Prefrontal Plasticity after a 3-Month Exercise Intervention in Older Adults Relates to Enhanced Cognitive Performance.

This study examined exercise intervention effects on older adults' brain structures and function. Brain data were analyzed from 47 healthy adults between 61 and 82 years of age who, in a previous study, showed cognitive improvement following a 3-month intervention. The participants were assigned to a motor exercise intervention group (n = 24), performing exercise training programs for a 12-week period, or a waiting control group (n = 23), abstaining from any exercise program. Structural analysis of the frontal cortex and hippocampus revealed increased gray matter volume and/or thickness in several prefrontal areas in the intervention group and reduced hippocampal gray matter volume in the control group. Importantly, the volume increase in the middle frontal sulcus in the intervention group was associated with a general cognitive improvement after the intervention. Functional analysis showed that the prefrontal functional connectivity during a working memory task differently changed in response to the intervention or waiting in the two groups. The functional connectivity decreased in the intervention group, whereas the corresponding connectivity increased in the control group, which was associated with maintaining cognitive performance. The current longitudinal findings indicate that short-term exercise intervention can induce prefrontal plasticity associated with cognitive performance in older adults.

Subjective cognitive decline and fall risk in community-dwelling older adults with or without objective cognitive decline.

BACKGROUND: The association between subjective cognitive decline and falls has not been clearly determined. AIMS: Our aim was to explore the effect of subjective cognitive decline on falls in community-dwelling older adults with or without objective cognitive decline. METHODS: We included 470 older adults (mean age 73.6 ± 5.2; 329 women) living in the community and obtained data on fall history directly from the participants. Subjective cognitive decline was assessed using a self-administered question. Objective cognitive function was measured using the Mini-Mental State Examination. Statistical analyses were carried out separately for participants with objective cognitive decline and those without. RESULTS: A multiple logistic regression analysis showed that, among participants without objective cognitive decline, subjective cognitive decline was positively associated with falls [OR 1.91; 95% confidence interval (CI) 1.17-3.12; p = 0.01). Conversely, among participants with objective cognitive decline, subjective cognitive decline was negatively associated with falls (OR 0.07; 95% CI 0.01-0.85, p = 0.04). DISCUSSION: The result suggests that the objective-subjective disparity may affect falls in community-dwelling older adults. CONCLUSIONS: The presence of subjective cognitive decline was significantly positively associated with falls among cognitively intact older adults. However, among their cognitively impaired peers, the absence of subjective cognitive decline was positively associated with falls.

Effect of Capacitive and Resistive electric transfer on haemoglobin saturation and tissue temperature.

PURPOSE: This study aims to evaluate the effects of Capacitive and Resistive electric transfer (CRet) and hotpack (HP) on haemoglobin saturation and tissue temperature. MATERIALS AND METHODS: The participants were 13 healthy males (mean age 24.5 ± 3.0). They underwent three interventions on different days: (1) CRet (CRet group), (2) HP (HP group) and (3) CRet without power (sham group). The intervention and measurement were applied at the lower paraspinal muscle. Indiba® active ProRecovery HCR902 was used in the CRet group, and the moist heat method was used in the HP group. Oxygenated, deoxygenated and total haemoglobin (oxy-Hb, deoxy-Hb, total-Hb) counts were measured before and after the 15-min interventions, together with the temperature at the skin surface, and at depths of 10 mm and 20 mm (ST, 10mmDT and 20mmDT, respectively). The haemoglobin saturation and tissue temperature were measured until 30 min after the intervention and were collected at 5-min intervals. Statistical analysis was performed for each index by using the Mann-Whitney U test for comparisons between all groups at each time point. RESULTS: Total-Hb and oxy-Hb were significantly higher in the CRet group than in the HP group continuously for 30 min after the intervention. The 10mmDT and 20mmDT were significantly higher in the CRet group than in the HP group from 10- to 30 min after intervention. CONCLUSIONS: The effect on haemoglobin saturation was higher in the CRet group than in the HP group. In addition, the CRet intervention warmed deep tissue more effectively than HP intervention.

Association between mild cognitive impairment and trajectory-based spatial parameters during timed up and go test using a laser range sensor.

