Navigation strategy training using virtual reality in six chronic stroke patients: A novel and explorative approach to the rehabilitation of navigation impairment

Consistency of spatial ability performance in children, adolescents, and young adults

Background

Spatial abilities are essential cognitive skills for many aspects of our everyday life that develop substantially throughout childhood and adolescence. While there are numerous measurement tools to evaluate these abilities, many of them have been designed for specific age groups hampering comparability throughout development. Thus, we determined test-retest-reliability and minimal detectable change for a set of tests that evaluate spatial ability performance in their variety in youth and compared them to young adults.

Methods

Children (age: 11.4 ± 0.5 years, n = 26), adolescents (age: 12.5 ± 0.7 years, n = 22), and young adults (age: 26.1 ± 4.0 years, n = 26) performed a set of five spatial ability tests twice, 20 min apart: Paper Folding Test (PFT), Mental Rotation Test (MRT), Water Level Task (WLT), Corsi Block Test (CBT), and Numbered Cones Run (NCR). Relative and absolute test-retest reliability was determined by calculating the intraclass correlation coefficient (ICC3,1) and the standard error of measurement (SEM), respectively. Further, the minimal detectable change (MDC95%) was calculated to identify clinically relevant changes between repeated measurements.

Results

Irrespective of test, reliability was "excellent" (i.e., ICC3,1 ≥ 0.75) in all age cohorts and the SEM values were rather small. The MDC95% values needed to identify relevant changes in repeated measurements of spatial ability performance ranged between 0.8 and 13.9% in children, 1.1 and 24.5% in adolescents, and 0.7 and 20.8% in young adults.

Conclusion

The determined values indicate that the investigated set of tests is reliable to detect spatial ability performance in healthy children, adolescents, and young adults.

“Everything looks the same”: wayfinding behaviour and experiences of stroke inpatients in rehabilitation clinics

Purpose

To examine stroke inpatients’ real-life wayfinding behaviour and how the built environment of rehabilitation clinics might influence their behaviour and experiences.

Methods

Stroke inpatients in seven rehabilitation clinics were observed (n = 70), each over the course of 12 consecutive hours. Their paths through the clinic and the locations of encountered wayfinding-related events were mapped on the floor plans and described in the written notes. The observations were supplemented by a survey asking patients about their wayfinding experiences.

Results

For a third of observed patients, at least one wayfinding-related event was observed on the observation day, and 50% of patients reported getting lost in their clinic at least once. Most wayfinding-related events occurred between patient rooms and therapy rooms, and patients frequently relied on backtracking or the help of the staff to find their way. Clinics’ layout organization was found to play a role in the wayfinding behaviour of patients.

Conclusions

Wayfinding is a common challenge that stroke inpatients encounter in rehabilitation clinics. Avoiding multiple decision nodes on the paths between patient rooms and therapy rooms and creating distinct identities for corridor segments in the decision nodes and the areas in front of elevators would likely improve wayfinding performance.

Could an Immersive Virtual Reality Training Improve Navigation Skills in Children with Cerebral Palsy? A Pilot Controlled Study

Children with cerebral palsy (CP) suffer deficits in their motor, sensory, and cognitive abilities, as well as in their visuospatial competences. In the last years, several authors have tried to correlate the visuospatial abilities with the navigational ones. Given their importance in everyday functions, navigation skills have been deeply studied using increasingly cutting-edge techniques such as virtual reality (VR). However, to our knowledge, there are no studies focused on training using immersive VR (IVR) in children with movement disorders. For this reason, we proposed an IVR training to 35 young participants with CP and conceived to improve their navigation skills in a "simil-real" environment while playing on a dynamic platform. A subgroup performed a part of the training which was specifically dedicated to the use of the allocentric strategy (i.e., looking for landmarks) to navigate the virtual environment. We then compared the children's navigation and spatial skills pre- and post-intervention. All the children improved their visual-spatial abilities; particularly, if the IVR activities specifically trained their ability to look for landmarks and use them to navigate. The results of this work highlight the potential of an IVR training program to increase the navigation abilities of patients with CPs.

