DDK Tasks Research Articles

Speed of Pitch Change in People with Parkinson’s Disease: A Pilot Study

Objective. To examine laryngeal maximum performance through a novel pitch diadochokinetic (DDK) task in people with Parkinson’s disease (PD) and healthy controls. Methods. This exploratory pilot study included a total of eight people with PD (seven male and one female) and eight healthy controls. Participants were instructed to rapidly transition or alternate between a chosen comfortable low and high pitch and were instructed to complete the task as a pitch glide. An Auditory Sawtooth Waveform Inspired Pitch Estimator-Prime model was used to first extract the pitch contour and then a customized MATLAB algorithm was used to compute and derive measures of pitch range and pitch slope. Results. Pitch range and slope were reduced in some participants with PD. Effects of age and disease duration were observed in people with PD: reductions in both pitch measures with increase in age and disease duration. Conclusions. A novel pitch DDK task may supplement the conventional laryngeal DDK task in the evaluation and treatment of motor speech and voice disorders. Individual variability analysis may provide specific diagnostic and therapeutic insights for people with PD.

Speech Production in Healthy Older Adults With or Without Amateur Singing Experience.

Amateur singing is a universal, accessible, and enjoyable musical activity that may have positive impacts on human communication. However, evidence of an impact of singing on speech articulation is still scarce, yet understanding the effects of vocal training on speech production could provide a model for treating people with speech deficits. The aim of this study was to examine speech production in younger and older adults with or without amateur singing experience. Thirty-eight amateur singers (aged 20-87 years, 23 women and 15 men) and 40 nonmusician active controls (aged 23-88 years, 19 women and 21 men) were recruited. A set of tasks were used to evaluate the oral motor sphere: two voice production tasks, a passage reading task, and a modified diadochokinetic (DDK) rates task performed at a natural rhythm and as quickly as possible. Our results show that older age was associated with lower reading rate, lower articulation rate, and articulation rate variability in the DDK task, as well as reduced accuracy for the phonologically complex stimuli. Most importantly, our results show an advantage for singers over cognitively active nonsingers in terms of articulatory accuracy in the most challenging situations. This result suggests extended maximal performance capacities in amateur singers perhaps resulting from the articulatory efforts required during singing. https://doi.org/10.23641/asha.24274813.

Speech timing and monosyllabic diadochokinesis measures in the assessment of amyotrophic lateral sclerosis in Canadian French

Purpose The primary objective of this study was to determine if speech and pause measures obtained using a passage reading task and timing measures from a monosyllabic diadochokinesis (DDK) task differ across speakers of Canadian French diagnosed with amyotrophic lateral sclerosis (ALS) presenting with and without bulbar symptoms, and healthy controls. The secondary objective was to determine if these measures can reflect the severity of bulbar symptoms. Method A total of 29 Canadian French speakers with ALS (classified as bulbar symptomatic [n = 14] or pre-symptomatic [n = 15]) and 17 age-matched healthy controls completed a passage reading task and a monosyllabic DDK task (/pa/ and /ta/), for up to three follow-up visits. Measures of speaking rate, total duration, speech duration, and pause events were extracted from the passage reading recordings using a semi-automated speech and pause analysis procedure. Manual analysis of DDK recordings provided measures of DDK rate and variability. Result Group comparisons revealed significant differences (p = < .05) between the symptomatic group and the pre-symptomatic and control groups for all passage measures and DDK rates. Only the DDK rate in /ta/ differentiated the pre-symptomatic and control groups. Repeated measures correlations revealed moderate correlations (rrm = > 0.40; p = < 0.05) between passage measures of total duration, speaking rate, speech duration, and number of pauses, and ALSFRS-R total and bulbar scores, as well as between DDK rate and ALSFRS-R total score. Conclusion Speech and pause measures in passage and timing measures in monosyllabic DDK tasks might be suitable for monitoring bulbar functional symptoms in French speakers with ALS, but more work is required to identify which measures are sensitive to the earliest stages of the disease.

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

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). 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. 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. 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 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.

