Chewing function and related parameters as a function of the degree of dementia: Is there a link between the brain and the mouth?

Correlation between GLCM-based texture features of the lateral pterygoid muscle and cognitive function in patients with idiopathic normal pressure hydrocephalus: a preliminary report

PURPOSE

The potential relationship between mastication ability and cognitive function in idiopathic normal pressure hydrocephalus (iNPH) patients is unclear. This report investigated the association between mastication and cognitive function in iNPH patients using the gray level of the co-occurrence matrix on the lateral pterygoid muscle.

METHODS

We analyzed data from 96 unoperated iNPH patients who underwent magnetic resonance imaging (MRI) between December 2016 and February 2023. Radiomic features were extracted from T2 MRI scans of the lateral pterygoid muscle, and muscle texture parameters were correlated with the iNPH grading scale. Subgroup analysis compared the texture parameters of patients with normal cognitive function with those of patients with cognitive impairment.

RESULTS

The mini-mental state examination score correlated positively with the angular second moment (P < 0.05) and negatively with entropy (P < 0.05). The dementia scale (Eide's classification) correlated negatively with gray values (P < 0.05). Gray values were higher in the cognitive impairment group (64.7 ± 16.6) when compared with the non-cognitive impairment group (57.4 ± 13.3) (P = 0.005). Entropy was higher in the cognitive impairment group (8.2 ± 0.3) than in the non-cognitive impairment group (8.0 ± 0.3) (P < 0.001). The area under the receiver operating characteristic curve was 0.681 (P = 0.003) and 0.701 (P < 0.001) for gray value and entropy, respectively.

CONCLUSION

Our findings suggest an association between heterogeneity of mastication and impaired cognitive function in iNPH patients and highlight muscle texture analysis as a potential tool for predicting cognitive impairment in these patients.

Feasibility of Oral Function Evaluation According to Dementia Severity in Older Adults with Alzheimer's Disease

Oral function evaluation in older adults with dementia is important for determining appropriate and practical dietary support plans; however, it can be challenging due to their difficulties in comprehending instructions and cooperating during assessments. The feasibility of oral function evaluation has not been well studied. This cross-sectional study aimed to determine the feasibility of oral function evaluation in older adults with Alzheimer's disease (AD) according to Functional Assessment Staging of Alzheimer's Disease (FAST) stages. In total, 428 older adults with AD (45 men and 383 women; mean age: 87.2 ± 6.2 years) were included. Multilevel logistic regression models were used to examine the prevalence of participants who were unable to perform oral function evaluations, including oral diadochokinesis (ODK), repeated saliva swallow test (RSST), and modified water swallow test (MWST). In comparison to the reference category (combined FAST stage 1-3), FAST stage 7 was associated with the infeasibility of ODK (adjusted odds ratio, 95% confidence interval = 26.7, 4.2-168.6), RSST (5.9, 2.2-16.1), and MWST (8.7, 1.6-48.5, respectively). Oral function evaluation is difficult in older adults with severe AD. Simpler and more practical swallowing function assessments and indicators that can be routinely observed are required.

Association between shortened dental configurations and health outcomes: a scoping review