Successful wayfinding in age: A scoping review on spatial navigation training in healthy older adults

Introduction

Spatial navigation is a complex cognitive function that declines in older age. Finding one’s way around in familiar and new environments is crucial to live and function independently. However, the current literature illustrates the efficacy of spatial navigation interventions in rehabilitative contexts such as pathological aging and traumatic injury, but an overview of existing training studies for healthy older adults is missing. This scoping review aims to identify current evidence on existing spatial navigation interventions in healthy older adults and analyze their efficacy.

Methods

To identify spatial navigation interventions and assessments and investigate their effectiveness, four electronic databases were searched (Pubmed, Web of Science, CINAHL and EMBASE). Two independent reviewers conducted a screening of title, abstract and full-texts and performed a quality assessment. Studies were eligible if (1) published in English, (2) the full text was accessible, (3) at least one group of healthy older adults was included with (4) mean age of 65 years or older, (5) three or more spatial navigation-related training sessions were conducted and (6) at least one spatial ability outcome was reported.

Results

Ten studies were included (N = 1,003, age-range 20–95 years, 51.5% female), only healthy older adults (n = 368, mean age ≥ 65) were assessed further. Studies differed in sample size (n = 22–401), type of training, total intervention duration (100 min–50 h), and intervention period (1–16 weeks).

Conclusion

The spatial navigation abilities addressed and the measures applied to elicit intervention effects varied in quantity and methodology. Significant improvements were found for at least one spatial ability-related outcome in six of 10 interventions. Two interventions achieved a non-significant positive trend, another revealed no measurable post-training improvement, and one study did not report pre-post-differences. The results indicate that different types of spatial navigation interventions improve components of spatial abilities in healthy older adults. The existing body of research does not allow conclusions on transferability of the trained components on everyday life spatial navigation performance. Future research should focus on reproducing and extending the promising approaches of available evidence. From this, valuable insights on healthy aging could emerge.

Trial Registration

This scoping review was preregistered at Open Science Framework (https://osf.io/m9ab6).

Virtual-Reality Performance-Based Assessment of Cognitive Functions in Adult Patients With Acquired Brain Injury: A Scoping Review

Individuals with acquired brain injury (ABI) commonly present with impairments in cognitive abilities. As these competencies seem to be predictive of patients' abilities to reintegrate into the everyday settings, it is crucial to assess them properly. However, previous research has indicated that patients may perform relatively well on standard tests of cognitive functioning, but may nonetheless encounter significant difficulties in organizing and executing everyday tasks. In order to overcome this issue, virtual reality (VR) methods have been introduced in clinical practice with the aim of creating assessments that simulate real-world activities and thus, provide a clearer picture of patients' functioning in everyday settings. This review offers an overview of VR assessment tools described in the scientific literature between 2010 and 2019. Overall, 38 relevant records describing 31 different tools were found. Among these tools, 16 assessed executive functions and prospective memory, while the other 15 assessed visuo-spatial abilities. Although promising results have been reported, our analysis indicated that about half of the tools deliver tasks that differ from everyday activities, thus limiting the generalizability of patients' performance to the real-world. Moreover, a variety of methodological shortfalls related to study Internal and External Validity have been highlighted, which hamper the possibility of drawing definite recommendations on tool choice. These limitations suggest the importance of putting considerable efforts into the improvement or development of VR tools for patients with ABI for both research and clinical purposes, considering the great potential of this form of assessment.

