The Cerebral Dominance and Laterality Preference in Adults with Persistent Developmental Stuttering

Abstract

Stuttering is reported to be the consequence of aberrant cerebral laterality in the processing and production of speech. The previous studies involving undirected attention to the stimuli during dichotic listening tests vary with their procedure and method, yielding inconclusive statements about the laterality of speech processing in persons with stuttering (PWS). This is also true with other laterality measures using imaging procedures, leading to equivocal results. Hence, there is a need to study the speech processing in PWS on a large sample using techniques that are more economical and simpler. The present study, a part of a large scale project, aimed to investigate the differences, if any, with respect to the handedness, footedness, ear and eye preference and the lateralization Index (LI) scores among PWS compared to persons with no stuttering (PWNS). Participants were 50 PWS and to PWNS in the age range of 18 to 30 years. All the participants were screened for hearing acuity and administered Modified Laterality Preference Schedule (MLPS) followed by Dichotic Consonant Vowel (CV) Test in Kannada Language. The statistical analysis showed no significant difference in the mean values of scores between PWS and PWNS on MLPS. However, the dichotic CV test results showed statistical significancant difference. The findings partially support observation by many authors that the left laterality of the speech motor system is incomplete in PWS where there is reduced left hemisphere activation, bilateral activation or widespread right hemisphere bias when listening to verbal information.