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The three common alleles of the APOE gene, ɛ2/ɛ3/ɛ4, have been linked to human spatial orientation. We investigated the genetic role of APOE in developmental topographical disorientation (DTD), a lifelong condition that results in topographical disorientation. We genotyped the APOE ɛ2/ɛ3/ɛ4 alleles in a cohort of 20 unrelated DTD probands, and found allele frequencies not statistically different from the those seen in the population as a whole. Therefore, we found no evidence that DTD occurs preferentially on a genetic background containing any particular APOE allele, making it unlikely that these APOE alleles are contributing to the development of DTD.

The ability to travel independently is a vital part of an autonomous life. It is important to investigate to what degree people with acquired brain injuries (ABI) suffer from navigation impairments. The aim of this study was to investigate the prevalence and characteristics of objective and subjective navigation impairments in the population of ABI patients. A large-scale online navigation study was conducted with 435 ABI patients and 7474 healthy controls. Participants studied a route through a virtual environment and completed 5 navigation tasks that assessed distinct functional components of navigation ability. Subjective navigation abilities were assessed using the Wayfinding questionnaire. Patients were matched to controls using propensity score matching. Overall, performance on objective navigation tasks was significantly lower in the ABI population compared to the healthy controls. The landmark recognition, route continuation and allocentric location knowledge tasks were most vulnerable to brain injury. The prevalence of subjective navigation impairments was higher in the ABI population compared to the healthy controls. In conclusion, a substantial proportion (39.1%) of the ABI population reports navigation impairments. We advocate the evaluation of objective and subjective navigation ability in neuropsychological assessments of ABI patients.

Developmental topographical disorientation (DTD) has been defined as a developmental deficit in human navigational skills in the absence of congenital or acquired brain damage. We report the case of Lost In Space Again (LISA), a 22-year-old woman with a normal development and no clinical history of neurological or psychiatric diseases, evaluated twice, with an interval of 5 years. The magnetic resonance imaging (MRI) examination did not reveal any morphological alteration, while diffusion tensor imaging (DTI) showed a structural connectivity deficit (a decreased fractional anisotropy—FA) in the parieto–prefrontal and parieto–premotor pathway. The behavioral assessment showed different deficits in spatial and navigational tasks, which seemed to be connected to a poor ability to form a cognitive map of the environment. Moreover, LISA displayed a poor performance in high-level face encoding and retrieval. The aim of this case report is to share new insight about DTD in order to deepen the knowledge of this specific neurodevelopmental disorder. In conclusion, this novel DTD case (1) supports the hypothesis of the existence of different DTD subtypes; (2) sustains the evidence that DTD can co-occur (or not) with deficit in face recognition; and (3) highlights the need for an in-depth examination from both a neurocognitive and behavioral point of view of a possible common developmental defect between the formation of cognitive maps and the recognition of faces that might be in mental imagery skills. Future directions will be also discussed.

Indoor localization technologies hold promise for many ambient intelligence applications, including in-situ navigational assistance for individuals with wayfinding difficulties. Given that the literature on indoor localization is vast and spans many different disciplines, we conducted a comprehensive review of the dominant technologies. We propose a taxonomy of localization technologies on the basis of the measured physical quantity. In particular, we identified, radio frequency, photonic, sonic and inertial localization technologies as leading solutions in the field. For each selected technology, the fundamental scientific mechanisms for localization are explained, key recent literature appraised and the merits and limitations are discussed. Recommendations are made regarding the creation of context-aware systems that can be used to enhance a user's topographical orientation skills.

Acquired prosopagnosia is usually a consequence of bilateral or right hemisphere lesions and is often associated with topographical disorientation and dyschromatopsia. Left temporo-occipital lesions sometimes result in a face recognition disorder but in a context of visual object agnosia with spared familiarity feelings for faces, usually in left-handers. We describe a patient with a left temporo-occipital hemorrhagic lesion unexpectedly resulting in a deficit of face familiarity, which could represent a mild form of associative prosopagnosia. Our patient failed to feel familiarity feelings even with very well-known famous faces but had neither visual object agnosia nor defects with semantics or naming of celebrities. This was confirmed even when the patient was re-tested a year later. We speculate that a graded lateralization of face processing could be at the basis of occasional cases of prosopagnosia. Electronic supplementary material The online version of this article (10.1007/s10072-020-04581-5) contains supplementary material, which is available to authorized users.