What Do Differences between Alternating and Sequential Diadochokinetic Tasks Tell Us about the Development of Oromotor Skills? An Insight from Childhood to Adulthood.

Oral diadochokinetic (DDK) tasks are common research and clinical tools used to test oromotor skills across different age groups. They include alternating motion rate (AMR) and sequential motion rate (SMR) tasks. AMR tasks involve repeating a single syllable, whereas SMR tasks involve repeating varying syllables. DDK performance is mostly discussed regarding the increasing rates of AMR and SMR tasks from childhood to adulthood, although less attention is given to the performance differences between SMR and AMR tasks across age groups. Here, AMR and SMR syllabic rates were contrasted in three populations: 7-9-year-old children, 14-16-year-old adolescents and 20-30-year-old adults. The results revealed similar syllabic rates for the two DDK tasks in children, whereas adolescents and adults achieved faster SMR rates. Acoustic analyses showed similarities in prosodic features between AMR and SMR sequences and in anticipatory coarticulation in the SMR sequences in all age groups. However, a lower degree of coarticulation was observed in children relative to adults. Adolescents, on the contrary, showed an adult-like pattern. These findings suggest that SMR tasks may be more sensitive to age-related changes in oromotor skills than AMR tasks and that greater gestural overlap across varying syllables may be a factor in achieving higher rates in SMR tasks.

Acoustic analysis and neuroimaging correlates of diadochokinetic rates in mild-moderate primary progressive apraxia of speech

Speech rate can be judged clinically using diadochokinetic (DDK) tasks, such as alternating motion rates (AMR) and sequential motion rates (SMR). We evaluated whether acoustic AMR/SMR speech rates would differentiate primary progressive apraxia of speech (PPAOS) from healthy controls, and determined how DDK rates relate to phonetic and prosodic speech characteristics and brain metabolism on FDG-PET. Rate was calculated for each of three AMRs (repetitions of ‘puh’, ‘tuh’, and ‘kuh’) and for SMRs (repetitions of ‘puhtuhkuh’) for 27 PPAOS patients and 52 controls who underwent FDG-PET. PPAOS patients were slower than controls on all DDK tasks. All DDK rates correlated with apraxia of speech severity, with strongest associations with prosodic speech features. Slower DDK rates were associated with hypometabolism in the right cerebellar dentate and left supplementary motor area. Performance on AMR rate, not just SMR rate, may be impaired in mild PPAOS, but sensitivity and specificity require further study.

An investigation about the relationship between dysarthria level of speech and the neurological state of Parkinson’s patients

Parkinson’s disease (PD) is the most common neurological disorder that typically affects elderly people. In the earlier stage of disease, it has been seen that 90% of the patients develop voice disorders namely hypokinetic dysarthria. As time passes, the severity of PD increases, and patients have difficulty performing different speech tasks. During the progression of the disease, due to less control of articulatory organs such as the tongue, jaw, and lips, the quality of speech signals deteriorates. Periodic medical evaluations are very important for PD patients; however, having access to a medical appointment with a neurologist is a privilege in most countries. Considering that the speech recording process is inexpensive and very easy to do, we want to explore in this paper the suitability of mapping information of the dysarthria level into the neurological state of patients and vice versa. Three levels of severity are considered in a multiclass framework using time–frequency (TF) features and random-forest along with an Error-Correcting Output Code (ECOC) approach. The multiclass classification task based on dysarthria level is performed using the TF features with words and diadochokinetic (DDK) speech tasks. The developed model shows an unweighted average recall (UAR) of 68.49% with the DDK task /pakata/ based on m-FDA level, and 48.8% with the word /petaka/ based on the UPDRS level using the Random Forest classifier. With the aim, to evaluate the neurological states using the dysarthria level, the developed models are used to predict the MDS-UPDRS-III level of patients. The highest matching accuracy of 32% with the word /petaka/ is achieved. Similarly, the multiclass classification framework based on MDS-UPDRS-III is applied to predict the dysarthria level of patients. In this case, the highest matching accuracy of 18% was obtained with the DDK tasks /pataka/.

