Impaired Navigation Research Articles

How spatial-cue reliability affects navigational performance in young and older adults

ABSTRACT Navigational abilities decline with age, but the cognitive underpinnings of this cognitive decline remain partially understood. Navigation is guided by landmarks and self-motion cues, that we address when estimating our location. These sources of spatial information are often associated with noise and uncertainty, thus posing a challenge during navigation. To overcome this challenge, humans and other species rely on navigational cues according to their reliability: reliable cues are highly weighted and therefore strongly influence our spatial behavior, compared to less reliable ones. We hypothesize that older adults do not efficiently weigh spatial cues, and accordingly, the reliability levels of navigational cues may not modulate their spatial behavior, as with younger adults. To test this, younger and older adults performed a virtual navigational task, subject to modified reliability of landmarks and self-motion cues. The findings revealed that while increased reliability of spatial cues improved navigational performance across both age groups, older adults exhibited diminished sensitivity to changes in landmark reliability. The findings demonstrate a cognitive mechanism that could lead to impaired navigation abilities in older adults.

In search of strategies to mitigate financial toxicity in survivorship care: A survey of 347 head and neck cancer survivors.

11060 Background: High costs of cancer treatment exert substantial financial toxicity for patients undergoing treatment. Growing literature suggests lasting financial toxicity (FT) after treatment completion. This calls for the development and integration of mitigating strategies in survivorship care to reduce FT; thereby improving the overall well-being of survivors. Methods: Cross-sectional survey data from 347 head and neck cancer survivors were analyzed to explore the relationship between FT and potential targets for intervention. We measured FT using the COmprehensive Score for financial Toxicity (COST, v1), and defined severe, moderate, and mild-to-no FT as having COST score ≤13, 14 to 25, and ≥26, respectively. The survey also collected information on demographics, quality of life, work and activity impairment, and cancer care coordination (CCC) communication and navigation subscales. We conducted logistic regression to examine which COST item is most predictive of severe FT, and mediation analysis using structural equation model to explore potential targets for interventions to reduce FT. Results: The average age of respondents was 65.5 yrs (SD=11.3). 334 completed COST; 6.3%, 22.2% reported severe and moderate FT, respectively. Study cohort included 20% diagnosed within 2 yrs, 45% 3-4 yrs and 35% ≥5 yrs; the proportion of patients reporting severe FT did not decrease by year since diagnosis (6%, 5.3%, and 7.7%, respectively, P=0.73). Of the 11 items in COST, financial stress was most predictive of severe FT. Survivors who rated financial stress as “very much” or “quite a bit” were 92.8 (P=0.02) times more likely to have severe FT. Higher financial stress was significantly associated with being < age 65, having higher comorbidity score, lower CCC-navigation score, higher activity impairment; navigation and activity impairment are potentially actionable. None of these four variables were statistically significantly associated with severe FT. Mediation analysis showed financial stress has strong mediation effect on severe FT, and survivors with low CCC-navigation scores and high activity impairment were 3.2 times (95% CI: 1.3 – 7.8; P=0.01) and 2.5 (95% CI: 1.1 – 5.2; P=0.02) more likely, respectively, to report high financial stress. Survivors with high financial stress were significantly more likely to be interested or very interested in receiving resources covering financial issues compared to those without (63.4% vs 17.8%, P<0.01). Conclusions: Survivorship care that incorporates interventions designed to improve coordination and navigation and decrease activity impairment can potentially mitigate FT for cancer survivors through reducing their financial stress. The Centers for Medicare and Medicaid Services began paying for navigation services in 2024, opening the opportunity to integrate these interventions into covered navigation services.

Development of a Prototype Global Positioning System Based Stick for Blind Patients

This paper presents a novel vision impairment assistive device to improve mobility and independence. This device consists of Arduino Nano microcontroller technology that powers the Satellite/GPS-based stick, which tracks and navigates in real-time. Arduino Nano’s adaptability and compactness enable our portable, affordable white cane replacement. Satellite signals let the stick locate the user, compute the best routes, and provide aural navigation cues through speakers or headphones. The obstacle detection sensors notify users of adjacent risks, improving safety. The proposed device is a stable and user-friendly technology that delivers a potential answer to visually impaired navigation issues after rigorous development and testing.