BACKGROUND: The Timed Up and Go (TUG) test may be a useful tool to detect not only mobility impairment but also possible cognitive impairment. In this cross-sectional study, we used the TUG test to investigate the associations between trajectory-based spatial parameters measured by laser range sensor (LRS) and cognitive impairment in community-dwelling older adults. METHODS: The participants were 63 community-dwelling older adults (mean age, 73.0 ± 6.3 years). The trajectory-based spatial parameters during the TUG test were measured using an LRS. In each forward and backward phase, we calculated the minimum distance from the marker, the maximum distance from the x-axis (center line), the length of the trajectories, and the area of region surrounded by the trajectory of the center of gravity and the x-axis (center line). We measured mild cognitive impairment using the Mini-Mental State Examination score (26/27 was the cut-off score for defining mild cognitive impairment). RESULTS: Compared with participants with normal cognitive function, those with mild cognitive impairment exhibited the following trajectory-based spatial parameters: short minimum distance from the marker (p = 0.044), narrow area of center of gravity in the forward phase (p = 0.012), and a large forward/whole phase ratio of the area of the center of gravity (p = 0.026) during the TUG test. In multivariate logistic regression analyses, a short minimum distance from the marker (odds ratio [OR]: 0.82, 95% confidence interval [CI]: 0.69-0.98), narrow area of the center of gravity in the forward phase (OR: 0.01, 95% CI: 0.00-0.36), and large forward/whole phase ratio of the area of the center of gravity (OR: 0.94, 95% CI: 0.88-0.99) were independently associated with mild cognitive impairment. CONCLUSIONS: In conclusion, our results indicate that some of the trajectory-based spatial parameters measured by LRS during the TUG test were independently associated with cognitive impairment in older adults. In particular, older adults with cognitive impairment exhibit shorter minimum distances from the marker and asymmetrical trajectories during the TUG test.

Generating linear regression model to predict motor functions by use of laser range finder during TUG.

PURPOSE: The purpose of this study was to investigate which spatial and temporal parameters of the Timed Up and Go (TUG) test are associated with motor function in elderly individuals. METHODS: This study included 99 community-dwelling women aged 72.9 ± 6.3 years. Step length, step width, single support time, variability of the aforementioned parameters, gait velocity, cadence, reaction time from starting signal to first step, and minimum distance between the foot and a marker placed to 3 in front of the chair were measured using our analysis system. The 10-m walk test, five times sit-to-stand (FTSTS) test, and one-leg standing (OLS) test were used to assess motor function. Stepwise multivariate linear regression analysis was used to determine which TUG test parameters were associated with each motor function test. Finally, we calculated a predictive model for each motor function test using each regression coefficient. RESULTS: In stepwise linear regression analysis, step length and cadence were significantly associated with the 10-m walk test, FTSTS and OLS test. Reaction time was associated with the FTSTS test, and step width was associated with the OLS test. Each predictive model showed a strong correlation with the 10-m walk test and OLS test (P < 0.01), which was not significant higher correlation than TUG test time. CONCLUSION: We showed which TUG test parameters were associated with each motor function test. Moreover, the TUG test time regarded as the lower extremity function and mobility has strong predictive ability in each motor function test.

Association between floating toe and toe grip strength in school age children: a cross-sectional study.

[Purpose] This study investigated the association between floating toe and toe grip strength. [Subjects and Methods] A total of 635 Japanese children aged 9-11 years participated in this study. Floating toe was evaluated using footprint images, while toe grip strength was measured using a toe grip dynamometer. All 1,270 feet were classified into a floating toe group and a normal toe group according to visual evaluation of the footprint images. Intergroup differences in toe grip strength were analyzed using the unpaired t-test and logistic regression analysis adjusted for age, gender, and Rohrer Index. [Results] There were 512 feet (40.3%) in the floating toe group. Mean toe grip strength of the feet with floating toe was significantly lower than that of normal feet (floating toe group, 12.9 ± 3.7 kg; normal toe group, 13.6 ± 4.1 kg). In addition, lower toe grip strength was associated with floating toe on logistic regression analysis after adjustment for age, gender, and Rohrer Index (odds ratio, 0.954; 95% confidence interval, 0.925-0.984). [Conclusion] This study revealed that lower toe grip strength was significantly associated with floating toe. Therefore, increasing toe grip strength may play a role in preventing floating toe in school age children.

