Swedish Test of Intelligibility for Children (STI-CH)--validity and reliability of a computer-mediated single word intelligibility test for children

Consonantal Landmarks as Predictors of Dysarthria among English-Speaking Adults with Cerebral Palsy

The current study explored the possibility that the consonantal landmarks served as predictors of dysarthric speech produced by English-speaking adults with cerebral palsy (CP). Additionally, the relationship between the perceptual severity of dysarthric speech and the consonantal landmarks was explored. The analyses included 210 sentences from the TORGO database produced by seven English-speaking CP speakers with dysarthria and seven typically developing controls matched in age and gender. The results indicated that the clinical group produced more total landmark features than did the control group. A binominal regression analysis revealed that the improper control of laryngeal vibration and the inability to tactically control the energy in a voiced segment would lead to the higher likelihood of dysarthric speech. A multinominal regression analysis revealed that producing too many +v and −v landmark features would lead to higher perceptual severity levels among the CP speakers. Together with literature, the current study proposed that the landmark-based acoustic analysis could quantify the differences in consonantal productions between dysarthric and non-dysarthric speech and reflect the underlying speech motor deficits of the population in concern.

Measuring intelligibility in spontaneous speech using syllables perceived as understood

PURPOSE

Intelligibility, the ability to convey a message by speech, is one of the most important variables in speech-language pathology. The assessment of intelligibility is a challenge especially when it comes to spontaneous speech. The aim of the study was to investigate validity and reliability of a method for assessment of intelligibility, syllables perceived as understood (SPU); a method that is more time-efficient than previous methods based on transcription, as it does not require a master transcript for reference.

METHOD

A group of 20 adult listeners transcribed stimuli consisting of spontaneous speech from 16 children (14 with speech sound disorder and two with typical speech and language development, age 4:4 to 8:1, M = 6:0). Intelligibility was calculated based on these orthographic transcripts, as a) proportion of syllables perceived as understood (SPU) and b) proportion of syllables correctly understood (SCU), with reference to a master transcript. Validity was checked through investigation of the correlation and difference between these two measures. Reliability was analysed with inter-listener reliability by intra-class correlation.

RESULTS

The correlation between SPU and SCU (the gold standard intelligibility score) was strong and statistically significant, with SPU being consistently higher than SCU. Inter-listener reliability for single measures of intra-class correlation of the assessment by syllables perceived as understood was moderate to low, whereas the inter-listener reliability for average measures of intra-class correlation was high.

CONCLUSIONS

The method based on SPU might be used for assessment of intelligibility if the median from several listeners is used or when comparing results from the same listener over time. The SPU method might therefore be a valuable tool in a clinical and research context as a more valid option than rating scales and a more time-efficient method than the gold standard SCU method. However, it should be noted that the reliability of the SPU is not as high as for the SCU.

Inteligibilidad: diferentes perspectivas de su concepto y evaluación. Una revisión sistemática

Una adecuada inteligibilidad es un indicador del éxito en la comunicación. Su interferencia, a causa de cualquier patología, debe ser abordada en los objetivos primordiales de la terapia. No obstante, los métodos para su evaluación son poco conocidos. Objetivo: desarrollar una revisión sistemática que describa los métodos empleados en la medición de la inteligibilidad y discutir la conceptualización de este constructo. Metodología: se realiza una búsqueda en las bases de datos PubMed, ScieLo y Science Direct para identificar artículos publicados entre 1990 y 2018. Análisis y discusiones: Se seleccionan 50 investigaciones en inglés, español y portugués, que mostraron preferencia por medidas objetivas de evaluación, por sobre las medidas subjetivas de escala. La inteligibilidad se define mejor como un constructo dependiente de la señal acústica, a diferencia del concepto de comprensibilidad. Esta revisión ofrece información actualizada y organizada para optimizar procedimientos clínicos y científicos de medición de la inteligibilidad. 

Audience Response System-Based Evaluation of Intelligibility of Children's Connected Speech - Validity, Reliability and Listener Differences

PURPOSE

We assessed audience response systems (ARS)-based evaluation of intelligibility, with a view to find a valid and reliable intelligibility measure that is accessible to non-trained participants. In addition, we investigated potential listener differences between pediatric speech and language pathologists (SLPs) and untrained adults.

