DDK rates in the paediatric clinic: a methodological minefield

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.

The automated screening of speech motor development in children based on the sequential motion rate

BACKGROUND

Motor skills in children have traditionally been examined via challenging speech tasks such as syllable repetition, and calculating the syllabic rate using a stopwatch or by inspecting the oscillogram followed by a laborious comparison of the scores on a look-up table representing the typical performances of children of the given age and sex. As the commonly used performance tables are over-simplified to allow for manual scoring, we raise the question of whether a computational model of motor skills development could be more informative, and could allow for the automated screening of children to detect underdeveloped motor skills.

METHODS

We recruited a total of 275 children aged four to 15 years. All the participants were native Czech speakers with no history of hearing or neurological impairments. We recorded each child's performance of/pa/-/ta/-/ka/syllable repetition. Various parameters of diadochokinesis (DDK; DDK rate, DDK regularity, voice onset time [VOT] ratio, syllable, vowel and VOT duration) were investigated in the acoustic signals using supervised reference labels. Female and male participants were analyzed separately by comparing younger, middle, and older age groups of children via ANOVA. Finally, we implemented a fully automated model that estimated the developmental age of a child based on the acoustic signal, and evaluated its accuracy using Pearson's correlation coefficient and normalized root-mean-squared errors (RMSEs).

RESULTS

The DDK rate reflected the ages of the children proportionally (p < 0.001). Other DDK parameters also showed strong sensitivity to age (p < 0.001), with the exception of VOT duration, which had a smaller effect (p = 0.091). The effect of age was found to be sex specific for the syllable length (p < 0.001) and DDK rate (p = 0.003). We observed that females spoke more slowly and had a longer VOT at preschool age (p < 0.001). The DDK rate obtained via the automated algorithm was strongly correlated with the reference (p < 0.001, Pearson's correlation coefficient of 0.97), with a low normalized RMSE of 3.77%.

CONCLUSIONS

As children develop their motor skills, they are capable of shortening the vowels to increase the rate of syllabic repetitions. The nonlinear development in childhood and adolescence, with a steady state in adulthood, follows a logistic function for the DDK rate. This study demonstrates that the development of motor skills can be examined sensitively and more appropriately by a fully automated noninvasive procedure that also accounts for the dispersion of values within age brackets.

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.

Diadochokinetic rates in healthy young and elderly Greek-speaking adults: The effect of types of stimuli

BACKGROUND

Diadochokinetic rates tasks are frequently used for the assessment of diadochokinesia (DKK) in young and elderly adults. However, there is scarce research on healthy elderly adults over 65 years old, and little is known about the effect of different types of stimuli (non-words/real words) in this specific population. Furthermore, the current research supports significant language variations, highlighting the need for language-specific norms.

AIMS

To investigate the effect of age, gender and type of stimuli (non-words versus real words) in DDK rates in healthy elderly adults of over 65 years of age, and to provide normative data for the Greek language.

METHODS & PROCEDURES

The participants were 791 healthy monolingual Greek-speaking adults (531 adults, aged 20-39 years; 157 participants aged 65-74 years; and 103 participants aged over 75 years). All participants were monolingual speakers of Greek and had normal hearing acuity, which allowed them to understand and follow instructions. Participants with a medical condition, which would affect DDK rates' 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 DDK rates significantly, with older adults achieving slower DDK rates for all speech stimuli (non-words/real words). Gender did not have an effect on the performance of DDK rates. The type of speech stimuli affected DDK rates significantly for all age groups. Analytically, trisyllabic non-word stimuli were articulated more slowly than disyllabic non-word stimuli, and real words were produced faster than non-words. A linear regression analysis revealed that only the repetition of non-words predicted 68.4% of the performance on the repetition of trisyllabic non-words.

CONCLUSIONS & IMPLICATIONS

The above results complement prior research, which supports that real word stimuli yield faster performance than non-word stimuli. Clinicians should keep in mind that age, language and type of stimuli (non-words/real words) affect significantly the performance of DDK rates, as well as the fact that different types of stimuli tap distinct underlying levels of speech. The current research highlights the need for language-specific norms for different populations.

WHAT THIS PAPER ADDS

What is already known on the subject DDK rates are significantly affected by the types of stimuli and language used. Moreover, the normal ageing process decreases performance in terms of DDK rates, but scarce evidence exists for healthy elderly adults over 65 years old. What this paper adds to existing knowledge Most studies have examined DDK rates in healthy elderly people with restricted samples and using non-word stimuli. The current study administered different types of stimuli (non-words/words) in a large sample of healthy elderly participants. This is also the first study to attempt to provide DDK normative data for this population in the Greek language. What are the potential or actual clinical implications of this work? The results of this study strongly suggest that clinicians should bear in mind the significant impact age and language have on performance in terms of DDK rates, especially when normative data are not available for a certain language or age group. Furthermore, non-word and real-word stimuli cannot be used interchangeably since they tap into distinct underlying levels of speech, thus providing clinicians with useful information about the level of breakdown and the proper treatment plan.

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.