Factors associating with shuttle walking test results in community-dwelling elderly people.

BACKGROUND: The shuttle walking test (SWT) is a simple, widely used method for assessing endurance performance in the elderly. Despite widespread community use, its associated factors are unclear. AIMS: We aim to identify previously undefined SWT association factors in community-dwelling elderly people. METHODS: Herein, 149 healthy elderly Japanese subjects performed the SWT, and were assessed for height, weight, smoking history, 10-m walk time, Timed Up and Go (TUG) scores, handgrip strength, skeletal mass index (SMI), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), cardio-ankle vascular index, and ankle brachial index. We divided men and women into higher and lower SWT score groups, compared between-group parameters, and performed stepwise multivariate logistic regression analysis to identify factors independently associated with SWT scores. RESULTS: Age, BMI, 10-m walk time, TUG score, SMI, FVC (L; %-predicted), and FEV1 (L; %-predicted) were significantly different between SWT score groups for men, while in women, significant differences were observed in age, TUG score, handgrip strength, FVC (L; %-predicted), and FEV1 (L; %-predicted) (p < 0.05). In the multivariate logistic regression model, 10-m walk time, and FEV1 showed significant associations with SWT results in men; among women, age was the only significantly associated factor (p < 0.05). CONCLUSIONS: Results indicate that better lung function and shorter walk time independently associate with SWT results in community-dwelling men; in women, age is the only association. Our findings may offer insight when considering the focus of community exercise programs among the elderly.

The physiological characteristics of community-dwelling elderly Japanese with airflow limitation: a cross-sectional study.

BACKGROUND AND AIMS: The aim of this study was to investigate the physiological characteristics of community-dwelling elderly subjects, aged ≥65 years, with airflow limitation in the Japanese community. METHODS: Subjects were recruited through local press advertisement, and 180 individuals were enrolled. Data on age, body mass index (BMI), gender, smoking history, and past medical history were obtained, as were pulmonary function parameters, skeletal muscle mass index, and physical activity. RESULTS: The final study population comprised 161 participants from whom we obtained valid spirometry results. The mean age of this population was 73.4 ± 4.4 years, and 78 participants (48.4 %) were men. The prevalence of airflow limitation was 29.2 % (n = 47). Subjects with airflow limitation were significantly older (P = 0.01) and had poorer pulmonary function (P < 0.01), lower BMI (P < 0.01), and lower skeletal muscle mass index (P = 0.03) than healthy elderly subjects. Furthermore, skeletal muscle mass index was significantly correlated with the percentage of predicted forced vital capacity (r = 0.45, P < 0.05) and forced expiratory volume in 1 s (r = 0.50, P < 0.05) only in men with airflow limitation. CONCLUSIONS: We found that the skeletal muscle mass index was significantly reduced in community-dwelling elderly with airflow limitation, and the skeletal muscle mass index was correlated with pulmonary function only in men with airflow limitation.

Gait measurement system for the multi-target stepping task using a laser range sensor.

For the prevention of falling in the elderly, gait training has been proposed using tasks such as the multi-target stepping task (MTST), in which participants step on assigned colored targets. This study presents a gait measurement system using a laser range sensor for the MTST to evaluate the risk of falling. The system tracks both legs and measures general walking parameters such as stride length and walking speed. Additionally, it judges whether the participant steps on the assigned colored targets and detects cross steps to evaluate cognitive function. However, situations in which one leg is hidden from the sensor or the legs are close occur and are likely to lead to losing track of the legs or false tracking. To solve these problems, we propose a novel leg detection method with five observed leg patterns and global nearest neighbor-based data association with a variable validation region based on the state of each leg. In addition, methods to judge target steps and detect cross steps based on leg trajectory are proposed. From the experimental results with the elderly, it is confirmed that the proposed system can improve leg-tracking performance, judge target steps and detect cross steps with high accuracy.