Is there a continuum between speech and other oromotor tasks? evidence from motor speech disorders

ABSTRACT Background Oral diadochokinetic (DDK) tasks are widely used in the assessment of patients with motor speech disorders (MSD). They require the repetition of homogeneous and of heterogeneous syllables at a maximum rate. The nature of DDK tasks is a matter of debate: although they are usually considered as “non-speech”, given the involvement of real speech syllables, they have also been recognized to share more properties and requirements with speech as compared to other oromotor behaviours (i.e., non-speech gestures). Additionally, the production of heterogeneous syllables has been suggested to exhibit closer correspondence with speech given the production of a cluster of different syllables, as compared to the repetition of a monosyllable. Each DDK task being differently related to speech supports the assumption of a continuum between speech and other oromotor processes, in which tasks with increasingly speech-like properties may overlap to a larger extent with speech. Aim To test the potentially differential relationship between speech and DDK tasks in patients with MSD. Traditional views of MSD claim that speech and other oromotor behaviours are impaired in patients with dysarthria, while patients with AoS present with speech being exclusively compromised. This suggests that DDK tasks should be differently affected in these two MSD populations. Moreover, in the framework of a continuum, oromotor tasks sharing some characteristics with speech (i.e., heterogeneous DDK task) should also be impaired in patients with AoS. Method Syllabic rates of a sentence production (SP) task are contrasted with those of homogeneous and heterogeneous DDK tasks in three pathological populations: patients with dysarthria due to Parkinson’s Disease (PD, n = 10) or due to amyotrophic lateral sclerosis (ALS, n = 10) and patients with apraxia of speech (AoS, n = 10); and 30 matched neurotypical controls. Results While patients with PD show similar rates across the SP and the DDK tasks relative to control speakers, patients with ALS display significantly slower rates across all tasks as compared to matched controls. Patients with AoS show reduced performances in the SP and in the heterogeneous DDK task, but not on the repetition of homogeneous syllables. Conclusions The findings of this study confirm that the repetition of heterogeneous syllables shares more principles and properties with speech than the homogeneous DDK task. This dissimilar relationship between speech and the two types of DDK tasks points to the existence of a continuum among oromotor tasks.

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

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. 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. 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. 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.

Oral diadochokinetic rates for real words and non-words in Greek-speaking children

Abstract This study examined the performance of Greek monolingual typically developing (TD) children on diadochokinetic (DDK) rates in real words and non-words and attempted to establish normative data for Greek. The effects of age, type of stimuli and gender were investigated. A total of 380 children aged 4.0–15.0 years as well as a control group of 313 adults participated in the study. Age significantly affected DDK performance, yet normative data differ from other studies. DDK rates for bisyllabic stimuli were faster than DDK rates for trisyllabic stimuli and real words were articulated faster than non-words. Adolescents aged 13.0–15.0 years were slower than adults both in real word and in non-word /ˈpataka/ repetition. Additionally, overall boys were significantly faster than girls. These findings show the need to: (a) implement real word stimuli in DDK tasks in order to better depict an individual’s oral-motor abilities and (b) establish language-specific normative data for TD children.

Psychometric Properties of Rapid Word-Based Rate Measures in the Assessment of Bulbar Amyotrophic Lateral Sclerosis: Comparisons With Syllable-Based Rate Tasks.

