The use of analogy in speech motor performance

Unpacking the black box of voice therapy: A clinical application and revision of the Motor Learning Classification Framework (MLCF)

PURPOSE

Voice therapy is a complex behavioural intervention. Understanding its components is integral for continued advancement of voice therapy research, translation of evidence into the clinical setting and improved client care. The Motor Learning Classification Framework (MLCF) offers an excellent opportunity for increasing such knowledge, specifically in relation to identifying variables that affect motor learning (ML), an important mechanism hypothesised to bring about voice change during voice therapy. The MLCF has shown promising results in identifying speech-language pathologists' (SLPs) use of ML variables during experimentally controlled voice therapy contexts. The purpose of this study was to test the feasibility of applying the framework in the clinical context of everyday voice therapy practice.

METHOD

Data consisted of two video-recorded voice therapy sessions representing usual voice therapy care. Classification of ML variables used by SLPs during the recorded sessions was attempted based on the MLCF.

RESULT

Several problematic features of the framework were identified. Based on deliberations between the authors of the current paper, the MLCF was revised using an iterative process. This resulted in the construction of an updated version of the framework (MLCF-V2). The MLCF-V2 organises ML strategies into two broad categories: directly observable behaviours and learning processes. The framework incorporates greater consideration of theory and empirical evidence supporting motivational, attentional focus and subjective error estimation influences on ML. Several examples of each ML variable are included as well as an attempt to provide clearer classification instruction.

CONCLUSION

It is anticipated that the MLCF-V2 will provide a more useful and reliable classification for use in future investigations of SLPs' use of ML variables during usual voice therapy practice.

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 Error Experience on Learning to Lower Speech Nasalance Level

Purpose This research aims to examine the effects of error experience when learning to speak with lowered nasalance level. Method A total of 45 typical speakers were instructed to learn to lower speech nasalance level in either an errorless (restricted possibility for committing errors) or an errorful (unrestricted possibility for committing errors) learning condition. The nasality level of the participants' speech was measured by a nasometer and quantified by nasalance scores (in percent). Errorless learners practiced producing speech with lowered nasalance level with a threshold nasalance score of 50% (the easiest target) at the beginning, which gradually decreased to a threshold of 10% (the most difficult target) at the end. The same set of threshold targets was presented to errorful learners, but in reverse order. Errors were defined by the proportion of speech, with a nasalance score exceeding the threshold. Retention and transfer tests were administered. Results Errorless learners displayed fewer errors and lower mean nasalance scores than errorful learners during the acquisition phase. Furthermore, errorless learners achieved lower mean nasalance scores than errorful learners in the retention and transfer tests. Conclusion These results suggest that errorless learning is more effective than errorful learning and that error experience has a detrimental effect on the acquisition of a novel speech motor task that requires minimization of the nasality level. Errorless learning may be a useful paradigm for the intervention and management of hypernasality in clinical settings where behavioral treatments are needed.

Examining the cognitive demands of analogy instructions compared to explicit instructions

PURPOSE

In many learning domains, instructions are presented explicitly despite high cognitive demands associated with their processing. This study examined cognitive demands imposed on working memory by different types of instruction to speak with maximum pitch variation: visual analogy, verbal analogy and explicit verbal instruction.

METHOD

Forty participants were asked to memorise a set of 16 visual and verbal stimuli while reading aloud a Cantonese paragraph with maximum pitch variation. Instructions about how to achieve maximum pitch variation were presented via visual analogy, verbal analogy, explicit rules or no instruction. Pitch variation was assessed off-line, using standard deviation of fundamental frequency. Immediately after reading, participants recalled as many stimuli as possible.

RESULT

Analogy instructions resulted in significantly increased pitch variation compared to explicit instructions or no instructions. Explicit instructions resulted in poorest recall of stimuli. Visual analogy instructions resulted in significantly poorer recall of visual stimuli than verbal stimuli.

CONCLUSION

The findings suggest that non-propositional instructions presented via analogy may be less cognitively demanding than instructions that are presented explicitly. Processing analogy instructions that are presented as a visual representation is likely to load primarily visuospatial components of working memory rather than phonological components. The findings are discussed with reference to speech therapy and human cognition.

Effects of error experience when learning to simulate hypernasality

PURPOSE

The purpose of this study was to evaluate the effects of error experience on the acquisition of hypernasal speech.

METHOD

Twenty-eight healthy participants were asked to simulate hypernasality in either an errorless learning condition (in which the possibility for errors was limited) or an errorful learning condition (in which the possibility for errors was not limited). The nasality level of the participants' speech was measured with a nasometer and reflected by nasalance scores (in percentages). Errorless learners practiced producing hypernasal speech with a threshold nasalance score of 10% at the beginning, gradually increasing to a threshold of 50% at the end. The same set of threshold targets were presented to errorful learners but in a reversed order. Errors were defined by the proportion of speech with a nasalance score below the threshold. A retention test and a transfer test were administered.

RESULTS

Relative to errorful learners, errorless learners displayed fewer errors and a higher mean nasalance score during acquisition. Furthermore, errorless learners outperformed errorful learners in both retention and transfer tests.

CONCLUSION

The results suggest that errorless learning is more effective than errorful learning in acquiring a novel speech motor task that involves manipulation of the nasality level of speech.

Effects of practice schedules on speech motor learning

The aim of this study was to evaluate the effects of various practice schedules on learning a novel speech task. Forty healthy Cantonese speakers were asked to learn to produce a Cantonese phrase with two target utterance durations (2500 and 3500 milliseconds). They were randomly assigned to one of four learning conditions, each completing a different practice schedule, namely Blocked only, Random only, Blocked-then-Random, and Random-then-Blocked. Two retention tests (one immediate and one delayed) and a transfer test were administered. The four groups of participants showed different patterns of learning, but achieved comparable levels of performance at the end of the acquisition phase. However, participants in the Blocked only condition were less able to differentiate the two target durations than those in the Random only condition during retention. Furthermore, participants who received both blocked and random practice were less adversely affected by the secondary task during the transfer test than those who received either blocked or random practice alone. These findings suggest that mixed practice schedules are more effective than either blocked or random practice, especially in transferring the acquired speech motor skills to a cognitively demanding situation. The results have clinical implications regarding optimal practice schedules for treatment intervention.

Influence of analogy instruction for pitch variation on perceptual ratings of other speech parameters

PURPOSE

Analogy is the similarity of different concepts on which a comparison can be based. Recently, an analogy of "waves at sea" was shown to be effective in modulating fundamental frequency (F0) variation. Perceptions of intonation were not examined, as the primary aim of the work was to determine whether analogy instruction had a negative impact on other parameters of the speech signal compared with explicit instruction. The purpose of this study was (a) to determine whether changes in the standard deviation of F0, acoustically, resulted in similar changes in the perception of pitch variability and (b) to determine the perceptual influence of analogy vs. explicit instructions on speech naturalness, loudness, and rate.

METHOD

Ten speech-language pathologists were asked to listen to and rate pitch variation, speech naturalness, loudness, and rate for 74 Cantonese speech samples using a visual analogue scale, which allowed raters to indicate their subjective perceptions of each parameter.

RESULTS

It is revealed that listeners perceived pitch variation to be greater and speech to be more natural in analogy-instructed, rather than explicitly instructed, speech. No differences were perceived for ratings of speech loudness or speech rate.

CONCLUSION

It is concluded that analogy instruction has a less negative impact on the naturalness of speech than explicit instruction and may provide a better method by which to manipulate desired pitch variation.