Effects of Physical Therapy on a Patient With Lemierre's Syndrome Who Had Atelectasis and Limited Range of Motion in the Neck.

Lemierre's syndrome (LS) is a severe infectious disease that can lead to the formation of neck abscesses and thrombosis. LS may be an indication for surgery; however, there are few reports on the physical therapy approaches used in patients with LS. A male patient in his 20s reported atelectasis and limited range of motion in the neck after resection of a deep neck abscess on the left side of the neck caused by LS. Thrombophlebitis was also observed around the neck lesion, indicating the risk of pulmonary embolism. Physical therapy was initiated with low-load, deep breathing exercises. Additional breathing exercises, such as respiratory assistance and positive pressure loading, were initiated after the administration of anticoagulants. Although the therapeutic intervention was delayed due to the unstable wound with partially resected muscle, it was assumed that the impairment of the range of motion in the neck was unlikely to persist as the patient was young. No critical adverse events were observed, and the range of motion was recovered such that the patient was able to resume playing baseball. The presence of a venous thrombus and inflammation may affect physical therapy; however, careful management of the exercise load could aid in the safe and effective treatment of LS without the incidence of complications, even in the early postoperative period.

Qualitative research concerning physiotherapy approaches to encourage physical activity in older adults with dementia.

BACKGROUND: Physical exercise is known to improve the level of activities of daily living and physical function in people with dementia; however, symptoms of dementia often pose challenges when implementing physical therapy. This study aimed to elucidate how physiotherapists (PTs) engage with older adults with dementia to encourage exercise and participation in physical activity. METHODS: In this qualitative study, four PTs working with older adults with dementia in long-term care facilities in Japan were recruited and interviewed. We used a modified grounded theory approach to assess how PTs engaged with older adults with dementia during physiotherapy sessions. RESULTS: Based on PT responses, five categories of engagement were identified: "make structured preparations for clients to begin physical activity," "link exercise therapy to a client's daily life," "discover changes in daily life," "ascertain cognitive function," and "accommodate client differences." Concepts were derived under each category. The category "make structured preparations for clients to begin physical activity" served as a preceding stage for PTs to engage with older adults with dementia. PTs linked exercise therapy to each client's daily life activities to encourage voluntary participation in daily physical activity. PTs ensured the performance of routine patterns of movement and modified these movement patterns per clients' differing paces. CONCLUSION: PTs provided exercise and movement training based on various degrees of client involvement and made structured preparations for clients to begin physical activity that were linked to exercise therapy. Our findings may prompt PTs to encourage older people with dementia to participate in physical therapy and benefit from exercise.

Association of life-space with light-intensity and moderate to vigorous-intensity physical activity in older adults using daycare rehabilitation facilities.

BACKGROUND: The use of assistive devices and the presence of caregivers in the living space of older people using daycare rehabilitation facilities may increase their physical activity. However, the exact relationship between these factors and physical activity has not been well established. OBJECTIVE: We aimed to examine whether assistive devices and caregivers were life-space factors associated with light-intensity physical activity (LPA) and moderate to vigorous-intensity physical activity (MVPA) among daycare rehabilitation facility users. METHODS: Forty-seven daycare rehabilitation facility users were recruited (mean age: 76.5 ± 8.6 years; men: 16; women: 31). LPA and MVPA were measured using accelerometers and averaged over 7 days. Life-space assessment (LSA) and the Geriatric Depression Scale score were assessed. The LSA includes composite life-space, maximal life-space (LS-M), life-space using equipment (LS-E), and independent life-space. Grip strength and maximum gait speed were measured two times, and the best results were used. RESULTS: Multiple regression analysis showed that LPA was significantly associated with sex (ß = 0.773), grip strength (ß = 0.434), and LS-M (ß = 0.325), whereas MVPA was significantly associated with age (ß = -0.421) and LS-E (ß = 0.455). CONCLUSION: A close association was found between LS-M and LS-E and the intensity of physical activity in older people who used daycare rehabilitation facilities.

Association of the prefrailty with global brain atrophy and white matter lesions among cognitively unimpaired older adults: the Nakajima study.

