Faculty Bibliography

Stroke recovery outcomes vary across individuals, motivating the search for biomarkers that can improve prediction. White matter hyperintensities (WMH) volume is a leading biomarker candidate, with FLAIR MRI typically used for WMH segmentation; however, T1-weighted (T1) MRI is often more available. Therefore, we evaluated the performance of two automated WMH segmentation methods (WMH-SynthSeg, SAMSEG) to determine whether WMH volume can be reliably estimated using T1 alone. We analyzed imaging data from 227 stroke patients across three datasets spanning early subacute to chronic recovery, with gold-standard WMH masks and stroke lesion masks manually traced on available T1 and FLAIR scans. WMH was segmented using T1 only as input to WMH-SynthSeg and SAMSEG, as well as using both T1 and FLAIR as input to SAMSEG, as previously implemented in stroke recovery research. Automated WMH segmentations were compared to the gold-standard WMH mask: spatial accuracy was assessed using Dice similarity index (SI) and cluster-level false negative ratio, while volumetric agreement was assessed using intraclass correlation, Pearson's correlation, and volume ratio. We used linear mixed-effects models to evaluate whether SI was influenced by factors such as WMH volume, stroke lesion volume, WMH contrast, age, sex, and days since stroke, with dataset as a random effect. WMH-SynthSeg using T1-only input produced more accurate and reliable WMH segmentations compared to SAMSEG with T1-only input and performed comparably to SAMSEG using both T1 and FLAIR input. WMH-SynthSeg using T1-only input may be used for WMH volume estimation in stroke recovery research in the absence of multimodal imaging.

Historically hindered by a lack of access to academic, political, financial, technological, scientific, and social resources, most people living with disability have been unable to successfully merge their lived experience with the traditional research process. The lack of this community's perspective has been an ongoing missed opportunity for the broadening and relevance of research around disability. Patient-scientists, however, bridge the gap. They are individuals who act as patient research partners (PRPs) with the valuable addition of a research and/or medical degree. Their embodied expertise, combined with their academic accreditation, seamlessly positions them to work within the academic system. With a foot in both worlds, they are equipped to generate real change for themselves and others living with their condition. Patients are encouraged to participate in their own clinical care, although PRPs remain relatively uncommon. Even more scarce are patient-scientists, who serve as intellectual peers with expertise in technical and experiential domains. Their research training gives them an invaluable role: to act as both scientist and patient at once. This special communication builds on ongoing efforts to bolster patient participation in rehabilitation research by focusing on patient-scientists and highlighting their potential to enhance rehabilitation research processes.

The Global Navigation Satellite System (GNSS) is commonly used for outdoor positioning. However, its effectiveness diminishes in urban canyons and indoor environments attributed to signal blockage. This study aims to explore the potential of GNSS signals penetrating indoor spaces through windows and to enhance indoor positioning with Three-Dimensional Mapping-Aided (3DMA) GNSS, a concept generally applied outdoors. The research employs a 3D model of a corridor with manually labeled window locations to predict satellite visibility within indoor areas. The study integrates Pedestrian Dead Reckoning (PDR) with an indoor Shadow-matching (I-SM) technique, utilizing an Extended Kalman Filter (EKF) to improve positioning accuracy. One of the findings indicates that the proposed method significantly enhances positioning performance and its availability, achieving a root mean square error (RMSE) that is 2 m better than using PDR alone or single epoch I-SM. The study concludes that integrating GNSS with I-SM technique and PDR can optimize an indoor positioning solution and highlights the potential for improved navigation solutions in complex urban environments.

BACKGROUND:Individuals with sensory processing disorders (SPDs) face challenges in wayfinding due to heightened sensitivity to environmental stimuli like noise and lighting. Although sensory maps have aided SPD individuals by aligning navigational routes with sensory needs, standardized protocols for creating these maps are lacking, with current methods largely qualitative. OBJECTIVE:This study aimed to establish a standardized, quantitative protocol for sensory map creation, evaluating sound, brightness, and crowding density in a healthcare setting to enhance map precision and support future automation. METHODS:Sensory data were collected from the 1st and 17th floors of a large urban ambulatory care center in New York City. A qualitative spatial audit was initially conducted, followed by quantitative measurements of sound (decibels), brightness (lux), and crowding density at designated nodes. Using Python, we developed Voronoi diagrams to visualize intensity distributions across floorplans, applying statistical methods to ensure data accuracy and consistency. RESULTS:Qualitative assessments identified high-stimulus areas, particularly in the main lobby and elevator zones, which aligned closely with quantitative findings. Brightness peaked in central, naturally lit areas, while noise levels were highest near heating, ventilation, and air conditioning (HVAC) systems and entry points. The quantitative method enabled a more nuanced representation, enhancing map detail and reliability. CONCLUSIONS:The developed quantitative protocol offers a robust framework for sensory mapping, improving accessibility for individuals with SPDs in complex spaces. This approach holds potential for automation, addressing current reproducibility limitations and advancing inclusive design in public and healthcare settings.

