Leg Sympathetic Response to Noxious Skin Stimuli is Similar in High and Low Level Human Spinal Cord Injury

Objective To determine if sympathetically mediated vasoconstriction in the lower extremities is injury level dependent. Although sympathetic responses have been measured in the limbs of people with high and low level SCI using blood flow measurements, including Doppler ultrasound and venous plethysmography, a direct comparison between injury levels has not been made. Methods Volunteers with chronic SCI were grouped according to injury level. Above T6: high level (HL, n = 7), and T6 and below: low level (LL, n = 6). All subjects had complete motor and sensory loss. Leg arterial flows were recorded by venous occlusion plethysmography, and continuous heart rate and mean arterial pressure (MAP) were measured. The conditioning stimulus consisted of transcutaneous stimulation to the arch of the contralateral foot. Results HL and LL subjects demonstrated a significant decrease in arterial conductance during stimulation with no significant difference found between groups. As expected, only group HL demonstrated a significant increase in MAP. Conclusions These results support our hypothesis that local (leg) sympathetic responses are similar for both high and low level SCI. Significance While low level SCI does not typically present with autonomic dysreflexia, bouts of increased reflex sympathetic activity could have ramifications for metabolism as well as renal and motor system functio

Leg Sympathetic Response to Noxious Skin Stimuli is Similar in High and Low Level Human Spinal Cord Injury

Objective To determine if sympathetically mediated vasoconstriction in the lower extremities is injury level dependent. Although sympathetic responses have been measured in the limbs of people with high and low level SCI using blood flow measurements, including Doppler ultrasound and venous plethysmography, a direct comparison between injury levels has not been made. Methods Volunteers with chronic SCI were grouped according to injury level. Above T6: high level (HL, n = 7), and T6 and below: low level (LL, n = 6). All subjects had complete motor and sensory loss. Leg arterial flows were recorded by venous occlusion plethysmography, and continuous heart rate and mean arterial pressure (MAP) were measured. The conditioning stimulus consisted of transcutaneous stimulation to the arch of the contralateral foot. Results HL and LL subjects demonstrated a significant decrease in arterial conductance during stimulation with no significant difference found between groups. As expected, only group HL demonstrated a significant increase in MAP. Conclusions These results support our hypothesis that local (leg) sympathetic responses are similar for both high and low level SCI. Significance While low level SCI does not typically present with autonomic dysreflexia, bouts of increased reflex sympathetic activity could have ramifications for metabolism as well as renal and motor system functio

An efficient shooting algorithm for Evans function calculations in large systems

In Evans function computations of the spectra of asymptotically constant-coefficient linear operators, a basic issue is the efficient and numerically stable computation of subspaces evolving according to the associated eigenvalue ODE. For small systems, a fast, shooting algorithm may be obtained by representing subspaces as single exterior products \cite{AS,Br.1,Br.2,BrZ,BDG}. For large systems, however, the dimension of the exterior-product space quickly becomes prohibitive, growing as $\binom{n}{k}$, where $n$ is the dimension of the system written as a first-order ODE and $k$ (typically $\sim n/2$) is the dimension of the subspace. We resolve this difficulty by the introduction of a simple polar coordinate algorithm representing ``pure'' (monomial) products as scalar multiples of orthonormal bases, for which the angular equation is a numerically optimized version of the continuous orthogonalization method of Drury--Davey \cite{Da,Dr} and the radial equation is evaluable by quadrature. Notably, the polar-coordinate method preserves the important property of analyticity with respect to parameters.Comment: 21 pp., two figure

Improvement of decadal predictions of monthly extreme Mei-yu rainfall via a causality guided approach

While the improved performance of climate prediction systems has allowed better predictions of the East Asian Summer Monsoon rainfall to be made, the ability to predict extreme Mei-yu rainfall (MYR) remains a challenge. Given that large scale climate modes (LSCMs) tend to be better predicted by climate prediction systems than local extremes, one useful approach is to employ causality-guided statistical models (CGSMs), which link known LSCMs to improve MYR prediction. However, previous work suggests that CGSMs trained with data from 1979–2018 might struggle to model MYR in the pre-1978 period. One hypothesis is that this is due to potential changes in causal processes, which modulate MYR in different phases of the multidecadal variability, such as the Pacific decadal oscillation (PDO). In this study, we explore this hypothesis by constructing CGSMs for different PDO phases, which reflect the different phases of specific causal process, and examine the difference in quality as well as with respect to difference drivers and thus causal links between CGSMs of different PDO phases as well as the non-PDO phase specific CGSMs. Our results show that the set of predictors of CGSMs is PDO phase specific. Furthermore, the performance of PDO phase specific CGSMs are better than the non-PDO phase specific CGSMs. To demonstrate the added value of CGSMs, the PDO phase specific versions are applied to the latest UK Met Office decadal prediction system, DePreSys4, and it is shown that the root-mean squared errors of MYR prediction based on PDO phase specific CGSMs is consistently smaller than the MYR predicted based on the direct DePreSys4 extreme rainfall simulations. We conclude that the use of a causality approach improves the prediction of extreme precipitation based solely on known LSCMs because of the change in the main drivers of extreme rainfall during different PDO-phases

Pilot Study: Assistive Technology as a Vocational Support for Individuals with Autism Spectrum Disorder

The purpose of this pilot study was to determine the effectiveness of video-based instruction (VBI) to support completion of vocational tasks. A mixed-method approach was utilized to explore the use of VBI on a personal digital assistant with individuals with autism spectrum disorder (ASD). Using two assembling cooking tasks, researchers investigated the level of independence with task completion through written instruction versus VBI. The results indicated a small non-significant increase in the level of independence with task completion during the VBI task independent of intelligence quotient (IQ) levels. Participant’s feedback of VBI was also noted as positive to help learn other tasks. This study presents evidence for the use of assistive technology to support task completion in the area of vocation for individuals with ASD

Pilot Study: Assistive Technology as a Vocational Support for Individuals with Autism Spectrum Disorder

The purpose of this pilot study was to determine the effectiveness of video-based instruction (VBI) to support completion of vocational tasks. A mixed-method approach was utilized to explore the use of VBI on a personal digital assistant with adults with autism spectrum disorder. Using two assembling cooking tasks, researchers investigated the level of independence with task completion through written instruction versus VBI. The results indicated a small non-significant increase in the level of independence with task completion during the intervention task independent of intelligence quotient (IQ) levels. Participant’s feedback of VBI was also noted as positive to help learn other tasks. This study presents evidence for the use of assistive technology to support task completion in the area of vocation.https://scholar.dominican.edu/ug-student-posters/1067/thumbnail.jp