Functional Movement Screen for Predicting Running Injuries in 18- to 24-Year-Old Competitive Male Runners.

The purpose of this study was to investigate whether the functional movement screen (FMS) could predict running injuries in competitive runners. Eighty-four competitive male runners (average age = 20.0 ± 1.1 years) participated. Each subject performed the FMS, which consisted of 7 movement tests (each score range: 0-3, total score range: 0-21), during the preseason. The incidence of running injuries (time lost because of injury ≤ 4 weeks) was investigated through a follow-up survey during the 6-month season. Mann-Whitney U-tests were used to investigate which movement tests were significantly associated with running injuries. The receiver-operator characteristic (ROC) analysis was used to determine the cutoff. The mean FMS composite score was 14.1 ± 2.3. The ROC analysis determined the cutoff at 14/15 (sensitivity = 0.73, specificity = 0.54), suggesting that the composite score had a low predictability for running injuries. However, the total scores (0-6) from the deep squat (DS) and active straight leg raise (ASLR) tests (DS and ASLR), which were significant with the U-test, had relatively high predictability at the cutoff of 3/4 (sensitivity = 0.73, specificity = 0.74). Furthermore, the multivariate logistic regression analysis revealed that the DS and ASLR scores of ≤3 significantly influenced the incidence of running injuries after adjusting for subjects' characteristics (odds ratio = 9.7, 95% confidence interval = 2.1-44.4). Thus, the current study identified the DS and ASLR score as a more effective method than the composite score to screen the risk of running injuries in competitive male runners.

Children with flat feet have weaker toe grip strength than those having a normal arch.

[Purpose] This study investigated the relationship between toe grip strength and foot posture in children. [Subjects and Methods] A total of 619 children participated in this study. The foot posture of the participants was measured using a foot printer and toe grip strength was measured using a toe grip dynamometer. Children were classified into 3 groups; flatfoot, normal, and high arch, according to Staheli's arch index. The differences in demographic data and toe grip strength among each foot posture group were analyzed by analysis of variance. Additionally, toe grip strength differences were analyzed by analysis of covariance, adjusted to body mass index, age, and gender. [Results] The number of participants classified as flatfoot, normal, and high arch were 110 (17.8%), 468 (75.6%), and 41 (6.6%), respectively. The toe grip strength of flatfoot children was significantly lower than in normal children, as shown by both analysis of variance and analysis of covariance. [Conclusion] A significant difference was detected in toe grip strength between the low arch and normal foot groups. Therefore, it is suggested that training to increase toe grip strength during childhood may prevent the formation of flat feet or help in the development of arch.

Effect of a Kinect-based exercise game on improving executive cognitive performance in community-dwelling elderly: case control study.

BACKGROUND: Decrease of dual-task (DT) ability is known to be one of the risk factors for falls. We developed a new game concept, Dual-Task Tai Chi (DTTC), using Microsoft's motion-capture device Kinect, and demonstrated that the DTTC test can quantitatively evaluate various functions that are known risk factors for falling in elderly adults. Moreover, DT training has been attracting attention as a way to improve balance and DT ability. However, only a few studies have reported that it improves cognitive performance. OBJECTIVE: The purpose of this study was to demonstrate whether or not a 12-week program of DTTC training would effectively improve cognitive functions. METHODS: This study examined cognitive functions in community-dwelling older adults before and after 12 weeks of DTTC training (training group [TG]) or standardized training (control group [CG]). Primary end points were based on the difference in cognitive functions between the TG and the CG. Cognitive functions were evaluated using the trail-making test (part A and part B) and verbal fluency test. RESULTS: A total of 41 elderly individuals (TG: n=26, CG: n=15) participated in this study and their cognitive functions were assessed before and after DTTC training. Significant differences were observed between the two groups with significant group × time interactions for the executive cognitive function measure, the delta-trail-making test (part B-part A; F1,36=4.94, P=.03; TG: pre mean 48.8 [SD 43.9], post mean 42.2 [SD 29.0]; CG: pre mean 49.5 [SD 51.8], post mean 64.9 [SD 54.7]). CONCLUSIONS: The results suggest that DTTC training is effective for improving executive cognitive functions. TRIAL REGISTRATION: Japan Medical Association Clinical Trial Registration Number: JMA-IIA00092; https://dbcentre3.jmacct.med.or.jp/jmactr/App/JMACTRS06/JMACTRS06.aspx?seqno=2682 (Archived by WebCite at http://www.webcitation.org/6NRtOkZFh).

