Development and test-retest reliability assessment of a low-cost, 3D printed tool for assessing different aspects of hand dexterity.

BACKGROUND: Hand dexterity assessments related to fine motor movements are routinely administered in clinical settings to ascertain an individual's hand function. However, to perform a detailed assessment multiple devices are needed which can be time-consuming and costly to administer. PURPOSE: We designed and assessed the test-retest reliability of a 3D printed dexterity device in a cohort of healthy young adults and community-dwelling older adults. This study examines the reliability of the device, association between perceived fine motor gripping and manipulation dexterity components, and dominant hand outperformance during both tasks. STUDY DESIGN: Test-retest study of a clinical measurement tool. METHODS: A convenience sample of thirty-six healthy community-dwelling older and young adults was included in our study. The device was used to collect data at two testing sessions to establish test-retest reliability. Fine motor manipulation dexterity was assessed by lifting notched pegs over a vertical barrier and inserting them into randomly oriented holes sequentially. Fine motor gripping dexterity was assessed by taking these notched pegs out of the holes, lifting them over the barrier and dropping them into a large container. RESULTS: Intraclass correlation coefficient (ICC)2,1 showed good to excellent test-retest reliability on the dominant and nondominant hands when using the device. Only modest association was found within-hand for the gripping versus manipulation dexterity tests. The between-hand motor gripping dexterity test demonstrated a strong association; however, between-hand the motor manipulation dexterity test was only moderately associated. CONCLUSION: The device was reliable, discriminated between the motor gripping and motor manipulating dexterity tasks, and was sensitive to handedness during the motor manipulating dexterity task. It shows promise as a hand dexterity assessment device which may provide efficiency and cost advantages. It is freely available via http://www.rehabtools.org/dexterity.html.

Digital bathroom scales with open source software provide valid dynamic ground reaction force data for assessment and biofeedback.

BACKGROUND: Measuring dynamic vertical ground reaction force allows for assessment of important clinical and physical capacity factors such as weight bearing asymmetry, force distribution, and rate of force development. However, current technologies for accurately assessing ground reaction force are typically expensive. RESEARCH QUESTION: The aim of this study was to examine the validity and reliability of obtaining static and dynamic ground reaction force data from low-cost modified digital bathroom scales. METHODS: Four modified bathroom scales, two units each of two different brands, were examined. Repeated mechanical loading trials were performed with known loads ranging from 0.01 to 65 kg, with acquired data compared against the known loading to calculate accuracy, hysteresis, and non-linearity. Dynamic trials consisting of 5 times sit-to-stand and weight-shifting were performed by 32 adults. Absolute and relative agreement intraclass correlation coefficient, and Pearson's and Spearman's correlations were performed to determine validity and reliability for the mechanical tests. Bland-Altmann plots were created for each comparison. Mean absolute error (MAE) and unbiased cross-correlation were performed on the dynamic data, comparing the calibrated data to the known values from a Bertec force platform. RESULTS: Hysteresis and non-linearity were excellent (<0.2 % full-scale), and mechanical test results showed excellent reliability and validity. Cross-correlation results for the dynamic data were excellent, however MAE for the more rapid sit-to-stand task was higher than the slower weight-shifting test. This may have been due to the low default sampling rate for the lowest noise setting of the HX711 amplifier (10 Hz). SIGNIFICANCE: In summary, our results suggest that digital bathroom scales can be easily and inexpensively modified to obtain accurate vertical ground reaction force data, with sensitivity to detect changes of as little as 0.01 kg.

Validity of a low-cost laser with freely available software for improving measurement of walking and running speed.

OBJECTIVES: Accurately measuring speed and acceleration during walking, running and sprinting has important implications for rehabilitation, planning training and talent identification in sporting and clinical populations. Light detection and ranging laser technology provides a continuous stream of distance data. It has the potential to allow rapid and precise measurement and may be advantageous compared with discrete methods of assessment, such as stopwatches and timing gates, which may be inaccurate over short distances. Therefore, the aim of this study was to assess the validity of a novel, low-cost and easy to implement laser-based system during walking and running trials. DESIGN: Cross-sectional study. METHODS: Thirty-two healthy adults performed walking and running trials from flying and static starts while monitored concurrently with reference standard three-dimensional motion analysis and laser systems. Velocity was calculated over short (0.5m) and longer (3m) intervals using both systems. Validity was assessed using absolute agreement intraclass correlation coefficients (ICC2,1), mean absolute errors, Pearson's correlations and regressions and Bland-Altman plots. RESULTS: All intraclass correlation coefficients and correlations were excellent (ICC>0.88, R>0.89). For the longer interval, all mean absolute errors were <0.03m/s (0.24-1.31%). Slightly higher mean absolute error values were reported for the shorter interval (3.16-5.10%), with the highest error of 0.184m/s evident for the flying start running trial. CONCLUSIONS: These results indicate that a low-cost and accessible laser system can be used to accurately assess walking and running speed. To aid implementation and further research, freely available hardware design descriptions and downloadable software can be accessed at www.rehabtools.org/LIDAR.

Three-dimensional cameras and skeleton pose tracking for physical function assessment: A review of uses, validity, current developments and Kinect alternatives.

