An easily attachable measurement system of joystick angle in a power wheelchair using IMUs for maneuvering logger.

Monitoring joystick operations in power wheelchairs (PWCs) is promising for investigating user-wheelchair interaction and providing quantitative measures to assess the user's driving performance. In this paper, an add-on measurement system, Power Wheelchair Maneuvering Logger (PWhML), is developed to provide an easy-to-implement and cost-effective solution for monitoring the user's joystick operations in PWCs. The proposed system uses two compact inertial measurement units (IMUs), which are respectively attached to the joystick and wheelchair armrest for movement sensing. A coordinate transformation-based method is proposed to estimate the joystick operating angles using the acceleration data measured by the attached IMUs. The accuracy of the proposed method was thoroughly evaluated under different conditions. The evaluation trials in a stationary PWC reported a mean absolute error (MAE) of 0.59° in the forward/backward direction and 0.64° in the leftward/rightward direction, validating the established geometry model for coordinate transformation. The subsequent driving experiments on outdoor test courses demonstrated the effectiveness and robustness of the proposed method in various terrain conditions (MAE of less than 3°). A clustering analysis based on the t-distributed stochastic neighborhood embedding method correctly categorized different driving activities using the joystick operating angles measured by PWhML. These results indicate that integrating the developed PWhML into PWCs can facilitate a quantitative measurement of the user's driving behavior, providing valuable insights to identify careless operation patterns and help PWC users to improve driving performance.

Quantification of User Driving Behavior in Motorized Mobility Scooters using CNN-based Head Pose Estimation Algorithm.

There is a growing concern regarding the driving safety of Motorized Mobility Scooters (MMSs) for the elderly and mobility-impaired individuals. Although various research has made progress in sensor-based driving assistance systems to identify environmental hazards, few studies focus on investigating the impact of user behavior on MMS driving. In this paper, a driving status logging (DSL) system is developed to measure the user's behavior while driving. A cross-correlation analysis is implemented to quantify the temporal relationship between the head movement and steering operation in the driving of MMSs. The preliminary results suggest that the head movement can be used as an appropriate index to predict the intended steering operation in the driving of MMSs. Moreover, the quantified head-steering lag time provides the possibility to identify the hazardous driving pattern of MMS users.Clinical Relevance- The investigation of user behavior has the potential to improve the safety of MMSs. In this study, the user behavior in the driving of MMSs was quantitatively measured using the developed DSL system. Consequently, the temporal relationship between head movement and steering operation was first quantified in MMS-related research. These outcomes provide valuable insights into developing behavioral interventions to address the user's risky behavior patterns, thereby promoting the driving safety of MMSs.

Estimation of Steering and Throttle Angles of a Motorized Mobility Scooter with Inertial Measurement Units for Continuous Quantification of Driving Operation.

With the growing demand from elderly persons for alternative mobility solutions, motorized mobility scooters (MMSs) have been gaining importance as an essential assistive technology to aid independent living in local communities. The increased use of MMSs, however, has raised safety issues during driving and magnified the necessity to evaluate and improve user driving skills. This study is intended to develop a novel quantitative monitoring method for MMS driving operation using inertial measurement units (IMUs). The proposed method used coordinate transformations around the rotational axes of the steering wheel and the throttle lever to estimate the steering and throttle operating angles based on gravitational accelerations measured by IMUs. Consequently, these operating angles can be monitored simply using an IMU attached to the throttle lever. Validation experiments with a test MMS in the stationary state confirmed the consistency of the proposed coordinate transformation with the MMS's geometrical structure. The driving test also demonstrated that the operating angles were estimated correctly on various terrains and that the effects of terrain inclination were compensated using an additional IMU attached to the scooter body. This method will be applicable to the quantitative monitoring of driving behavior and act as a complementary tool for the existing skills' evaluation methods.

Perspectives of Multidisciplinary Professional Teams during Assessment Processes for ATD Selection in the Japanese Public Provision System.

Selection of assistive technology devices (ATDs), which are imperative for persons with disabilities to improve their quality of life, requires collaboration of users and multidisciplinary professionals. However, it is still unknown how to design and implement an adequate collaborative work flow and a professional team. Under Japanese governmental ATD provision system, based on the application by clients, ATDs are mainly selected through collaborative processes with the clients and health professionals in public organizations, rehabilitation counseling centers (RCCs). By employing qualitative study methods in this study, we investigated the ATD selection process in which health professionals in RCCs collaboratively assess clients with physical disabilities so as to support them in selecting the adequate ATDs. To identify the perspectives required for ATD selection completely, the assessment processes were recorded and analyzed with a pseudo setting in two RCCs. Content analysis of the conversations between the client and professionals revealed the characteristics of the information exchanged in the assessment processes. A total of 760 assessment items were identified, thus indicating a broad array of interest. Despite the richness of information collected for the assessment, half of the assessment items did not have corresponding items in the documents that were employed during the prescription process. Thematic analysis of the interviews that followed revealed the common values and collaborative processes in ATD selection, which were shared and elaborated among the staff in daily social interactions. To facilitate implementation of ATD provision in various areas with few resources, it may be effective to convert this tacit-to-tacit knowledge sharing into a more explicit sharing by promoting analyses of good practices.