Individuals affected by Developmental Topographical Disorientation (DTD) get lost on a daily basis, even in the most familiar of surroundings such as their neighbourhood, the building where they have worked for many years, and, in extreme cases, even in their own homes. Individuals with DTD report a lifelong selective inability to orient despite otherwise well-preserved general cognitive functions, and the absence of any acquired brain injury or neurological condition, with general intelligence reported to be within the normal range. To date, the mechanisms underlying such a selective developmental condition remain unknown. Here, we report the findings of a 10-year-long study investigating the behavioural and cognitive mechanisms of DTD in a large sample of 1211 cases. We describe the demographics, heritability pattern, self-reported and objective spatial abilities, and some personality traits of individuals with DTD as compared to a sample of 1624 healthy controls; importantly, we test the specific hypothesis that the presence of DTD is significantly related to the inability of the individuals to form a mental representation of the spatial surroundings (i.e., a cognitive map). We found that individuals with DTD reported relatively greater levels of neuroticism and negative affect, and rated themselves more poorly on self-report measures of memory and imagery skills related to objects, faces, and places. While performing interactive tasks, as a group, the individuals with DTD performed slightly worse on a scene-based perspective-taking task, and, notably struggled to solve tasks that demand the generation and use of a cognitive map. These novel findings help define the phenotype of DTD, and lay the foundation for future studies of the neurological and genetic mechanisms of this lifelong condition.

Spatial orientation is an important function in daily life because it allows us to reach a target place when moving through our environment, using self-centered (egocentric) or environmental information (allocentric). Compared to other cognitive functions, spatial orientation has been studied less in preschool ages. Some brain areas, such as the hippocampus and the temporal as well as the parietal and frontal cortices, are involved in spatial orientation. Therefore, when these brain regions are altered in neurological conditions or in atypical development in children, we would expect impairment of spatial abilities. The aim of this study is to review studies, published in recent years, that use egocentric and allocentric spatial orientation tasks for assessing spatial memory in preschool children, with the final goal of finding out which tests could be included in a clinical neuropsychological evaluation. We observed that although egocentric spatial orientation emerges first during development, allocentric spatial orientation tasks are employed at very early ages. Most of these tasks are performed in real environments, allowing children's self-movements and using environmental modifications, but technologies such as virtual or augmented reality are increasingly used. Other aspects are discussed, such as the lack of consensus in the nomenclature, the difficulty of tracing the course of development of spatial orientation, or the ecological validity of the tests used. We finally observed that there is greater interest in studying the allocentric framework than the egocentric one, which makes it difficult to compare the use of the two frames of reference during a neuropsychological evaluation in preschool-aged children.

ObjectiveHeading disorientation is a type of pure topographical disorientation. Reported cases have been very few and its underlying mechanism remains unclear. We report an unusual presentation of a 60-year-old man with recurrent transient heading disorientation heralding an acute posterior cerebral artery infarction.DesignCase report.ConclusionAcquired injury to the right retro-splenial region can result in a specific variant of topographical disorientation known as heading disorientation that may present as an atypical transient ischaemic attack-like symptom heralding acute cerebral infarction.

The ability to form a mental representation of the surroundings is a critical skill for spatial navigation and orientation in humans. Such a mental representation is known as a "cognitive map" and is formed as individuals familiarize themselves with the surrounding, providing detailed information about salient environmental landmarks and their spatial relationships. Despite evidence of the malleability and potential for training spatial orientation skills in humans, it remains unknown if the specific ability to form cognitive maps can be improved by an appositely developed training program. Here, we present a newly developed computerized 12-days training program in a virtual environment designed specifically to stimulate the acquisition of this important skill. We asked 15 healthy volunteers to complete the training program and perform a comprehensive spatial behavioral assessment before and after the training. We asked participants to become familiar with the environment by navigating a small area before slowly building them up to navigate within the larger and more complex environment; we asked them to travel back and forth between environmental landmarks until they had built an understanding of where those landmarks resided with respect to one another. This process repeated until participants had visited every landmark in the virtual town and had learned where each landmark resided with respect to the others. The results of this study confirmed the feasibility of the training program and suggested an improvement in the ability of participants to form mental representations of the spatial surrounding. This study provides preliminary findings on the feasibility of a 12-days program in training spatial orientation skills. We discuss the utility and potential impact of this training program in the lives of the many individuals affected by topographical disorientation as a result of an acquired or developmental condition.