METHOD

Sixteen one-minute samples of connected speech were compiled, collected from 14 children with a speech sound disorder (SSD) and two children with typical speech. 16 SLPs and 13 untrained adults participated in a series of ARS listening sessions, where they were fitted with headphones and hand controls, and instructed to click a button whenever they did not understand the child speaking. Listeners' button clicks were registered and, for each speech sample, totaled into an (un)intelligibility index. The proportion of syllables perceived correctly - based on orthographic listener transcripts - was used as a reference score of intelligibility.

RESULTS

The ARS-based intelligibility scores correlated strongly with the intelligibility reference score. Reliability was high across listener groups and weaker for single listeners. No significant difference was found between the evaluations of SLPs and untrained adults.

CONCLUSIONS

ARS-based evaluation offers a valid and reliable measure of intelligibility of particular value in research as a practical tool for collecting input from listeners without experience or knowledge of SSDs. We stress that the ARS design presupposes a listener panel, and that evaluations obtained from individual listeners are predictably inadequate in terms of reliability.

Intelligibility of Children With Speech Sound Disorders Evaluated by Listeners With Swedish as a Second Language

Purpose This study aimed to investigate the intelligibility of children's atypical speech in relation to listeners' language background. Method Forty-eight participants listened to and transcribed isolated words repeated by children with speech sound disorders. Participants were divided into, on the one hand, a multilingual group (n = 29) that was further divided into subgroups based on age of acquisition (early, 0-3 years; intermediate, 4-12 years; and late, > 12 years) and, on the other hand, a monolingual comparison group (n = 19). Results The monolingual listeners obtained higher intelligibility scores than the multilingual listeners; this difference was statistically significant. Participants who acquired Swedish at an older age (> 4 years) were found to have lower scores than other listeners. The later the age of acquisition, the less of the atypical speech was decoded correctly. A further analysis of the transcriptions also revealed a higher level of nonwords among the incorrect transcriptions of the multilinguals than that of the monolinguals who used more real words, whereas both groups were equally prone to using blanks when they did not perceive a word. Conclusions This indicates a higher risk of communicative problems between late acquirers of Swedish and children with speech sound disorders. Clinical implications, such as involving communication partners in the intervention process, are discussed as well as possible linguistic explanations to the findings. This study could be seen as a starting point in the field of research regarding the relations between the language background of the listener and the ability to perceive atypical speech.

Profiling Speech Sound Disorders for Clinical Validation of the Computer Articulation Instrument

Purpose The current article presents data from 2 studies on clinical groups of children referred for speech assessment. The aims of these studies are to validate the Computer Articulation Instrument (CAI) with the known-group validation method and to determine the differential diagnostic power of the resulting speech profiles. Method Study 1 examined known-group validity by comparing the scores of 93 children diagnosed with speech-language difficulties on the picture naming (PN) task of the CAI with intelligibility judgments given by speech-language pathologists. In Study 2, the speech profiles of 41 children diagnosed with speech sound disorders (SSDs), consisting of 4-6 factor scores extracted from the 4 tasks of the CAI, namely, PN, nonword imitation (NWI), word and nonword repetition, and maximum repetition rate (MRR), were validated against clinical judgments of severity of the SSD given by speech-language pathologists. Results In Study 1, a repeated-measures analysis of variance revealed a significant effect of intelligibility level on the PN performance of the CAI and there were highly significant correlations between intelligibility and PN performance in the expected direction. Neither intelligibility level nor PN performance was related to nonverbal intelligence and language scores. The analysis of variance and a series of t tests in Study 2 revealed significant differences between the moderate and severe groups for the CAI factors based on PN and NWI and the bisyllabic and trisyllabic sequences of MRR, but not for the factor word and nonword proportion of whole-word variability based on word and nonword repetition, and the monosyllabic sequences of MRR. These results suggest that, especially, the tasks PN, NWI, and the bisyllabic and trisyllabic sequences of MRR are most sensitive for diagnosing SSDs. Conclusions The findings of these 2 studies support the known-group validity of the CAI. Together with the results of a previous study of our group on reliability and validity ( van Haaften et al., 2019 ), we can conclude that the CAI is a reliable and valid tool for assessment of children with SSDs.