This study mapped definitions of shortened dental configurations and health outcomes employed in association studies. A scoping review was conducted using the PubMed/Medline, Scopus, Web of Science, SciELO and Cochrane databases. Two trained researchers selected studies and extracted data. Studies that investigated the association between shortened dental configurations (exposure) and person-centered outcomes (general and oral health) related to health behavior (dietary patterns). Clinical outcomes were classified according to the International Classification of Functioning, Disability and Health and the International Classification of Diseases of the World Health Organization (WHO). Shortened dental configurations were defined as at least 20/21 teeth or the position of the teeth, including esthetics, dental occlusion and periodontal status (Eichner Index, Shortened Dental Arches, Functional Dentition Classification System, Posterior Occluding Pairs, Functional Tooth Units). The initial search resulted in 12,525 records in English, Portuguese and Spanish, 432 of which addressed the association of interest. General health (n = 203) and oral health (n = 201) were addressed in a similar number of studies. Most outcomes were related to general health (n = 184), the most frequent of which were endocrine, nutritional or metabolic diseases (n = 57) and mental functions (n = 26). Person-centered measures were addressed in 153 studies, most of which were about oral health and oral health-related quality of life (n = 62). Oral health outcomes were predominantly related to intake functions (n = 44) and diseases or disorders of the orofacial complex (n = 24). Dietary patterns (n = 43) and mortality (n = 38) were also studied. The cross-sectional design (n = 257) and non-probabilistic sampling (n = 218) were more frequent. The shortened dental configurations defined by the WHO were the most frequent in the studies (n = 206). The effects of shortened dental configurations have been investigated mainly in relation to endocrine, nutritional or metabolic diseases and measures of oral health-related quality of life. The findings point to a diversity of health outcomes assessed and substantial methodological variability.

White matter abnormalities mediate the association between masticatory dysfunction and cognition among older adults

BACKGROUND

Masticatory parameters, such as reduced number of teeth and posterior contacts, have been shown to be associated with reduced cognitive status. The underlying mechanisms that affect these associations, are however, not well understood.

OBJECTIVES

The study aims to investigate the association between masticatory dysfunction and cognition and explore the mediating effect of brain structure.

METHODS

In this cross-sectional study, 45 older adults with subjective masticatory dysfunction (mean age 72.3 ± 4.0 years) were included. Mini-Mental State Examination score <25, brain trauma, neurological disease, neurodegenerative disorders, depression or poor Swedish language skills were criteria for exclusion. Cognitive functions (executive function and episodic memory) and masticatory dysfunction defined by functional occluding status (FOS; the number of occluding units and number of remaining teeth) were analysed with partial correlation models. Structural magnetic resonance imaging was performed on 28 feasible participants. Multiple regression analyses were performed to evaluate the predictive value of brain structure and white matter hypointensities (WM-hypo) on cognitive functions. A mediation analysis was applied to assess significant predictor/s of the association between FOS and cognition.

RESULTS

Both episodic memory and executive functions were positively correlated with FOS. WM-hypo predicted cognitive status (executive function, p ≤ .01). WM-hypo mediated 66.6% (p = 0.06) of the association between FOS and executive functions.

CONCLUSION

Associations between FOS and cognitive functions are reported, where FOS, a potential modifiable risk factor, was related to both episodic memory and executive functions. The mediating effect of WM-hypo on the association between FOS and executive functions highlights the impact of the vascularisation of the brain on the link between mastication and cognition. The present study provides increased knowledge that bridges the gap between masticatory dysfunction and cognition.

Risk factors of cognitive impairment: Impact of decline in oral function

Cognitive impairment and subsequent dementia are the major causes of disability and need for nursing care among older people in worldwide. The purpose is to review well-known risk factors for cognitive impairment and dementia, focusing on the relationship between decline in oral function and current prevention strategies. Various non-modifiable and modifiable risk factors are related to cognitive impairment. Effects of oral function to cognitive impairment is not yet well recognized in the medical community, although masticatory function, occlusal force, and number of teeth have been reported to be related to cognitive function. Furthermore, occlusal force rather than number of teeth was significantly related to the early stages of cognitive impairment, and that a decline in occlusal force seemed to lead to cognitive impairment directly and indirectly through dietary intake. This relationship was significant only for occlusal force, which may be associated with the early stages of cognitive decline. Nutritional change caused by reduced masticatory function is suggested as a possible explanation. Therefore, rehabilitation or maintenance of oral function should be sought to prevent cognitive impairment.

Dementia and the history of disease in older adults in community

INTRODUCTION

Many studies have revealed the effect of medical history on dementia. The aim of this study was to explore the relationship between the history of disease and onset of dementia.