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

BACKGROUND

Oral-Diadochokinesis (oral-DDK) tasks measure how quickly and accurately one can repeat a series of target sounds. Thus, they are a popular tool for evaluating oral-motor skills for individuals with various speech disorders. Typically, oral-DDK tasks involve rapid repetition of non-words. For several populations (e.g., young children, older adults), it has been suggested that repetitions of real words may be more suitable, commonly resulting in faster rates. Yet, the literature is either silent or inconsistent regarding this real-word repetition advantage for other age groups, from preschoolers to young adults. It is not clear whether performance accuracy is affected as well. Specifically, for Hebrew speakers, this data is missing.

AIMS

The goal of this study was to compare rate and accuracy for non-word and real-word repetition, in four groups of Hebrew-speaking individuals; preschoolers (5 years old), younger elementary school children (7 years old), adolescents (15 years old) and young adults (25 years old). Secondary goals were to provide a developmental pattern for oral-DDK rates for Hebrew speakers, and to compare it to the English norms.

METHODS & PROCEDURES

All participants (n=150) had typical speech and language development. They were asked to repeat "pataka" (non-word) and "bodeket" (Hebrew real word) as quickly and accurately as possible for 10 sec. Production rates (syllables per second) and accuracy (on a 5-point scale) were measured.

OUTCOMES & RESULTS

As expected, oral-DDK rates gradually increased with age, with similar rates for both real- and non-words. Accuracy scores were higher for real- than non-word repetition, across all age groups. For the group of school-age children, the Hebrew rates differed from the English ones.

CONCLUSIONS & IMPLICATIONS

A real-word repetition advantage was documented only for repetition accuracy, but not for rate. These findings can be explained as each stimulus involves different demands on an individual's neuro-motor and linguistic processing abilities. Further research using real- and non-word tasks should be conducted with clinical populations to assess whether both procedures could assist in differential diagnosis between various speech disorders. Finally, the large differences between children of different ages, as well as the apparent rate differences between Hebrew and English, highlight the need to create age- and language-sensitive norms.

Diadochokinetic rate in Saudi and Bahraini Arabic speakers: Dialect and the influence of syllable type

Arabic is spoken by more than 420 million people worldwide and still there are a limited number of studies on dialects of the Gulf Arabic regions where most selected respondents are male speakers. This study aimed to explore and establish normative data for the Diadochokinetic Rate (DDK) for two dialects (Saudi Arabia’s Najdi and Bahrain’s Bahraini) speakers. Furthermore, it aimed to investigate whether there are differences between the two dialects and whether sex differences are evident. In addition, it investigated syllable type differences. The study used the monosyllables /ba, da, ga/ and the multisyllabic sequence /badaga/ to analyse the DDK rates. Acoustic analysis was carried out to obtain DDK rates for the syllables. A mixed model ANOVA was performed to investigate dialect and sex differences, in addition, to syllable type. The study included 40 males and 40 female speakers from each of the two dialects. Results showed that for DDK, Saudi speakers had faster DDK rates for the monosyllables /ba/, /da/, /ga/, than Bahrainis, while, no significant differences were observed for the multisyllabic sequences. However, there were no differences between male and female speakers with regard to the DDK rates. The syllable /ga/ showed the slowest DDK rate among the monosyllables while the multisyllabic sequences displayed the slowest DDK rates. In brief, normative data for DDK rates for clinic were determined for the Arabic Nadji and Bahrain’s Bahraini dialects. DDK rate was shown to be more sensitive to dialect differences for the monosyllable tasks. However, no sex differences were observed for the Arabic dialects in this study across all DDK tasks.

Meaningful Words and Non-Words Repetitive Articulatory Rate (Oral Diadochokinesis) in Persian Speaking Children

Repetitive articulatory rate or Oral Diadochokinesis (oral-DDK) shows a guideline for appraisal and diagnosis of subjects with oral-motor disorder. Traditionally, meaningless words repetition has been utilized in this task and preschool children have challenges with them. Therefore, we aimed to determine some meaningful words in order to test oral-DDK in Persian speaking preschool children. Participants were 142 normally developing children, (age range 4-6 years), who were asked to produce /motæka, golabi/ as two meaningful Persian words and /pa-ta-ka/ as non-word in conventional oral-DDK task. We compared the time taken for 10-times fast repetitions of two meaningful Persian words and the tri-syllabic nonsense word /pa-ta-ka/. Praat software was used to calculate the average time that subjects took to produce the target items. In 4-5 year old children, [Formula: see text] of time taken for 10-times repetitions of /pa-ta-ka, motæka, golabi/ were [Formula: see text], and [Formula: see text] seconds respectively, and in 5-6 year old children were [Formula: see text], and [Formula: see text] seconds respectively. Findings showed that the main effect of type of words on oral diadochokinesis was significant ([Formula: see text]). Children repeated meaningful words /motæka, golabi/ faster than the non-word /pa-ta-ka/. Sex and age factors had no effect on time taken for repetition of oral-DDK test. It is suggested that Speech Therapists can use meaningful words to facilitate oral-DDK test for children.

