Oral hypofunction is a new concept that addresses the oral function of older adults. Few studies have investigated the relationship between oral hypofunction and general health conditions such as frailty, sarcopenia, and mild cognitive impairment. This paper explores these relationships in a large-scale, cross-sectional cohort study. The relationships of oral hypofunction with frailty, sarcopenia, and mild cognitive impairment were examined using data from 832 individuals who participated in the 2018 health survey of the residents of Tarumizu City, Kagoshima Prefecture, Japan. Individuals with frailty, sarcopenia, and mild cognitive impairment had significantly higher rates of oral hypofunction. Frailty was independently associated with deterioration of the swallowing function (odds ratio 2.56; 95% confidence interval, 1.26–5.20), and mild cognitive impairment was independently associated with reduced occlusal force (odds ratio 1.48; 95% confidence interval, 1.05–2.08) and decreased tongue pressure (odds ratio 1.77; 95% confidence interval, 1.28–2.43). There was no independent association found between sarcopenia and oral function. In conclusion, early intervention for related factors such as deterioration of the swallowing function in frailty, reduced occlusal force, and decreased tongue pressure in mild cognitive impairment could lead to the prevention of general hypofunction in older adults.

To explore the effect of mirror box therapy based on the mirror neuron (MN) system of the primary motor cortex (M1), we examined if direct (without a mirror) and indirect (with a mirror) observation of self-movement in healthy subjects induced changes in motor evoked potential (MEP) evoked by transcranial magnetic stimulation (TMS). MEPs were elicited from the first dorsal interosseous (FDI) and the flexor carpi radialis (FCR) muscles. Somatosensory evoked potentials (SEPs) during self-movement observation were also recorded. Both observations of self-movement with and without a mirror increased MEP amplitude. In addition, increase in MEP amplitude was specific to the prime mover muscle involved in the observed movement. The SEPs increased similar to the MEPs during both observations of self-movement with and without a mirror. We conclude that although the MN system can be activated by observing self-movement in a manner similar to that achieved by observing movement of another person, there were no detectable effect on corticospinal excitability that were specific to movements observed with a mirror.

Aim The present cross‐sectional study examined the associations of social frailty status with loss of muscle mass and weakness among community‐dwelling older adults. Methods Data from 353 older adults (74.8% women) who had participated in a community‐based health check survey (Tarumizu Study) were analyzed. Social frailty was defined using responses to five questions (going out less frequently, rarely visiting friends, feeling unhelpful to friends or family, living alone and not talking with someone every day). Participants with two or more components were considered socially frail. We assessed appendicular skeletal muscle mass using bioelectrical impedance analysis and calculated appendicular skeletal muscle index. Dominant handgrip strength was assessed. Loss of skeletal muscle mass (appendicular skeletal muscle index <7.0 kg/m2 for men, <5.7 kg/m2 for women) and muscle weakness (handgrip strength <26 kg for men, <18 kg for women) were determined based on the Asian Working Group for Sarcopenia criteria. Results The prevalence of social frailty was 14.7%. A higher prevalence of muscle weakness and loss of skeletal muscle mass in participants with social frailty was shown than in those without (muscle weakness 44.2% vs 23.6%, P ≤ 0.05; loss of skeletal muscle mass 59.6% vs 46.2%, P = 0.07). Social frailty was independently associated with muscle weakness (odds ratio 2.04, 95% confidence interval 1.06–3.95), but not with loss of skeletal muscle mass (odds ratio 1.47, 95% confidence interval 0.78–2.76) after adjusting for covariates. Conclusions Social frailty status could be associated with muscle weakness, though not a loss of skeletal muscle mass. Geriatr Gerontol Int 2019; 19: 76–80.

Subjective memory complaints (SMCs) may predict the onset of dementia. The purpose of this study was to clarify characteristics of performance of activities of daily living (ADL) for older adults with SMCs and to offer support options that enable them to maintain their community-based lifestyle. A self-administered questionnaire was sent to 2000 randomly selected members of CO-OP Kagoshima, and 621 responded. 270 responders answered all questions were categorized into SMC (+) group and SMC (−) group (n = 133). Participants were evaluated the Process Analysis of Daily Activity for Dementia. A 2-sample t-test or the Chi-square test were used to compare the averages of continuous variables or the proportions of categorical variables. The results showed the SMC (+) group ranked significantly lower in ability to use the telephone, shop, cook, do housekeeping, manage finances, and manage medications compared with the SMC (−) group. In addition, the SMC (+) group was significantly less independent than the SMC (−) group in many processes requiring the use of tools, operation of machines, management of goods, selection of tools, and monitoring. To enable continued independence of older adults’ experiencing SMCs, it may be important to analyze their performance of ADL and to develop plans for supporting their strengths.

The aim of this study was to clarify the topographical localization of motor-related regional hemodynamic signal changes during motor execution (ME) and motor imagery (MI) by using near-infrared spectroscopy (NIRS), as this technique is more clinically expedient than established methods (e.g., fMRI). Twenty right-handed healthy subjects participated in this study. The experimental protocol was a blocked design consisting of 3 cycles of 20 s of task performance and 30 s of rest. The tapping sequence task was performed with their fingers under 4 conditions: ME and MI with the right or left hand. Hemodynamic brain activity was measured with NIRS to monitor changes in oxygenated hemoglobin (oxy-Hb) concentration. Oxy-Hb in the somatosensory motor cortex (SMC) increased significantly only during contralateral ME and showed a significant interaction between task and hand. There was a main effect of hand in the left SMC. Although there were no significant main effects or interactions in the supplemental motor area (SMA) and premotor area (PMA), oxy-Hb increased substantially under all conditions. These results clarified the topographical localization by motor-related regional hemodynamic signal changes during ME and MI by using NIRS.