PURPOSE/UNASSIGNED:Navigating urban environments poses significant challenges for individuals who are blind or have low vision, especially in areas affected by construction. Construction zones introduce hazards such as uneven surfaces, barriers, hazardous materials, excessive noise, and altered routes that obstruct familiar paths and compromise safety. Although navigation tools assist in trip planning, they often overlook these temporary obstacles. Existing hazard detection systems also struggle with the visual variability of construction sites. METHODS/UNASSIGNED:We developed a computer vision-based assistive system integrating three modules: an open-vocabulary object detector to identify diverse construction-related elements, a YOLO-based model specialised in detecting scaffolding and poles, and an optical character recognition module to interpret construction signage. RESULTS/UNASSIGNED:In static testing at seven construction sites using images from multiple stationary viewpoints, the system achieved 88.56% overall accuracy. It consistently identified relevant objects within 2-10 m and at approach angles up to 75°. At 2-4 m, detection was perfect (100%) across all angles. Even at 10 m, six of seven sites remained detectable within a 15° approach. In dynamic testing along a 0.5-mile urban route containing eight construction sites, the system analysed every frame of a first-person walking video. It achieved 87.26% accuracy in distinguishing construction from non-construction areas, rising to 92.0% with a 50-frame majority vote filter. CONCLUSION/UNASSIGNED:The system can reliably detect construction sites in real time and at sufficient distances to provide advance warnings, enabling individuals with visual impairments to make safer mobility decisions, such as proceeding with caution or rerouting.

BACKGROUND/UNASSIGNED:Outdoor navigation poses significant challenges for people with blindness or low vision, yet the role of gaze behaviour in supporting mobility remains underexplored. Fully sighted individuals typically adopt consistent scanning strategies, whereas those with visual impairments rely on heterogeneous adaptations shaped by residual vision and experience. METHODS/UNASSIGNED:We conducted a comparative eye-tracking study of fully sighted, low vision, blind, and fully blind participants navigating outdoor routes. Using a wearable eye tracker, we quantified fixation counts, fixation rate, fixation area, direction, peak fixation location, and walking speed. RESULTS/UNASSIGNED:Walking speed declined systematically with worsening vision. Fixation count increased with greater impairment, reflecting slower travel times and more frequent sampling. Fixation rate differed across groups, though between-group differences were generally not significant between most groups. Fixation spatial coverage decreased along the continuum of vision loss. Fixation patterns were most consistent in the fully sighted group. Peak fixation locations were centred in fully sighted participants but shifted outward and became more variable with impairment. CONCLUSION/UNASSIGNED:Gaze strategies during navigation form a graded continuum across vision groups, with fully sighted and fully blind participants at opposite poles and low vision and blind groups spanning the middle. Visual acuity alone does not predict functional gaze use, as rehabilitation experience and adaptive strategies strongly shape behaviour. These findings highlight the need for personalised rehabilitation and assistive technologies, with residual gaze patterns offering insight into mobility capacity and training opportunities for safer navigation.IMPLICATIONS FOR REHABILITATIONDistinct Residual Vision Patterns: This research reveals that residual vision patterns differ significantly, with fully sighted individuals exhibiting a consistent fixation pattern while low vision participants show more varied strategies during navigation.Highly Individualised Gaze Behaviours: Low vision participants demonstrate highly individualised gaze behaviours, indicating that a one-size-fits-all approach is inadequate for effective rehabilitation.Tailored Assistive Solutions: Assistive technologies and rehabilitation programs should be designed to address these unique, individualised needs, providing personalised feedback and training to enhance mobility and safety.