Effects of older age on visual and self-motion sensory cue integration in navigation.

Older adults demonstrate impairments in navigation that cannot be explained by general cognitive and motor declines. Previous work has shown that older adults may combine sensory cues during navigation differently than younger adults, though this work has largely been done in dark environments where sensory integration may differ from full-cue environments. Here, we test whether aging adults optimally combine cues from two sensory systems critical for navigation: vision (landmarks) and body-based self-motion cues. Participants completed a homing (triangle completion) task using immersive virtual reality to offer the ability to navigate in a well-lit environment including visibility of the ground plane. An optimal model, based on principles of maximum-likelihood estimation, predicts that precision in homing should increase with multisensory information in a manner consistent with each individual sensory cue's perceived reliability (measured by variability). We found that well-aging adults (with normal or corrected-to-normal sensory acuity and active lifestyles) were more variable and less accurate than younger adults during navigation. Both older and younger adults relied more on their visual systems than a maximum likelihood estimation model would suggest. Overall, younger adults' visual weighting matched the model's predictions whereas older adults showed sub-optimal sensory weighting. In addition, high inter-individual differences were seen in both younger and older adults. These results suggest that older adults do not optimally weight each sensory system when combined during navigation, and that older adults may benefit from interventions that help them recalibrate the combination of visual and self-motion cues for navigation.

VisiSense: A Comprehensive IOT-based Assistive Technology System for Enhanced Navigation Support for the Visually Impaired

The field of visually impaired assistive technology looks for novel approaches to enhance independence and navigation. In this field, systems have to reliably identify and transmit environmental data in order to facilitate visually impaired users' safe and effective navigation. Developing a sophisticated framework for assistive technology that significantly enhances visually impaired navigation is the goal of this research. Make object detection and environmental awareness more efficient, dependable, and intuitive. This study introduces VISISENSE, "A Comprehensive IoT-Based Assistive Technology System for Enhanced Navigation Support for the Visually Impaired." VISISENSE is an IoT-based system with multiple components that enhances object detection. For primary environmental sensing, a handstick with implant sensors, a visual capture and transmission unit for processing visual data, and edge computing for object detection and classification are used. The system makes use of the R-CNN global computer vision model hosted on a cloud server, Mobinet computer vision models, and Logistic Regression with Iterative Learning. VISISENSE's effectiveness is demonstrated by a performance analysis of its object detection accuracy, processing speed, resource utilization, energy consumption, latency, and false positive rate. In all of these categories, VISISENSE performs better than Smart Stick and Smart Navigation. The data includes the fastest processing time of 17 ms, the most efficient resource utilization of 41%, and object detection accuracy of up to 99% at 2 Mbps load. Across all load conditions, VISISENSE has the lowest false positive rate, energy consumption, and latency. The VISISENSE assistive technology system is developed for the visually impaired. Its excellent object detection and navigation accuracy, speed, and efficiency enhance user experience and hold the potential to increase the independence and quality of life for visually impaired people. This research contributes to a significant advancement in assistive devices-smart, responsive technologies for the visually impaired.

Avoidance, confusion or solitude? Modelling how noise pollution affects whale migration

Many baleen whales are renowned for their acoustic communication. Under pristine conditions, this communication can plausibly occur across hundreds of kilometres. Frequent vocalisations may allow a dispersed migrating group to maintain contact, and therefore benefit from improved navigation via the “wisdom of the crowd”. Human activities have considerably inflated ocean noise levels. Here we develop a data-driven mathematical model to investigate how ambient noise levels may inhibit whale migration. Mathematical models allow us to simultaneously simulate collective whale migration behaviour, auditory cue detection, and noise propagation. Rising ambient noise levels are hypothesised to influence navigation through three mechanisms: (i) diminished communication space; (ii) reduced ability to hear external sound cues and; (iii) triggering noise avoidance behaviour. Comparing pristine and current soundscapes, we observe navigation impairment that ranges from mild (increased journey time) to extreme (failed navigation). Notably, the three mechanisms induce qualitatively different impacts on migration behaviour. We demonstrate the model’s potential predictive power, exploring the extent to which migration may be altered under future shipping and construction scenarios.