Physical frailty has been associated with adverse outcomes such as dementia. However, the underlying structural brain abnormalities of physical frailty are unclear. We investigated the relationship between physical frailty and structural brain abnormalities in 670 cognitively unimpaired individuals (mean age 70.1 years). Total brain volume (TBV), hippocampal volume (HV), total white matter hypointensities volume (WMHV), and estimated total intracranial volume (eTIV) on the 3D T1-weighted images were automatically computed using FreeSurfer software. Participants were divided into two states of physical frailty (robust vs. prefrail) based on the revised Japanese version of the Cardiovascular Health Study criteria. The multivariable-adjusted mean values of the TBV-to-eTIV ratio was significantly decreased, whereas that of the WMHV-to-eTIV ratio was significantly increased in the prefrail group compared with the robust group. Slowness, one of the components of physical frailty, was significantly associated with reduced TBV-to-eTIV and HV-to-eTIV ratios, and slowness and weakness were significantly associated with an increased WMHV-to-eTIV ratio. Our results suggest that the prefrail state is significantly associated with global brain atrophy and white matter hypointensities. Furthermore, slowness was significantly associated with hippocampal atrophy.

Physical therapy processes-interactions between a physical therapist and an older client with dementia.

BACKGROUND: In Japan, the population aging rate highlights the need to examine various care provisions for older adults with dementia, including physical therapy. However, despite its positive effects, there are also many challenges associated with providing physical therapy for older adults with dementia. OBJECTIVE: This qualitative case study examined the interactions between a physical therapist and a patient with dementia and the process by which physical therapy was provided to her. METHODS: This study utilized a modified grounded theory approach to analyze the interview of one physical therapist, a woman with four years of clinical experience who specializes in physical therapy for older adults who provided a 20-minute physical therapy session to her client, a woman in her 80s with dementia who sought to maintain her ability to perform activities of daily living and preserve her independence. Data were collected in January 2017. RESULTS: Fifteen concepts that represent aspects of the services that the therapist provided to her client were identified. Five distinct categories were derived: 1) foundations of the relationship; 2) understanding individual factors; 3) supporting execution of functional activities; 4) assessing cognitive function; and 5) support to ensure safety in daily living. CONCLUSION: Physical therapists help older adults with dementia execute functional activities, which helps ensure their safety and independence, and fosters strong therapist-client relationships. Future studies should interview multiple physical therapists to generate additional concepts. Further, quantifying these concepts and developing tools to assess clients will improve care provision and inform physical therapists with limited experience in treating patients with dementia.

Diabetes Mellitus, Elevated Hemoglobin A1c, and Glycated Albumin Are Associated with the Presence of All-Cause Dementia and Alzheimer's Disease: The JPSC-AD Study.

BACKGROUND: Glucose dysmetabolism is an important risk factor for dementia. OBJECTIVE: We investigated the associations of diabetes mellitus, the levels of glycemic measures, and insulin resistance and secretion measures with dementia and its subtypes in a cross-sectional study. METHODS: In this study, 10,214 community-dwelling participants were enrolled. Hemoglobin A1c (HbA1c), the homeostasis model assessment (HOMA) for insulin resistance (HOMA-IR), the HOMA of percent ß-cell function (HOMA-ß), and the glycated albumin (GA) was evaluated. The associations of each measure with Alzheimer's disease (AD) and vascular dementia (VaD) were investigated. RESULTS: The multivariable-adjusted odds ratios (ORs) of AD were significantly higher in participants with diabetes mellitus than in those without diabetes (1.46 [95% CI: 1.08-1.97]). Higher HbA1c levels were significantly associated with AD at diabetes (≥6.5%) and even at prediabetes (5.7 %-6.4 %) levels; multivariable-adjusted ORs for AD in participants at the diabetes level were 1.72 (95% CI: 1.19-2.49), and those in participants at the prediabetes level were 1.30 (95% CI: 1.00-1.68), compared with those in normal participants. Moreover, higher GA levels were associated with AD. No associations were observed between the diabetic status or the levels of glycemic measures and VaD. In addition, no significant relationships were observed between insulin resistance and secretion measurements and AD and VaD. CONCLUSION: Our findings indicate that diabetes mellitus and hyperglycemia are significantly associated with AD, even in individuals at the prediabetes level.

Effects of functional variants of vitamin C transporter genes on apolipoprotein E E4-associated risk of cognitive decline: The Nakajima study.