Dealing with the unknown - addressing challenges in evaluating unintelligible speech

When investigating the interaction between speech production and intelligibility, unintelligible speech portions are often of particular interest. Therefore, the fact that the standard quantification of speech production - the Percentage of Consonants Correct (PCC) - is only computed on intelligible speech is unsatisfying. Our purpose was to evaluate a new quantification of speech production: the Percentage of Intelligible and Correct Syllables (PICS) designed to address this limitation. A secondary purpose was to explore a task designed to elicit connected speech - concurrent commenting - offering more control of intended speech production compared to free conversation. Nine children with SSD participated in four speech elicitation tasks, varying with respect to ecological validity, and to degree of control: (1) word imitation, (2) picture naming, (3) concurrent commenting of a silent short video, and (4) free conversation. Speech accuracy was analysed in terms of PCC-Revised (PCC-R) and PICS, and intelligibility with regards to the Proportion of Intelligible Syllables (PINTS). A strong correlation was observed between PICS and PCC-R, supporting the construct validity of PICS. Further, a moderate correlation was seen between PICS and PINTS, presumably reflecting that these measures capture different - although related - constructs. No difference was seen between concurrent commenting and free conversation in terms of articulation proficiency or intelligibility; however, this needs further investigation based on more data. Nevertheless, we suggest concurrent commenting as a useful method for eliciting connected speech; in retaining more control over intended target words compared to free conversation, this task may be particularly useful in the context of unintelligible speech.

An Investigation of the Clinical Use of a Single-Word Procedure to Assess Intelligibility (Swedish Test of Intelligibility for Children) and an Evaluation of the Validity and Reliability of the Intelligibility in Context Scale

Purpose Intelligibility is a core concept of speech-language pathology, central both to the assessment of speech disorders and to intervention in such disorders. One purpose of this study was to investigate the reliability and usability of a single-word assessment procedure, the Swedish Test of Intelligibility for Children (STI-CH), in a clinical setting. Another purpose was to investigate the validity and reliability of an assessment method designed to assess functional intelligibility: the Intelligibility in Context Scale (ICS). Method Thirty children aged 4;1-10;1 years;months were recruited from speech-language pathology clinics in Western Sweden. Each child's treating speech-language pathologist served as listener in the STI-CH assessment while the ICS was completed by each child's parents. External listeners (2 last-year speech-language pathology students) were used to assess the validity of the speech-language pathology. Results The mean duration of the test procedure for the STI-CH was about 19 min, and 57% of the test sessions were reported as difficult. There was a weak but statistically significant correlation between the results from the STI-CH and the ICS ( r = .40, p < .05), and both methods showed high reliability in terms of interlistener reliability (intraclass correlation exceeding .97) and internal consistency, respectively. Conclusions The STI-CH had high reliability and was time efficient but had some procedural problems. The ICS had moderate validity but high reliability. The STI-CH is promising for clinical use but needs to be developed further. The validity of the ICS can be discussed and needs to be further investigated.

Tutorial: Speech Assessment for Multilingual Children Who Do Not Speak the Same Language(s) as the Speech-Language Pathologist

PURPOSE

The aim of this tutorial is to support speech-language pathologists (SLPs) undertaking assessments of multilingual children with suspected speech sound disorders, particularly children who speak languages that are not shared with their SLP.

METHOD

The tutorial was written by the International Expert Panel on Multilingual Children's Speech, which comprises 46 researchers (SLPs, linguists, phoneticians, and speech scientists) who have worked in 43 countries and used 27 languages in professional practice. Seventeen panel members met for a 1-day workshop to identify key points for inclusion in the tutorial, 26 panel members contributed to writing this tutorial, and 34 members contributed to revising this tutorial online (some members contributed to more than 1 task).