Effect of the Information Support Robot on the Daily Activity of Older People Living Alone in Actual Living Environment.

Information support robots (ISRs) have the potential to assist older people living alone to have an independent life. However, the effects of ISRs on the daily activity, especially the sleep patterns, of older people have not been clarified; moreover, it is unclear whether the effects of ISRs depend on the levels of cognitive function. To investigate these effects, we introduced an ISR into the actual living environment and then quantified induced changes according to the levels of cognitive function. Older people who maintained their cognitive function demonstrated the following behavioral changes after using the ISR: faster wake-up times, reduced sleep duration, and increased amount of activity in the daytime (p < 0.05, r = 0.77; p < 0.05, r = 0.89, and p < 0.1, r = 0.70, respectively). The results suggest that the ISR is beneficial in supporting the independence of older people living alone since living alone is associated with disturbed sleep patterns and low physical activity. The impact of the ISR on daily activity was more remarkable in the subjects with high cognitive function than in those with low cognitive function. These findings suggest that cognitive function is useful information in the ISR adaptation process. The present study has more solid external validity than that of a controlled environment study since it was done in a personal residential space.

Assessment of driving skills of a mobility scooter using driving operation logs.

A mobility scooter is a major assistive technology that replaces human ambulatory functions for people with disabilities. A license is often not required for driving a mobility scooter; therefore, less skilled drivers might create safety concerns. An effective way of reducing these safety risks is by assessing the driving skills of users. The existing assessment measures mostly score the task performance using manual observations. In this study, we have developed a novel assessment system that logs the driving operations by using add-on sensors. This system can monitor the operations of a mobility scooter including the angles of the throttle lever and the steering tiller. The subjects were seven older adults who participated in the driving test involving six tasks; the driver performances were video recorded, and the vehicle operation data were logged. The video analysis showed that two subjects crashed their scooters into objects or made contact with objects during the test course. To extract the characteristic patterns of the operations from the logs, 2D histograms of the operational status durations were investigated for each subject and task. Subsequent analysis of the operation logs identified the two subjects who had crashed their vehicles during the test drive. Our results proved that the driving operation logs could be used complementarily as a simple and low-cost tool for assessing a person's driving skills.

Mechanical Regulation Underlies Effects of Exercise on Serotonin-Induced Signaling in the Prefrontal Cortex Neurons.

Mechanical forces are known to be involved in various biological processes. However, it remains unclear whether brain functions are mechanically regulated under physiological conditions. Here, we demonstrate that treadmill running and passive head motion (PHM), both of which produce mechanical impact on the head, have similar effects on the hallucinogenic 5-hydroxytryptamine (5-HT) receptor subtype 2A (5-HT2A) signaling in the prefrontal cortex (PFC) of rodents. PHM generates interstitial fluid movement that is estimated to exert shear stress of a few pascals on cells in the PFC. Fluid shear stress of a relevant magnitude on cultured neuronal cells induces ligand-independent internalization of 5-HT2A receptor, which is observed in mouse PFC neurons after treadmill running or PHM. Furthermore, inhibition of interstitial fluid movement by introducing polyethylene glycol hydrogel eliminates the effect of PHM on 5-HT2A receptor signaling in the PFC. Our findings indicate that neuronal cell function can be physiologically regulated by mechanical forces in the brain.

Construction of a soft wearable body cooling system for persons with spinal cord injury.

This paper describes the construction of a body cooling system to avoid heatstroke for survivors of cervical spinal cord injury. For accomplishment of this purpose, we chose the neck as a cooling point of the body, and we constructed a prototype neck cooling head with a refrigerated circulator. The neck cooling head was made by thin heat-welding thermoplastic films with high thermal conductivity. To test our proposed system, we conducted experiments on two unimpaired participants in a room which simulated a hot summer day (33 [°C], relative humidity 40%). Reduction of sweating were observed, and the average skin temperatures and the core temperature of the head with cooling increased more slowly than those without cooling. The estimated cooling power of the proposed system was about 10 [W] with 50 [W] total power consumption of the cooling head.

Characterization of the pierce two-node model under exercise load by parameter optimization toward construction of a modified thermal model for persons with spinal cord injury.

