Estimates of functional cerebral hemispheric differences in monolingual and bilingual people who stutter: dichotic listening paradigm

ABSTRACT

Recent studies indicate functional cerebral hemispheric processing differences between monolinguals and bilinguals who stutter, as well as monolinguals and bilinguals who do not stutter. Eighty native German speakers, half of whom were also proficient speakers of English as a second language (L2), were assessed on a dichotic listening paradigm using CV syllables as stimuli. The participants were organised into four different groups according to speech status and language ability: 20 monolinguals who stutter, 20 bilinguals who stutter, 20 monolinguals who do not stutter, and 20 bilinguals who do not stutter. A right ear advantage (REA) was observed across all groups with no significant group differences in regard to hemispheric asymmetry. Although MWS (18 dB) and BWS (16 dB) crossed over to an LEA at an earlier point compared to the MWNS (5 dB) and BWNS (2 dB), the difference between groups was minor and not significant. Thus, a significant difference in REA resistance, as proposed by other researchers, was not reflected in the current study neither for people who stutter nor for bilinguals. In addition, no meaningful relationship was found between dichotic listening and stuttering severity, as well as the four language modalities (listening, speaking, reading, writing). Thus, we contend that neither stuttering nor bilingualism has any non-trivial effect on functional cerebral hemispheric differences in language processing in dichotic listening.

KEYWORDS:

• Developmental stuttering
• bilingualism
• dichotic listening paradigm
• hemispheric asymmetry
• language lateralisation

Declaration of interests

The authors report no conflicts of interest.

Notes

¹ Prior to data collection, statistical power was determined to decide on an appropriate sample size. In consultation with a statistician, it was calculated that a minimum sample size of 16 participants per group was required.

² Complete data for the Dichotic Listening Paradigm were obtained from 70 participants (14 BWS, 18 BWNS, 20 MWS, 18 MWNS), and incomplete data from 10 participants (6 BWS, 2 BWNS, 2 MWNS). The data from these participants were not included in the statistical analysis of the L = R and IID conditions since the participants failed to provide correct answers for the stimuli presented to the left and right ears.

Additional information

Funding

Support for the preparation of this manuscript was provided in part by the School of Applied Sciences at the University of Mississippi.