Purpose Rapid maximum performance repetition tasks have increasingly demonstrated their utility as clinimetric markers supporting diagnosis and monitoring of bulbar disease in amyotrophic lateral sclerosis (ALS). A recently developed protocol uses novel real-word repetitions instead of traditional nonword/syllable sequences in hopes of improving sensitivity to motor speech impairments by adding a phonological target constraint that would activate a greater expanse of the motor speech neuroanatomy. This study established the psychometric properties of this novel clinimetric protocol in its assessment of bulbar ALS and compared performance to traditional syllable sequence dysdiadochokinetic (DDK) tasks. Specific objectives were to (a) compare rates between controls and speakers with symptomatic versus presymptomatic bulbar disease, (b) characterize their discriminatory ability in detecting presymptomatic bulbar disease compared to healthy speech, (c) determine their articulatory movement underpinnings, and (d) establish within-individual longitudinal changes. Method DDK and novel tongue ("ticker"-TAR) and labial ("pepper"-LAR) articulatory rates were compared between n = 18 speakers with presymptomatic bulbar disease, n = 10 speakers with symptomatic bulbar disease, and n = 13 healthy controls. Bulbar disease groups were determined by a previously validated speaking rate cutoff. Discriminatory ability was determined using receiver operating characteristic analysis. Within-individual change over time was characterized in a subset of 16 participants with available longitudinal data using linear mixed-effects models. Real-time articulatory movements of the tongue front, tongue dorsum, jaw, and lips were captured using 3-D electromagnetic articulography; effects of movement displacement and speed on clinimetric rates were determined using stepwise linear regressions. Results All clinimetric rates (traditional DDK tasks and novel tasks) were reduced in speakers with symptomatic bulbar disease; only TAR was reduced in speakers with presymptomatic bulbar disease and was able to detect this group with an excellent discrimination ability (area under the curve = 0.83). Kinematic analyses revealed associations with expected articulators, greater motor complexity, and differential articulatory patterns for the novel real-word repetitions than their DDK counterparts. Only LAR significantly declined longitudinally over the disease course. Conclusion Novel real-word clinimetric rate tasks evaluating tongue and labial articulatory dysfunction are valid and effective markers for early detection and tracking of bulbar disease in ALS.

Sports Related Concussion Impacts Speech Rate and Muscle Physiology

ABSTRACT Objective Establish objective and subjective speech rate and muscle function differences between athletes with and without sports related concussion (SRC) histories and provide potential motor speech evaluation in SRC. Methods Over 1,110 speech samples were obtained from 30, 19–22 year-old athletes who had sustained an SRC within the past 2 years and 30 pair-wise matched control athletes with no history of SRC. Speech rate was measured via average time per syllable, average unvoiced time per syllable, and expert perceptual judgment. Speech muscle function was measured via surface electromyography over the obicularis oris, masseter, and segmental triangle. Group differences were assessed using MANOVA, bootstrapping and predictive ROC analyses. Results Athletes with SRC had slower speech rates during DDK tasks than controls as evidenced by longer average time per syllable longer average unvoiced time per syllable and expert judgment of slowed rate. Rate measures were predictive of concussion history. Further, athletes with SRC required more speech muscle activation than controls to complete DDK tasks. Conclusion Clear evidence of slowed speech and increased muscle activation during the completion of DDK tasks in athletes with SRC histories relative to controls. Future work should examine speech rate in acute concussion.

Evaluation of Diadochokinesis in Greek Preschoolers With Speech Sound Disorders Using a Diadochokinetic Rates Protocol

The study aimed at evaluating the diadochokinetic (DDK) skills of Greek-speaking preschool children with phonological disorder (PD) by means of a structured evaluation protocol and at proposing cut-off points for children at risk of speech impairment. The participants were 36 children with PD and 60 typically developing (TD) peers. The groups were matched on age and gender. The PD group performed significantly slower than the TD group in all speech DDK tasks but not in the oral-motor tasks. The ROC analysis showed a statistically significant positive discrimination for all speech tasks. The internal consistency of the protocol was excellent (Cronbach’s α = .844), while complex stimuli showed a better discriminatory ability. The obtained results agree with Dodd’s classification for speech sound disorders (SSDs). Different types of speech stimuli must be included in the evaluation of DDK performance as a clinical predictor for preschoolers with SSDs who face difficulties in speech maturation.