In this study, we attempted to develop a thermal model for estimating a body temperature in persons with spinal cord injury (SCI) during exercise. To clarify requisites for the SCI thermal model, we compared actual body temperature of SCI subjects with that calculated with a standard thermal model, that is, the Pierce two-node model. Model optimization by the parameter search method was able to fit the model-estimated skin and core temperature with those in able-bodied subjects during repeated exercise and rest. However, there remained a phase shift between actual and model-estimated core temperature trends in SCI subjects even after the optimization. The comparison of the optimized parameter combinations revealed that the Pierce two-node model was able to express loss of sweating in the SCI subjects, but unable to express delay in heat accumulation and dissipation. These results suggest that SCI thermal model requires additional nodes that express the speed and extent of heat transfer in the body of SCI persons.

Validation of the ULCEAT methodology by applying it in retrospect to the Roboticbed.

BACKGROUND: In answer to the increasing demand for care by the Japanese oldest portion of the population, an extensive programme of life support robots is under development, advocated by the Japanese government. Roboticbed® (RB) is developed to facilitate patients in their daily life in making independent transfers from and to the bed. The bed is intended both for elderly and persons with a disability. OBJECTIVE: The purpose of this study is to examine the validity of the user and user's life centred clinical evaluation of assistive technology (ULCEAT) methodology. To support user centred development of life support robots the ULCEAT method was developed. By means of the ULCEAT method the target users and the use environment were re-established in an earlier study. METHOD: The validity of the method is tested by re-evaluating the development of RB in retrospect. Six participants used the first prototype of RB (RB1) and eight participants used the second prototype of RB (RB2). RESULTS: The results indicated that the functionality was improved owing to the end-user evaluations. Therefore, we confirmed the content validity of the proposed ULCEAT method. CONCLUSION: In this study we confirmed the validation of the ULCEAT methodology by applying it in retrospect to RB using development process. This method will be used for the development of Life-support robots and prototype assistive technologies.

Estimation of wheelchair states during movement using WELL-SphERE for evaluation of power wheelchair safety.

To comprehensively evaluate the usability and safety of a power wheelchair (PWC), monitoring multimodal data related to the PWC in a real environment is crucial. In most studies exploring actual wheelchair conditions, modification of PWCs has been required. Especially modification of controlling circuits aiming for measurement of joystick operation may lead to controller malfunction and thus increase safety risk. It is essential, therefore, to ensure the safety of PWC users during experiments so that they can measure PWC-related data with their own wheelchairs. To achieve this aim, we developed a recording device that is easily installed on PWCs without any electronic modifications. The device, called a "WELL-SphERE," has sensing units that can be attached to PWCs a data management unit that can store and transfer measurement data. Here, we focused on joystick operation logged by the system. Seven participants were pre-tested to examine the characteristics of logged operations during runs through four test courses. Subsequently, all participants completed a questionnaire regarding the difficulty of the test courses. From these results, we classified the logged operations into four categories of "wheelchair states." Two participants--a novice driver and a mature driver--were also evaluated to verify the accuracy of the estimated wheelchair states. The accuracies of the estimates by the mature and novice driver were 98.8% and 89.0%, respectively. The wheelchair states for both participants showed characteristic patterns. Therefore, the wheelchair states estimated with the data logged using WELL-SphERE are valid indicators of the wheelchair conditions during movement.

Thermophysiological responses induced by a body heat removal system with Peltier devices in a hot environment.

Individuals with spinal cord injuries often experience thermoregulation disorders as well as sensory and motor disabilities. In order to prevent such individuals from becoming hyperthermic, we developed a body heat removal system (BHRS) with thermoelectric devices. Our BHRS comprises four Peltier devices mounted on a wheelchair backrest and continuously transfers body heat through the contacting interface to the external environment. Here, we characterized thermophysiological responses induced by this novel contact-type cooling system. A cooling experiment in a hot environment with five able-bodied subjects demonstrated that sweating and systolic blood pressure in the back-cooling (BC) trial were significantly suppressed compared with those in no-cooling (NC) trial, while no difference was found in oral and skin temperatures. A correlation was observed between chest skin temperature and blood flow in the NC trial; this was not observed in the BC trial. These results suggest that BHRS modulates normal thermoregulatory responses, including sweating and vascular dilation and has the capability to partly replace these functions.

Light-addressed single-neuron stimulation in dissociated neuronal cultures with sparse expression of ChR2.