Apolipoprotein E E4 (APOE4) is a risk factor for cognitive decline. A high blood vitamin C (VC) level reduces APOE4-associated risk of developing cognitive decline in women. In the present study, we aimed to examine the effects of functional variants of VC transporter genes expressed in the brain (SLC2A1, SLC2A3, and SLC23A2) on APOE4-associated risk of developing cognitive decline. This case-control study involved 393 Japanese subjects: 252 cognitively normal and 141 cognitively impaired individuals (87 mild cognitive impairment and 54 dementia). Database searches revealed that rs1279683 of SLC23A2, and rs710218 and rs841851 of SLC2A1 are functional variants that are significantly associated with the altered expression of the respective genes and genotyped as three single nucleotide variants (SNVs). When stratified by SNV genotype, we found a significant association between APOE4 and cognitive decline in minor allele carriers of rs1279683 (odds ratio [OR] 2.02, 95% CI, 1.05-3.87, p = 0.035) but not in the homozygote carriers of the major allele. Significant associations between APOE4 and cognitive decline were also observed in participants with major allele homozygotes of rs710218 (OR 2.35, 95% CI, 1.05-5.23, p = 0.037) and rs841851 (OR 3.2, 95% CI, 1.58-6.46, p = 0.0012), but not in minor allele carriers of the respective SNVs. In contrast, the three functional SNVs showed no significant effect on cognitive decline. Our results imply that functional SNVs of VC transporter genes can affect APOE4-associated risk of developing cognitive decline via altered VC levels in the brain.

[Factors Associated with Self-reported Medication Adherence in Japanese Community-dwelling Elderly Individuals: The Nakajima Study].

Medication non-adherence in the elderly population is a major problem, preventing them from obtaining optimal therapeutic effects. Identifying the factors affecting medication adherence is crucial for improving and maintaining health among the elderly population and enhance healthcare economy. The purpose of this study was to examine the prevalence of self-reported medication adherence, and identify the associated factors and the influence of health-related quality of life (HRQOL) in the Japanese community-dwelling elderly population. This cross-sectional study was part of the Nakajima study and targeted inhabitants aged ≥60 years who underwent health examinations in 2017. Data regarding medication adherence were acquired through interviews and self-administered questionnaires. Medication adherence were assessed using a visual analog scale, and HRQOL was assessed by EuroQol five-dimensional questionnaire with 3 levels. Among the 455 participants, low and high medication adherence were seen in 9.7% and 66.2% of the participants, respectively (visual analog scores <80% and ≥95%, respectively). Medication adherence was significantly lower in participants taking medications ≥3 times daily than in those taking medications once or twice daily; a regimen involving drug administration ≥3 times daily had significantly lower odds of medication adherence. The use of a drug profile book and HRQOL had significant positive association with medication adherence. Our results suggest that low dosing frequency and using a drug profile book was positively associated with medication adherence among elderly persons, which in turn could enhance their QOL.

Effect of the Abdominal Draw-In Maneuver and Bracing on Abdominal Muscle Thickness and the Associated Subjective Difficulty in Healthy Individuals.

We evaluated the trunk abdominal muscle thickness while performing different exercises to identify the most effective training and to investigate the subjective difficulty associated with exercising. Twenty-eight men (mean age: 21.6 ± 0.9 years) without orthopedic diseases were enrolled. Ultrasonic imaging was used to measure the thickness of the transversus abdominis (TA), internal oblique, and external oblique muscles while at rest and while performing the abdominal draw-in maneuver and abdominal bracing. Measurements were made in the supine and sitting positions, and the subjective difficulty in performing each exercise was examined using a 5-level evaluation scale. The TA and internal oblique muscle thicknesses were significantly greater during the abdominal draw-in maneuver (ADIM) than during bracing or resting, in the supine and sitting positions. The subjective difficulty of abdominal bracing (AB) was graded significantly higher than that of ADIM. Additionally, a correlation between subjective difficulty and muscle thickness was found for the TA and IO. Our results may contribute to the choice of more effective exercises for spinal stability.

Investigation into Deep Breathing through Measurement of Ventilatory Parameters and Observation of Breathing Patterns.

