The stepping test, and infrared depth sensor, provide reliable measures of balance in community-dwelling older adults.

[Purpose] The purpose was to examine relationships between variables characterizing the 20-second stepping test movement pattern, assessed with an infrared depth sensor (KinectTM), and measurements of dynamic and static balance. [Participants and Methods] A total of 27 independent-living, older adults (7 males and 20 females) participated in this study. For each participant, the stepping test total movement distance, movement displacement, knee movement distance, and step number were calculated from Kinect closed joint-point coordinate data. Dynamic and static balance were assessed using a NeuroCom Balance Master Platform system. [Results] The stepping test total movement distance had a moderate negative correlation with endpoint excursion (r=-0.469) and a moderate positive correlation with total movement distance, corrected for knee movement distance (r=0.557). Step numbers had a moderate negative correlation with stepping test total movement distance (r=-0.667) and total movement distance, corrected for knee movement distance (r=-0.531). Division into high and low-balance sub-groups (based on endpoint excursion or sway velocity scores) revealed that stepping test total movement distances and movement displacements were greater, and step numbers were fewer, in low balance groups. [Conclusion] The stepping test, combined with a KinectTM-assessed movement pattern provides a simple, objective, reliable means for assessing balance in community-dwelling, independent-living older adults.

Functional roles and localization of hydrolases in the Japanese mitten crab Eriocheir japonica.

The Japanese mitten crab Eriocheir japonica inhabits rivers throughout Japan and is being cultivated for food. To conduct aquaculture efficiently, it is crucial to comprehend the physiological functions of the target organisms. However, there is a lack of fundamental information on Japanese mitten crabs. In this study, hydrolases were extracted from the midgut glands of Japanese mitten crabs and their metabolic activities were analyzed. An enzyme with hydrolytic activity was discovered within the cytosol of the midgut gland. Western blot analysis also revealed that the Japanese mitten crab contains a hydrolase with cross-reactivity to human carboxylesterase 1 (hCES1) antibodies. The substrate specificity of the S9 fraction of the midgut gland was investigated and, interestingly, it was revealed that it reacts well with indomethacin phenyl ester and fluorescein diacetate, which are substrates of hCES2, not substrates of hCES1. Furthermore, this enzyme was observed to metabolize the ester derivative of astaxanthin, which is a red pigment inherent to the Japanese mitten crab. These findings underscore the significance the midgut gland in the Japanese mitten crab as an important organ for metabolizing both endogenous and exogenous ester-type compounds.

Differences in gaze behaviors between trainees and experts during endovascular therapy for cerebral aneurysms: a preliminary study using a cerebral aneurysm model.

In the neuroendovascular field, the training of operators has become an important issue. Recently, eye-tracking technology has been introduced into various fields of medical education. This study aimed to apply eye-tracking technology to the training of neuroendovascular therapy. Six neurosurgeons, including three neuroendovascular specialists and three trainees, at our institution and related facilities participated in the study. Eye movement was recorded by the eye-tracking device during the microcatheter navigation and coil placement into the silastic aneurysm model under biplane X-ray fluoroscopy. Eye-tracking analysis during neuroendovascular therapy was feasible in all six subjects. In microcatheter navigation, specialists tended to more frequently switch their attention between frontal and lateral images than trainees. In coil embolization, the overall gaze frequency tended to increase, and the average fixation duration tended to decrease as the number of experienced cases increased. Inexperienced operators tend to fix their gaze when they are operators than when they are assistants. More experienced operators tended to look at the microcatheter longer in the coil insertion task. The eye-tracking analysis may be useful for operator training in neuroendovascular therapy. Experts may have moved their eyes more frequently than trainees to gaze at the right place. In the future, it will be necessary to collect gaze data for more operators in various tasks.

A 20-sec Stepping Test and KINECTTM Sensor Provides Objective Quantification of Movement/Balance Dysfunction in Older Individuals.

