Oral diadochokinesis and associated oro‐facial function in young and old German mother‐tongue speakers: A cross‐sectional study

Abstract

Objectives The aims of this study were to compare oral diadochokinesis and to test associations with oro‐facial functional parameters in healthy young and old German speakers. Background Oral diadochokinesis is a key component in the concept of oro‐facial hypofunction and relates to tongue and lip motor function but may depend on the linguistic background. Materials and methods Healthy German speakers with a minimum of 20 teeth were recruited to form a young (<60 years) and an older group (≥60 years). Oral diadochokinesis was assessed as the number of repetitions/s for the monosyllables /pa/, /ta/ and /ka/ to evaluate movement capacity of the lip, the anterior region of the tongue and the posterior region of the tongue, respectively. Maximum voluntary lip force, maximum voluntary bite force, masticatory performance, maximum voluntary tongue pressure, xerostomia and swallowing function were assessed with validated instruments. Results are presented as median (IQR). Results Sixty participants formed the younger group (n = 35, 30.0 years [24.0‐49.0]) and the older group (n = 25, 64.0 years [62.0‐72.0]). Counts/s of /ta/ were different between age groups (younger group: 6.0 vs older group: 5.4) but not for syllables /pa/ (younger group: 6.0 vs older group: 5.8) and /ka/ (younger group: 5.6 vs older group: 5.0). The oral diadochokinesis with /pa/ was overall associated with maximum voluntary lip force; oral diadochokinesis performed with /ta/ was associated with tongue pressure, and oral diadochokinesis with /ka/ with swallowing function. Masticatory performance was not associated with oral diadochokinesis but with maximum voluntary bite force, xerostomia and with maximum voluntary tongue pressure. Conclusions The published thresholds for oral diadochokinesis should be reconsidered in non‐Japanese mother‐tongue speakers. However, they still play an important role in the overall concept of oro‐facial functional assessment.

Factors associated with age-related changes in oral diadochokinesis and masticatory function in healthy old adults

“…Swallowing disorders, or dysphagia, can be caused by aging, swallowing-related muscle degeneration, sarcopenia, physical frailty, and comorbidities, leading to malnutrition, aspiration pneumonia, significant mortality, and morbidity [ 9 ]. Swallowing requires the coordinated activity of many nerves and muscles of the mouth, lips, pharynx, and esophagus [ 10 , 11 ]. In particular, oropharyngeal dysphagia encompassing the oral cavity, representing an initial voluntary component, is an essential domain [ 10 ].…”

“…Tongue-lip motor function, an indicator of orofacial function, is generally assessed using oral diadochokinesis (ODK) based on linguistic background [ 4 , 11 ]. Decreased tongue-lip motor function can be a result of sensory impairments in brain function or perioral muscle function, such as Parkinson’s disease, traumatic injury, head and neck surgery, muscle atrophy, and malnutrition [ 4 ].…”

“…The lips also help to create a tight seal that prevents food and liquids from leaking during the swallowing reflex and traps food in the buccal or labial sulci [ 10 – 12 ]. Moreover, some researchers have reported controversial outcomes regarding ODK parameters, e.g., that an ODK /pa/ score < 6.2 times/s is associated with swallowing problems, suggesting the importance of the maximum voluntary lip force [ 4 , 11 , 12 ]. There is neither sufficient evidence for the association of each component of ODK /pa/, /ta/, and /ka/ with changes in tongue-lip motor function, especially swallowing function, depending on aging, nor enough data to apply in clinical investigations.…”

“…However, there are controversial findings about the association between MP and salivary flow in vulnerable old individuals [ 19 , 20 ]. A cross-sectional study on tongue-lip motor function and orofacial functions reported that xerostomia was negatively correlated with tongue-lip force and reduced ODK /ka/, increasing the likelihood of subjective swallowing difficulties in older individuals [ 11 ].…”

Factors related to subjective evaluation of difficulty in chewing among community‐dwelling older adults

“…One of the factors that strongly influence the decline of masticatory function is the decrease in the number of teeth. 1,2 In addition to these factors, various other factors such as occlusal force, 3,4 tongue pressure, 5,6 and tongue-lip motor function 7 have been reported to be related to masticatory function. Many of these factors decrease or decline with age, resulting in the decline in masticatory function.…”