Abstract
Certain conditions are known to eliminate stuttering immediately. These conditions are referred to as fluency-inducing conditions, and they infer abnormalities of attentional characteristics among people who stutter. The aims of this study were to elucidate how the motor performance of stutterers is influenced by attentional foci: external focus of attention and internal focus of attention. A typing task involving sequential key pressing was conducted under the external focus and internal focus conditions among 13 adults who stutter and 12 matched control adults who do not stutter. Typing accuracy and typing speed were analyzed. The results revealed that the typing speed was significantly lower under the internal focus condition than the external focus condition in both groups, indicating that internal focus reduces the efficiency of finger movement compared to external focus. Moreover, for adults who stutter, typing accuracy also decreased significantly under the internal focus condition. It is speculated that adults who stutter are more vulnerable to disruptions in motor control under internal focus conditions than adults who do not stutter. The clinical implications of these findings are discussed.