A Virtual Navigation Training Promotes the Remapping of Space in Allocentric Coordinates: Evidence From Behavioral and Neuroimaging Data

Allocentric space representations demonstrated to be crucial to improve visuo-spatial skills, pivotal in every-day life activities and for the development and maintenance of other cognitive abilities, such as memory and reasoning. Here, we present a series of three different experiments: Experiment 1, Discovery sample (23 young male participants); Experiment 2, Neuroimaging and replicating sample (23 young male participants); and Experiment 3 (14 young male participants). In the experiments, we investigated whether virtual navigation stimulates the ability to form spatial allocentric representations. With this aim, we used a novel 3D videogame (MindTheCity!), focused on the navigation of a virtual town. We verified whether playing at MindTheCity! enhanced the performance on spatial representational tasks (pointing to a specific location in space) and on a spatial memory test (asking participant to remember the location of specific objects). Furthermore, to uncover the neural mechanisms underlying the observed effects, we performed a preliminary fMRI investigation before and after the training with MindTheCity!. Results show that our virtual training enhances the ability to form allocentric representations and spatial memory (Experiment 1). Experiments 2 and 3 confirmed the behavioral results of Experiment 1. Furthermore, our preliminary neuroimaging and behavioral results suggest that the training activates brain circuits involved in higher-order mechanisms of information encoding, triggering the activation of broader cognitive processes and reducing the working load on memory circuits (Experiments 2 and 3).

Spatial knowledge acquired from first-person and dynamic map perspectives

As we become familiar with an environment through navigation and map study, spatial information is encoded into a mental representation of space. It is currently unclear to what degree mental representations of space are determined by the perspective in which spatial information is acquired. The overlapping model of spatial knowledge argues that spatial information is encoded into a common spatial representation independent of learning perspective, whereas the partially independent model argues for dissociated spatial representations specific to the learning perspective. The goal of this study was to provide insight into this debate by investigating the cognitive functions underlying the formation of spatial knowledge obtained through different learning perspectives. Hundred participants studied an ecologically valid virtual environment via a first-person and map perspective. The map employed in the study was dynamic, allowing for the disentanglement of learning perspective and sequential information presentation. Spatial knowledge was examined using an array of navigation tasks that assessed both route and survey knowledge. Results show that distinct visuospatial abilities predict route knowledge depending on whether an environment is learned via a first-person or map perspective. Both shared and distinct visuospatial abilities predicted the formation of survey knowledge in the two perspective learning conditions. Additionally, sequential presentation of map information diminishes the perspective dependent performance differences on spatial tasks reported in earlier studies. Overall, the results provide further evidence for the partially dissociated model of spatial knowledge, as the perspective from which an environment is learned influences the spatial representation that is formed.

Building Embodied Spaces for Spatial Memory Neurorehabilitation with Virtual Reality in Normal and Pathological Aging

Along with deficits in spatial cognition, a decline in body-related information is observed in aging and is thought to contribute to impairments in navigation, memory, and space perception. According to the embodied cognition theories, bodily and environmental information play a crucial role in defining cognitive representations. Thanks to the possibility to involve body-related information, manipulate environmental stimuli, and add multisensory cues, virtual reality is one of the best candidates for spatial memory rehabilitation in aging for its embodied potential. However, current virtual neurorehabilitation solutions for aging and neurodegenerative diseases are in their infancy. Here, we discuss three concepts that could be used to improve embodied representations of the space with virtual reality. The virtual bodily representation is the combination of idiothetic information involved during virtual navigation thanks to input/output devices; the spatial affordances are environmental or symbolic elements used by the individual to act in the virtual environment; finally, the virtual enactment effect is the enhancement on spatial memory provided by actively (cognitively and/or bodily) interacting with the virtual space and its elements. Theoretical and empirical findings will be presented to propose innovative rehabilitative solutions in aging for spatial memory and navigation.

