonotactic probability and phonological similarity on serial nonword recall among adults who do and do not stutter. Manuscript submitted.

  • Sasisekaran, J., & Lei, X. (2021). Developmental differences in the availability of cognitive resources supporting rhyming and dual tasking. Journal of Speech, Language, and Hearing Research, 40(1), 1-15.

Presentations

  • Lei, X., & Munson, B. (2021, December). Variability in the production of /s/ by adults who do and do not stutter. Poster presentation at American Acoustical Society, Session 4aSC, Seattle.

  • Lei, X., & Sasisekaran, J. (2021, April). Verbal recall and sympathetic nervous system response in adults who stutter. Oral presentation at Cognitive Science spring research day, University of Minnesota – Twin Cities, Online.

  • Lei, X., & Sasisekaran, J. (2021, January). Verbal recall and sympathetic nervous system response in adults who stutter. Poster presentation at the 12th Oxford Dysfluency Conference, online.

  • Sasisekaran, J., Basu S., & Lei, X, Swany, J., & Kamano, M. (2020, November). 11783: The effects of task variations on sample length, language complexity, and stuttering disfluencies. Proposal accepted at the Annual Convention of the American Speech-Language-Hearing Association, San Diego, CA (Convention canceled).

  • Sasisekaran, J., Basu S., & Lei, X. (2019, November). Effects of syntactic complexity of utterances on disfluent speech in children. Poster presented at the Annual Convention of the American Speech-Language-Hearing Association, Orlando, FL.

  • Lei, X. & Raimy, E (2018, March). Acoustic properties of phonologically mismatched errors as evidence for the time course of allophonic rules in single-word production. Poster presented at the American Association for Applied Linguistics Annual Conference. Chicago, IL.

  • Lei, X. & Borkenhagen, M. (2017, October). Structural competition effect in L1 Mandarin speakers’ production of English articles. Oral presentation at the Second Language Research Forum. Columbus, OH.