Evaluating rate and accuracy of real word vs. non-word diadochokinetic productions from childhood to early adulthood in Hebrew speakers

Diadochokinesis Performance and Its Link to Cognitive Control: Alternating Versus Non-Alternating Diadochokinesis

PURPOSE

In a previous publication, we observed that maximum speech performance in a nonclinical sample of young adult speakers producing alternating diadochokinesis (DDK) sequences (e.g., rapidly repeating "pataka") was associated with cognitive control: Those with better cognitive switching abilities (i.e., switching flexibly between tasks or mental sets) showed higher DDK accuracy. To follow up on these results, we investigated whether this previously observed association is specific to the rapid production of alternating sequences or also holds for non-alternating sequences (e.g., "tatata").

METHOD

For the same sample of 78 young adults as in our previous study, we additionally analyzed their accuracy and rate performance on non-alternating sequences to investigate whether executive control abilities (i.e., indices of speakers' updating, inhibition, and switching abilities) were more strongly associated with production of alternating, as compared with non-alternating, sequences.

RESULTS

Of the three executive control abilities, only switching predicted both DDK accuracy and rate. The association between cognitive switching (and updating ability) and DDK accuracy was only observed for alternating sequences. The DDK rate model included a simple effect of cognitive switching, such that those with better switching ability showed slower diadochokinetic rates across the board. Thus, those with better cognitive ability showed more accurate (alternating) diadochokinetic production and slower maximum rates for both alternating and non-alternating sequences.

CONCLUSION

These combined results suggest that those with better executive control have better control over their maximum speech performance and show that the link between cognitive control and maximum speech performance also holds for non-alternating sequences.

Oral-diadochokinesis between Parkinson's disease and neurotypical elderly among Malaysian-Malay speakers

BACKGROUND

Parkinson's disease (PD) has an impact on speech production, manifesting in various ways including alterations in voice quality, challenges in articulating sounds and a decrease in speech rate. Numerous investigations have been conducted to ascertain the oral-diadochokinesis (O-DDK) rate in individuals with PD. However, the existing literature lacks exploration of such O-DDK rates in Malaysia and does not provide consistent evidence regarding the advantage of real-word repetition.

AIMS

To explore the effect of gender, stimuli type and PD status and their interactions on the O-DDK rates among Malaysian-Malay speakers.

METHODS & PROCEDURES

O-DDK performance of 62 participants (29 individuals with PD and 33 healthy elderly) using a non-word ('pataka'), a Malay real-word ('patahkan') and an English real-word ('buttercake') was audio recorded. The number of syllables produced in 8 s was counted. A hierarchical linear modelling was performed to investigate the effects of stimuli type (non-word, Malay real-word, English real-word), PD status (yes, no), gender (male, female) and their interactions on the O-DDK rate. The model accounted for participants' age as well as the nesting of repeated measurements within participants, thereby providing unbiased estimates of the effects.

OUTCOMES & RESULTS

The stimuli effect was significant (p < 0.0001). Malay real-word showed the lowest O-DDK rate (5.03 ± 0.11 syllables/s), followed by English real-word (5.25 ± 0.11 syllables/s) and non-word (5.42 ± 0.11 syllables/s). Individuals with PD showed a significantly lower O-DDK rate compared to healthy elderly (4.73 ± 0.15 syllables/s vs. 5.74 ± 0.14 syllables/s, adjusted p < 0.001). A subsequent analysis indicated that the O-DDK rate declined in a quadratic pattern. However, neither gender nor age effects were observed. Additionally, no significant two-way interactions were found between stimuli type, PD status and gender (all p > 0.05). Therefore, the choice of stimuli type has no or only limited effect considering the use of O-DDK tests in clinical practice for diagnostic purposes.

CONCLUSIONS & IMPLICATIONS

The observed slowness in O-DDK among individuals with PD can be attributed to the impact of the movement disorder, specifically bradykinesia, on the physiological aspects of speech production. Speech-language pathologists can gain insights into the impact of PD on speech production and tailor appropriate intervention strategies to address the specific needs of individuals with PD according to disease stages.

WHAT THIS PAPER ADDS

What is already known on this subject The observed slowness in O-DDK rates among individuals with PD may stem from the movement disorder's effects on the physiological aspects of speech production, particularly bradykinesia. However, there is a lack of consistent evidence regarding the influence of real-word repetition and how O-DDK rates vary across different PD stages. What this study adds to existing knowledge The O-DDK rates decline in a quadratic pattern as the PD progresses. The research provides insights into the advantage of real-word repetition in assessing O-DDK rates, with Malay real-word showing the lowest O-DDK rate, followed by English real-word and non-word. What are the potential or actual clinical implications of this work? Speech-language pathologists can better understand the evolving nature of speech motor impairments as PD progresses. This insight enables them to design targeted intervention strategies that are sensitive to the specific needs and challenges associated with each PD stage. This finding can guide clinicians in selecting appropriate assessment tools for evaluating speech motor function in PD patients.