Quantification of changes in gait characteristics associated with intermittent claudication in patients with lumbar spinal stenosis.

STUDY DESIGN: Cross-sectional observational study. OBJECTIVE: To quantify changes in gait characteristics associated with claudication after continuous walking, and to investigate the relationship between walking capacity and gait characteristics in patients with lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA: Walking difficulty due to pain or neurological symptoms accompanied by continuous walking may have negative effects on gait characteristics in patients with LSS. However, there are few detailed reports on the association of these changes with intermittent claudication and their relationship with walking capacity. METHODS: For this study, 11 LSS patients with intermittent claudication were recruited. The subjects continued walking until they expressed a difficulty in continuing further. Postural sway, autocorrelation peak (AC), stride frequency (SF), and coefficient of variance (CV) were analyzed using accelerometers. To detect changes in gait parameters, we compared acceleration at the start and at the end of the walking task. RESULTS: Walking difficulty during the test increased from 4 (interquartile range, 1-5) to 9 (interquartile range, 7-10). The postural sway significantly increased after the onset of maximum walking difficulty. AC, SF, or CV did not show significant change. Maximum walking distance significantly correlated with postural sway at the cervical sensor (r=-0.64), and CV (ρ=-0.66), an index of gait variability, at the beginning of the walking task. CONCLUSIONS: The change in gait parameters associated with claudication during continuous walking is detectable using accelerometers. Postural sway increases after the provocation of walking difficulty due to pain or neurological symptoms. In addition, walking capacity correlated with postural sway of the upper trunk and gait variability during walking initiation. This methodology warrants further studies to confirm its usefulness as an assessment tool for patients with LSS.

Self-assessment tool of disease activity of rheumatoid arthritis by using a smartphone application.

OBJECTIVES: The disease activities of rheumatoid arthritis (RA) tend to fluctuate between visits to doctors, and a self-assessment tool can help patients accommodate to their current status at home. The aim of the present study was to develop a novel modality to assess the disease activity of RA by a smartphone without the need to visit a doctor. SUBJECTS AND METHODS: This study included 65 patients with RA, 63.1 ± 11.9 years of age. The 28-joint disease activity score (DAS28) was measured for all participants at each clinic visit. The patients assessed their status with the modified Health Assessment Questionnaire (mHAQ), a self-assessed tender joint count (sTJC), and a self-assessed swollen joint count (sSJC) in a smartphone application. The patients' trunk acceleration while walking was also measured with a smartphone application. The peak frequency, autocorrelation (AC) peak, and coefficient of variance of the acceleration peak intervals were calculated as the gait parameters. RESULTS: Univariate analyses showed that the DAS28 was associated with mHAQ, sTJC, sSJC, and AC (p<0.05). In a stepwise linear regression analysis, mHAQ (ß = 0.264, p<0.05), sTJC (ß = 0.581, p<0.001), and AC (ß = -0.157, p<0.05) were significantly associated with DAS28 in the final model, and the predictive model explained 67% of the DAS28 variance. CONCLUSIONS: The results suggest that noninvasive self-assessment of a combination of joint symptoms, limitations of daily activities, and walking ability can adequately predict disease activity of RA with a smartphone application.

A novel infrared laser device that measures multilateral parameters of stepping performance for assessment of fall risk in elderly individuals [corrected].