Effects of Physical Exercise Interventions on Spatial Orientation in Children and Adolescents: A Systematic Scoping Review

Background: Regular physical exercise plays an integral part in the psychomotor and psychosocial development of children and adolescents, with complex motor and cognitive processes closely linked. Spatial abilities, one aspect of cognitive functioning start to evolve from earliest childhood and reach adult-like levels by early adolescence. As they have been associated with good spatial orientation, wayfinding, map-reading skills, problem solving or analyzing spatial information, these skills facilitate independence and autonomy while growing up. Despite promising results, only few studies investigate this relation between physical exercise and spatial abilities. To use this benefit and develop purposive physical exercise interventions, it is essential to summarize the current evidence. Objectives: This literature review aims to systematically summarize findings regarding the impact of physical exercise interventions on spatial abilities in healthy children and adolescents and identify knowledge gaps. Methods: A systematic search of the literature according to the PRISMA guidelines was conducted on the databases Pubmed, Web of Science, Cochrane Library, SportDiscus, and PsycInfo from their inception date till March 2021. Additionally, Google Scholar and refence lists of relevant publications were searched. A descriptive analysis of results was conducted. Results: The literature search identified a total of N = 1,215 records, 11 of which met the inclusion criteria and were analyzed in this review. A total of 621 participants aged 4 to 15 years participated in the studies. Exercise interventions included sport-specific activities, motor-coordinative exercises, high-intensity functional training or spatial orientation/navigation training. Five studies evaluated training effects on mental rotation performance (i.e., Mental Rotation Test), four studies investigated visuo-spatial working memory function/spatial memory (i.e., Corsi Block Test, Virtual Reality Morris Water Maze) and two studies tested spatial orientation capacity (i.e., Orientation-Running Test). Overall, results show a potential for improvement of spatial abilities through physical exercise interventions. However, keeping the diversity of study designs, populations and outcomes in mind, findings need to be interpreted with care. Conclusions: Despite growing interest on the effects of physical exercise interventions on spatial abilities and promising findings of available studies, evidence to date remains limited. Future research is needed to establish how spatial ability development of healthy children and adolescents can be positively supported.

The Role of Virtual Reality in Screening, Diagnosing, and Rehabilitating Spatial Memory Deficits

Impairment of spatial memory, including an inability to recall previous locations and navigate the world, is often one of the first signs of functional disability on the road to cognitive impairment. While there are many screening and diagnostic tools which attempt to measure spatial memory ability, they are often not representative of real-life situations and can therefore lack applicability. One potential solution to this problem involves the use of virtual reality (VR), which immerses individuals in a virtually-simulated environment, allowing for scenarios more representative of real-life without any of the associated risks. Here, we review the evidence surrounding the use of VR for the screening and diagnosis of spatial memory impairments, including potential limitations and how it compares to standard neuropsychological tests. We will also discuss the evidence regarding the potential use of VR in the rehabilitation of spatial memory deficits, which has not been well studied, but which could be game-changing if proven successful.

Healthcare Professionals' Acceptance of Digital Cognitive Rehabilitation

With technological possibilities in healthcare steadily increasing, more tools for digital cognitive rehabilitation become available. Acceptance of such technological advances is crucial for successful implementation. Therefore, we examined technology acceptance specifically for this form of rehabilitation in a sample of healthcare providers involved in cognitive rehabilitation. An adjusted version of the Technology Acceptance Model (TAM) questionnaire was used, including the subscales for perceived usefulness, perceived ease of use, subjective norm (toward use), and intention to use, which all contribute to actual use of a specific technology. Results indicate a generally favorable attitude toward the use of digital cognitive rehabilitation and positive responses toward the TAM constructs. Only for subjective norm, a neutral mean response was found, indicating that this could pose a potential obstacle toward implementation. Potential differences between subgroups of different age, gender, and professional background were assessed. Age and gender did not affect the attitude toward digital cognitive rehabilitation. Occupational therapists showed lower scores than healthcare psychologists and physiatrists with regard to perceived usefulness, possibly linked to a difference in operational and managerial tasks. The findings of his study stimulate further implementation of digital cognitive rehabilitation, where the role of subjective norms should be specifically considered.

