Phonologic processing in adults who stutter: electrophysiological and behavioral evidence

Area of Science:

• Neuroscience
• Speech and Language Sciences
• Cognitive Psychology

Background:

• Stuttering is a complex speech disorder with debated etiological factors.
• Previous research has explored phonological processing deficits in individuals who stutter.
• Understanding cognitive load and brain activity in stuttering is crucial for effective interventions.

Purpose of the Study:

• To investigate phonological processing, cognitive load, and hemispheric involvement in adults who stutter compared to normally fluent speakers.
• To examine event-related brain potentials (ERPs), accuracy, and reaction times (RTs) during a rhyme judgment task.
• To test theories positing a core phonological deficit as the cause of stuttering.

Main Methods:

• 11 adults who stutter and 11 normally fluent speakers performed a rhyme judgment task with visually presented word pairs.
• Word pairs varied in phonological and orthographic congruence (congruent vs. incongruent).
• Measured ERPs, judgment accuracy, and RTs to assess cognitive processing and brain activity.

Main Results:

• Both groups showed similar phonological processing indexed by ERPs, accuracy, and RTs.
• Adults who stutter exhibited longer RTs, indicating greater sensitivity to cognitive load from incongruent stimuli.
• Adults who stutter displayed right hemisphere asymmetry in the rhyme judgment task, unlike fluent speakers.

Conclusions:

• Findings do not support a core phonological processing deficit in stuttering.
• Adults who stutter appear more vulnerable to increased cognitive loads.
• Greater right hemisphere involvement in late cognitive processes may characterize stuttering.