The effect of real word stimuli versus non-word stimuli on oral diadochokinetic rates across the life span: An item discrimination analysis

BACKGROUND

Diadochokinetic (DDK) rate tasks are extensively used in the evaluation of speech disorders; however, it is unclear how the different types of speech stimuli affect DDK rate performance.

AIMS

To investigate the effect of age, gender and type of stimuli (non-words versus real words) on the DDK rates in individuals across the lifespan and to provide normative data for Greek. Also to examine the discrimination ability of the speech DDK stimuli administered (non-words and real words) based on a dual DDK assessment protocol using a polytomous item response theory (IRT) model.

METHODS & PROCEDURE

The participants were 1747 monolingual Greek speakers (376 children, aged 4-17 years; and 1371 adults, aged 18-90+ years). All participants had normal hearing acuity which allowed them to understand and follow instructions. Participants with a medical condition or a language disorder which would affect DDK rate performance were excluded from the study. The time-by-count method was used, and all participants had to repeat as accurately and fast as possible: (1) four disyllabic non-words (/'gaba/, /'taka/, /'kata/, /'baga/), (2) four disyllabic real words (/'kapa/, /'tapa/, /ka'la/, /'paka/) and (3) two trisyllabic non-words (/'pataka/, /'badaga/). All responses were recorded and the speech samples that did not include at least 5 s of correct repetitions were excluded from the analysis.

OUTCOMES & RESULTS

Age affected significantly DDK rates with performance increasing gradually until approximately the age of 40 and then gradually decreasing. Gender had no effect. Overall, there was a significant advantage of disyllabic real word stimuli over disyllabic non-word stimuli and of trisyllabic non-word stimuli over disyllabic non-word stimuli on DDK rates performance. IRT analysis suggested that the data fit the polytomous model reasonably well and all DDK stimuli (real words and non-words) showed a strong relationship (loadings > 0.50) with the latent trait.

CONCLUSIONS & IMPLICATIONS

The current study complements prior research which supports that age and type of stimuli significantly affect DDK rates performance. It is the first study, that testifies to the benefit of real-word stimuli over non-word stimuli on DDK rates across the lifespan in a large representative sample. The implementation of IRT analysis provides empirical evidence about the discrimination ability of the DDK stimuli administered and confirms the reliability of this dual DDK assessment protocol. These findings are valuable for clinicians who work with motor speech disorders.

WHAT THIS PAPER ADDS

What is already known on this subject Age, type of stimuli (real words versus non-words) and language significantly affect DDK rates performance. Current research strongly suggests the administration of language-specific norms since language-dependent features seem to have a noteworthy effect on the DDK rates, but scarce evidence exists about the discriminatory ability of the DDK speech stimuli commonly administered. What this study adds to the existing knowledge Conflicting findings have been reported about the effect of different types of DDK speech stimuli (real words and non-words) but no study to date has evaluated their discriminatory abilities. The current study is the first to implement a polytomous IRT model to examine this issue. This is also the first study to attempt an investigation of the effect of types of stimuli (real words versus non-words) on a large representative sample across the lifespan (4-90+ years) and to provide normative data for Greek. What are the practical and clinical implications of this work? The present study offers concrete evidence about the advantage of real-word stimuli over non-word stimuli in Greek, as well as normative data for the Greek-speaking populations. Moreover, the IRT analysis testifies to the discriminatory ability of real-word and non-word stimuli affirming the reliability of the present dual DDK assessment protocol as a psychometrically sound measure of DDK ability. The above has significant value for clinicians who work with individuals with motor speech disorders as the protocol can help them with the diagnosis and differential diagnosis of motor speech disorders.

Oral diadochokinetic production in children with typical speech development and speech-sound disorders

BACKGROUND

AIMS: To investigate the developmental trajectory of the rate and perceptual assessment of oral diadochokinesis (DDK) in typically developing children compared with adults. Also to examine the characteristics of DDK productions in children with speech sound disorders (SSD) and the relationship between DDK production and percentage of consonants correct (PCC).