Neuropsychological studies on acquired topographical disorientation have provided useful insights into the contribution of different brain regions to human navigation. However, little is known about the possibility to restore navigational skills after brain damage. Here we describe the case of No Longer Lost (NLL), a 49-year-old man who complained of severe topographical disorientation following traumatic brain injury. Extensive neuropsychological evaluation at baseline revealed selective episodic memory deficits and topographical disorientation. NLL underwent 8-week imagery-based treatment (IBT) inspired by current cognitive models of human spatial navigation. After IBT, NLL improved topographical skills and episodic memory. From a clinical point of view, the present study describes a model-based intervention for topographical disorientation. From a theoretical point of view, it provides new insights into the cognitive models of human spatial navigation and straightforward evidence about common phylogenetic roots of brain mechanisms devoted to spatial navigation and memory.

Spatial navigation tasks reveal small differences between normal and pathological aging and may thus disclose potential neuropsychological predictors of neurodegenerative diseases. The aim of our study was to investigate which navigational skills are compromised in the early phase of pathological aging as well as the extent to which they are compromised. We performed an extensive neuropsychological evaluation based on working memory and learning tasks (i.e., Corsi Block-Tapping Test and Walking Corsi Test) involving both reaching and navigational vista spaces. We also assessed spatial navigation skills in the real world by asking participants to perform route-learning and landmark-recognition tasks. We conducted a cross-sectional study on nineteen patients with a diagnosis of mild cognitive impairment (MCI) who displayed either an isolated memory deficit (single-domain amnestic MCI, MCIsd; N = 3) or a memory deficit associated with deficits in other cognitive functions (multi-domain MCI, MCImd; N = 16) as well as on nineteen healthy control participants. The groups' performances were compared by means of mixed factorial ANOVA and two-sample t-tests. We found that patients with MCI performed worse than controls, especially when they were required to learn spatial positions within the navigational vista space. Route-learning within the real environment was also impaired whereas landmark-recognition was spared. The same pattern of results emerged in the MCImd subgroup. Moreover, single case analyses on MCIsd patients revealed a dissociation between learning of spatial positions within navigational vista space and within reaching space. These results suggest that topographical learning is compromised in the early phase of MCIsd and MCImd and that spatial navigation tasks may be used to better characterize topographical disorientation in MCI patients as well as for the early diagnosis of pathological aging.

Topographical disorientation refers to inability to recognize the environment, as well as to orient, to find the right way into a familiar or new environment and to use a map for the orientation. These functions are based on neuronal activity of posterior parietal cortex, retrosplenial cortex and the posterior part of cingular gyrus, medial temporal lobe, lingual gyrus and prefrontal cortex and are considered within egocentric or allocentric (exocentric) reference systems. Object locations in the egocentric system are evaluated with respect to the subject's body position while object locations in the allocentric reference frame are evaluated with respect to the object-to-object relations in the external environment. Topographical orientation disorders are observed in local lesions of the brain and in neurodegenerative diseases. The topographical disorientation may be due to landmark аgnosia, egocentric disorientation, heading disorientation and anterograde disorientation. Clinical tests for the diagnosis of topographical disorientation include blanket methods and navigation tasks in real or virtual space. The restorative and compensatory strategies are used in rehabilitation of patients with topographical disorientation. Clarification of the general strategy and selection of the optimal neurorehabilitation methods depend on the causes and severity of brain lesions.Топографическая дезориентация - нарушение способности узнавать местность и ее ориентиры, распознавать свое положение в пространстве, находить ранее знакомые и запоминать новые маршруты, использовать карту для ориентации. Функции топографической ориентировки обеспечиваются задними отделами теменной коры, ретроспленальной корой и задними отделами поясной извилины, медиальными отделами височной доли, язычной извилиной и префронтальной корой и осуществляются в эгоцентрической или аллоцентрической системах отсчета. В эгоцентрической (тело-центрированной) системе человек оценивает расположение предметов по отношению к осям и плоскостям собственного тела; аллоцентрическая система основывается на пространственных отношениях между предметами и не связана с ориентацией субъекта. Нарушения топографической ориентации наблюдаются при очаговых поражениях головного мозга и нейродегенеративных заболеваниях. Они могут иметь в основе агнозию ориентиров на местности, эгоцентрическую дезориентацию, дезориентацию в направлении и антероградную дезориентацию. В диагностике топографической дезориентации применяются бланковые методики, задания на перемещение в реальном или виртуальном трехмерном пространстве. Реабилитация больных с топографической дезориентацией использует восстановительные и компенсаторные стратегии. Выбор общей стратегии реабилитации и конкретных методик во многом зависит от причины и степени повреждения головного мозга.