AIM/UNASSIGNED:Sensory substitution devices (SSDs) can convert environmental information into an accessible format for people who are blind or have low vision (pBLV). Yet, current SSDs often passively deliver all of the information available with limited user control, potentially leading to confusion and/or cognitive overload. To address this issue, this work proposes a selective, gesture-controlled system intended to improve information relevance and reduce cognitive overload. METHODS/UNASSIGNED:We present Point-To-Tell 2, a system that enables pBLV to privately and efficiently select which information to convey through simple pointing-based gestural control. By integrating a monocular camera with AI-driven pipelines for depth estimation, hand pose tracking, and object detection/segmentation, the system identifies the users' 3D pointing direction and announces the names and distances of objects as they are pointed at, thereby connecting an object's spatial position and identity through hand proprioception. RESULTS/UNASSIGNED:Validation tests in controlled indoor environments show high hand pose tracking accuracy, ensuring reliable ray-casting and object selection despite declining object recognition at longer distances. Distance estimates are stable at close range, though a systematic bias is present. CONCLUSION/UNASSIGNED:This work introduces and technically validates an assistive system designed to improve the usability of assistive technologies by focusing system feedback-potentially reducing users' cognitive load and enhancing their spatial comprehension by leveraging concurrent hand proprioception. Future work will involve user testing and expanding system features to further enhance its practicality across more diverse scenarios.

After stroke, upper extremity (UE) motor recovery may be mediated in part by transcallosal projections between hemispheres. The interhemispheric competition model posits that transcallosal inhibition (TI) from the contralesional hemisphere is abnormally strengthened following stroke and interferes with motor recovery. This model has recently been questioned. In this longitudinal study, we aimed to definitively confirm or refute a maladaptive role of contralesional TI in subacute motor recovery. We assessed 30 mild-to-moderately impaired subjects over the six months following ischemic stroke. We tracked contralesional TI and motor functions in the proximal and distal segments of the paretic UE. We used transcranial magnetic stimulation to examine the ipsilateral silent period (iSP) in an arm and hand muscle. We used quantitative and clinical testing to examine deficits in muscle strength, motor control, and individuation; UE segmental impairment; and UE activity limitation. We assessed the relationships of contralesional TI to motor functions in the subacute period. Despite recovery of most motor functions in the proximal and distal UE, contralesional TI was largely static and unrelated to recovery of any motor function. There were inconsistent associations between stronger TI, less hand impairment, and less activity limitation in the subacute period overall. We found no compelling evidence to suggest a maladaptive role of contralesional TI in UE motor recovery in mild-to-moderately impaired stroke subjects. The scattered associations between stronger TI and better levels of paretic UE function suggest a potential supportive role rather than a limiting one. These findings challenge the validity of the interhemispheric competition model in the subacute recovery period, and prompt reconsideration of neuromodulatory strategies that subacutely target contralesional TI.

INTRODUCTION/BACKGROUND:Poststroke depression affects approximately 30% of stroke survivors and is linked to worse functional outcomes, cognitive decline, reduced quality of life and increased mortality. While early treatment of poststroke mental health conditions is critical, current pharmacological options offer limited efficacy. Music listening interventions are a promising, low-risk, accessible and affordable alternative that may enhance recovery through engagement of reward-related brain circuits. However, most music listening studies have focused on the acute stage of stroke, lack objective measures of music engagement and rarely assess underlying neural mechanisms. To address these gaps, we propose a feasibility study of a remotely delivered music-listening intervention for individuals with chronic stroke, incorporating objective tracking of music exposure and multimodal assessments of mental health, cognitive, neural and physiological changes. METHODS AND ANALYSIS/METHODS:We will conduct a parallel group randomised controlled feasibility trial enrolling 60 patients with chronic stroke from a well-characterised stroke registry in New York City. Participants will be randomised to either an intentional music listening (IML) group or an active control group that listens to audiobooks. The study includes a 4-week preintervention period during which no treatment is administered; this phase is designed to assess the stability of outcome measures. Following this, participants will engage in 1-hour daily listening sessions over a 4-week intervention period. All listening activity (ie, track identity, duration and engagement) will be continuously tracked using custom open-source software, providing a measure of treatment dose. Behavioural outcomes related to mental health will be assessed at baseline, preintervention, postintervention and 3-month follow-up. Multimodal biomarkers (functional and structural MRI, electrodermal activity and heart rate) will be collected preintervention and postintervention. The primary objective is to establish feasibility, defined by rates of retention and adherence, treatment fidelity, feasibility, acceptability and participant burden. Secondary outcomes include recruitment and randomisation rates. This trial will provide essential data to inform the design of future large-scale clinical studies of IML for poststroke mental health recovery. ETHICS AND DISSEMINATION/BACKGROUND:The study was approved by New York University's Institutional Review Board (FY2024-8826). All human participants will provide written informed consent prior to participation and will be adequately compensated for their time. Results will be reported in peer-reviewed journals. TRIAL REGISTRATION NUMBER/BACKGROUND:NCT07127159.