The Effectiveness of Home-Based Training Software Designed to Influence Strategic Navigation Preferences in Healthy Subjects

One approach to the rehabilitation of navigation impairments is to train the use of compensatory egocentric or allocentric navigation strategies. Yet, it is unknown whether and to what degree training programs can influence strategic navigation preferences. In validating this approach, the key assumption that strategic preference can be changed by using a navigation training was assessed in a group of healthy participants (n = 82). The training program consisted of a psychoeducation session and a software package that included either allocentric or egocentric navigation exercises in virtual environments. Strategic navigation preference, objective and self-reported spatial abilities were assessed in pre- and post-training sessions. Based on their pre-training strategic preference, participants received either the egocentric training (n = 19) or the allocentric training (n = 21) version of the training. These participants engaged in four training sessions over a period of 2-3 weeks. The second group of participants did not use the training software (n = 43) and served as a control group. The results show that 50% of participants that received the egocentric training shifted from an allocentric to and an egocentric strategic preference. The proportion of participants that switched their strategic preference as a result of the allocentric training was identical to this proportion in the control group (19%). The training did not affect objective and self-reported navigation abilities as measured in the pre- and post-training sessions. We conclude that strategic navigation preferences can be influenced by using home-based training in healthy participants. However, using the current approach, only a preference shift from an allocentric to an egocentric navigation strategy could be achieved. The effectiveness of this navigation strategy training should next be assessed in relevant patient populations.

Neurorehabilitation of Spatial Memory Using Virtual Environments: A Systematic Review

In recent years, virtual reality (VR) technologies have become widely used in clinical settings because they offer impressive opportunities for neurorehabilitation of different cognitive deficits. Specifically, virtual environments (VEs) have ideal characteristics for navigational training aimed at rehabilitating spatial memory. A systematic search, following PRISMA guidelines, was carried out to explore the current scenario in neurorehabilitation of spatial memory using virtual reality. The literature on this topic was queried, 5048 papers were screened, and 16 studies were included, covering patients presenting different neuropsychological diseases. Our findings highlight the potential of the navigational task in virtual environments (VEs) for enhancing navigation and orientation abilities in patients with spatial memory disorders. The results are promising and suggest that VR training can facilitate neurorehabilitation, promoting brain plasticity processes. An overview of how VR-based training has been implemented is crucial for using these tools in clinical settings. Hence, in the current manuscript, we have critically debated the structure and the length of training protocols, as well as a different type of exploration through VR devices with different degrees of immersion. Furthermore, we analyzed and highlighted the crucial role played by the selection of the assessment tools.

Increase of frontal neuronal activity in chronic neglect after training in virtual reality

OBJECTIVES

A third of patients with stroke acquire spatial neglect associated with poor rehabilitation outcome. New effective rehabilitation interventions are needed. Scanning training combined with multisensory stimulation to enhance the rehabilitation effect is suggested. In accordance, we have designed a virtual-reality based scanning training that combines visual, audio and sensori-motor stimulation called RehAtt^® . Effects were shown in behavioural tests and activity of daily living. Here, we use fMRI to evaluate the change in brain activity during Posner's Cuing Task (attention task) after RehAtt^® intervention, in patients with chronic neglect.

METHODS

Twelve patients (mean age = 72.7 years, SD = 6.1) with chronic neglect (persistent symptoms >6 months) performed the interventions 3 times/wk during 5 weeks, in total 15 hours. Training effects on brain activity were evaluated using fMRI task-evoked responses during the Posner's cuing task before and after the intervention.

RESULTS

Patients improved their performance in the Posner fMRI task. In addition, patients increased their task-evoked brain activity after the VR interventions in an extended network including pre-frontal and temporal cortex during attentional cueing, but showed no training effects during target presentations.

CONCLUSIONS

The current pilot study demonstrates that a novel multisensory VR intervention has the potential to benefit patients with chronic neglect in respect of behaviour and brain changes. Specifically, the fMRI results show that strategic processes (top-down control during attentional cuing) were enhanced by the intervention. The findings increase knowledge of the plasticity processes underlying positive rehabilitation effects from RehAtt^® in chronic neglect.