Several neuropsychological case studies report brain-damaged individuals with concurrent impairments in face recognition (i.e., prosopagnosia) and topographical orientation. Recently, individuals with a developmental form of topographical disorientation have also been described, and several case reports of individuals with developmental prosopagnosia provide anecdotal evidence of concurrent navigational difficulties. Clearly, the co-occurrence of these difficulties can exacerbate the negative psychosocial consequences associated with each condition. This paper presents the first detailed case report of an individual (FN) with developmental prosopagnosia alongside difficulties in topographical orientation. FN's performance on an extensive navigational battery indicated that she primarily has difficulties in the formation and retrieval of cognitive maps. We then evaluated the effectiveness of a short-term virtual reality training programme and found that she is able to form a cognitive map of a particular environment following intense overlearning. Surprisingly, FN's performance on a face recognition task also improved following training. While the latter finding was unexpected and requires further exploration, the training programme reported here may help to alleviate some of the compounded negative psychosocial consequences that are associated with difficulties in finding both locations and people.

Lesions of the medio‐parietal lobes are linked with topographical and temporal disorientation, and are of interest to understanding mental time. We examined a 39‐year‐old man who worked as a driving instructor before cerebral hemorrhage, and followed his case for 8 years including neuropsychological testing and brain imaging. The patient had mild anterograde episodic amnesia, but no semantic amnesia. He felt that time passed too quickly, and developed a compulsive routine to compensate, although he was able to count time at a normal speed. Furthermore, he was unable to accurately sketch the layout of his house and to make a cross‐reference type timetable for the future. Brain magnetic resonance imaging showed lesions of the left anterior–posterior cingulate gyrus, and N‐isopropyl‐[123I] p‐iodoamphetamine single‐photon emission computed tomography showed decreased blood flow mainly of the left medio‐parietal lobe.

Topographical disorientation is frequent among patients after a stroke and can be well explored with virtual environments (VEs). VEs also allow for the addition of stimuli. A previous study did not find any effect of non-contextual auditory stimuli on navigational performance in the virtual action planning-supermarket (VAP-S) simulating a medium-sized 3D supermarket. However, the perceptual or cognitive load of the sounds used was not high.We investigated how non-contextual auditory stimuli with high load affect navigational performance in the VAP-S for patients who have had a stroke and any correlation between this performance and dysexecutive disorders.Four kinds of stimuli were considered: sounds from living beings, sounds from supermarket objects, beeping sounds and names of other products that were not available in the VAP-S. The condition without auditory stimuli was the control. The Groupe de réflexion pour l'évaluation des fonctions exécutives (GREFEX) battery was used to evaluate executive functions of patients.The study included 40 patients who have had a stroke (n=22 right-hemisphere and n=18 left-hemisphere stroke). Patients' navigational performance was decreased under the 4 conditions with non-contextual auditory stimuli (P0.05), especially for those with dysexecutive disorders. For the 5 conditions, the lower the performance, the more GREFEX tests were failed. Patients felt significantly disadvantaged by the non-contextual sounds sounds from living beings, sounds from supermarket objects and names of other products as compared with beeping sounds (P0.01). Patients' verbal recall of the collected objects was significantly lower under the condition with names of other products (P0.001). Left and right brain-damaged patients did not differ in navigational performance in the VAP-S under the 5 auditory conditions.These non-contextual auditory stimuli could be used in neurorehabilitation paradigms to train patients with dysexecutive disorders to inhibit disruptive stimuli.

