Negative practice versus repetitive drill: A pilot randomised controlled trial of learning a voice motor skill

Participants will be asked to practice in one of 3 ways depending on their group allocation : 1) Negative practice condition - produce a dysphonic voice quality then produce a clear, effortless voice quality for 50 trials, 10 times/day for 5 days. 2) Repetitive Drill condition - produce a clear, effortless voice quality for 50 trials, 10 times/day for 5 days. 3) The control group will not practice The treatment will be delivered by a 4th year student speech pathologist, under the supervision of the chief investigator. Negative practice or repetitive drill practice group Participants in the repetitive drill and negative practice groups will attend a 1 hour session at baseline during which time they will listen to scripted instructions that are tailored to their respective treatment group, and a video of an expert clinician modeling the Optimal Phonation Task (OPT). The student investigator will guide the participants through the entire pre-practice phase of learning the OPT and provide feedback where needed. The participants must be able to produce the task such that it approximates the model by the end of this session. Control group Participants in the control group will be instructed to complete crosswords to ensure they do not think about or practice the OPT. The investigators will not tell the participants not to think about the OPT because people do not do what they are told and often do the opposite instead (Ovretveit, 2009; Sharp, 1973 as cited in Mayton II, 2009). Independent practice After participants master the vocal task during the therapy session, they will move on to the practice phase. This requires them to practice the task 50 times for 10 repetitions a day for five consecutive days in accordance with motor learning recommendations (Maas et al., 2008). Childhood apraxia of speech treatment research guided the investigators in determining the number of trials to be done per practice session (Murray, McCabe, & Ballard, 2012; Maas & Farinella, 2012). The type of practice done by participants will depend on the treatment group they are assigned to. Participants in the control group must not practice the OPT. During each practice session, participants in the repetitive drill group will practice 50 trials of the OPT the correct way (gentle onset, quietly, effortlessly). During each practice session, participants in the negative practice group will practice the wrong way (hard onset, effortful, loud) of performing the OPT immediately followed by the correct way, and think about the difference in sensation in their vocal tract after each set (2 trials), for a total of 50 trials. Both the repetitive drill and negative practice groups will practice a total of 500 trials of the OPT a day. The entire practice phases will be conducted by participants alone in their own time. For each practice session, participants must record the time of practice, number of trials completed, practice environment, and effort required to produce the OPT in their individual logbooks. Participants will also need to video record all practice trials they do, so that the investigators can verify that all participants practiced the OPT according to the agreed protocol by reviewing all videos to check the number of trials practiced.