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.

Speech Performance among Healthy Malay Female Speakers during Dual Tasks and Sentence Complexity.

OBJECTIVES: This study aimed to identify how different dual tasks influence speech performance among young Malay speakers by manipulating the complexity of sentences. Fifteen female speakers (20-30 years old) were audio recorded while executing a series of simple and complex sentence repetition tasks. METHODS: Hierarchical linear modeling was conducted to examine the effects of task (speech task only, speech + cognitive tasks, speech + linguistic tasks, and speech + manual tasks) and sentence complexity (simple vs. complex), as well as their interaction on 3 outcome measures (word accuracy rate [WAR], response reaction time [RRT], and duration of sentence [DoS]). RESULTS: Significantly higher WAR were found when participants read the sentences only compared to when they completed another task simultaneously. The pairwise comparison further revealed that the conditions of speech + manual tasks produced the lowest WAR. For RRT, participants responded significantly faster when they only read the sentences (mean = 1.36, SE = 0.17) than when they read the sentences and conducted another task at the same time (mean = 1.66, SE = 0.14; p < 0.0001). A pairwise comparison showed that the conditions of speech + manual tasks produced the longest DoS. Neither the effect of sentence complexity nor the interaction between task and sentence complexity was statistically significant across WAR, RRT, and DoS. CONCLUSIONS: The results augment what is known about interference between speech and other concurrent tasks and provides evidence that divided attention affects manual task performance more than other tasks. In addition, sentence complexity did not affect speech performance in healthy adults. This paradigm could be used in future studies to serve as a clinical marker that can potentially distinguish mild cognitive impairment from normal aging.

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.