This pilot study investigated motor learning and neuroplasticity in persons who do and do not stutter before and after participation in a phonation onset training protocol. Outcomes included phonation onset time and percent change in oxygenation level of hemoglobin using fNIRS in prescribed brain areas as a result of training. The authors hypothesized that people who stutter (PWS) would 1) exhibit a breakdown in auditory perception to motor production interactions, 2) demonstrate a difference in the way in which they perceive and learn motor information compared to someone who does not stutter (nPWS), and 3) exhibit reduced brain activity correlations between brain regions involved in perceived auditory targets and those involved in automatic motor production. 4 PWS and 4 nPWS between the ages of 20 to 59 participated in the study. There were no statistically significant between-group interactions, although there was a statistically significant within-subject change for production of breathy onset after training. Perception testing resulted in a ceiling effect, which must be addressed before further investigation. Observations were made utilizing graphed fNIRS data, which suggested right-sided auditory overactivation and left-sided suppression in PWS, as was hypothesized. The findings from the present pilot study serve as a cause for further investigation to either confirm or deny hemodynamic trends observed between PWS and nPWS
