MedStar National Rehabilitation Hospital

Abstract Accurate diagnosis of urinary tract infection (UTI) in individuals with neurogenic lower urinary tract dysfunction (NLUTD) due to spinal cord injury or disease (SCI/D) remains a major clinical challenge. Standard diagnostic tools—including urine dipstick, urinalysis, and culture—lack population-specific reference ranges, and existing criteria are often insufficient to distinguish infection from background variability. To address this gap, we conducted a longitudinal study to define the range of “normal” variability in common urinary biomarkers among individuals with SCI/D who manage their bladders using intermittent catheterization (IC). Participants with NLUTD due to SCI/D who manage their bladders with IC provided urine samples at least two weeks apart, while asymptomatic. We assessed urinary white blood cell count, nitrite, leukocyte esterase, culture-based findings, and urine neutrophil gelatinase-associated lipocalin (uNGAL) to characterize intra-individual stability and inter-individual variation in biomarker profiles. Findings demonstrate that urine parameters exhibit measurable but bounded variability in the absence of UTI, and that deviations beyond these thresholds may support more accurate and individualized UTI diagnosis. By defining the normal range within which values vary without the emergence of symptoms, we hope to further inform clinical and researcher decision-making around variability that moves an individual beyond their normal range of variation in these urinary markers. Operationalizing biologic variability can reduce diagnostic uncertainty and improve antimicrobial stewardship in this frequently overtreated population.

Many studies have analyzed what organizational features distinguish the left and right hemispheres of the human brain, with most differences typically being found in language areas. In this analysis, we test whether supervised learning can categorize an unseen hemisphere as right or left based on functional connectivity. Using data from the Human Connectome Project, we find success to be extremely high (accuracies > .90) in right-handed participants (Edinburgh Handedness Inventory [EHI] > 0). Accuracies are still high, but slightly lower when trained on left-handed participants (EHI ≤ 0). In a third analysis, we test whether the same can be done to identify handedness along with hemisphere chirality. This does not succeed, however, we show that individuals’ hemispheres are less distinct the more left-handed they are. Our findings can inform developmental and post-injury work on hemispheric organization.

BackgroundImpaired balance regulation after stroke puts patients and therapists at a heightened risk of injury during rehabilitation. Body weight support systems (BWSS) allow patients to safely conduct gait and balance training while minimizing risk and the fear of falling. Integrating perturbation-based balance training (PBT) modules with a BWSS may lead to further improvements.ObjectiveThis study aimed to evaluate the impact of a ceiling-track-mounted BWSS plus an integrated PBT (BWSS-P) module on the rehabilitation of stroke-related gait and balance impairments.MethodsA multisite randomized active-comparator controlled trial was conducted. Inpatients with Berg Balance Scale (BBS) scores ≥21/56 were recruited from 4 sites. Participants completed 2-to-6 BWSS or BWSS-P study sessions. Both groups conducted the same balance and gait regimen, with the BWSS-P group also receiving 8 balance perturbations per session. BBS, Activities-Specific Balance Confidence, and 10 Meter Walk Test assessments were collected.ResultsA total of 126 patients were approached with 99 yielding sufficient data for analysis. With a corrected α level of .0054, both groups showed significant in-group changes over time for all outcomes evaluated (P≤.001). However, the primary outcome measure, the BBS, did not show evidence of a difference between BWSS and BWSS-P groups over time (F1,97=1.57; P=0.21) via linear mixed effects modeling with type III Wald F test with Kenward-Roger degrees of freedom. No significant between-group differences were noted for either secondary outcome measure, the Activities-Specific Balance Confidence scale (F1,94.99=0.36; P=.55), or 10 Meter Walk Test (F1,97=4.15; P=.04).ConclusionsAlthough significant between-group differences were not observed, participants in both groups demonstrated similar improvements from before to after assessment. This novel PBT technology shows promise as an option for gait and balance recovery training, especially for individuals with impaired balance control or fear of falling. The BWSS-P intervention contributed positively to rehabilitation outcome overall and should be considered as a viable treatment modality when clinically appropriate.