METHODS & PROCEDURES

Participants were 316 typically developing children and 90 children with SSD from 3 to 9 years old, as well as 20 adults with normal speech. The mono-, bi- and trisyllabic nonsense strings containing Korean tense consonants and the vowel [a] were used for DDK tasks. The number of iterations per s was measured as the DDK rate for each stimulus. The perceptual assessment of DDK productions was also performed for regularity, accuracy and rate.

OUTCOMES & RESULTS

The DDK rates increased throughout childhood, but the oldest children, 9-year-olds in the current study, did not achieve adult-like rates for all mono- and trisyllabic strings. Children with SSD also did not show significant differences from typically developing children when the DDK productions were analysed using only accurate tokens. The PCC of children with SSD showed higher correlations with regularity, accuracy and rate of perceptual ratings than the timed DDK rate.

CONCLUSIONS & IMPLICATIONS

This study highlighted the fact that the comprehensive evaluation of DDK productions may provide even more useful information about children's oral motor skills.

WHAT THIS PAPER ADDS

What is already known on the subject Rates of DDK reflect the motor skills of the articulatory systems independently of phonological skills; therefore, the tasks are widely used in the diagnostic evaluations of speech disorders in both children and adult populations. However, a substantial number of studies have questioned the validity and usefulness of DDK rates for evaluating speech abilities. Also, the literature suggested that the measure of DDK rate alone does not provide a clear and useful indication of children's oral motor skills. DDK tasks should be analysed in terms of accuracy and consistency as well as rate. What this paper adds to the existing knowledge The literature reporting normative DDK performance has mainly been based on English speakers. As different consonants have different temporal characteristics, the linguistic and segmental features of DDK tasks can impact the DDK rate. This study established a norm for DDK rate for Korean-speaking children and investigated the developmental trajectory of DDK performance in typically developing children compared with adults. This study suggested that the comprehensive evaluation of DDK productions may provide even more useful information about children's oral motor skills by examining the characteristics of DDK productions in children with SSD. What are the potential or actual clinical implications of this work? This study provided normative data of young Korean-speaking children aged 3-9 years. Normative data in children under 5 years of age are valuable given that the majority of children referred for speech difficulty assessments are between 3 and 5 years of age, but only a few studies have provided the normative data in young children. This study showed that many children could not complete DDK tasks correctly and provided additional support for the notion that other aspects of DDK performance, including accuracy and regularity, may yield more useful diagnostic indications than timed DDK rates alone.

Oral Diadochokinetic Performance on Perceptual and Acoustic Measures for Typically Developing Cantonese-Speaking Preschool Children

PURPOSE

This study investigated native Cantonese-speaking preschool children's diadochokinetic performance, including rate, accuracy, and regularity. The second aim of this study was to examine whether language-specific patterns exist by comparing diadochokinetic rates with the average DKK rate for native English speakers.

METHOD

Sixty-four typically developing preschool children who were native Cantonese speakers participated. The diadochokinetic task administered to the children involved repetitions of monosyllabic, disyllabic, and trisyllabic words and nonsense words. The maximum performance of the children was compared by diadochokinetic rate (number of syllables per second), accuracy (percentage of matched production), and regularity (pairwise variability indexes, known as PVIs).

RESULTS

Monosyllabic units were produced faster, more accurately, and more regularly than multisyllabic units. Word repetition showed higher accuracy and generally lower regularity than nonsense words but similar rates. Older children were faster and more regular (higher raw PVI of initial consonants) than younger children, but younger children performed as accurately as them. When compared with data from English speakers, the diadochokinetic rates of Cantonese children were generally lower.

CONCLUSIONS

Developmental progression was evident in terms of rate and regularity. The distinctive accuracy and regularity patterns between word and nonsense word repetition suggest a clinical value for both stimulus types. Language typology plays a role in diadochokinetic rate, supporting the use of language-specific reference data in practice. The typical diadochokinetic profile obtained in this study could serve as a clinical reference for speech motor assessments.

Oral and Laryngeal Diadochokinesis Across the Life Span: A Scoping Review of Methods, Reference Data, and Clinical Applications

PURPOSE

The aim of this study was to conduct a scoping review of research on oral and laryngeal diadochokinesis (DDK) in children and adults, either typically developing/developed or with a clinical diagnosis.

METHOD

Searches were conducted with PubMed/MEDLINE, Google Scholar, CINAHL, and legacy sources in retrieved articles. Search terms included the following: DDK, alternating motion rate, maximum repetition rate, sequential motion rate, and syllable repetition rate.