Usher syndrome, Type 1C (USH1C) is an autosomal recessive inherited disorder in which a mutation in the gene encoding harmonin is associated with multi-sensory deficits (i.e., auditory, vestibular, and visual). USH1C (Usher) mice, engineered with a human USH1C mutation, exhibit these multi-sensory deficits by circling behavior and lack of response to sound. Administration of an antisense oligonucleotide (ASO) therapeutic that corrects expression of the mutated USH1C gene, has been shown to increase harmonin levels, reduce circling behavior, and improve vestibular and auditory function. The current study evaluates the organization of exploratory movements to assess spatial organization in Usher mice and determine the efficacy of ASO therapy in attenuating any such deficits. Usher and heterozygous mice received the therapeutic ASO, ASO-29, or a control, non-specific ASO treatment at postnatal day five. Organization of exploratory movements was assessed under dark and light conditions at two and six-months of age. Disruptions in exploratory movement organization observed in control-treated Usher mice were consistent with impaired use of self-movement and environmental cues. In general, ASO-29 treatment rescued organization of exploratory movements at two and six-month testing points. These observations are consistent with ASO-29 rescuing processing of multiple sources of information and demonstrate the potential of ASO therapies to ameliorate topographical disorientation associated with other genetic disorders.

Objective: Landmark agnosia is a rare type of navigation impairment, for which various definitions have been presented. From a clinical as well as theoretical perspective, consensus on the characteristics of landmark agnosia would be valuable. In the current study we review the literature concerning landmark agnosia and present a new case study. Existing literature highlights the importance of examining familiar as well as novel landmark processing and substantial variation in performance patterns of individual patients.Method: We performed a case study with patient KS, a 53-year-old male, suffering from landmark agnosia, making use of elaborate neuropsychological screening and virtual reality-based tests of navigation ability.Results: Our extensive examination of his impairment shows that landmark agnosia can be very narrow; in KS it is restricted to recognition of newly learned landmarks only. Also, he has no trouble recognizing familiar landmarks that are not part of a navigated route.Conclusions: The literature review shows that the right temporal lobe, and the right hippocampus in particular are the main lesion sites for landmark agnosia. Furthermore, our case study substantiates that this disorder can occur for both familiar and novel landmarks, and can affect novel landmarks in isolation from familiar landmarks. Moreover, it can occur in isolation from problems with processing route information.

We recently developed a new clinical test named card placing test (CPT) which can assess a subject's ability to deal with visuospatial information. The CPT requires a subject to recreate an array of three cards, each of which was randomly placed on eight grids around the subject, before (CPT-A) and after the subject's rotation (CPT-B). With this design, the CPT can assess a subject's ability to represent visuospatial information either egocentrically (CPT-A) or allocentrically (CPT-B). We administered the test on two patients with topographical disorientation; one with egocentric disorientation and another with heading disorientation. The patient with egocentric disorientation demonstrated poor performances on both CPT-A and CPT-B. The patient with heading disorientation, on the other hand, showed good record results for CPT-A but poor ones for CPT-B. An implication is that the patient with egocentric disorientation had disorder in an egocentric reference frame per se, while the patient with heading disorientation could not integrate information on the spatial locations derived from an egocentric reference frame with that on changes of the body directions. We suggest that the CPT is a simple and useful clinical test to evaluate patients with topographical disorientation.