Characteristics of Diadochokinesis in Typically Developing Children and Adults

Purpose: The purpose of this study was to examine the characteristics of the rate and perceptual judgment of diadochokinesis (DDK) in typically developing children and adults.Methods: Participants were typically developing children aged 2;6 to 9;11 and normal adults. For DDK tasks, they were asked to repeat [p*a], [t*a], [k*a], [p*at*a], and [p*at*ak*a] accurately and quickly with one breath. The number of repetitions per second was measured as DDK rate for each stimuli. The perceptual judgment of DDK were also performed in terms of regularity, rate, and accuracy using a three-point scale.Results: Children showed increases in the number of repetitions per second for all the DDK tasks with age. However, all the children groups between ages 2;6 and 9:11 exhibited significantly slower DDK rates than adults. In the perceptual judgment of DDK tasks, accuracy, rate, and consistency of sequential motion rates using [p*at*a] and [p*at*ak*a] showed statistically significant differences across age groups. Children demonstrated similar accuracy of SMR tasks with adults after age 6;0.Conclusion: This study showed developmental patterns of speech motor skills based on rate, accuracy, and consistency of DDK tasks. This study provides references for assessing speech motor skills related to children with speech difficulties.

Maximum Speech Performance and Executive Control in Young Adult Speakers.

Purpose This study investigated whether maximum speech performance, more specifically, the ability to rapidly alternate between similar syllables during speech production, is associated with executive control abilities in a nonclinical young adult population. Method Seventy-eight young adult participants completed two speech tasks, both operationalized as maximum performance tasks, to index their articulatory control: a diadochokinetic (DDK) task with nonword and real-word syllable sequences and a tongue-twister task. Additionally, participants completed three cognitive tasks, each covering one element of executive control (a Flanker interference task to index inhibitory control, a letter-number switching task to index cognitive switching, and an operation span task to index updating of working memory). Linear mixed-effects models were fitted to investigate how well maximum speech performance measures can be predicted by elements of executive control. Results Participants' cognitive switching ability was associated with their accuracy in both the DDK and tongue-twister speech tasks. Additionally, nonword DDK accuracy was more strongly associated with executive control than real-word DDK accuracy (which has to be interpreted with caution). None of the executive control abilities related to the maximum rates at which participants performed the two speech tasks. Conclusion These results underscore the association between maximum speech performance and executive control (cognitive switching in particular).

Speech inconsistency and its association with speech production, phonological awareness and nonword repetition skills

ABSTRACT The purpose of this study was to investigate relationships between speech inconsistency, speech production skills, phonological awareness and nonword repetition (NWR) in 24 preschool-aged Finnish-speaking children with speech sound disorder (SSD) and in 31 children with typical speech and language development (TD). Speech inconsistency was assessed by a picture-naming task repeated three times during one assessment session. The participants’ speech production skills were assessed with the Finnish Test for Phonology and a diadochokinetic (DDK) task. Phonological awareness was investigated by the tasks of Rhyme and initial syllable awareness and Syllable segmentation, and NWR by ten 2-4-syllabic nonwords. The findings indicated that the children with SSD were less accurate in speech production and NWR than the children with TD. No difference was found in phonological awareness. Among the children with SSD, speech inconsistency was correlated with accuracy in overall speech production, DDK task, and NWR. Among the children with TD, speech inconsistency was correlated with accuracy in overall speech production, partly with phonological awareness, and with NWR. The results provide support for the idea that when assessing speech inconsistency in children with SSD, a process-oriented approach may be needed in order to obtain an adequately broad picture of their skill profiles.

Automated Acoustic Analysis of Oral Diadochokinesis to Assess Bulbar Motor Involvement in Amyotrophic Lateral Sclerosis.

Purpose The purpose of this article was to validate a novel acoustic analysis of oral diadochokinesis (DDK) in assessing bulbar motor involvement in amyotrophic lateral sclerosis (ALS). Method An automated acoustic DDK analysis was developed, which filtered out the voice features and extracted the envelope of the acoustic waveform reflecting the temporal pattern of syllable repetitions during an oral DDK task (i.e., repetitions of /tɑ/ at the maximum rate on 1 breath). Cycle-to-cycle temporal variability (cTV) of envelope fluctuations and syllable repetition rate (sylRate) were derived from the envelope and validated against 2 kinematic measures, which are tongue movement jitter (movJitter) and alternating tongue movement rate (AMR) during the DDK task, in 16 individuals with bulbar ALS and 18 healthy controls. After the validation, cTV, sylRate, movJitter, and AMR, along with an established clinical speech measure, that is, speaking rate (SR), were compared in their ability to (a) differentiate individuals with ALS from healthy controls and (b) detect early-stage bulbar declines in ALS. Results cTV and sylRate were significantly correlated with movJitter and AMR, respectively, across individuals with ALS and healthy controls, confirming the validity of the acoustic DDK analysis in extracting the temporal DDK pattern. Among all the acoustic and kinematic DDK measures, cTV showed the highest diagnostic accuracy (i.e., 0.87) with 80% sensitivity and 94% specificity in differentiating individuals with ALS from healthy controls, which outperformed the SR measure. Moreover, cTV showed a large increase during the early disease stage, which preceded the decline of SR. Conclusions This study provided preliminary validation of a novel automated acoustic DDK analysis in extracting a useful measure, namely, cTV, for early detection of bulbar ALS. This analysis overcame a major barrier in the existing acoustic DDK analysis, which is continuous voicing between syllables that interferes with syllable structures. This approach has potential clinical applications as a novel bulbar assessment.