METHODS

This was a multi-center, cross-sectional study, with 2595 older adults enrolled. The onset of dementia was evaluated with Revised Hasegawa Dementia Scale (HDS-R). The diagnosed diseases after the age of 40 of the participants were investigated, including respiratory system diseases, digestive system diseases, cardiovascular diseases, endocrine disorders, genitourinary system diseases, nervous system disease, sensory system diseases, dental/oral diseases, bone/joint diseases and mental illnesses.

RESULTS

Data of 2458 older adults were analyzed. Univariate analysis showed that diabetes, thyroid disease, mental illness, hearing loss, stroke, dental/oral disease, Denture use, fracture/osteoporosis, kidney disease and number of diseases were risk factors for dementia. After controlling for demographic sociological variables, diabetes, dental/oral disease, and denture use were independent risk factors for dementia. Thyroid disease (P = 0.313), mental illnesses (P = 0.067), hearing loss (P = 0.595), stroke (P = 0.538), fractures/osteoporosis (P = 0.069), kidney disease (P = 0.168) were no longer significant to dementia.

CONCLUSION

Diabetes, dental/oral disease and denture use were main risk factors for dementia.

Association between Dementia Severity and Oral Hygiene Management Issues in Older Adults with Alzheimer's Disease: A Cross-Sectional Study

Oral hygiene management issues vary across types and clinical stages of dementia. We aimed to clarify the issues related to oral hygiene management in older adults with Alzheimer's disease (AD) according to stages defined by the Functional Assessment Staging of Alzheimer's Disease (FAST). In all, 397 records (45 men and 352 women; average age, 86.8 years; age range, 65-106) from older adults with AD were used for the cross-sectional study. We used data from a cohort of older adults (≥65 years old) who required long-term care and lived in the Omorimachi area of Yokote City, Akita Prefecture, Japan. Multilevel logistic regression analysis was conducted to examine the associations of the FAST stage, set as the exposure variable, with oral hygiene management parameters set as outcome variables. Compared to the reference category (combined FAST stage 1-3), FAST stages 6 and 7 had significantly higher odds ratios for refusal of oral health care, dependence in performing oral health care, and rinsing and gargling disability. FAST stages 4 and 7 were associated with dental plaque accumulation. Oral health care for older adults with AD should be planned appropriately according to dementia severity.

Use of handgrip strength measurement as an alternative for assessing chewing function in people with dementia

Background

Chewing ability and handgrip strength can be independent explanatory factors of physical fitness. The usability of measurement procedures for assessing chewing function in people with dementia seems to be limited. This study aimed to show an association between handgrip strength and chewing function to enable the use of handgrip strength measurement as an alternative for determining chewing parameters in people with dementia. 

Methods

The data analysed here are part of the OrBiD (Oral Health, Bite Force and Dementia) pilot study. A total of 120 participants were assigned to five evaluation groups based on their cognitive abilities using the Mini-Mental State Examination (MMSE). The MMSE groups in this data analysis were “no dementia” (noDem, MMSE 28–30), “mild cognitive impairment” (mCI, MMSE 25–27), and “mild dementia” (mDem, MMSE 18–24). Handgrip strength, maximum occlusal force, and chewing efficiency were measured. 

Results

The Mini-Mental State Examination scores among all participants (n = 71) resulted in a median of 27 and a range of 18–30. An association between maximum handgrip strength and the cognitive impairment of the participants was shown. Nevertheless, the use of handgrip strength measurement as an alternative for determining chewing function was not verified in this study.

Conclusions

The feasibility and reliability of chewing function measurements in people with dementia should be investigated. Existing measurement procedures may need to be adapted or new assessments may need to be developed to be usable in people with dementia.

Trial registration

ClinicalTrials.gov NCT03775772.