BACKGROUND AND AIMS: Avoiding falls requires fast and appropriate step responses in real-life situations. We developed a step-tracking device that uses an infrared laser sensor for convenient assessment of stepping performance, including concurrent assessment of temporal and spatial parameters. In the present study, we created a new index for assessment of fall risk that uses step speed and accuracy measurements. The purpose of this study was to determine whether the new index could discriminate between elderly individuals with different risks of falling. METHODS: One hundred and fifty-two community-dwelling elderly individuals (73.9 ± 4.6 years) participated and performed stepping tasks as quickly as possible on a plus-shaped mat in response to optical cues. The step-tracking device with the infrared sensor detected the motion and position of both legs in the step field. The device recorded temporal and spatial parameters, foot-off and foot-contact time, step length, and the percentage of correctly executed steps. We used the coefficients of a logistic regression model to develop "stepping-response score" based on the weighted sum of these temporal and spatial parameters. RESULTS: The faller group had significantly worse stepping-response score than the non-faller group (p < 0.001). A stepwise logistic regression analysis demonstrated that stepping-response score was independently associated with falling (odds ratio = 0.15; p < 0.001). The ROC curve had a moderate AUC (0.73) for stepping-response score (sensitivity 73.0 %; specificity 69.7 %). CONCLUSIONS: This study indicates that the stepping-response score calculated from measurements obtained using the new step-tracking device can identify elderly individuals who are at a risk of falling.

Relationship between depression and risk of malnutrition among community-dwelling young-old and old-old elderly people.

OBJECTIVES: This study explores the association between nutritional status and depression among healthy community-dwelling young-old (aged 65-74) and old-old elderly (aged 75 and older). METHOD: A cross-sectional design was implemented. A total of 274 community-dwelling older individuals (142 young-old; 132 old-old) were assessed using the Geriatric Depression Scale (GDS), Mini-Nutritional Assessment Short-Form (MNA-SF) and Life-Space Assessment. Logistic regression analysis was used to determine if depression was independently associated with risk of malnutrition, stratified by age (young-old vs. old-old). RESULTS: In the logistic regression model for young-old, being at risk of malnutrition (MNA-SF (≦11) was strongly associated with depression (GDS (≧5;) (likelihood ratio ν = 6.26; 95% confidence interval [CI]: 1.91-20.49). In contrast, in the old-old group, the model was not statistically significant. CONCLUSION: Depression and nutritional status were strongly correlated in young-old but not in old-old community-dwelling elderly. This study reveals that not only the factors correlated with but also the symptoms of depression may vary among different age stratifications of the elderly.

Development of measurement system for task oriented step tracking using laser range finder.

BACKGROUND: Avoiding a fall requires fast and appropriate step responses, stepping speed as a fall risk indicator has only been assessed in older adults. We have developed a new measurement system that applies a laser range finder to assess temporal and spatial parameters of stepping performance such as step speed, length, and accuracy. This measurement system has higher portability, lower cost, and can analyze a larger number of temporal and spatial parameters than existing measurement systems. The aim of this study was to quantify the system for measuring reaction time and stride duration by compared to that obtained using a force platform. METHODS: Ten healthy young adults performed steps in response to visual cues. The measurement system applied a laser range finder to measure the position and velocity of the center of each leg and of both legs.We applied the developed measurement system to the rhythmic stepping exercise and measured reaction time and stride duration. In addition, the foot-off time and foot-contact time were quantified using the measurement system, and compared to the foot-off time and foot-contact time quantified using a force platform. RESULTS: We confirmed that the measurement system can detect where a participant stood and measured reaction time and stride duration.Remarkable consistency was observed in the test-retest reliability of the foot-off time and foot-contact time quantified by the measurement system (p < 0.001). The foot-off time and foot-contact time quantified by the measurement system were highly correlated with the foot-off time and foot-contact time quantified by the force platform (reaction time: r = 0.997, stride duration: r = 0.879; p < 0.001). CONCLUSIONS: The new measurement system provided a valid measure of temporal step parameters in young healthy adults.The validity of the system to measure reaction time and stride duration was evaluated, and confirmed by applying to the rhythmic stepping exercise.

Objective assessment of abnormal gait in patients with rheumatoid arthritis using a smartphone.