International audience; Spatial navigation, which involves higher cognitive functions, is frequently implemented in daily activities, and is critical to the participation of human beings in mainstream environments. Virtual reality is an expanding tool, which enables on one hand the assessment of the cognitive functions involved in spatial navigation, and on the other the rehabilitation of patients with spatial navigation difficulties. Topographical disorientation is a frequent deficit among patients suffering from neurological diseases. The use of virtual environments enables the information incorporated into the virtual environment to be manipulated empirically. But the impact of manipulations seems differ according to their nature (quantity, occurrence, and characteristics of the stimuli) and the target population. We performed a systematic review of research on virtual spatial navigation covering the period from 2005 to 2015. We focused first on the contribution of virtual spatial navigation for patients with brain injury or schizophrenia, or in the context of ageing and dementia, and then on the impact of visual or auditory stimuli on virtual spatial navigation. On the basis of 6521 abstracts identified in 2 databases (Pubmed and Scopus) with the keywords « navigation » and « virtual », 1103 abstracts were selected by adding the keywords "ageing", "dementia", "brain injury", "stroke", "schizophrenia", "aid", "help", "stimulus" and "cue"; Among these, 63 articles were included in the present qualitative analysis. Unlike pencil-and-paper tests, virtual reality is useful to assess large-scale navigation strategies in patients with brain injury or schizophrenia, or in the context of ageing and dementia. Better knowledge about both the impact of the different aids and the cognitive processes involved is essential for the use of aids in neurorehabilitation.

Objective Topographical disorientation is a frequent issue in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). Such impairments are replicated with virtual reality analogs of large-scale spatial navigation tasks. Objective: to evaluate whether visual cues are helpful for virtual spatial navigation and memory in AD and MCI patients. Material/patients and methods Twenty AD patients, 18 MCI patients and 20 age-matched healthy controls (HC) were included. All the participants had to reproduce actively a path including 5 intersections with one landmark at each that they had seen before passively. Three cueing conditions for navigation were proposed: salient landmarks, directional arrows and a map. A path without visual cues served as control condition. Navigation time and number of trajectory mistakes were recorded. After navigation, free recall and recognition of landmarks, landmarks ordering, choice of direction at each intersection and choice of patho outline were assessed. Results With the presence of directional arrows, no significant difference was found between groups concerning the number of trajectory mistakes and navigation time. The number of trajectory mistakes did not differ significantly between AD patients and MCI patients on the path with arrows, the path with salient landmarks and the path with a map. There were significant correlations between the number of trajectory mistakes under the arrow condition and executive tests (TMT and FAB), and between the number of trajectory mistakes under the salient landmark condition and memory tests (FCSRT 16 items and forward verbal span). Discussion – conclusion Visual cueing such as directional arrows and salient landmarks appears helpful for spatial navigation and memory tasks in AD and MCI patients. These visual cueing offers new research avenues for neurorehabilitation, such as the use of augmented reality in real-life settings to support the navigational capabilities of MCI and AD patients.

Buchwald (1878 ) used the term 'mirror writing' to indicate writing in the reverse direction to what is normal in a particular language and in which the individual letters are also reversed. Cases of healthy individuals (i.e., Leonardo da Vinci and Lewis Carroll) as well as brain-damaged patients have been described in the literature. Here, we report the case of PM, a 70-year-old right-handed woman who showed right hemiplegia and mirror writing following a stroke in the left lenticular nucleus and internal capsulae. PM underwent a complete neuropsychological evaluation, which included copying, dictation and spontaneous writing in both hemispaces with both hands. She was also tested for topographical disorientation, visuo-spatial disorders and body schema deficits. We observed isolated mirror writing only when PM wrote with the left hand, without differences between hemispaces. She also showed a left-right disorientation, a body topological map disorder and an egocentric misrepresentation. The presence of mirror writing not confined to one hemispace and the co-presence of executive function disorders, as well as anosognosia, suggests damage to our patient's sub-cortical frontal network. As no previous interpretation fits with PM's symptoms, we hypothesize that mirror writing resulted from damage to her egocentric frame of reference. This hypothesis allows us to interpret the patient's array of disorders, including mirror writing, body topological map disorder, left-right confusion and egocentric representation.

The present field experiment examined how multi-trial visuo-spatial learning and memory performance are impacted by excessive arousal, instigated by a potentially life-threatening event (i.e., a first parachute jump). Throughout a parachute training activity, subjective and neuroendocrine (i.e., cortisol) stress levels were assessed of 61 male military cadets who were randomly assigned to a control (n = 30) or a jump stress condition (n = 31). Post-stress learning and memory capacity was assessed with a 10-trial path-learning task that permitted emergence of learning curves. Pre-activity cortisol concentrations indicated a significant neuroendocrine anticipatory stress response in the stress group. Following parachuting, subjective stress levels and salivary cortisol reactivity differed significantly between groups. Visuo-spatial path-learning performance was impaired significantly after jump stress exposure, relative to the control group. Moreover, examination of the learning curves showed similar learning and memory performance at onset of the trials, with curves bifurcating as the task became more complex. These findings are in accordance with leading theories that acknowledge a moderating effect of task complexity. In sum, the present study extends knowledge concerning anticipatory stress effects, endogenously instigated cortisol reactivity, and the influence of extreme arousal on visuo-spatial path learning.