RESULTS

Three hundred sixty articles were retrieved and included in the review. Data source tables for children and adults list the number and ages of study participants, DDK task, and language(s) spoken. Cross-sectional data for typically developing children and typically developed adults are compiled for the monosyllables /pʌ/, /tʌ/, and /kʌ/; the trisyllable /pʌtʌkʌ/; and laryngeal DDK. In addition, DDK results are summarized for 26 disorders or conditions.

DISCUSSION

A growing number of multidisciplinary reports on DDK affirm its role in clinical practice and research across the world. Atypical DDK is not a well-defined singular entity but rather a label for a collection of disturbances associated with diverse etiologies, including motoric, structural, sensory, and cognitive. The clinical value of DDK can be optimized by consideration of task parameters, analysis method, and population of interest.

Improving speech characteristics of young adults with congenital dysarthria: An exploratory study comparing articulation training and the Beatalk method

INTRODUCTION

This exploratory study compared the effects of two speech therapy approaches on speech characteristics of young adults with congenital dysarthria resulting from various etiologies: a) articulation training focusing on consonant articulation exercises at various levels (isolation, syllables, and words), and b) the Beatalk method, based on human beatboxing, i.e., producing various instrumental sounds in an a-cappella musical context. Both interventions were designed to increase participants' speech intelligibility.

METHODS

Twelve adults with congenital dysarthria and reduced speech intelligibility participated in treatment groups for eight weeks. Six participants were assigned to the articulation training group, and six to the Beatalk group. Intelligibility of single words and continuous speech, voice measures, and oral-diadochokinesis rates were measured before and after the treatment.

RESULTS

The results showed that the Beatalk intervention yielded a significant overall pre- to post-treatment effect. Specifically, it resulted in gains in articulatory accuracy and intelligibility for single words. Improvements were not noted following articulation training.

CONCLUSIONS

The results present initial evidence of the positive effect of the Beatalk method as an intervention tool for adults with congenital dysarthria. This relatively easy-to-learn technique shows promise, as it involves intense and repetitive production of speech sounds while controlling rhythm and breathing in an enjoyable context.

Oral diadochokinetic rates across languages: Multilingual speakers comparison

BACKGROUND

It is unclear whether oral diadochokinetic rate (oral-DDK) performance is affected by different languages within a multilingual country.

AIMS

This study investigated the effects of age, sex, and stimulus type (real word in L1, L2 vs. non-word) on oral-DDK rates among healthy Malaysian-Malay speakers in order to establish language- and age-sensitive norms. The second aim was to compared the nonword 'pataka' oral-DDK rates produced by Malaysian-Malay speakers on currently available normative data for Hebrew speakers and Malaysian-Mandarin speakers.

METHODS & PROCEDURES

Oral-DDK performance of 90 participants (aged 20-77 years) using nonword ('pataka'), Malay real word ('patahkan'), and English real word ('buttercake') was audio recorded. The number of syllables produced in 8 seconds was calculated. Mixed analysis of variance (ANOVA) was conducted to examine the effects of stimulus type (nonword, Malay, and English real word), sex (male, female), age (younger, 20-40 years; middle, 41-60 years; older, ≥61 years), and their interactions on the oral-DDK rate. Data obtained were also compared with the raw data of Malaysian-Mandarin and Hebrew speakers from the previous studies.

OUTCOMES & RESULTS

A normative oral-DDK rate has been established for healthy Malaysian-Malay speakers. The oral-DDK rate was significantly affected by stimuli (p < 0.001). Malay real word showed the slowest rate, whereas there was no significant difference between English real word and nonword. The oral-DDK rate for Malay speakers was significantly higher than Mandarin and Hebrew speakers across stimuli (all p < 0.01). Interestingly, oral-DDK rates were not affected by age group for Malay speakers.

CONCLUSIONS & IMPLICATIONS

Stimuli type and language affect the oral-DDK rate, indicating that speech-language therapists should consider using language-specific norms when assessing multilingual speakers.

WHAT THIS PAPER ADDS

What is already known on the subject Age, sex, and language are factors that need to be considered when developing oral-DDK normative protocol. It is unclear whether oral-DDK performance is affected by different languages within a multilingual country. What this paper adds to existing knowledge No ageing effect across real word versus nonword on oral-DDK performance was observed among Malaysian-Malay speakers, contrasting with current available literature that speech movements slow down as we age. Additionally, Malaysian-Malay speakers have faster oral-DDK rates than Malaysian-Mandarin and Hebrew speakers across all stimuli. What are the potential or actual clinical implications of this work? Establishing normative data of different languages will enable speech-language therapists to select the appropriate reference dataset based on the language mastery of these multilingual speakers.