Background: Tests such as the Functional Independence Measure (FIM) are widely used measures of infirmity and burden of care. However, these scales are largely qualitative and especially problematic when assessing movement-based tasks. Effective, reliable analysis of human movement is technically complicated and expensive, but an infrared depth sensor is potentially a low-cost, portable devise which may provide a quantitative aspect to clinical testing. Our purpose was to assess the utility of a 20-sec stepping test (ST) and KinectTM infrared-depth sensor in providing objective evaluation of balance toward identifying disability in older adults.Methods: Men and women between 64 and 90 years of age, consisting of independent (IG; n = 37) and dependent (DG; n = 38) living at community, geriatric day-care center in Japan. Total movement distance (TMD) and greatest displacement (MMD) were calculated from KinectTM recording of the ST.Results: DG had lower FIM scores than IG. TMD and MMD were significantly greater in DG than IG, while step number and rate were lower in DG. Receiver-operator characteristic analysis showed TMD, TMD/step, MMDstep, and MMD corrected for time and height strongly discriminated between assignment to DG or IG with moderate sensitivity and specificity.Conclusions: Greater TMD and MMD observed during a 20-sec ST appear to indicate disability with moderate sensitivity and specificity in older adults. Measures of movement distance (e.g. TMD, MMD) appear indicative of changes in dynamic balance due to a circuitous movement pattern generated by aberrant step replacement with repeated stepping-in-place.

Evaluating activities of daily living using an infrared depth sensor: KINECTTM.

PURPOSE: With a growing proportion of elderly people in the population, the maintenance of activities of daily living (ADLs) in elderly people is crucial to keep medical costs down. We investigated the ADL measurement accuracy of KINECTTM and Kinect Studio. To eliminate the subjectivity of conventional methods, we numerically assessed motions with computer analysis. METHODS: Eighteen actions that repeated "move" and "stationary" phases, including movement of arms, legs, head and torso were measured using KINECTTM. Errors and standard deviations of joint coordinates at the stationary points outputted from KINECT Studio were evaluated. Simultaneous measurements were performed with KINECTTM using conventional high-performance motion capture, and the output was treated as a true value for comparison. RESULTS: In most motions, errors of the joint coordinates were within 100 mm; however, there were two cases where errors due to the skeleton-model estimation by KINECT Studio increased. Firstly, when a part of the body unexpectedly moved out of the infrared measurable area, and secondly, when parts of the body overlapped each other on the KINECTTM image. CONCLUSIONS: KINECTTM and Kinect Studio are effective for ADL assessment when positions that cause large errors are excluded. Since KINECTTM has sufficient precision, it should also be possible to develop a more appropriate ADL evaluation system with a new algorithm of skeleton-model estimation that does not depend on KINECT Studio. Implications for Rehabilitation The KINECTTM and Kinect Studio are effective for ADL assessment when positions that cause large errors are excluded With an increasing proportion of elderly people in the population, the maintenance of activities of daily living (ADLs) in elderly people is crucial to keep medical costs down Systems such as the KINECTTM can support these goals.

A saliency based motion detection model of visual system considering visual adaptation properties.

The purpose of this study is to construct a mathematical model which predicts saliency regions in high-speed egocentric-motion movies, filmed by an embedded camera in a driving vehicle, by reproducing the characteristics of the area MT and MST neurons' receptive fields with consideration of visual adaptation properties. The area MT neurons integrate from the area V1 activation and respond well to regions where higher motion contrasts exist. While the area MST neurons detect global motions such as expansion, contraction, rotation, and so on. We modeled the area MT neurons' receptive fields as a center-surround spatial summation of counter sided motion vectors of visual scenery. The area MST neurons in our model integrate the responses of the MT neurons by convolving with spacial weight functions of which central portions are biased to preferred direction. Visual adaptations were taken as the primary delay filters for each visual feature channel to deplete the saliency of stationary objects and regions during particular frames. The simulation results for the movies which were taken in a running vehicle indicate that the proposed model detects more salient objects around the vanishing point than the conventional saliency based model. To evaluate the performance of proposed model, we defined the moving-NSS (normalized scan-path salience) scores as the averaged NSS scores in each moving time window. The moving-NSS scores for motion images of our model were higher than those of the conventional model.

Quantitative assessments of arousal by analyzing microsaccade rates and pupil fluctuations prior to slow eye movements.