The feasibility and practicality of auxiliary detection of spatial navigation impairment in patients with mild cognitive impairment due to Alzheimer's disease by using virtual reality

BackgroundSpatial disorientation in patients with mild cognitive impairment due to Alzheimer's disease (MCI due to AD) has become a subject of great interest. Medical practitioners are concerned about the serious issue of these patients who are getting lost. Therefore, the early detection of MCI due to AD is crucial. New methodsWe designed virtual reality (VR) protocols to test spatial recognition abilities. Our devices mainly included the Vive Pro Eye and the Steam VR program. We tested the three groups: young cognitively unimpaired (YCU), older cognitively unimpaired (OCU) and MCI due to AD. We also administered the Cognitive Abilities Screening Instrument and the Questionnaire on Everyday Navigational Ability for comparison. ResultsWe adopted the testing results of 2 YCU, 3 OCU, and 4 MCI due to AD for analysis. Concerning cognitive abilities, YCU and OCU had better performance than MCI due to AD respectively. It was consistent with the recent memory and the total scores of the Cognitive Abilities Screening Instrument. Comparison with existing methodsWe introduced a real-life setting, the Tzu-Chiang campus at National Cheng Kung University, into the VR environment. It allowed us to assess daily road-recognizing abilities of participants in a controlled testing environment. ConclusionsSeveral limitations were considered in this study, such as limited number of participants and low-quality images on the screen. Nonetheless, this device has the potential to serve as a screening tool for MCI due to AD based on its feasibility and practicality.

Functional Dizziness as a Spatial Cognitive Dysfunction.

(1) Background: Persistent postural-perceptual dizziness (PPPD) is a common chronic dizziness disorder with an unclear pathophysiology. It is hypothesized that PPPD may involve disrupted spatial cognition processes as a core feature. (2) Methods: A cohort of 19 PPPD patients underwent psycho-cognitive testing, including assessments for anxiety, depression, memory, attention, planning, and executive functions, with an emphasis on spatial navigation via a virtual Morris water maze. These patients were compared with 12 healthy controls and 20 individuals with other vestibular disorders but without PPPD. Vestibular function was evaluated using video head impulse testing and vestibular evoked myogenic potentials, while brain magnetic resonance imaging was used to exclude confounding pathology. (3) Results: PPPD patients demonstrated unique impairments in allocentric spatial navigation (as evidenced by the virtual Morris water maze) and in other high-demand visuospatial cognitive tasks that involve executive functions and planning, such as the Towers of London and Trail Making B tests. A factor analysis highlighted spatial navigation and advanced visuospatial functions as being central to PPPD, with a strong correlation to symptom severity. (4) Conclusions: PPPD may broadly impair higher cognitive functions, especially in spatial cognition. We discuss a disruption in the creation of enriched cognitive spatial maps as a possible pathophysiology for PPPD.