Efficacy of ICT-Based Neurocognitive Rehabilitation Programs for Acquired Brain Injury

Abstract. This systematic review aims to analyze the methods used in the assessment of the efficacy of Neurocognitive Rehabilitation Programs (NRP) based on Information and Communication Technologies in patients with Acquired Brain Injury, namely platforms and online rehabilitation programs. Studies with the main purpose of evaluating the efficacy of those programs were retrieved from multiple literature databases, accordingly to inclusion and exclusion criteria. The inclusion and analysis of the studies followed preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) and Cochrane Collaboration Guidelines. Thirty-one studies were included in this review. Results showed that most studies used a pre-post methodological design, with few studies performing assessment moments during intervention or follow-up. Attention, memory, and executive functions were the cognitive variables considered by a larger number of studies at the assessment of NRP efficacy. Despite that, there is a growing evidence on the inclusion of variables related to everyday functioning in this process, increasing its ecological validity. Concerning the instruments used, the studies presented a large heterogeneity of the instruments and methods used, even for the same assessment purpose, highlighting a lack of consensus regarding assessment protocol. Psychophysiological and neuroimaging techniques are seldom used on this field. This review identifies the main characteristics of the methodology used at the assessment of NRP and potential limitations, providing useful information to guide the practice of the health care professionals in rehabilitation of Acquired Brain Injury. It also suggests new directions for future studies.

A Usability Study of a Serious Game in Cognitive Rehabilitation: A Compensatory Navigation Training in Acquired Brain Injury Patients

Acquired brain injury patients often report navigation impairments. A cognitive rehabilitation therapy has been designed in the form of a serious game. The aim of the serious game is to aid patients in the development of compensatory navigation strategies by providing exercises in 3D virtual environments on their home computers. The objective of this study was to assess the usability of three critical gaming attributes: movement control in 3D virtual environments, instruction modality and feedback timing. Thirty acquired brain injury patients performed three tasks in which objective measures of usability were obtained. Mouse controlled movement was compared to keyboard controlled movement in a navigation task. Text-based instructions were compared to video-based instructions in a knowledge acquisition task. The effect of feedback timing on performance and motivation was examined in a navigation training game. Subjective usability ratings of all design options were assessed using questionnaires. Results showed that mouse controlled interaction in 3D environments is more effective than keyboard controlled interaction. Patients clearly preferred video-based instructions over text-based instructions, even though video-based instructions were not more effective in context of knowledge acquisition and comprehension. No effect of feedback timing was found on performance and motivation in games designed to train navigation abilities. Overall appreciation of the serious game was positive. The results provide valuable insights in the design choices that facilitate the transfer of skills from serious games to real-life situations.

What do randomized controlled trials say about virtual rehabilitation in stroke? A systematic literature review and meta-analysis of upper-limb and cognitive outcomes

BACKGROUND

Virtual-reality based rehabilitation (VR) shows potential as an engaging and effective way to improve upper-limb function and cognitive abilities following a stroke. However, an updated synthesis of the literature is needed to capture growth in recent research and address gaps in our understanding of factors that may optimize training parameters and treatment effects.

METHODS

Published randomized controlled trials comparing VR to conventional therapy were retrieved from seven electronic databases. Treatment effects (Hedge's g) were estimated using a random effects model, with motor and functional outcomes between different protocols compared at the Body Structure/Function, Activity, and Participation levels of the International Classification of Functioning.

RESULTS

Thirty-three studies were identified, including 971 participants (492 VR participants). VR produced small to medium overall effects (g = 0.46; 95% CI: 0.33-0.59, p < 0.01), above and beyond conventional therapies. Small to medium effects were observed on Body Structure/Function (g = 0.41; 95% CI: 0.28-0.55; p < 0.01) and Activity outcomes (g = 0.47; 95% CI: 0.34-0.60, p < 0.01), while Participation outcomes failed to reach significance (g = 0.38; 95% CI: -0.29-1.04, p = 0.27). Superior benefits for Body Structure/Function (g = 0.56) and Activity outcomes (g = 0.62) were observed when examining outcomes only from purpose-designed VR systems. Preliminary results (k = 4) suggested small to medium effects for cognitive outcomes (g = 0.41; 95% CI: 0.28-0.55; p < 0.01). Moderator analysis found no advantage for higher doses of VR, massed practice training schedules, or greater time since injury.

