Effects of electromyographic terminal feedback on motor learning of the relaxed phonation task

Abstract

The present study investigated the effects of terminal feedback on the learning of relaxed phonation using a motor learning paradigm. Twelve dysphonic participants were evenly and randomly assigned to two groups of conditions: with terminal feedback and without terminal feedback. During training, all participants were asked to read aloud sentence stimuli with four Chinese characters. Participants in the terminal feedback group received surface electromyographic (sEMG) biofeedback from the thyrohyoid site after reading every two sentences. Participants in the ‘no feedback’ group did not receive any feedback throughout the training sessions. A delayed retention test was conducted one week after training to evaluate motor learning. Results showed that motor learning was achieved in the ‘no feedback’ group, as demonstrated by a greater reduction of sEMG levels at the thyrohyoid site, comparing to the terminal feedback group. In order to assess how the participants perceived their learning, Voice Activity and Participation Profile (VAPP) (Ma & Yiu, 2001) was used. A great reduction in the Total VAPP scores during the pre- and posttreatment measurements was obtained from participants in the terminal feedback group. However, an increase in the Total VAPP scores was observed in the ‘no feedback’ group. The results indicated that participants’ perception towards their learning was affected by the amount of feedback they received during therapy and their perceptions did not necessarily parallel the actual benefits of the therapy. In summary, motor learning was evidenced in the ‘no feedback group’, which supported the hypothesis that provision of few or no terminal feedback would be more beneficial to motor learning as there was no concentration of attention focus on the laryngeal area with the absence of feedback.