Spatial navigation performance differentiates Alzheimer´s disease biomarker positive and biomarker negative cognitively impaired older adults

AbstractBackgroundSpatial navigation deficits including egocentric (body‐centered) and allocentric (world‐centered) navigation impairment are present early in Alzheimer´s disease (AD). We evaluated a potential of a realistic‐looking spatial navigation task to differentiate older adults with amnestic mild cognitive impairment (aMCI) who have positive AD biomarkers (AD aMCI) from those with negative AD biomarkers (non‐AD aMCI).MethodParticipants with AD aMCI (n = 24), non‐AD aMCI (n = 25), mild AD dementia (n = 14) and cognitively normal (CN) older adults (n = 35) underwent spatial navigation assessment in the virtual Supermarket task. Participants passively travelled through the supermarket and followed different routes to reach specific locations. In the final location, the participants had to indicate their starting location (egocentric heading) and their current location and final heading orientation on an aerial spatial map of the supermarket (distance from the correct location and allocentric heading, respectively, both measures of allocentric navigation).ResultIn the egocentric heading, the AD aMCI and mild AD dementia groups indicated their original starting location less accurately than the CN group (p<0.001) and with similar accuracy as the non‐AD aMCI group (p> = 0.219). The non‐AD aMCI group did not significantly differ from the CN group (p = 0.055). In the first allocentric task (distance from the correct location), the AD aMCI group and mild AD dementia groups indicated their positions on a paper aerial map of the supermarket with greater distance errors compared to the non‐AD aMCI group (p< = 0.013) and CN (p<0.001) groups. The non‐AD aMCI group had comparable performance to the CN group (p = 0.172). In the second allocentric task (allocentric heading), both the AD aMCI and mild AD dementia groups made more errors indicating final heading orientation than the non‐AD aMCI (p< = 0.040) and the CN (p<0.001) groups. The non‐AD aMCI group had worse performance than the CN group (p = 0.004). The sensitivity and specificity for discriminating AD aMCI and non‐AD aMCI was 72% and 71%, respectively.ConclusionBoth, egocentric and allocentric spatial navigation tasks detected spatial navigation impairment in older adults with AD aMCI. However, only the allocentric tasks differentiated AD aMCI from non‐AD aMCI. The virtual Supermarket task has a potential to become a screening tool for early AD‐related spatial navigation deficits.

Rescuing impaired cortical‐hippocampal interactions during sleep with 40Hz stimulation directed to hippocampus in 3xTg‐AD/PVcre mice

AbstractBackgroundIn preclinical Alzheimer’s disease (AD), spatial learning and memory is impaired (Allison et al., 2016). We reported similar impairments in 6‐month 3xTg‐AD female mice on a virtual spatial‐reorientation‐task (VM) that requires memory for using landmarks to navigate (Cushing et al., 2020). Memory replay during sleep is critical for learning related plasticity (Ego‐Stengel & Wilson, 2009; Jadhav et al, 2012; Maingret et al, 2016), and hippocampal‐cortical dysfunction is a potential mechanism for memory impairments in AD (Gennaro et al, 2017; Khan et al, 2014). Consistent with this hypothesis, we previously found deficits in hippocampal‐parietal cortex (HPC‐PC) coordination during sleep coinciding with impairments on the VM (Cushing et al, 2020). 40Hz stimulation has been shown to clear AD pathology in mice (Iaccarino et al, 2016; Martorell et al, 2019), and improve functional connectivity in preclinical AD patients (He et al, 2021), but see (Soula et al, 2023).MethodThus, we assessed HPC‐PC coordination in 3xTg‐AD/PVcre mice learning the VM. We implanted a 16‐tetrode recording array targeting PC and HPC and an optical fiber targeting HPC. Daily recording sessions of rest‐task‐rest commenced as mice learned the VM, followed by HPC optogenetic stimulation, with either 40Hz or SHAM stimulation. We assessed sleep quality metrics, delta waves (DW) in PC, and HPC markers of memory replay (SWRs) during slow wave sleep (SWS).ResultIn SHAM stimulated mice SWR‐DW cross‐correlations were reduced, similar to 3xTg‐AD mice (Cushing et al, 2020); while in the 40Hz stimulated mice, this phase‐locking was rescued. Furthermore, the 40Hz stimulated mice have restored performance on the VM compared to SHAM mice. However, this rescued HPC‐PC coupling no longer predicted performance as in NonTg animals (Cushing et al, 2020). Instead, DWTs independently predicted performance in 40Hz animals, but not SHAM animals. We also found paradoxical reduction of amyloid beta in contralateral PC and ventral CA1, but no reduction in contralateral dorsal CA1, synaptically closer to where stimulation occurred.ConclusionThus, 40Hz stimulation of HPC rescued learning and memory related functional interactions in the HPC‐PC network during sleep and as a consequence rescued impairments in spatial navigation, despite a decoupling between HPC‐PC coupling and learning and memory.