Defects confined to spatial memory can severely affect a variety of daily life activities, such as remembering the location of objects or navigating the environment, until now the skills involved have been mostly assessed with regard to the visual domain using traditional pencil and paper tests. Our aim was to test the efficacy of a recently developed psychometric instrument (Walking Corsi Test: WalCT) to assess the specific contribution of spatial memory to the complex task of retrieving route knowledge. The WalCT is a 3 × 2.5-m version of the well-known Corsi Block-tapping Test (CBT), in which patients are required to memorize (and replicate) a sequence of body displacements. We assessed the ability of left and right brain-damaged patients, as well as healthy young and senior controls, to perform both the CBT and the WalCT. Results showed differences related to age in the healthy individuals and specific functional dissociations in the brain-damaged patients. The double dissociations found in this study demonstrate the importance of having a task able to detect navigational disorders, because virtual reality tasks are often much too difficult for aged brain-damaged patients to perform.

A 66-year-old, right-handed male, was admitted to our hospital with difficulty in recognizing faces and colors. He had suffered a stroke in the right occipital region three years earlier that had induced left homonymous hemianopsia, but not prosopagnosia. A neurological examination revealed prosopagnosia, color agnosia, constructional apraxia, and topographical disorientation, but not either hemineglect or dressing apraxia. The patient was unable to distinguish faces of familiar persons such as his family and friends, as well as those of unfamiliar persons such as doctors and nurses. Brain MRI demonstrated an old infarction in the right medial occipital lobe and a new hemorrhagic infarction in the left medial occipital lobe, including the fusiform and lingual gyrus. It is unclear whether a purely right medial occipital lesion can be responsible for prosopagnosia, or whether bilateral medial occipital lesions are necessary for this occurrence. The current case indicated that bilateral medial occipital lesions play an important role in inducing porsopagnosia.

Introduction Topographical disorientation is defined as the inability to recognize familiar or unfamiliar environments. While its slowly progressive development is a common feature of neurodegenerative processes like Alzheimer's dementia, acute presentations are less frequent and mostly caused by strategic lesions within the cerebral navigation network. Depending on the lesion site, topographical disorientation can originate from deficits in landmark recognition and utilization for route planning (egocentric navigation deficit), or disturbance of an overarching cognitive map of the spatial environment (allocentric navigation deficit). However, objective measurements of spatial navigation performance over time are largely missing in patients with topographical disorientation. Methods We here report a 55‐year‐old patient with acute topographical disorientation as the single symptom of right‐sided hippocampal hemorrhage and present quantitative gaze‐monitoring head camera‐based analyses of his path‐finding strategy and visual exploration behavior in a real space navigation paradigm. Results The patient exhibited severe allocentric and also egocentric navigation deficits during the acute phase, shown by higher error rates at finding target items. In addition, he showed a more extensive use of search saccades toward, and fixations on, landmarks that could potentially serve as spatial cues. These deficits had been completely compensated for after four months, when the patient performed unremarkably in the real space navigation task, and used even more strongly allocentric path optimization strategies than age‐matched controls. Conclusions This case report highlights the integral function and right‐sided dominance of the hippocampal formation in the cerebral navigation network in humans. It shows that the cognitive map can be restored completely despite a residual hippocampal lesion, which illustrates the enormous plasticity of the cerebral navigation network in humans.

Since there is no cure for glioblastoma multiforme (GBM), the goal of treatment becomes prolonging the survival through cytoreduction while minimising neurological deficits. In this case report, laser interstitial thermal therapy (LITT) was used once the tumour progressed into the isthmus of the cingulate gyrus. One year after temporal lobectomy, disorders of memory, emotion, personality and navigation, likely related to limbic system involvement along with hallucinations and fluctuating cognition occurred as the tumour progressed. After ablation of the posterior cingulum, worsening of topographical disorientation was observed. Per literature review, delirium has been noted in patients with strokes involving the right-sided temporo-parieto-occipital junction, and topographical disorientation has been associated with lesions of the right posterior cingulum. Alternative causes of these deficits were ruled out, leaving structural changes as the primary explanation. This is the first report of the neurological deficits associated with tumour progression and vasogenic oedema in this region.

