# Key Takeaways * Anodal tDCS **did not enhance motor learning** in either group and even led to slower performance in AWS. * Motor learning improvements **plateaued earlier** under anodal tDCS, which may suggest an unexpected disruption rather than facilitation of practice effects. * Contrary to previous findings, AWS under sham stimulation performed **similarly to controls**, challenging assumptions about fundamental motor deficits in AWS. # Identification of Patterns and Relationships * A significant male-to-female ratio difference and age difference were observed in the sham condition of the stutter group. However, these demographic differences did not significantly impact reaction time or sequence duration performance. * The observed performance variability across task blocks suggests individual differences in learning curves, aligning with research on trial-to-trial variability as a fundamental aspect of motor learning. * No significant differences were found in reaction time or sequence duration between the sham stutter group (StutSham), sham control group (ConSham), and anodal control group (ConAnodal), possibly due to a small sample size or task sensitivity issues. * The anodal stimulation in the stutter group (StutAnodal) led to slower sequence durations, suggesting exacerbation of motor timing issues, aligning with research indicating atypical motor responses in people who stutter. * The StutAnodal group exhibited an early plateau in reaction time improvement, implying a reduced practice effect and potential limitations in neural plasticity. * Variability in sequence duration performance in individuals who stutter suggests individualized effects of anodal transcranial direct current stimulation (tDCS), highlighting the need for personalized tDCS protocols. # Findings in Relation to Hypotheses * The hypothesis predicted that anodal tDCS would improve sequential motor practice in both groups, but results did not support this. * The control group showed no significant improvement in reaction time or sequence duration with anodal tDCS, possibly due to suboptimal stimulation parameters. * Contrary to the hypothesis, the stutter group exhibited slower sequence durations with anodal tDCS, indicating performance impairment rather than enhancement. * Greater variability in individual responses within the stutter group challenges the notion of a uniform tDCS effect and suggests that neural modulation differs across individuals. * Findings imply that standard tDCS protocols based on healthy adults may not be effective for individuals who stutter due to distinct neurophysiological substrates.