RESULTS

This tutorial draws on international research evidence and professional expertise to provide a comprehensive overview of working with multilingual children with suspected speech sound disorders. This overview addresses referral, case history, assessment, analysis, diagnosis, and goal setting and the SLP's cultural competence and preparation for working with interpreters and multicultural support workers and dealing with organizational and government barriers to and facilitators of culturally competent practice.

CONCLUSION

The issues raised in this tutorial are applied in a hypothetical case study of an English-speaking SLP's assessment of a multilingual Cantonese- and English-speaking 4-year-old boy. Resources are listed throughout the tutorial.

Speech intelligibility in Parkinson's disease patients with zona incerta deep brain stimulation

OBJECTIVES

To investigate the effects of l-dopa (Levodopa) and cZi-DBS (deep brain stimulation in caudal zona incerta) on spontaneous speech intelligibility in patients with PD (Parkinson's disease).

MATERIALS AND METHODS

Spontaneous utterances were extracted from anechoic recordings from 11 patients with PD preoperatively (off and on l-dopa medication) and 6 and 12 months post bilateral cZi-DBS operation (off and on stimulation, with simultaneous l-dopa medication). Background noise with an amplitude corresponding to a clinical setting was added to the recordings. Intelligibility was assessed through a transcription task performed by 41 listeners in a randomized and blinded procedure.

RESULTS

A group-level worsening in spontaneous speech intelligibility was observed on cZi stimulation compared to off 6 months postoperatively (8 adverse, 1 positive, 2 no change). Twelve months postoperatively, adverse effects of cZi-DBS were not frequently observed (2 positive, 3 adverse, 6 no change). l-dopa administered preoperatively as part of the evaluation for DBS operation provided the overall best treatment outcome (1 adverse, 4 positive, 6 no change).

CONCLUSIONS

cZi-DBS was shown to have smaller negative effects when evaluated from spontaneous speech compared to speech effects reported previously. The previously reported reduction in word-level intelligibility 12 months postoperatively was not transferred to spontaneous speech for most patients. Reduced intelligibility due to cZi stimulation was much more prominent 6 months postoperatively than at 12 months.

Intelligibility in Context Scale: Normative and Validation Data for English-Speaking Preschoolers

Purpose

The purpose of this study was to describe normative and validation data on the Intelligibility in Context Scale (ICS; McLeod, Harrison, & McCormack, 2012c) for English-speaking children.

Method

The ICS is a 7-item, parent-report measure of children's speech intelligibility with a range of communicative partners. Data were collected from the parents of 803 Australian English-speaking children ranging in age from 4;0 (years;months) to 5;5 (37.0% were multilingual).

Results

The mean ICS score was 4.4 ( SD = 0.7) out of a possible total score of 5. Children's speech was reported to be most intelligible to their parents, followed by their immediate family, friends, and teachers; children's speech was least intelligible to strangers. The ICS had high internal consistency (α = .94). Significant differences in scores were identified on the basis of sex and age but not on the basis of socioeconomic status or the number of languages spoken. There were significant differences in scores between children whose parents had concerns about their child's speech ( M = 3.9) and those who did not ( M = 4.6). A sensitivity of .82 and a specificity of .58 were established as the optimal cutoff. Test–retest reliability and criterion validity were established for 184 children with a speech sound disorder. There was a significant low correlation between the ICS mean score and percentage of phonemes correct ( r = .30), percentage of consonants correct ( r = .24), and percentage of vowels correct ( r = .30) on the Diagnostic Evaluation of Articulation and Phonology (Dodd, Hua, Crosbie, Holm, & Ozanne, 2002). Thirty-one parents completed the ICS related to English and another language spoken by their child with a speech sound disorder. The significant correlations between the scores suggest that the ICS may be robust between languages.

Conclusions

This article provides normative ICS data for English-speaking children and additional validation of the psychometric properties of the ICS. The robustness of the ICS was suggested because mean ICS scores were not affected by socioeconomic status, number of languages spoken, or whether the ICS was completed in relation to English or another language. The ICS is recommended as a screening measure of children's speech intelligibility.