It is well known that a decline of arousal level causes of poor performance of movements or judgments. Our previous study indicates that microsaccade (MS) rates and pupil fluctuations change before slow eye movements (SEMs) (Honda et al. 2013). However, SEM detection of this study was obscure and insufficient. In this study, we propose a new SEM detection method and analyze MS rates and pupil fluctuations while subjects maintain their gaze on a target. We modified Shin et al.'s method, which is optimized for EOG (electrooculography) signals, to extract the period of sustaining SEMs using a general eye tracker. After SEM detection, we analyzed MS rates and pupil fluctuations prior to the initiation of SEMs. As a result, we were able to detect SEMs more precisely than in our previous study. Moreover, the results of eye movements and pupil fluctuations analyses show that gradual rise of MS rate and longitudinal miosis are observed prior to the initiation of SEMs, which is consistent with our previous study. These findings suggest that monitoring eye movements and pupil fluctuations may evaluate the arousal level more precisely. Further, we found that these tendencies become more significant when they are restricted to the initial SEMs.

Quantitative evaluation of arousal level based on the analyses of microsaccade rates and pupil fluctuations.

In this study, we proposed an objective estimation of decline of arousal level by analyzing microsaccade rate and pupil fluctuation while subjects were continuously gazing a fixation target. Previous studies show that the slow eye movements (SEMs) could be a candidate for an indicator of decline of arousal. However, it is not sufficient to evaluate transition of arousal states since SEMs appear just prior to sleep onset. To establish more objective assessment of arousal, we examined the effects of the transition of arousal on microsaccade rate and pupil fluctuation. The subjects were instructed to indicate by mouse clicks when they were aware of having slept. We have analyzed the eye movement and pupil fluctuation data in advance of the occurrence of SEMs which were detected just before the mouse clicks. In the results, longitudinal pupil diameter shrinking and gradual rise of microsaccade rate were observed prior to SEMs. These results suggest that the arousal level could be evaluated by monitoring eye movements and pupil fluctuations.

Attentional effects on gaze preference for salient loci in traffic scenes.

Alerting drivers for self-regulation of attention might decrease crash risks attributable to absent-minded driving. However, no reliable method exists for monitoring driver attention. Therefore, we examined attentional effects on gaze preference for salient loci (GPS) in traffic scenes. In an active viewing (AV) condition requiring endogenous attention for traffic scene comprehension, participants identified appropriate speeds for driving in presented traffic scene images. In a passive viewing (PV) condition requiring no endogenous attention, participants passively viewed traffic scene images. GPS was quantified by the mean saliency value averaged across fixation locations. Results show that GPS was less during AV than during PV. Additionally, gaze dwell time on signboards was shorter for AV than for PV. These results suggest that, in the absence of endogenous attention for traffic scene comprehension, gaze tends to concentrate on irrelevant salient loci in a traffic environment. Therefore, increased GPS can indicate absent-minded driving. PRACTITIONER SUMMARY: The present study demonstrated that, without endogenous attention for traffic scene comprehension, gaze tends to concentrate on irrelevant salient loci in a traffic environment. This result suggests that increased gaze preference for salient loci indicates absent-minded driving, which is otherwise difficult to detect.

Isolation and characterization of glutathione reductase from Physarum polycephalum and stage-specific expression of the enzyme in life-cycle stages with different oxidation-reduction levels.

Physarum polycephalum has a life cycle with several distinct phases that have different oxidation-reduction requirements. To investigate the relationship between the life cycle and the oxidation-reduction state, we isolated glutathione reductase (GR; EC 1.6.4.2) from Physarum microplasmodia. The enzyme was found to be a homodimer with a subunit M(r) of 49,000, and K(m) values for oxidized glutathione and NADPH of 40 and 28.6 microM, respectively. We then constructed a cDNA library from microplasmodium mRNA and cloned GR cDNA from the library. The isolated cDNA consisted of 1,475 bp encoding a polypeptide of 452 amino acids. The amino acid sequence similarity was about 50% with GRs of other organisms, and several conserved sequence motifs thought to be necessary for activity are evident in the Physarum enzyme. Escherichia coli transformed with an expression vector containing the cDNA synthesized the active GR. Genomic Southern blot analysis indicated that the GR gene is present as a single copy in the Physarum genome. Immunoblot analysis and RT-PCR analysis detected GR mRNA expression in the microplasmodium, plasmodium, and sclerotium, but not in the spore or flagellate. GR activity was low in the spore and flagellate. These results suggest that the glutathione oxidation-reduction system relates to the Physarum life cycle.