Validation of 24-hour ambulatory gait assessment in Parkinson's disease with simultaneous video observation

<p>Abstract</p> <p>Background</p> <p>Parkinson's disease (PD) is a neurodegenerative disorder resulting in motor disturbances that can impact normal gait. Although PD initially responds well to pharmacological treatment, as the disease progresses efficacy often fluctuates over the course of the day, and clinical management would benefit from long-term objective measures of gait. We have previously described a small device worn on the shank that uses acceleration and angular velocity sensors to calculate stride length and identify freezing of gait in PD patients. In this study we extend validation of the gait monitor to 24-h using simultaneous video observation of PD patients.</p> <p>Methods</p> <p>A sleep laboratory was adapted to perform 24-hr video monitoring of patients while wearing the device. Continuous video monitoring of a sleep lab, hallway, kitchen and conference room was performed using a 4-camera security system and recorded to hard disk. Subjects (3) wore the gait monitor on the left shank (just above the ankle) for a 24-h period beginning around 5 pm in the evening. Accuracy of stride length measures were assessed at the beginning and end of the 24-h epoch. Two independent observers rated the video logs to identify when subjects were walking or lying down.</p> <p>Results</p> <p>The mean error in stride length at the start of recording was 0.05 m (SD 0) and at the conclusion of the 24 h epoch was 0.06 m (SD 0.026). There was full agreement between observer coding of the video logs and the output from the gait monitor software; that is, for every video observation of the subject walking there was a corresponding pulse in the monitor data that indicated gait.</p> <p>Conclusions</p> <p>The accuracy of ambulatory stride length measurement was maintained over the 24-h period, and there was 100% agreement between the autonomous detection of locomotion by the gait monitor and video observation.</p

Effects of Brightness on Distance Judgments in Head Mounted Displays

Many HMD applications are improved when people perceive and act similarly in the virtual world as they would in an equivalent real environment. However, multiple studies show people underestimate egocentric distances in HMDs while being reasonably accurate in the real world. Some studies also show that brightness in the periphery may be one factor influencing these distance judgments. We built upon this previous work and examine if the brightness of the entire screen affects distance judgments. Using direct blind-walking, we compared a bright environment to an artificially darkened one with a between-subject experiment. The results of the experiment indicate that overall brightness has no significant effect on egocentric distance judgment. We discuss the implications of our findings in the context of previous work. Our findings may help designers of HMD software featuring dark environments (e.g., some entertainment applications)

Red blood cell distribution width independently predicts medium-term mortality and major adverse cardiac events after an acute coronary syndrome

Red blood cell distribution width independently predicts medium-term mortality and major adverse cardiac events after an acute coronary syndrome

Red blood cell distribution width at emergency department admission increases the accuracy of the HEART score for predicting death in patients with chest pain

Red blood cell distribution width at emergency department admission increases the accuracy of the HEART score for predicting death in patients with chest pain

Long-duration spaceflight adversely affects post-landing operator proficiency

Moore, ST ORCiD: 0000-0003-3995-4912Performance of astronaut pilots during space shuttle landing was degraded after a few weeks of microgravity exposure, and longer-term exposure has the potential to impact operator proficiency during critical landing and post-landing operations for exploration-class missions. Full-motion simulations of operationally-relevant tasks were utilized to assess the impact of long-duration spaceflight on operator proficiency in a group of 8 astronauts assigned to the International Space Station, as well as a battery of cognitive/sensorimotor tests to determine the underlying cause of any post-flight performance decrements. A ground control group (N = 12) and a sleep restriction cohort (N = 9) were also tested to control for non-spaceflight factors such as lack of practice between pre- and post-flight testing and fatigue. On the day of return after 6 months aboard the space station, astronauts exhibited significant deficits in manual dexterity, dual-tasking and motion perception, and a striking degradation in the ability to operate a vehicle. These deficits were not primarily due to fatigue; performance on the same tasks was unaffected after a 30-h period of sleep restriction. Astronauts experienced a general post-flight malaise in motor function and motion perception, and a lack of cognitive reserve apparent only when faced with dual tasks, which had recovered to baseline by four days after landing. © 2019, The Author(s)

Torsional (roll) eye position data from all 10 subjects (mean and 95%CI) without (blue trace) and with (red trace) 5 mA GVS.

<p>There was a significant increase in ocular torsion during GVS relative to baseline, which was unaffected by repeated GVS exposure.</p

Comparison of no-GVS vs GVS Conditions (paired t-test, df = 9, two-tailed).

<p>Comparison of mean (SD) computerized dynamic posturography (CDP) composite equilibrium (EQ) score and vestibular index, and peak-to-peak ocular torsion, for each of the 14 test sessions over 36 weeks.</p><p>Comparison of no-GVS vs GVS Conditions (paired t-test, df = 9, two-tailed).</p