Using Virtual Reality to Assess Spatial Cognition in Subjective Cognitive Decline and Mild Cognitive Impairment due to Alzheimer’s Disease

AbstractBackgroundSpatial navigation impairment (SNI) is prevalent in people with Alzheimer’s disease (AD) continuum and may appear in the initial clinical stage. To detect this deficit in people at risk may not only help to prevent getting lost or missing incidents, but also provide a useful clinical feature for diagnosis. Traditional assessments for SNI include questionnaires, paper pencil and maze tests, or video games. Although a real‐world setting is more valid, direct, and accurate, it has many unexpected conditions such as weather, obstacles, or accidents. Thanks to technology, virtual reality (VR) is a new way to assess SNI.MethodWe used PJVR to test spatial navigation ability in cognitively unimpaired (CU), subjective cognitive decline (SCD) and mild cognitive impairment due to AD (MCI‐AD). The PJVR is the VR version (Vive Pro Eye Head‐mounted Display, HTC) of the PJ device, which was developed by Pai and Jan and has been successfully verified its power to discriminate each other among CU, MCI, and mild AD. With a map provided and using joysticks or handles, participants were requested to reach five points in a 660‐meter path on our university campus. Linear deviation in meters in each point was treated as the variable for comparison. A pre‐test training course was given to facilitate the procedure.Result118 subjects signed informed consent and 87 (73.7%) completed the trials, including 18 CU, 41 SCD and 28 MCI‐AD. Fourteen, or 11.9%, of all participants failed the trials due to cybersickness. The averaged linear deviations of the CU, SCD and MCI‐AD were 36.1 (38.2), mean (S.D.), 40.8 (44.4), and 93.7 (46.8) meters respectively (p<0.000). The linear deviation of the PJVR of the participants was correlated with the Questionnaire on Everyday Navigation Abilities (p<0.001), indicating a good real‐world validity.ConclusionAlthough the rate of cybersickness is higher as compared with the reports from Western countries, most of the participants completed the trials. The PJVR is feasible to assess spatial cognition and able to discriminate CU/SCD from MCI‐AD. To simplify PJVR to be practical is important to welcome the era of digital cognitive assessment.

Blockade of adenosine A2A receptors reverses early spatial memory defects in the APP/PS1 mouse model of Alzheimer’s disease by promoting synaptic plasticity of adult-born granule cells

BackgroundThe over-activation of adenosine A2A receptors (A2AR) is closely implicated in cognitive impairments of Alzheimer's disease (AD). Growing evidence shows that A2AR blockade possesses neuroprotective effects on AD. Spatial navigation impairment is an early manifestation of cognitive deficits in AD. However, whether A2AR blockade can prevent early impairments in spatial cognitive function and the underlying mechanism is still unclear.MethodsA transgenic APP/PS1 mouse model of AD amyloidosis was used in this study. Behavioral tests were conducted to observe the protective effects of A2AR blockade on early spatial memory deficits in 4-month old APP/PS1 mice. To investigate the underlying synaptic mechanism of the protective effects of A2AR blockade, we further examined long-term potentiation (LTP) and network excitation/inhibition balance of dentate gyrus (DG) region, which is relevant to unique synaptic functions of immature adult-born granule cells (abGCs). Subsequently, the protective effects of A2AR blockade on dendritic morphology and synaptic plasticity of 6-week-old abGCs was investigated using retrovirus infection and electrophysiological recordings. The molecular mechanisms underlying neuroprotective properties of A2AR blockade on the synaptic plasticity of abGCs were further explored using molecular biology methods.ResultsAPP/PS1 mice displayed DG-dependent spatial memory deficits at an early stage. Additionally, impaired LTP and an imbalance in network excitation/inhibition were observed in the DG region of APP/PS1 mice, indicating synaptic structural and functional abnormalities of abGCs. A2AR was found to be upregulated in the hippocampus of the APP/PS1 mouse model of AD. Treatment with the selective A2AR antagonist SCH58261 for three weeks significantly ameliorated spatial memory deficits in APP/PS1 mice and markedly restored LTP and network excitation/inhibition balance in the DG region. Moreover, SCH58261 treatment restored dendritic morphology complexity and enhanced synaptic plasticity of abGCs in APP/PS1 mice. Furthermore, SCH58261 treatment alleviated the impairment of synaptic plasticity in abGCs. It achieved this by remodeling the subunit composition of NMDA receptors and increasing the proportion of NR2B receptors in abGCs of APP/PS1 mice.ConclusionsBlockade of A2AR improves early spatial memory deficits in APP/PS1 mice, possibly by reversing synaptic defects of abGCs. This finding suggests that A2AR blockade could be a potential therapy for AD.

