Abstract
Fluency-shaping enhances the speech fluency of persons who stutter, yet underlying conditions and neuroplasticity-related mechanisms are largely unknown. While speech production-related brain activity in stuttering is well studied, it is unclear whether therapy repairs networks of altered sensorimotor integration, imprecise neural timing and sequencing, faulty error monitoring, or insufficient speech planning. Here, we tested the impact of one-year fluency-shaping therapy on resting-state fMRI connectivity within sets of brain regions subserving these speech functions. We analyzed resting-state data of 22 patients who participated in a fluency-shaping program, 18 patients not participating in therapy, and 28 fluent control participants, measured one year apart. Improved fluency was accompanied by an increased synchronization within the sensorimotor integration network. Specifically, two connections were strengthened; the left inferior frontal gyrus showed increased connectivity with the precentral gyrus at the representation of the left laryngeal motor cortex, and the left inferior frontal gyrus showed increased connectivity with the right superior temporal gyrus. Thus, therapy-associated neural remediation was based on a strengthened integration of the command-to-execution pathway together with an increased auditory-to-motor coupling. Since we investigated task-free brain activity, we assume that our findings are not biased to network activity involved in compensation but represent long-term focal neuroplasticity effects.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Contacts: Alexandra Korzeczek alexandra.kore{at}posteo.de; Annika Primaßin annika.primassin{at}fh-muenster.de; Alexander Wolff von Gudenberg awvgudenberg{at}kasseler-stottertherapie.de; Peter Dechent Peter.Dechent{at}medizin.uni-goettingen.de; Walter Paulus wpaulus{at}med.uni-goettingen.de; Martin Sommer martin.sommer{at}med.uni-goettingen.de
The entire manuscript on rs-fMRI data was updated to clarify; dMRI data was excluded to simplify; Figure 2 was revised and Figure 3 is new; Figures 3 and 4 were excluded; Supplemental files updated.