IntroductionAs the population ages, the prevention of falls is an increasingly important public health problem. Balance assessment forms an important component of fall-prevention programs for older adults. The recent development of cost-effective and highly responsive virtual reality (VR) systems means new methods of balance assessment are feasible in a clinical setting. This proof-of-concept study made use of the submillimeter tracking built into modern VR head-mounted displays (VRHMDs) to assess balance through the use of visual–vestibular conflict. The objective of this study was to evaluate the validity, acceptability, and reliability of using a VRHMD to assess balance in older adults.Materials and methodsValidity was assessed by comparing measurements from the VRHMD to measurements of postural sway from a force plate. Acceptability was assessed through the use of the Simulator Sickness Questionnaire pre- and postexposure to assess possible side effects of the visual–vestibular conflict. Reliability was assessed by measuring correlations between repeated measurements 1 week apart. Variables of possible importance that were found to be reliable (r≥0.9) between tests separated by a week were then tested for differences compared to a control group. Assessment was performed as a cross-sectional single-site community center-based study in 13 older adults (≥65 years old, 80.2±7.3 years old, 77% female, five at risk of falls, eight controls). The VR balance assessment consisted of four modules: a baseline module, a reaction module, a balance module, and a seated assessment.ResultsThere was a significant difference in the rate at which participants with a risk of falls changed their tilt in the anteroposterior direction compared to the control group. Participants with a risk of falls changed their tilt in the anteroposterior direction at 0.7°/second vs 0.4°/second for those without a history of falls. No significant differences were found between pre/postassessment for oculomotor score or total Simulator Sickness Questionnaire score. Both the force plate and the head-mounted display balance-assessment system were able to detect differences between conditions meant to mask visual and proprioceptive information.ConclusionThis VRHMD is both affordable and portable, causes minimal simulator sickness, and produces repeatable results that can be used to assess balance in older adults.

We report on the natural history of diaphanospondylodysostosis (DSD) in the longest known survivor. DSD is a rare form of autosomal recessive vertebral dysotosis recently identified to be caused by a mutation in the BMPER gene. This condition is characterized by absent or severely delayed ossification of vertebral bodies, short broad thorax, short neck, protuberant abdomen, marked respiratory insufficiency, and normal appendicular skeleton. It is one of a number of spinal dysostoses, which are a heterogeneous group of axial skeletal malformations occurring during blastogenesis with continued evolution after birth. Significant medical intervention and at-home support contributed to the long-term survival of our patient. The patient had tracheomalacia, which resulted in respiratory insufficiency with thoracic insufficiency syndrome (TIS). Tracheostomy and vertical expandable prosthetic titanium rib (VEPTR) insertion operations ameliorated his symptoms. In addition, comprehensive physical and occupational therapy was performed due to chronic hypotonia. A consistent feature of all described DSD cases thus far are renal findings of dysplasia, nephrogenic rests or nephroblastomatosis, and/or cysts. The patient's renal cysts were monitored with serial ultrasounds at approximately 6-month intervals. The patient was diagnosed with bilateral renal cysts by ultrasound as a neonate, with eventual diagnosis at approximately 20 months of age with nephroblastoma suggesting this maybe an intrinsic part of DSD. The lack of other cases with nephroblastoma is likely related to the previously reported short period of survival.

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SUMMARY A no‐moving‐parts, 30 frames/s, laser‐beam scanning confocal reflected‐light microscope has been developed. In principle, the technique can be extended to fluorescence and transmission light microscopy. Acousto‐optic beam deflectors controlled by digital electronics move a laser beam in a 512‐line interlaced 8·5 times 8·5‐mm raster. The light passes through a beam splitter, enters an inverted microscope through the side camera port, and is imaged at the object by the microscope objective. Reflected light returns through the objective, exits the camera port, is reflected off the beam splitter, and is imaged on to the photocathode of an image dissector tube (IDT). Confocality is provided by raster scanning the IDT aperture coincident with the congruent image of the laser beam incident on the object. Real‐time jitter‐free reflected light images of a variety of biological objects have been produced. Computer‐controlled alignment of the laser scan and IDT is performed in several seconds.

Evaluation and control of respirable crystalline silica (RCS) exposures are critical components of an effective mine industrial hygiene program. To provide more timely exposure data in the field, an end-of-shift Fourier transform infrared (FT-IR) spectrometry method has been developed for evaluation of direct-on-filter RCS. The present study aimed to apply this FT-IR method using field samples collected in three Northwestern U.S. metal/nonmetal mines and compare the results to traditional laboratory X-ray diffraction analysis (XRD). Seventy-five dust samples were analyzed using both methods. Samples for each mine were split in half by random assignment, with half used to create a calibration factor for the FT-IR analysis and half used to apply the calibration. Nonparametric correlational and two-sample comparative tests were used to assess the strength of association and the level of agreement between the two methods. Strong, positive correlations were observed between FT-IR and XRD RCS concentrations, with Spearman rank correlation coefficients ranging between 0.84 and 0.97. The mean RCS concentrations determined through FT-IR analysis were lower than through XRD analysis, with mean differences ranging from -4 to -133 ug/m and mean percent errors ranging from 12% to 28%. There was a statistically significant improvement in the level of agreement between log FT-IR and log XRD RCS concentrations following calibration at two of the three mines, with mean differences of -0.03 (p = 0.002) and -0.02 (p = 0.044) in the log scale. The reduction in mean difference following calibration at the other mine was not statistically significant (mean log scale difference = -0.05, p = 0.215), but the differences between FT-IR and XRD were not significantly different without calibration (mean log scale difference = -0.07, p = 0.534). The results indicate that mine-specific calibration factors can improve the level of agreement between RCS concentrations determined via a field-based, end-of-shift FT-IR method in metal/non-metal mines as compared to traditional XRD analysis.