We present the case of F.G., a healthy, normally developed 22-year-old male subject affected by a pervasive disorder in environmental orientation and navigation who presents no history of neurological or psychiatric disease. A neuro-radiological examination showed no evidence of anatomical or structural alterations to the brain. We submitted the subject for a comprehensive neuropsychological assessment of the different cognitive processes involved in topographical orientation to evaluate his ability to navigate the spatial environment. The results confirmed a severe developmental topographical disorder and deficits in a number of specific cognitive processes directly or indirectly involved in navigation. The results are discussed with reference to the sole previously described case of developmental topographical disorientation (Pt1; Iaria et al., 2009). F.G. differs from the former case due to the following: the greater severity of his disorder, his complete lack of navigational skills, the failure to develop compensatory strategies, and the presence of a specific deficit in processing the spatial relationships between the parts of a whole. The present case not only confirms the existence of developmental topographical-skill disorders, but also sheds light on the architecture of topographical processes and their development in human beings.

Topographical disorientation (TD) has not been as extensively studied as other frequent manifestations of Alzheimer's disease (AD). OBJECTIVE: To verify the occurrence of TD and to identify the neuropsychological dysfunctions associated with TD in AD. METHOD: Thirty patients with probable AD, their caregivers and 30 subjects without dementia (controls) were interviewed with a questionnaire and evaluated with tests related to topographical orientation. RESULTS: AD patients, even those with mild dementia, differ from controls in the questionnaire on topographical orientation and in most neuropsychological tests except for tests of spatial working memory, point localization, three dimension and nonsense figure copy. When the performances in the neuropsychological tests of patients with mild or moderate dementia were compared, only landmark recognition and route description were more impaired in moderate dementia. CONCLUSION: TD occurs even in mild dementia of AD, a finding apparently not explained by the impairments of more elementary spatial functions.

We report herein a patient of poststroke dementia (PSD) following left medial occipitoparietal hemorrhage triggered by drainage of an acute traumatic subdural hematoma. The patient, an independent 73-year-old man, became dependent due to dementia. Cognitive dysfunction was characterized by moderately decreased IQ, severe memory disturbances, topographical disorientation, executive dysfunction and loss of self-awareness. Cognitive dysfunction has not advanced for 3 years. Hypo-perfusion in the whole brain, particularly in the left temporal and parietal regions, was visible on 123I-IMP SPECT images. Magnetic resonance imaging demonstrated damage to the left posterior cingulate cortex, cingulate bundle, superior parietal lobule and subcortical region of the occipital lobe. The fornix was spared. Some subcortical small spotted lesions were detected, but periventricular lucency was not prominent. Structures known to be important in memory but spared by the lesion included the thalamus and basal forebrain. Small spotted subcortical lesions were detected in bilateral hippocampi, which are also known to be important in memory, but these were probably silent lesions. This case suggested that dementia is brought on by the lesion of the left posterior cingulate bundle and retrosplenial cortex causing amnesia by disrupting the cingulate-hippocampal connection or the retrosplenial cortex itself, with the lesion of the left occipitoparietal subcortex causing frontal dysfunction by disrupting the dorsal limbic pathway and occipitofrontal fasciculus of the prefrontal circuits.

A 68-year-old man was admitted to our hospital for rehabilitation of topographical disorientation. Brain magnetic resonance imaging revealed infarction in the right medial side of the occipital lobe. On neuropsychological testing, he scored low for the visual information-processing task; however, his overall cognitive function was retained. He could identify parts of the picture while describing the context picture of the Visual Perception Test for Agnosia but could not explain the contents of the entire picture, representing so-called simultanagnosia. Further, he could morphologically perceive both familiar and new scenes, but could not identify them, representing so-called scene agnosia. We report this case because simultanagnosia associated with a right occipital lobe lesion is rare.