In this protocol, two deep breathing patterns were shown to 15 participants to determine an easy yet effective method of breathing exercise for future application in a clinical setting. The women in their twenties were seated comfortably in a chair with back support. They were fitted with an airtight mask connected to a gas analyzer. Three electrodes were placed on the chest connected to a wireless transmitter for relaying to the electrocardiograph. They executed a 5 min rest phase, followed by 5 min of deep breathing with a natural breathing pattern, terminating with a 5 min rest phase. This was followed by a 10 min intermission before commencing the second instruction phase of substituting the natural breathing pattern with the diaphragmatic breathing pattern. Simultaneously, the following took place: a) continuous collection, measurement and analysis of the expired gas to assess the ventilatory parameters on a breath-by-breath basis; b) measurement of the heart rate by an electrocardiograph; and c) videotaping of the participant's thoracoabdominal movement from a lateral aspect. From the video capture, the investigators carried out visual observation of the fast-forward motion-images followed by classification of the breathing patterns, confirming that the participants had carried out the method of deep breathing as instructed. The amount of oxygen uptake revealed that, during deep breathing, the work of breathing decreased. The results from the expired minute ventilation, respiration rate and tidal volume confirmed increased ventilatory efficiency for deep breathing with the natural breathing pattern compared to that with the diaphragmatic breathing pattern. This protocol suggests a suitable method of instruction for assessing deep breathing exercises on the basis of oxygen consumption, ventilatory parameters, and chest wall excursion.

Effect of moderate exercise intensities on the cortical activity in young adults.

[Purpose] To examine the influence of different exercise intensities on cortical activity. [Participants and Methods] Twenty-six healthy adults aged 20-30 years performed exercise at three intensities on a bicycle ergometer as follows: (a) 15-minute exercise at 40% peak oxygen uptake, (b) same as (a) but at 60% peak oxygen uptake, and (c) 15 minutes of rest. The cognitive function of the participants was measured before and after exercise by the Paced Auditory Serial Addition Test (PASAT) under these three conditions. The cerebral blood flow in the left prefrontal and temporal cortices was measured using near-infrared spectroscopy during the PASAT. [Results] The PASAT score was significantly higher after exercise under condition (b) than before exercise (41.4 ± 9.1 vs. 47.7 ± 8.3). The cerebral blood flow in the prefrontal cortex under condition (b) was significantly increased compared to that under condition (c), as determined by the Tukey method (0.019 ± 0.030 vs. -0.008 ± 0.044). Significant differences were not observed in the cerebral blood flow in the temporal cortex under these three conditions. [Conclusion] Cortical activation of the frontal lobe increased after high-intensity aerobic exercise with no change in the cortical activity of the temporal lobe.

Higher Blood Vitamin C Levels are Associated with Reduction of Apolipoprotein E E4-related Risks of Cognitive Decline in Women: The Nakajima Study.

BACKGROUND: Antioxidants like vitamins C and E may minimize the risk for Alzheimer's disease. OBJECTIVE: We examined whether vitamins C and E modify the apolipoprotein E (APOE) E4-related risks for developing cognitive decline. METHODS: We conducted a population-based prospective study including Japanese residents aged 65 years from Nakajima, Japan. The participants received an evaluation of cognitive function and underwent blood tests including tests for vitamins C and E levels and APOE phenotypes. The APOE E4-by-gender-by-vitamin C or E interactions on developing cognitive decline were analyzed. RESULTS: Of 606 participants with normal cognitive function determined using a baseline survey (2007-2008), 349 completed the follow up survey between 2014 and 2016. In women with APOE E4, significantly reduced risk for cognitive decline was observed for the highest blood vitamin C concentration tertile [multivariate OR 0.10 (95% CI 0.01-0.93)] compared with the lowest tertile. In men without APOE E4, significantly reduced risk for cognitive decline was observed for the highest blood vitamin E concentration tertile [multivariate OR 0.19 (0.05-0.74)] as compared with the lowest tertile. CONCLUSION: Our results demonstrate significant beneficial effects of vitamins C and E in reducing the risk of cognitive decline in women with APOE E4 and men without APOE E4, respectively.

Comparison of two instructions for deep breathing exercise: non-specific and diaphragmatic breathing.

[Purpose] Breathing exercises are frequently prescribed to reduce pulmonary complications after abdominal and thoracic surgery. Appropriate instructions ensuring the integrity of the self-exercise are important. This study compared the effects of two instructions, focusing on non-specific breathing (NB) and diaphragmatic breathing (DB) patterns, respectively, on the ventilatory efficiency and work of breathing. [Subjects and Methods] The participants were healthy men (n=15) and women (n=15). Ventilatory parameters, heart rate, and autonomic nervous system activity were measured during natural and deep breathing phases performed under the two instructions (NB and DB), with the deep breathing phase following the natural breathing phase. [Results] For both men and women, ventilatory efficiency was increased during deep breathing relative to natural breathing, regardless of the instructions. In women, the increment in ventilatory efficiency during deep breathing was greater under NB compared to that under DB. The work of breathing decreased during deep breathing in women under both instructions, but did not change in men under DB. [Conclusion] Under NB instruction, deep breathing elicits similar or greater effects on ventilatory efficiency compared to that under DB instruction.