Oral-diadochokinetic rates for Hebrew-speaking school-age children: real words vs. non-words repetition

Oral-diadochokinesis (DDK) tasks are a common tool for evaluating speech disorders. Usually, these tasks involve repetitions of non-words. It has been suggested that repeating real words can be more suitable for preschool children. But, the impact of using real words with elementary school children has not been studied yet. This study evaluated oral-DDK rates for Hebrew-speaking elementary school children using non-words and real words. The participants were 60 children, 9-11 years old, with normal speech and language development, who were asked to repeat "pataka" (non-word) and "bodeket" (Hebrew real word). Data replicate the advantage generally found for real word repetition with preschoolers. Children produced real words faster than non-words for all age groups, and repetition rates were higher for the older children. The findings suggest that adding real words to the standard oral-DDK task with elementary school children may provide a more comprehensive picture of oro-motor function.

Pediatric laryngeal diadochokinetic rates: establishing a normative database

OBJECTIVE

Laryngeal diadochokinetic (L-DDK) rate is a measure of laryngeal neural integrity. The objectives for this study included the following: (1) establish the first comprehensive pediatric normative database for L-DDK rates (DDK) using the Voice Evaluation Suite, a computerized voice analysis program; and (2) analyze normal L-DDK rates for age and gender differences.

STUDY DESIGN

Cross-sectional study with planned data collection.

SETTING

Outpatient pediatric otolaryngology clinic.

SUBJECTS AND METHODS

Three hundred seven children aged 4 to 18 with normal voices. L-DDK rates were collected during a 6-month period. Main outcome measures included age, gender, and L-DDK rates.

RESULTS

Three hundred seven children (151 girls and 156 boys) were evaluated. There was no statistically significant difference between the overall mean L-DDK rate of boys (2.69 syllables/s) compared to girls (2.55 syllables/s; P > .05). Further analysis of all individual age groups did not reveal any statistical significance between boys and girls. There was a statistically significant difference among children aged 4 to 11 compared to those 12 to 18 years old. Among boys aged 4 to 11, the mean rate was 2.49 syllables per second, whereas among 12- to 18-year-olds, the rate was 2.95 syllables per second (P < .01). The mean rate was 2.40 syllables per second among girls aged 4 to 11 and 2.74 syllables per second for those aged 12 to 18 (P < .01).

CONCLUSION

This is the largest normative pediatric L-DDK analysis in the English literature. The findings suggest that neurolaryngeal development approaches adult maturation at the beginning of the teenage years. These data have the potential application for objective measurement of neurolaryngeal coordination in children with neurologic impairment and also in children who have undergone nerve reinnervation procedures.

Analysis of diadochokinesis in ataxic dysarthria using the motor speech profile program

AIMS

The Diadochokinetic Rate Analysis (DRA) in the KayPENTAX Motor Speech Profile is a computer program for the analysis of diadochokinesis (DDK). The objective of this study is to evaluate the suitability, reliability, and concurrent validity of the results from the DRA protocol and hand measurement for individuals with ataxic dysarthria, which is characteristically associated with dysdiadochokinesis.

METHODS

Twenty-one participants with ataxic dysarthria were recorded as they repeated various syllables as quickly and steadily as possible. The DDK samples were executed by the DRA protocol at different thresholds and were also hand-measured. Analyses were based on the percentage of nonexecutable DDK samples, defined as samples in which the lowest peak intensity during CV syllables is lower than the highest peak intensity during intersyllable pauses, and the comparisons of the results between repeated analyses at different thresholds and between automatic and manual measuring methods.

RESULTS

(1) More than one third of the DDK samples were nonexecutable; (2) the reliability at different thresholds and concurrent validity between different measuring methods were both satisfactory, and (3) temporal variation parameters were more inconsistent between different measuring methods than intensity variation parameters.

CONCLUSION

DRA has notable limitations in its clinical application but there is a considerable potential for improving its performance.

Evaluating rate, accuracy, and fluency of young children's diadochokinetic productions: a preliminary investigation

Diadochokinetic (DDK) rates are commonly assessed in children with speech-language disorders, even though the implications of fast or slow DDK rates are not clear. This study explored the possibility that the accuracy and fluency of DDK productions may provide a meaningful supplement to traditional measures of DDK rate. Participants were 15 boys, age 3-7, with normal speech-language development, who were asked to produce "puh-tuh-kuh" or "pattycake" in a standard DDK task. Analyses revealed that normally developing children produce frequent articulation errors but few disfluencies during DDK tasks. Errors and disfluencies did not affect DDK rate, suggesting that the rate of DDKs may be a relatively insensitive measure of children's speaking abilities. Although an expected correlation was found between age and overall DDK rate, no correlations were found between age and the frequency of articulation errors or speech disfluencies. Findings suggest that measures of DDK accuracy and fluency may provide information about children's speech development that is independent of age and may be more closely related to oral motor development than rate. Overall, results underscore concerns with the interpretation of DDK rate and highlight ways that rate measures might be supplemented with measurement of accuracy and fluency in the evaluation of children's speaking abilities.

EDUCATIONAL OBJECTIVES

The reader will learn about a technique that may facilitate the evaluation of young children's oral DDK abilities. The reader will learn about the frequency and type of errors children produce on DDKs and how this information can be used in the assessment of children's oral motor abilities.