Type, dose, and outcomes of physical therapy interventions for unilateral peripheral vestibular hypofunction: protocol for a systematic review

BackgroundUnilateral peripheral vestibular hypofunction can result in symptoms of dizziness, gaze and gait instability, and impaired navigation and spatial orientation. These impairments and activity limitations may negatively impact an individual’s quality of life, ability to perform activities of daily living, drive, and work. There is strong evidence supporting vestibular physical therapy for reducing symptoms, improving gaze and postural stability, and improving function in individuals with vestibular hypofunction. However, there is great variability in clinical practice with regard to the type of interventions and only weak evidence to guide optimal exercise dosage. It is important to identify the most appropriate interventions and exercise dosage to optimize and accelerate recovery of function and to decrease distress. The objective of this systematic review is to determine which interventions and which doses are most effective in decreasing dizziness or vertigo, improving postural control, and improving quality of life in adults with unilateral peripheral vestibular hypofunction.MethodsThe literature will be systematically searched using the following online databases: PubMed/MEDLINE, EMBASE, Web of Science (Science and Social Science Citation Index), Cumulative Index for Nursing and Allied Health Literature (CINAHL), and The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials [CENTRAL], Cochrane Methodology Register). The review will include randomized controlled trials (RCTs), including cluster RCTs, to assess the beneficial effects of the interventions. Assessment of methodological quality and risk of bias will be performed by two independent, blinded reviewers using the PEDro scale and Cochrane Risk of Bias version 2, respectively. The primary outcome measure will be change in self-perceived handicap related to dizziness from baseline to the end of the study, measured using the Dizziness Handicap Inventory. Other relevant outcome measures will include self-reported change in symptoms (to include severity, frequency, and duration) such as verbal or visual analog scales for dizziness. Tertiary outcome measures will include questionnaires related to disability and/or quality of life.DiscussionThis systematic review will identify, evaluate, and integrate the evidence on the effectiveness of physical therapy interventions for unilateral peripheral vestibular hypofunction in an adult population. We anticipate our findings may inform individualized treatment and future research. Clinical recommendations generated from this systematic review may inform vestibular physical therapy treatment of individuals with unilateral peripheral vestibular hypofunction.Trial registrationIn accordance with the guidelines, our systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 06 August 2021 (registration number CRD42021266163). In the event of protocol amendments, the date of each amendment will be accompanied by a description of the change and the rationale.

A comparison of behavioral paradigms assessing spatial memory in tree shrews.

