>*"Intervention that precisely targets the neurological basis of stuttering"* This is a great topic for discussion! [This ](https://utoronto.scholaris.ca/server/api/core/bitstreams/d753d435-8c83-470d-83f6-d035ed3fba23/content)NEW research from 2025 may be helpful towards this end goal. **Research:** *The Effects of Anodal Transcranial Direct Current Stimulation on Motor Sequence Practice in Typically Fluent Adults and Adults Who Stutter (2025)* **Abstract** *Background: Developmental stuttering involves dysregulation in the cortico-basal gangliathalamo-cortical circuit, impacting speech and non-speech motor control. While Transcranial Direct Current Stimulation (tDCS) enhances speech motor learning in stuttering, its effects on non-speech motor skills are not studied. This project aimed to assess anodal tDCS effects on a finger sequencing task.* *Methods: Thirty right-handed adults who stutter and twenty controls received anodal tDCS at 2mA or sham stimulation at 0mA on the right primary motor region (M1) for 20 minutes. Sequence duration and reaction time were measured.* *Results: All cohorts performed similarly except for the stutter group under anodal tDCS, which displayed longer sequence durations and reduced improvement in reaction times.* *Discussion: The findings suggest that anodal tDCS on the right M1 negatively affects motor sequence practice in stuttering, possibly due to differences in neural activity in the M1. Further research on interventions targeting cortical excitability is warranted* **Research findings:** This thesis examined how anodal transcranial direct current stimulation (tDCS) over the right primary motor cortex (M1) affects sequential motor learning, measured by a finger tapping task, in adults who stutter (AWS) and those who do not stutter (controls). The study had two main objectives: # 1) Effect of Anodal tDCS on Motor Performance * **Contrary to expectations**: Anodal tDCS **did not significantly change reaction times or sequence durations** in the control group. In AWS, anodal tDCS did not alter reaction times but led to **significantly slower sequence durations**, indicating a negative effect on performance. * **Block-by-block analysis**: An unexpected pattern emerged where **performance improvements plateaued earlier** in the anodal condition than in the sham condition. The control group reached this plateau after the **6th block**, while the AWS group reached it after the **7th block**. Reaction times in the anodal condition became **slower after a certain number of blocks**, suggesting a potential disruption in motor learning processes. # 2) Comparison Between AWS and Control Group * **Surprisingly**: Under the sham condition, AWS **did not differ significantly** from controls in either reaction time or sequence duration. Block-by-block analysis also showed no significant **interaction between group and block**, meaning motor performance progressed similarly between AWS and controls.