Brain stimulation in stuttering: Participant experiences with transcranial Direct Current Stimulation (tDCS)

There is growing interest in non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) in stuttering therapy. However, limited information is available on how such innovative interventions are perceived by target participants. The aim of this study was to qualitatively examine the acceptability and social validity of tDCS in individuals with developmental stuttering in the context of participants' experiences and perceptions of the intervention process and changes in their social lives. The study was based on semi-structured interviews with 10 adults with developmental stuttering who had previously participated in the active tDCS stimulation group. Data were analyzed using inductive thematic analysis. Five main themes were identified: (1) reasons for participation; (2) perception of the intervention and emotional responses; (3) experiences related to the intervention process; (4) perceived effects of tDCS and (5) recommendations for the future. Participants reported temporary fluency improvements and increased self-confidence, emphasizing that the intervention was generally manageable and acceptable. These subjective evaluations offer insight into how tDCS was experienced without implying clinical efficacy. Results should be interpreted with caution, as interviews were conducted without blinding and responses may have been influenced by social desirability or complicity bias. Importantly, despite prior quantitative measurements from the same intervention showing no significant objective improvements in speech fluency, participants still described positive subjective experiences. This contrast between quantitative outcomes and experiential reports highlights the importance of incorporating individuals' perceptions into evaluations of novel therapeutic approaches. Participants' hopes and suggestions provide valuable guidance for future developments in the field.