Individual neurons are heterogeneous and have profound impact on population activity in a complex cortical network. Precise experimental control of the firing of multiple neurons would be therefore beneficial to advance our understanding of cell-network interactions. Except for direct intracellular stimulation, however, it is difficult to gain precise control of targeted neurons without inducing antidromic activation of untargeted neurons. To overcome this problem, we attempt to create a sparse group of photosensitized neurons via transfection of Channelrhodopsin-2 (ChR2) in primary dissociated cultures and then deliver light-addressed stimulation exclusively to these target neurons. We first show that liposome transfection was able to express ChR2 in 0.3-1.9% of cells plated depending on cell density. This spatially sparse but robust expression in our neuronal cultures offered the capability of single cell activation by illuminating a spot of light. We then demonstrated that delivering a pulsed train to photo-activate a single neuron had a substantial effect on the activity level of an entire neuronal culture. Furthermore, the activity level was controllable by altering the frequency of light illumination when 4 neurons were recruited as stimulation targets. These results suggest that organized activation of a very small population of neurons can provide better control over global activity of neuronal circuits than can single-neuron activities by themselves.

Voltage-sensitive-dye imaging of microstimulation-evoked neural activity through intracortical horizontal and callosal connections in cat visual cortex.

Recently, intrinsic signal optical imaging has been widely used as a routine procedure for visualizing cortical functional maps. We do not, however, have a well-established imaging method for visualizing cortical functional connectivity indicating spatio-temporal patterns of activity propagation in the cerebral cortex. In the present study, we developed a novel experimental setup for investigating the propagation of neural activities combining the intracortical microstimulation (ICMS) technique with voltage sensitive dye (VSD) imaging, and demonstrated the feasibility of this setup applying to the measurement of time-dependent intra- and inter-hemispheric spread of ICMS-evoked excitation in the cat visual cortices, areas 17 and 18. A microelectrode array for the ICMS was inserted with a specially designed easy-to-detach electrode holder around the 17/18 transition zones (TZs), where the left and right hemispheres were interconnected via the corpus callosum. The microelectrode array was stably anchored in agarose without any holder, which enabled us to visualize evoked activities even in the vicinity of penetration sites as well as in a wide recording region that covered a part of both hemispheres. The VSD imaging could successfully visualize ICMS-evoked excitation and subsequent propagation in the visual cortices contralateral as well as ipsilateral to the ICMS. Using the orientation maps as positional references, we showed that the activity propagation patterns were consistent with previously reported anatomical patterns of intracortical and interhemispheric connections. This finding indicates that our experimental system can serve for the investigation of cortical functional connectivity.

Light-addressed stimulation under Ca(2+) imaging of cultured neurons.

Light addressing is an emerging and sophisticated technique that can induce pinpoint and/or patterned neuronal activation in cultured neurons. We previously developed a light-addressable electrode using hydrogenated amorphous silicon (a-Si:H), which was sandwiched between a tin oxide (SnO(2)) substrate and a passivation layer of zinc antimonate (ZnOSb(2)O(5)) dispersed epoxy. This research developed an experimental system that simultaneously implemented light-addressed stimulation and Ca(2+) imaging of neuronal activities. The translucent and thin laminated structure of our electrode permitted optical accesses from two directions: Ca(2+) imaging from above and light addressing from beneath. The submillisecond bright/dark switching property of our electrode offered light-addressed stimulation without causing interference with Ca(2+) imaging. To provide patterned illumination for light addressing, a digital micromirror device was installed in the system as an active photomask. The system could induce pinpoint neuronal activation at a cellular level.

Light-addressable planar electrode with hydrogenated amorphous silicon and low-conductive passivation layer for stimulation of cultured neurons.

Conventional multielectrode arrays (MEAs) cannot always access desired neurons due to low electrode density and small number of electrode. To overcome this problem, we propose a light-addressable planar electrode on a glass substrate. The electrode has a 3-layer structure, namely a transparent SnO2 layer, an hydrogenated amorphous silicon (a-Si:H) layer, and a passivation layer. Illumination to the a-Si:H layer increases the conductivity of a-Si:H and creates a virtual electrode at the surface of the illuminated site. In the present study, we developed a low-conductive zinc antimonate-dispersed epoxy layer. This layer could successfully prevent penetration of culture medium and thus deterioration of a-Si:H layer. A fluo-4 calcium imaging demonstrated that, when the whole area of electrode was illuminated, negative-monophasic voltage-controlled pulses could also successfully activate neurons cultured on the electrode. Moreover, the focused illumination to the electrode resulted in the selective activation of neurons around the illuminated area.

Easy-to-prepare assembly array of Tungsten microelectrodes.

This paper provides a detailed process flow for fabricating an easy-to-prepare, inexpensive, dense array of tungsten microelectrodes. We designed the process flow to minimize routine tasks by separating an initial preparation of a master mold from a routine preparation of substrate replication, array assembly and tip processing. Sandblast processing first produced a glass mold with a pattern of a series of protruding lines at a requested interval of a few hundred micrometers. Copying the groove pattern onto polystyrene mass-produced a replica substrate. Tungsten probes were then aligned on the substrate, and the tips of probes were finely processed in the block.