Nonword Repetition Task to Evaluate Syllable Stress as a Motor Class

• Main Author: Cobun, Emily R.
• Language: EN
• Published: West Virginia University 2017
• Subjects: Speech therapy
• Online Access: http://pqdtopen.proquest.com/#viewpdf?dispub=10272855

<p> Current speech therapy methods and theories are based on generalized motor program (GMP) theory (Schmidt, 1975). GMP theory states a single GMP, or motor program, directs multiple movements of speech (Maas et al., 2008). Additionally, GMP theory asserts these similar muscle movements are part of the same motor class, which allows a GMP to direct performance on novel, untrained patterns of movements (i.e., what is termed &ldquo;transfer performance&rdquo;; Chamberlin &amp; Magill, 1992; Schmidt, 1975). Alternatively, movements outside of a learned motor class will be more difficult to perform because a different GMP is controlling these movements. Currently, syllable stress patterns are theorized as the GMP when planning motor speech tasks. This study aims to help clarify the method through which motor speech movements are learned. </p><p> Meigh et al. (in press) conducted a study to learn more about speech motor planning. This study found that syllable stress, which was the expected GMP for speech production, did not direct transfer performance on untrained stimuli following training on a speech-like task. Instead, participants encoded speech sound (i.e., phoneme) information during training that influenced transfer results. In Meigh&rsquo;s study, participants were trained using a speech production task but the testing procedure was not speech-based. Meigh&rsquo;s results and interpretation may have been impacted by the study design because of the &ldquo;mismatch&rdquo; between modes of training and testing in this study. Therefore, the current study replicated and extended Meigh&rsquo;s experiment using a speech-based training and transfer task. </p><p> Twenty-four participants (16 females and 3 males) produced nonsense words (i.e., nonwords) using a motor learning design, which included mass amounts of training followed by an evaluation of performance on untrained stimuli. During training, participants produced different syllable stress patterns while repeating a training list of nonwords. Following training, participants repeated a list of both trained and untrained nonwords that varied in similarity to the trained stimuli. All untrained stimuli varied by motor class (i.e., syllable stress pattern), as well as the phonemes (or sounds). Accuracy of nonword productions were evaluated across transfer stimuli sets, and results revealed participants had learned syllable stress <i>and</i> phoneme information during training. These results align with a GMP theory and Meigh (in press) suggesting that more than one GMP memory representation may be encoded during motor learning.</p>