Impairments in spatial navigation in humans can be preclinical signs of Alzheimer's disease. Therefore, cognitive tests that monitor deficits in spatial memory play a crucial role in evaluating animal models with early stage Alzheimer's disease. While Chinese tree shrews (Tupaia belangeri) possess many features suitable for Alzheimer's disease modeling, behavioral tests for assessing spatial cognition in this species are lacking. Here, we established reward-based paradigms using the radial-arm maze and cheeseboard maze for tree shrews, and tested spatial memory in a group of 12 adult males in both tasks, along with a control water maze test, before and after bilateral lesions to the hippocampus, the brain region essential for spatial navigation. Tree shrews memorized target positions during training, and task performance improved gradually until reaching a plateau in all 3 mazes. However, spatial learning was compromised post-lesion in the 2 newly developed tasks, whereas memory retrieval was impaired in the water maze task. These results indicate that the cheeseboard task effectively detects impairments in spatial memory and holds potential for monitoring progressive cognitive decline in aged or genetically modified tree shrews that develop Alzheimer's disease-like symptoms. This study may facilitate the utilization of tree shrew models in Alzheimer's disease research.

Threat impairs flexible use of a cognitive map.

Goal-directed behavior requires adaptive systems that respond to environmental demands. In the absence of threat (or presence of reward), individuals can explore many behavioral trajectories, effectively interrogating the environment across multiple dimensions. This leads to flexible, relational memory encoding and retrieval. In the presence of danger, motivation shifts to an imperative state characterized by a narrow focus of attention on threatening information. This impairs flexible, relational memory. We test how these motivational shifts (Murty & Adcock, 2017) affect behavioral flexibility in an ecologically valid setting. Participants learned the structure of maze-like environments and navigated to the location of objects in both safe and threatening contexts. The latter contained a predator that could 'capture' participants, leading to electric shock. After learning, the path to some objects was unpredictably blocked. forcing a detour for which one route was significantly shorter. We predicted that threat would push participants toward an imperative state, leading to less efficient and less flexible navigation. Threat caused participants to take longer paths to goal objects and less efficient detours when obstacles were encountered. Threat-related impairments in detour navigation persisted after controlling for non-detour navigation performance. and non-detour navigation was not a reliable predictor of detour navigation, This suggests a specific impairment in flexible navigation during detours, an impairment unlikely to be explained by more general processes like predator avoidance or divided attention that may be present during non-detour navigation. These results provide ecologically valid evidence that dynamic, observable threats reduce flexible use of cognitive maps to guide behavior.

An effective obstacle detection system using deep learning advantages to aid blind and visually impaired navigation

Blind and visually impaired people face different challenges when navigating indoors and outdoors. In this context, we suggest developing an obstacle detection system based on a modified YOLO v5 neural network architecture. The suggested system is capable of recognizing and locating a set of landmark indoor and outdoor objects that are extremely useful for Blind and Visually Impaired (BVI) navigation aids. Training and evaluation experiments were conducted using two datasets: the IODR dataset for indoor object detection and the MS COCO dataset for outdoor object detection. We used several optimization strategies, such as model width scaling, quantization, and channel pruning, to guarantee that the suggested work is implemented in embedded devices in a lightweight manner. The proposed system was successful in achieving results that were extremely competitive in terms of processing time as well as the precision of obstacle detection.

How pathways' configuration impacts wayfinding in young and older adults

Wayfinding capabilities stem from interactions between cognitive processes and environmental elements. Previous studies that have attempted to improve human wayfinding by architectural designs mainly focused on environmental cues for supporting landmark-based navigation. The current study, however, tests whether wayfinding can be improved by strengthening route learning. We hypothesized that relying on route-target associations is easier if each target is accessed via a specific route, rather than through several alternative paths. Accordingly, we predicted that in a star-shaped design of pathways in which the center of the star serves as the origin of the routes and the arms of the star host the destinations, it would be easier to form route-target associations, than in pathway configurations in the shape of a grid, wherein each target can be accessed via several paths. Furthermore, as older adults show selective impairments in landmark-based navigation, and tend to over-rely on route strategies, we hypothesized that star-shaped configurations will particularly support wayfinding in older adults. To test these hypotheses, younger (n = 68) and older (n = 60) adults performed a virtual-navigation task in an environment comprised of either a “grid” or “star” configuration of pathways. Our findings indicate that wayfinding performance in older adults was inferior to that of younger adults, regardless of the design. Yet, navigational performance in the star-shaped condition was better compared to the grid-shaped design, in both age-groups, proposing that star-shaped configurations of pathways strengthen route-based navigation. The findings therefore suggest that wayfinding could be improved through architectural designs that strengthen route-learning.