Differences in Dementia Beliefs between Non-Demented Public Screeners and In-Home Screeners and Their Potential Impact on Future Dementia Screening Intention: The Nakajima Study.

In many cohort studies of dementia, while differences in sociodemographic characters between responders and non-responders of dementia screening have been reported, differences in dementia beliefs have been relatively less known. The aims of this study were to clarify dementia beliefs and to explore potential impacts on an intention to attend a future dementia screening in public screeners and in-home screeners, respectively. We performed a cross-sectional population-based study using a question about an intention to attend a future dementia screening and a questionnaire on dementia beliefs. Subjects were all residents aged 65 years or older in the north area of Nakajima, Japan (n = 385). All subjects were asked to attend a public dementia screening first. An in-home dementia screening was subsequently conducted in subjects with non-responders to a public screening. The questionnaire consisted of four dementia beliefs: "perceived susceptibility," "perceived severity," "perceived barriers," and "perceived benefits." Public screeners significantly expressed an intention to attend a future dementia screening more than in-home screeners (p = 0.002). In in-home screeners, low "perceived severity" were significantly associated with an intention to attend a future dementia screening [adjusted OR (95% CI) = 0.51 (0.32-0.80)]. In both public and in-home screeners, high "perceived benefits" were significantly associated with an intention to attend a future dementia screening [adjusted OR (95% CI) = 2.13 (1.46-3.10); adjusted OR (95% CI) = 2.56 (1.22-5.35), respectively]. It is necessary to reduce "perceived severity" among in-home screeners to increase dementia screening participants.

Changes in thickness of the transversus abdominis during the abdominal drawing-in manoeuvre and expiratory muscle training in elderly people.

[Purpose] It has been reported that exercises focusing upon the transversus abdominis (TrA) ameliorate low back pain (LBP). We investigated whether expiratory muscle training (EMT) can promote activity of the TrA to the same degree as the abdominal drawing-in manoeuvre (ADIM) in elderly individuals. [Subjects and Methods] Twenty-one elderly subjects (9 males, 12 females; mean age, 84.9 ± 6.6 years) without LBP symptoms were included. Using ultrasound imaging we measured changes in thickness of the lateral abdominal muscles, TrA, internal oblique muscle (IO), and external oblique muscle (EO) during ADIM and EMT. The load in EMT was set to 15% of maximal expiratory pressure. [Results] TrA showed a significant increase in muscle thickness during ADIM and EMT compared with at rest. A significant increase in muscle thickness was noted for EMT in comparison with ADIM. No significant differences were found for IO and EO. [Conclusion] In elderly people, EMT may be an effective alternative to ADIM for promoting activity of the TrA and can be used as an exercise to maintain TrA function.

A foot-care program to facilitate self-care by the elderly: a non-randomized intervention study.

OBJECTIVE: We aimed to evaluate a foot-care awareness program designed to improve foot morphology, physical functioning, and fall prevention among the community-dwelling elderly. Eleven independent community-dwelling elderly women (aged 61-83 years) were provided with foot-care advice and shown effective foot-care techniques to perform regularly for 6 months, and compared with a control group of 10 elderly women who did not receive any intervention. Measurements of foot form, functional capacity, subjective foot movement, and physical function were taken at baseline and 6-month follow-up. RESULTS: At follow-up, improvements were seen in the intervention group in foot morphology, subjective foot movement, foot pressure, and balance. In the intervention group, 90% of women had maintained or improved foot form and none of them had fallen during the post-intervention period, compared to the control group where 30% improved foot form (p = 0.0075) and four (40%) of them had fallen. Therefore, a foot-care program may have the potential to prevent falls and improve mobility among the elderly. Trial Registration UMIN-CTR No. UMIN000029632. Date of Registration: October 19, 2017.

Key function for obstacle crossing in hemiplegic persons with varied degrees of spasticity.