A speech measure for early stratification of fast and slow progressors of bulbar amyotrophic lateral sclerosis: lip movement jitter

Objective: To assess the utility of novel measures derived from a rapid syllable repetition task (i.e. oral dysdiadochokinesis [DDK]) in early stratification of fast and slow progressive bulbar amyotrophic lateral sclerosis (ALS) and prediction of bulbar disease progression rate. Methods: Fifty-four individuals with ALS were tracked longitudinally on their oral DDK and global bulbar/speech performance (i.e. bulbar subscore on the ALS Functional Rating Scale-Revised [ALSFRS-R]; articulation rate during passage reading) for a four-month average duration. Based on the bulbar deterioration rate over the tracked period, the participants were stratified as 14 fast bulbar progressors and 40 slow bulbar progressors using a posteriori classification approach. To determine if oral DDK performance predicts the differential bulbar disease progression trajectories in these individuals during the early stages of the tracked period (prior to significant bulbar/speech signs), twenty-two measures of lip motor performance in an oral DDK task were derived to (1) differentiate fast and slow bulbar progressors using the Receiver Operating Characteristic analysis and (2) predict bulbar disease progression rates across all individuals using linear regressions. Results: Movement jitter, a measure of temporal variability of alternating lip movement during DDK, showed 80% sensitivity and 95% specificity in differentiating fast and slow bulbar progressors early in the disease, and outperformed the ALSFRS-R bulbar subscore and articulation rate. Movement jitter also predicted bulbar disease progression rates across participants. Conclusion: Findings provided preliminary validation of the clinical value of movement jitter during oral DDK in patient stratification and bulbar disease prognosis.

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.

Oral and Laryngeal Diadochokinetic Rate in Multiple Sclerosis: Relationship to Disease Progression

Background: The first purpose of this study was to investigate the rate of oral and laryngeal Diadochokinesis (DDK) in Multiple Sclerosis (MS) patients in comparison with healthy people. The second goal was to determine if DDK rate has any relationship with the disease progression. Methods: In this cross-sectional study, two groups were enrolled: MS patients (n=31) and healthy subjects (n=14) . The samples of DDK tasks were collected. The scores of Expanded Disability Status Scale (EDSS) and duration of disease were considered as the indices of disease progression. Results: There were significant differences between the two groups in the rates of all DDK tasks (P≤0.001). Significant correlations were found between laryngeal DDK tasks and disease progression (r = - 0.488, r = -0.396, r = -0.444, r = - 0.667, P ≤ 0.027). Two oral DDK tasks were in correlation with EDSS and the disease duration (r = -0.403, r = -0.446, r =-0.521, r = -0.465, p≤0.025). There were high correlations between functional systems of EDSS (pyramidal, cerebellar and brainstem) and DDK tasks (r = - 0.448, r = -452, r = -0.458, r =-0.379, P ≤ 0.036). Conclusions: In the present study, poor performance in DDK tasks provided evidence for insufficient motor control over related speech subsystems in MS. These findings suggest that DDK rate is a sensitive beneficial speech motor control assessment in MS. Moreover, DDK tasks might be introduced as additional prognostic parameters for detecting disease progression and evaluating treatment achievements.