Visual saliency assistance mechanism based on visually impaired navigation systems

Visually impaired people face significant challenges in their work, studies, and daily lives. Nowadays, numerous visually impaired navigation devices are available to help visually impaired people solve daily life problems. These devices typically include modules for target recognition, distance measurement, and text reading aloud. They are designed to help visually impaired people avoid obstacles and understand the presence of things around them through text reading aloud. Due to the need to avoid all potential obstacles, the target recognition algorithms embedded in these devices must recognize a wide range of targets. However, the text reading aloud module cannot read all of them. Therefore, we designed a visual saliency assistance mechanism that simulates the regions that humans may pay the most attention to in the whole picture. The output of the visual saliency assistance mechanism is overlaid with the target recognition result, which can greatly reduce the target number of text reading aloud. This way, the visually impaired navigation device can not only help to avoid obstacles but also help visually impaired people understand the interest targets of most people in the whole picture. The visual saliency assistance mechanism we designed consists of three components: a spatio-temporal feature extraction (STFE) module, a spatio-temporal feature fusion (STFF) module, and a multi-scale feature fusion (MSFF) module. The STFF module fuses long-term spatio-temporal features and improves the temporal memory between frames. The MSFF module fully integrates information at different scales to improve the accuracy of saliency prediction. Therefore, this proposed visual saliency model can assist in the efficient operation of visually impaired navigation systems. The area under roc curve judd (AUC-J) metric of the proposed model was 93.9%, 93.8%, and 91.5% on three widely used saliency datasets: Holly-wood2, UCF Sports, and DHF1K, respectively. The results show that our proposed model outperforms the current state-of-the-art models.

Application of Behavioral Tests for Evaluation of an Experimental Model of Alzheimer's Disease in Female Rats.

Alzheimer's disease was modeled in female Wistar rats aged 4 months by stereotaxic bilateral injection of a synthetic peptide β-amyloid (Aβ1-42) into the hippocampus. Behavioral tests (open field, Y-maze, passive avoidance, and Morris water maze) revealed significant impairment of memory and spatial navigation 8 weeks after β-amyloid administration. At this term, the cognitive impairments typical of Alzheimer's disease are reproduced. The experimental model of Alzheimer's disease proposed by us can be used in preclinical studies of drugs for the treatment of this pathology.

Improved Spatial Knowledge Acquisition through Sensory Augmentation.

Sensory augmentation provides novel opportunities to broaden our knowledge of human perception through external sensors that record and transmit information beyond natural perception. To assess whether such augmented senses affect the acquisition of spatial knowledge during navigation, we trained a group of 27 participants for six weeks with an augmented sense for cardinal directions called the feelSpace belt. Then, we recruited a control group that did not receive the augmented sense and the corresponding training. All 53 participants first explored the Westbrook virtual reality environment for two and a half hours spread over five sessions before assessing their spatial knowledge in four immersive virtual reality tasks measuring cardinal, route, and survey knowledge. We found that the belt group acquired significantly more accurate cardinal and survey knowledge, which was measured in pointing accuracy, distance, and rotation estimates. Interestingly, the augmented sense also positively affected route knowledge, although to a lesser degree. Finally, the belt group reported a significant increase in the use of spatial strategies after training, while the groups' ratings were comparable at baseline. The results suggest that six weeks of training with the feelSpace belt led to improved survey and route knowledge acquisition. Moreover, the findings of our study could inform the development of assistive technologies for individuals with visual or navigational impairments, which may lead to enhanced navigation skills and quality of life.