[Purpose] To evaluate various key functions related to obstacle crossing motions in hemiplegic people based on the paralysis degree. [Subjects and Methods] Thirty-seven patients with maintenance-stage hemiplegia who could independently ambulate outdoors were included. Subjects' crossing movements were measured using obstacles with heights of 10%, 20%, and 30% of the trochanter length. The relationship among maximal crossing height and isometric knee extension muscle strength, one leg standing time, Trunk Impairment Scale score, disease duration, and subject age was examined, as was the target variable of maximum crossing height and the top four measurement items, to determine the explanatory variables. The participants were grouped based on Brunnstrom Recovery Stages III-IV (severe spasticity) and V-VI (mild spasticity). [Results] The explanatory variables were the Trunk Impairment Scale in the severe spasticity group and unaffected side-knee extension muscle strength in the mild spasticity group (contribution rates: 75.6% and 21.0%, respectively). [Conclusion] Trunk function in the severe spasticity group majorly contributed to crossing obstacles. Furthermore, knee extension muscle strength on the unaffected side in the mild spasticity group moderately contributed to crossing obstacles. Selecting and implementing a physical therapy routine that is aimed at improving function, depending on the severity of paralysis, is necessary.

Transformative learning experience for physical therapy students through a community health promotion project for mothers of hearing-challenged children.

[Purpose] The purpose of this project was to expose physical therapy students to transformative learning through a community health promotion project for mothers of hearing-challenged children. [Subjects and Methods] The participants were three mothers with their respective hearing-challenged child and twenty physical therapy students. The project consisted of seven sessions supervised throughout by a physical therapy instructor. The students participated in seven sessions, while the mothers were required to attend only two sessions of a health checkup and exercise program. [Results] Through the interaction between the mothers and students, the former felt physically and mentally refreshed, and the latter experienced transformative learning. The mother's physical status showed that all parameters for health variables were within normal range. However, it was found that mothers had little time for their personal mental or physical well-being because their focus was on planning and executing daily assignments for development of the child's verbal skills. [Conclusion] This project contributed to the students' learning experience and provided them with tools for possible future interest and involvement in community activity. The exercise session appeared to stimulate in the mothers an awareness and importance of their own personal and mental well-being.

Consumption of green tea, but not black tea or coffee, is associated with reduced risk of cognitive decline.

Our objective was to determine whether the consumption of green tea, coffee, or black tea influences the incidence of dementia and mild cognitive impairment (MCI) in older people. We conducted a population-based prospective study with Japanese residents aged >60 years from Nakajima, Japan (the Nakajima Project). Participants received an evaluation of cognitive function and blood tests. The consumption of green tea, coffee, and black tea was also evaluated at baseline. Of 723 participants with normal cognitive function at a baseline survey (2007-2008), 490 completed the follow up survey in 2011-2013. The incidence of dementia during the follow-up period (mean ± SD: 4.9 ± 0.9 years) was 5.3%, and that of MCI was 13.1%. The multiple-adjusted odds ratio for the incidence of overall cognitive decline (dementia or MCI) was 0.32 (95% CI: 0.16-0.64) among individuals who consumed green tea every day and 0.47 (95% CI: 0.25-0.86) among those who consumed green tea 1-6 days per week compared with individuals who did not consume green tea at all. The multiple-adjusted odds ratio for the incidence of dementia was 0.26 (95% CI: 0.06-1.06) among individuals who consumed green tea every day compared with those who did not consume green tea at all. No association was found between coffee or black tea consumption and the incidence of dementia or MCI. Our results indicate that green tea consumption is significantly associated with reduced risk of cognitive decline, even after adjustment for possible confounding factors.

Differences in the prevalence of dementia and mild cognitive impairment and cognitive functions between early and delayed responders in a community-based study of the elderly.

Significant differences exist in demographic characteristics between responders and non-responders in population-based studies on mental health and cognitive status, but much less is known regarding differences in the prevalence of dementia and cognitive dysfunction between them. Here we compared the prevalence of dementia and mild cognitive impairment between early responders of a mass brain function examination and delayed responders (non-responders of the mass brain function examination) in a survey of elderly Japanese citizens (≥65 years) to evaluate non-responder bias. All residents in an area of Nakajima, Japan, were considered as potential candidates (n = 783). Participants of a mass brain function examination were considered as "early responders." The cognitive functions of delayed responders were assessed by home visits. To assess the correlation between sociodemographic characteristics and cognitive functions, the early and delayed responders completed the same questionnaires and neuropsychological tests. Delayed responders (n = 320) were significantly older and less educated than the early responders (n = 307). The delayed responders also exhibited a higher frequency of dementia and mild cognitive impairment than the early responders, even when the groups were restricted to the age group 65-89 years. Our results suggest that population-based studies likely underestimate the prevalence of dementia and mild cognitive impairment, especially if the participation rate is low.