A disturbance in gait pattern is a serious problem in patients with rheumatoid arthritis (RA). The aim of the present study was to examine the utility of the smartphone gait analysis application in patients with RA. The smartphone gait analysis application was used to assess 39 patients with RA (age 65.9 ± 10.0 years, disease duration 11.9 ± 9.4 years) and age-matched control individuals (mean age, 69.1 ± 5.8 years). For all RA patients, the following data were obtained: disease activity score (DAS) 28, modified health assessment questionnaire (mHAQ), and assessment of walking ability. Patients walked 20 m at their preferred speed, and trunk acceleration was measured using a Smartphone. After signal processing, we calculated the following gait parameters for each measurement terminal: peak frequency (PF), autocorrelation peak (AC), and coefficient of variance (CV) of the acceleration peak intervals. The gait parameters of RA and control groups were compared to examine the comparability of the 2 groups. Criterion-related validity was determined by evaluating the correlation between gait parameters and clinical parameters using Spearman's correlation coefficient. The RA group showed significantly lower scores for the walking speed, AC, and CV than the control group. There were no significant differences in PF. PF (gait cycle) was mildly associated with gait speed (P < 0.05). AC (gait balance) was moderately associated with the DAS, mHAQ, gait ability, and gait speed (P < 0.05). CV (gait variability) was moderately associated with the DAS, gait ability, and gait speed (P < 0.05). This is the first study to examine the use of a smartphone device for gait pattern measurement. The results suggest that some gait parameters recorded using the smartphone represent an acceptable assessment tool for gait in patients with RA.

Reliability and validity of gait analysis by android-based smartphone.

Smartphones are very common devices in daily life that have a built-in tri-axial accelerometer. Similar to previously developed accelerometers, smartphones can be used to assess gait patterns. However, few gait analyses have been performed using smartphones, and their reliability and validity have not been evaluated yet. The purpose of this study was to evaluate the reliability and validity of a smartphone accelerometer. Thirty healthy young adults participated in this study. They walked 20 m at their preferred speeds, and their trunk accelerations were measured using a smartphone and a tri-axial accelerometer that was secured over the L3 spinous process. We developed a gait analysis application and installed it in the smartphone to measure the acceleration. After signal processing, we calculated the gait parameters of each measurement terminal: peak frequency (PF), root mean square (RMS), autocorrelation peak (AC), and coefficient of variance (CV) of the acceleration peak intervals. Remarkable consistency was observed in the test-retest reliability of all the gait parameter results obtained by the smartphone (p<0.001). All the gait parameter results obtained by the smartphone showed statistically significant and considerable correlations with the same parameter results obtained by the tri-axial accelerometer (PF r=0.99, RMS r=0.89, AC r=0.85, CV r=0.82; p<0.01). Our study indicates that the smartphone with gait analysis application used in this study has the capacity to quantify gait parameters with a degree of accuracy that is comparable to that of the tri-axial accelerometer.

Neural Correlates of Working Memory Maintenance in Advanced Aging: Evidence From fMRI.

Working memory (WM)-related brain activity is known to be modulated by aging; particularly, older adults demonstrate greater activity than young adults. However, it is still unclear whether the activity increase in older adults is also observed in advanced aging. The present functional magnetic resonance imaging (fMRI) study was designed to clarify the neural correlates of WM in advanced aging. Further, we set out to investigate in the case that adults of advanced age do show age-related increase in WM-related activity, what the functional significance of this over-recruitment might be. Two groups of older adults - "young-old" (61-70 years, n = 17) and "old-old" (77-82 years, n = 16) - were scanned while performing a visual WM task (the n-back task: 0-back and 1-back). WM effects (1-back > 0-back) common to both age groups were identified in several regions, including the bilateral dorsolateral prefrontal cortex (DLPFC), the inferior parietal cortex, and the insula. Greater WM effects in the old-old than in the young-old group were identified in the right caudal DLPFC. These results were replicated when we performed a separate analysis between two age groups with the same level of WM performance (the young-old vs. a "high-performing" subset of the old-old group). There were no regions where WM effects were greater in the young-old group than in the old-old group. Importantly, the magnitude of the over-recruitment WM effects positively correlated with WM performance in the old-old group, but not in the young-old group. The present findings suggest that cortical over-recruitment occurs in advanced old age, and that increased activity may serve a compensatory function in mediating WM performance.