Effects of Error Experience on Learning to Lower Speech Nasalance Level

The Role of Instructions in Motor Learning of Oral Versus Nasalized Speech Targets

PURPOSE

The purpose of this study was to investigate how general, implicit instructions with auditory-perceptual emphasis; specific, explicit instructions with biomechanical focus; or both affect learning of oral-nasal balance control in speech.

METHOD

Thirty healthy, vocally untrained participants were assigned to one of three instructional groups (i.e., implicit, explicit, and integrated) and learned to produce oral versus nasalized vowel-, syllable-, and phrase-level targets during once-weekly sessions over 4 weeks. Learning gains and performance variability were analyzed using nasometry.

RESULTS

We observed a significant main effect of instruction type on learning gains at phrase level (p = .016). Specifically, the integrated group (M = 59.8%) significantly outperformed the explicit group (M = 37.9%) and numerically outperformed the implicit group (M = 45.1%). For nasalized phrase targets, results revealed a significant main effect of instruction type on performance variability (p = .042), but pairwise comparisons between instruction groups were not significant.

CONCLUSIONS

The integration of implicit processes via auditory-perceptual modeling and explicit processes via relevant biomechanical directives resulted in larger motor learning gains, especially at higher levels of task complexity (i.e., phrase) compared to providing implicit or explicit instruction alone. The higher performance variability (i.e., less stable productions) that was sometimes induced by explicit instruction did not negatively impact learning when integrated with implicit instruction. Clinical implications for speech/voice therapy models are discussed.

Development of a Psychometric Measure of the Propensity to Consciously Control and Monitor Speech Production

Purpose A speech-specific reinvestment scale (SSRS) is a psychometric measure of the propensity to consciously control and monitor speech production. This study develops and validates an SSRS as well as examines its relationship with speech performance with the moderating effects of trait social anxieties (i.e., social interaction anxiety, public speaking anxiety, and social phobia). Method Scale development involves the following stages: (a) initial item generation based on relevant literature, (b) item evaluation through cognitive interviews with 24 healthy respondents, (c) scale reliability and validity tests using cross-sectional survey data from 498 healthy respondents, and (d) test-retest reliability assessment using longitudinal survey data from 185 healthy respondents. Respondents' speech performance is quantified using speech examination scores. Hierarchical moderated regression analyses are conducted to examine the moderating effects of trait social anxieties. Results The validated SSRS comprises 35 items, which can be categorized into four subdimensions, namely, speech movement self-consciousness, public consciousness of speech content, speech manner, and speech movement. Results show that respondents with low trait social anxieties indicate a generally positive relationship between public consciousness of speech movement and speech performance, whereas respondents with high trait social anxieties exhibit a nonsignificant relationship. Conclusions SSRS offers a reliable and valid method for assessing the predisposition for conscious speech control and monitoring, which plays a role in speech performance and is moderated by an individual's level of trait social anxiety. SSRS is a potential assessment tool for speech-language pathologists to evaluate the impacts of conscious speech control and monitoring on individuals with speech impairment.

Effects of Knowledge of Task on Control of Oral-Nasal Balance in Speech

<b><i>Introduction:</i></b> Previous research has shown that altering the nasal signal level auditory feedback changed the control of oral-nasal balance in normal speakers. The present study investigated whether knowledge of the task and the instruction not to compensate would change the participants’ response to the manipulation. <b><i>Methods:</i></b> Twenty participants (10 females) in 2 groups continuously repeated a sentence while their nasal signal level was increased or decreased and fed back to them via headphones, so the speakers heard themselves as more or less nasal, respectively. After the first recording session, participants were debriefed about the true nature of the experiment. They were instructed not to compensate in the second recording session. The outcome measures were the percentage changes of nasalance scores from the first baseline. <b><i>Results:</i></b> Statistical analysis using a repeated measures analysis of variance showed an effect of the nasal signal level, <i>F</i>(5,80) = 2.51, <i>p</i> = 0.049, and a nasal signal level by knowledge of task interaction effect, <i>F</i>(5,80) = 3.25, <i>p</i> = 0.019. Post hoc tests showed that the maximum nasal signal level auditory feedback resulted in a significant decrease of nasality from the initial baseline. <b><i>Conclusion:</i></b> Despite knowledge of the task, speakers were unable to resist compensating. As found in previous research, there was a numerically higher compensation response at the maximum than at the minimum nasal signal level auditory feedback condition.