The influence of bite force strength on brain activity: A functional magnetic resonance imaging study

Kanayama, Takeo; Miyamoto, Hiroyuki; Yokoyama, Atsuro; Takahashi, Toshiyuki; Shibuya, Yasuyuki

doi:10.5430/jbgc.v5n1p28

Cited by 2 publications

(1 citation statement)

References 16 publications

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“…Previous studies have reported that the degree of change in cerebral blood flow varies depending on the hardness of the chewing object or food [ 29 ]. It has been reported that moderately hard food increases cerebral blood flow, and Onozuka et al [ 30 ] reported that masticating a moderately hard gum increased the activity of the primary sensorimotor cortex, insula and operculum than masticating a hard gum. Increased cerebral blood flow and neuronal activity may explain the increased cognition.…”

Section: Discussionmentioning

confidence: 99%

Effects of masticatory exercise on cognitive function in community-dwelling older adults

Kim¹

2021

THC

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BACKGROUND: Mastication improves cognitive function by activating cerebral cortical activity, and it is important to demonstrate the cognitive effects of masticatory training using a variety of different interventions. OBJECTIVE: This study aimed to evaluate the effects of masticatory exercise on cognitive function in healthy older adults living in the community. METHODS: For six weeks, twelve participants performed a masticatory exercise using a NOSICK exerciser device, and thirteen subjects performed daily life without masticatory exercises. Trail Making Test, Digit Span Test, and Stroop test were used to measure the cognitive function. RESULTS: The participants in the experimental group showed significant improvements in TMT-A/B (p= 0.001 and 0.004), DST-forward (p= 0.001), and ST-word (p= 0.001). The effect sizes after the intervention were calculated as (1.2 and 0.8) for TMT-A/B, (0.8 and 0.2) for Digit Span Test forward/backward, and (0.6 and 0.2) for Stroop test color/word. CONCLUSIONS: We suggest that the masticatory exercises improve cognitive function in healthy older adults. Therefore, masticatory exercises can be used as a therapeutic exercise during cognitive rehabilitation.

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Section: Discussionmentioning

confidence: 99%

Effects of masticatory exercise on cognitive function in community-dwelling older adults

Kim¹

2021

THC

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Functional quantification of oral motor cortex at rest and during tasks using activity phase ratio: A zero-setting vector functional near-infrared spectroscopy study

Arai¹,

Kato²,

Kato³

2022

Front. Physiol.

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Oral frailty associated with oral hypokinesia may cause dementia. Functional near-infrared spectroscopy (fNIRS) can be used while the participants are in seating position with few restrictions. Thus, it is useful for assessing brain function, particularly oral motor activity. However, methods for identifying oral motor cortex (OMC) activation via the scalp have not been established. The current study aimed to detect OMC activation, an indicator of activity phase ratio (APR), which reflects increased oxygen consumption (0 < [deoxyhemoglobin (ΔDeoxyHb) or 0 < {[ΔDeoxyHb- oxyhemoglobin (ΔOxyHb)/√2]}, via fNIRS to accurately identify local brain activity. The APR, calculated via zero-set vector analysis, is a novel index for quantifying brain function both temporally and spatially at rest and during tasks. In total, 14 healthy participants performed bite tasks for 3 s per side for 10 times while in the sitting position. Then, time-series data on concentration changes in ΔOxyHb and ΔDeoxyHb were obtained via fNIRS. The anatomical location of the OMC was determined using a pooled data set of three-dimensional magnetic resonance images collected in advance from 40 healthy adults. In the zero-set vector analysis, the average change in ΔOxyHb and ΔDeoxyHb concentrations was utilized to calculate the APR percentage in 140 trials. The significant regions (z-score of ≥2.0) of the APR and ΔOxyHb in the task were compared. During the bite task, the APR significantly increased within the estimated OMC region (56–84 mm lateral to Cz and 4–20 mm anterior to Cz) in both the right and left hemispheres. By contrast, the ΔOxyHb concentrations increased on the bite side alone beyond the OMC region. The mean APR at rest for 2 s before the task showed 59.5%–62.2% in the left and right OMCs. The average APR for 3 s during the task showed 75.3% for the left OMC and 75.7% for the right OMC during the left bite task, and 65.9% for the left OMC and 80.9% for the right OMC during the right bite task. Interestingly, the average increase in APR for the left and right OMCs for the left bite task and the right bite task was 13.9% and 13.7%, respectively, showing almost a close match. The time course of the APR was more limited to the bite task segment than that of ΔOxyHb or ΔDexyHb concentration, and it increased in the OMC. Hence, the APR can quantitatively monitor both the resting and active states of the OMC in the left and right hemispheres. Using the zero-set vector-based fNIRS, the APR can be a valid indicator of oral motor function and bite force.

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The influence of bite force strength on brain activity: A functional magnetic resonance imaging study

Cited by 2 publications

References 16 publications

Effects of masticatory exercise on cognitive function in community-dwelling older adults

Effects of masticatory exercise on cognitive function in community-dwelling older adults

Functional quantification of oral motor cortex at rest and during tasks using activity phase ratio: A zero-setting vector functional near-infrared spectroscopy study

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