CONCLUSION

VR can effect significant gains on Body Structure/Function and Activity level outcomes, including improvements in cognitive function, for individuals who have sustained a stroke. The evidence supports the use of VR as an adjunct for stroke rehabilitation, with effectiveness evident for a variety of platforms, training parameters, and stages of recovery.

Enhancing endogenous capacity to repair a stroke-damaged brain: An evolving field for stroke research

Stroke represents a severe medical condition that causes stroke survivors to suffer from long-term and even lifelong disability. Over the past several decades, a vast majority of stroke research targets neuroprotection in the acute phase, while little work has been done to enhance stroke recovery at the later stage. Through reviewing current understanding of brain plasticity, stroke pathology, and emerging preclinical and clinical restorative approaches, this review aims to provide new insights to advance the research field for stroke recovery. Lifelong brain plasticity offers the long-lasting possibility to repair a stroke-damaged brain. Stroke impairs the structural and functional integrity of entire brain networks; the restorative approaches containing multi-components have great potential to maximize stroke recovery by rebuilding and normalizing the stroke-disrupted entire brain networks and brain functioning. The restorative window for stroke recovery is much longer than previously thought. The optimal time for brain repair appears to be at later stage of stroke rather than the earlier stage. It is expected that these new insights will advance our understanding of stroke recovery and assist in developing the next generation of restorative approaches for enhancing brain repair after stroke.

A systematic investigation of navigation impairment in chronic stroke patients: Evidence for three distinct types

OBJECTIVE

In a recent systematic review, Claessen and van der Ham (2017) have analyzed the types of navigation impairment in the single-case study literature. Three dissociable types related to landmarks, locations, and paths were identified. This recent model as well as previous models of navigation impairment have never been verified in a systematic manner. The aim of the current study was thus to investigate the prevalence of landmark-based, location-based, and path-based navigation impairment in a large sample of stroke patients.

METHOD

Navigation ability of 77 stroke patients in the chronic phase and 60 healthy participants was comprehensively evaluated using the Virtual Tübingen test, which contains twelve subtasks addressing various aspects of knowledge about landmarks, locations, and paths based on a newly learned virtual route. Participants also filled out the Wayfinding Questionnaire to allow for making a distinction between stroke patients with and without significant subjective navigation-related complaints.

RESULTS

Analysis of responses on the Wayfinding Questionnaire indicated that 33 of the 77 participating stroke patients had significant navigation-related complaints. An examination of their performance on the Virtual Tübingen test established objective evidence for navigation impairment in 27 patients. Both landmark-based and path-based navigation impairment occurred in isolation, while location-based navigation impairment was only found along with the other two types.

CONCLUSIONS

The current study provides the first empirical support for the distinction between landmark-based, location-based, and path-based navigation impairment. Future research relying on other assessment instruments of navigation ability might be helpful to further validate this distinction.

Brain training: hype or hope?

Brain training is topical yet controversial. Effects are often limited to trained tasks; and near and far effects to untrained tasks or everyday life measures are often small or lacking altogether. More recent approaches use evidence from cognitive neuroscience on neuroplasticity, resulting in novel cognitive interventions. This special issue encompasses the state of the art of these interventions. Two systematic reviews and nine experimental studies in a variety of patient groups or healthy participants are included, the results of which mostly confirm earlier findings: effects on trained tasks are consistently reported, but generalisation in terms of functional outcome is limited and little evidence is found of long-term effects. In general, the studies show promising, yet challenging training effects on cognition in healthy persons and patients with cognitive deficits. As such, they may be seen as positive "proof of principle" studies, highlighting that cognitive enhancement is possible. The field of brain training, however, is in urgent need of larger and more thoroughly designed studies. These future studies should also include outcome measures on daily functioning, self-efficacy and quality of life in addition to neuropsychological tests or tasks related to cognitive functioning.