The Effect of a Masticatory Muscle Training Program on Chewing Efficiency and Bite Force in People with Dementia

Until now, no study has investigated the effects of masticatory muscle training on chewing function in people with dementia. This study aimed to investigate whether physiotherapeutic exercises for the masticatory muscles have an influence on chewing efficiency and bite force in people with dementia. In a clinical trial with stratified randomization subjects were assigned to three groups based on the Mini Mental State Examination (MMSE: group 1—28–30, group 2—25–27, group 3—18–24). Each group was divided into an experimental (ExpG, intervention) and control group (ConG, no intervention). As intervention a Masticatory Muscle Training (MaMuT) (part 1: three physiotherapeutic treatments and daily home exercises, part 2: daily home exercises only) was carried out. Chewing efficiency and bite force were recorded. The MaMuT influenced the masticatory performance regardless of the cognitive state. Bite force increased in ExpG 1 and 2. Without further training, however, the effect disappeared. Chewing efficiency increased in all ExpG. After completion of the training, the ExpG 2 and 3 showed a decrease to initial values. Subjects of ExpG 1 showed a training effect at the final examination, but a tendency toward the initial values was observed. ExpG 3 seemed to benefit most from the physiotherapeutic exercises in terms of improving chewing efficiency by the end of the intervention phase. ExpG 1 showed the greatest gain in bite force. The MaMuT program is a potential method of improving masticatory performance in people with cognitive impairment or dementia when used on a daily basis.

Impact of an Oral Hygiene Intervention in People with and without Dementia on Oral Health Parameters-Results from the Oral Health, Bite Force, and Dementia (OrBiD) Pilot Study

This study aimed to assess the influence of an oral hygiene intervention on oral health, depending on the degree of dementia. A clinical evaluation of oral health parameters (index of decayed, missing, and filled teeth (DMFT-index), periodontal screening index (PSI), oral hygiene index (OHI), and bleeding on probing (BOP)) was performed in 120 subjects assigned to five groups, based on the mini mental state examination (MMSE) at baseline and after 12 months. Each MMSE group (no dementia (noDem, MMSE 28–30), mild cognitive impairment (mCI, MMSE 25–27), mild dementia (mDem, MMSE 18–24), moderate dementia (modDem, MMSE 10–17), and severe dementia (sDem, MMSE ≤ 9)) was split into control (no intervention) and experimental groups (intervention on oral hygiene: increased frequency, daily usage of high-fluoride toothpaste). In total, 99 out of 120 subjects were included in the analysis. The dropout rate was high in subjects with modDem and sDem due to death. In subjects with noDem, mCI, and mDem, no changes in the DMFT were found, but improvements in the OHI, BOP, and PSI were observed. Subjects with modDem or sDem demonstrated a deterioration in DMFT; however, in these patients, OHI improved in all control and experimental groups, BOP improved in the experimental group only, and PSI did not improve at all. The scope of improving oral health parameters by increasing the recall frequency and by continuously using high fluoride toothpaste is at its limits in people with severe dementia. Multidimensional approaches should be sought to improve the oral health of vulnerable older patients.

Transition of Living Arrangement and Cognitive Impairment Status among Chinese Older Adults: Are They Associated?

Background and Objectives: Living arrangement is a crucial factor for older adults' health. It is even more critical for Chinese older adults due to the tradition of filial piety. With the aging of China's population, the prevalence of cognitive impairment among older adults has increased. This study examines the association between living arrangement transition and cognitive function among Chinese older adults. Materials and Methods: Using three waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS; 2008-2009, 2011-2012, and 2014), we analyzed data for older adults (age ≥ 65) who lived with other household members and reported good cognitive function or mild cognitive impairment when they participated in the survey. Multistate Cox regression was employed to study changes in cognitive function. Results: Older adults who transitioned to living alone had lower risk of cognitive impairment (hazard ratio (HR) = 0.66, 95% CI: 0.52, 0.83; p < 0.01), compared with those who continued to live with other household members. Moving into an institution was also not associated with cognitive impairment. Conclusions: With older adults' transition to living alone, public health practitioners or social workers might educate them on the benefits of such a living arrangement for cognitive function.