BACKGROUND: Three-dimensional camera systems that integrate depth assessment with traditional two-dimensional images, such as the Microsoft Kinect, Intel Realsense, StereoLabs Zed and Orbecc, hold great promise as physical function assessment tools. When combined with point cloud and skeleton pose tracking software they can be used to assess many different aspects of physical function and anatomy. These assessments have received great interest over the past decade, and will likely receive further study as the integration of depth sensing and augmented reality smartphone cameras occurs more in everyday life. RESEARCH QUESTION: The aim of this review is to discuss how these devices work, what options are available, the best methods for performing assessments and how they can be used in the future. METHODS: Firstly, a review of the Microsoft Kinect devices and associated artificial intelligence, automated skeleton tracking algorithms is provided. This includes a narrative critique of the validity and clinical utility of these devices for assessing different aspects of physical function including spatiotemporal, kinematic and inverse dynamics data derived from gait and balance trials, and anatomical assessments performed using the depth sensor information. Methods for improving the accuracy of data are examined, including multiple-camera systems and sensor fusion with inertial monitoring units, model fitting, and marker tracking. Secondly, alternative hardware, including other structured light and time of flight methods, stereoscopic cameras and augmented reality leveraging smartphone and tablet cameras to perform measurements in three-dimensional space are summarised. Software options related to depth sensing cameras are then discussed, focussing on recent advances such as OpenPose and web-based methods such as PoseNet. RESULTS AND SIGNIFICANCE: The clinical and non-laboratory utility of these devices holds great promise for physical function assessment, and recent developments could strengthen their ability to provide important and impactful health-related data.

Open-source 3D printed sensors for hand strength assessment: Validation of low-cost load cell and fabric sensor-based systems.

BACKGROUND/AIM: Pinch and grip strength assessment is commonly performed in occupational therapy practice. However, the typically utilised methods are limited to pinch or grip dynamometers and do not readily translate to handling everyday objects. With the advent of consumer-grade 3D printing and low-cost sensor systems, the possibilities for creating customised assessment devices are expanding. As a first step in determining the validity of low-cost sensor systems, their data must be compared to a gold standard. Consequently, this study examined the criterion validity of two such systems for measuring pinch strength, specifically a small load cell and pressure-sensing fabric, with a mechanical pinch gauge. METHODS: A total of 33 participants performed strength tests using a mechanical pinch grip device, which had a plastic 3D printed cover with a pressure-sensing fabric overlaid on it to allow for simultaneous criterion validation, and a small load cell with a plastic 3D printed casing designed for comfortable pinch grip assessment. RESULTS: The simultaneously assessed fabric sensor and mechanical pinch grip device showed excellent absolute (ICC2,k  = 0.94) and relative (Pearson's R = 0.90) agreement. Both devices showed similar excellent relative (R > 0.75) agreement with the load cell despite non-simultaneous assessment. These findings indicate that 3D printed sensors incorporating a load cell and a pressure-sensing fabric can be used to replicate a pinch grip assessment performed with a mechanical pinch gauge. CONCLUSIONS: This study lays the foundation for these sensor systems to be modified for use as assessment tools during the performance of functional tasks using everyday objects. Additionally, because both systems generate real-time force data they could be used for biofeedback as part of rehabilitation and strengthening programs. To aid uptake and future research using these systems, the 3D print models, step-by-step hardware design and software programs used are provided in an open-source format at www.rehabtools.org/otsensors.html.

Targeted screening for Trichomonas vaginalis in women, a pH-based approach.

In the genitourinary medicine clinic setting, the most practical and widely used method of diagnosing Trichomonas vaginalis (TV) is direct microscopy of a wet mount preparation (WMP) of a sample taken from the posterior vaginal fornix. We retrospectively reviewed the potential impact of further limiting WMP to women with a vaginal pH > or =4.5. In total, 5/100 women with TV diagnosed on WMP had a recorded vaginal pH <4.5. One case of TV was identified in 1000 consecutive WMPs performed in women with vaginal pH <4.5. Our review demonstrates that, in our two groups, TV as diagnosed by WMP is strongly associated with a vaginal pH > or =4.5.

Expression, purification, and evidence for the interaction of the two nucleotide-binding folds of the sulphonylurea receptor.

The ATP-sensitive potassium channel is made up of four pore forming Kir6.2 subunits, surrounded by four regulatory sulphonylurea receptor (SUR) subunits. The latter subunit contains two nucleotide-binding folds (NBFs) that confer the ability on the channel to sense changes in the metabolic status ([ATP]/[ADP]) of the cell and couple the changes to the membrane potential of the cell. In an attempt to better understand the mechanisms by which NBFs influence the activity of the channel, we have expressed the NBF domains with C-terminally added epitopes (FLAG to NBF1 and His(6) to NBF2) in Escherichia coli and the rabbit reticulocyte lysate system and examined the ability of these domains to interact with each other and with Kir6.2. Both NBFs could be expressed to high levels in E. coli and purified to homogeneity from inclusion bodies. Re-folding of the proteins proved to be unsuccessful. However, we were able to obtain small amounts of radio-labelled NBFs in a soluble state. Using co-immunoprecipitation, we demonstrate that the radio-labelled NBF1 and NBF2 interact with each other. Neither of the NBFs bound to Kir6.2 expressed in the presence of canine microsomes.