Left hemisphere stroke causes functional changes to the language network and may shift aspects of language processing to right hemisphere homotopes of perisylvian language regions. The result of right hemisphere recruitment is unclear. Studies suggest the right pars triangularis (rPTr) engagement in language processing corresponds to higher dysfunction. As a result, the region is a site for inhibitory neuromodulation, with evidence that inhibiting the region improves language function in persons with aphasia (PWA). However, studies have also found no relationship between rPTr functional activity and language performance in PWA. The mixed evidence regarding the rPTr suggests additional work is needed to understand the role of the region in PWA. We propose that the white matter connections that support communication between regions may be an important mediator. Thus, we sought to investigate if left hemisphere stroke leads to changes in the structural topological properties of the region. We used measures from network control theory (NCT) to compare the theoretical capacity of the rPTr to integrate communication across brain modules (i.e., boundary controllability [BC]) in the brain, in 60 PWA and 62 controls. We also examined whether BC corresponded to different aspects of language processing (i.e., semantic and phonological) in PWA. We found that PWA had a higher BC in the rPTr relative to controls. Higher BC was associated with fewer phonological errors in a picture naming task. These findings suggest that left hemisphere stroke causes shifts in the structural role of right hemisphere regions that relate to language processing in PWA.

Native signers have life-long expertise with a visual-gestural language that is produced by movements of the hands through space and constrained by spatial features, such as orientation, movement path, location, and handshape. Because language is typically lateralized to the brain’s left hemisphere, lifelong processing of visual-spatial linguistic features might also result in left-lateralized processing of non-linguistic visual-spatial materials in native signers. Consistent with this hypothesis, behavioral studies have reported enhanced motion, velocity, and orientation discrimination among signers when stimuli are presented in the right visual field, and one fMRI study found a leftward shift in activation of motion processing area MT-MST for native signers viewing moving flow fields. However, few other imaging studies have investigated MT-MST lateralization in signers, and heterogeneous subject samples make interpretation difficult. Here we used fMRI to investigate lateralization for processing coherent motion in 19 deaf native signers and 19 hearing non-signers, contrasting a coherent motion direction judgment task with viewing of static dots (control). Group-level activation maps revealed bilateral MT-MST activation in both deaf and hearing participants and no significant group differences in lateralization (p=0.80). Compared to hearing participants, deaf subjects showed significant activation in auditory motion regions (p=0.002), which was lateralized to the right hemisphere. These results align with auditory deprivation research showing cross-modal changes in the deaf, with RH dominance in auditory motion regions for processing coherent motion. However, the findings do not support previous reports on LH lateralization for visual processing due to life-long sign exposure.

Urinary tract infection (UTI) is the most common infection for people with neurogenic lower urinary tract dysfunction (NLUTD) due to spinal cord injury/disease (SCI/D). While the current diagnostic pillars include symptoms, inflammation, and bacterial load, each is uniquely problematic when applied to NLUTD-related UTI. Authoritative guidelines have not taken into account the impact of bladder management on symptoms; baseline inflammation in the absence of symptoms limits usefulness of white blood count; and bacteriuria in the absence of symptoms and limitations of standard urine culture (SUC) limits utility of SUC-based determination of bacterial load. Newer approaches are being developed to better guide diagnosis and antibiotic use. These include the Urinary Symptom Questionnaires for Neurogenic Bladder for symptom measurement and decision-making around symptoms, novel inflammatory markers (urine NGAL, IL-1, and IL-8), and culture-independent microbial detection methods. Rapid antimicrobial susceptibility testing (AST) methods have been developed utilizing a number of different approaches, increasing the likelihood of point-of-care application in the future. Advancements in UTI diagnosis will include reconceptualization of "urine is sterile" to "eubiosis and dysbiosis," symptom complexes to aid decision-making, use of novel inflammatory markers, and less reliance on SUC with increased emphasis on culture-independent methods for bacterial identification, AST, and decision-making.