Neuropsicologia dei DIsturbi VIsuo-spaziali e della Navigazione

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AREE DI RICERCA

 
Il laboratorio Di.Vi.Na. si occupa di ricerca relativa alla capacità di orientamento topografico, cioè la capacità di muoversi con successo in un ambiente per andare da un luogo ad un altro.
 
- Studio dei sistemi di rappresentazione visuo-spaziale.
 
- Studio della neuropsicologia della rappresentazione ambientale.
 
- Studio della neuropsicologia dei processi di navigazione ambientale.
 
- Preparazione e standardizzazione su soggetti normali di paradigmi sperimentali per lo studio dei deficit neuropsicologici della rappresentazione e della navigazione ambientale da applicare in ricerche su pazienti cerebrolesi, da effettuare in spazi in convenzione con il Dipartimento presso altra struttura di ricerca (IRCCS Fondazione Santa Lucia)
 
 
PERSONALE STRUTTURATO:
 
Cecilia Guariglia
 
Daniele Nico
 
 
ASSEGNISTI DI RICERCA:
 
Giuseppe Iaria 
 
 
STUDENTI SPECIALIZZANDI:
 
Filippo Bianchini
 
Liana Palermo
 
Laura Zompanti
 
 
 
Il laboratorio dei disturbi visuo-spaziali e della navigazione (Di.Vi.Na.) è coordinato dalla prof.ssa Cecilia Guariglia, ordinario presso la Facoltà di Medicina e Psicologia, Università “Sapienza” di Roma. Il laboratorio ha sede presso il Centro Ricerche in Neuropsicologia della Fondazione Santa Lucia (IRCCS), via Ardeatina 306, Roma. 
 
 
 
Abstract delle principali pubblicazioni sulla capacità di orientamento topografico e i suoi deficit
 
Developmental topographical disorientation in a healthy subject.
(Bianchini F, Incoccia C, Palermo L, Piccardi L, Zompanti L, Sabatini U, Peran P, Guariglia C.)
 
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.
 
Lack of orientation due to a congenital brain malformation: a case study.
(Iaria G, Incoccia C, Piccardi L, Nico D, Sabatini U, Guariglia C.)
 
Topographical disorientation is usually described in patients who have lost the ability to orient themselves as a consequence of acquired focal brain damage. Here, we describe the case of a 20-year-old woman with a congenital brain malformation who has never been able to orient herself within the environment. We addressed in detail her ability to orient and navigate within the environment by administering a number of tasks in both ecological and experimental surroundings. The results indicate a complete inability to use any kind of strategy useful for orientation.
 
Topographical disorientation in a patient who never developed navigational skills: the (re)habilitation treatment.
(Incoccia C, Magnotti L, Iaria G, Piccardi L, Guariglia C.)
 
Although many cases of topographical disorientation are described in the literature, very few attempts have been made to rehabilitate this deficit, most likely because it is a multi-faceted syndrome in which different patients are affected by different topographical deficits. Therefore, it is not easy to develop a single rehabilitation programme to improve all types of topographical disorders. We describe the rehabilitation of a young woman with selective and pervasive topographical disorientation who never developed navigational skills due to a cerebral malformation bilaterally involving the retrorolandic regions. During treatment, the patient was trained to explore her surroundings carefully, to orient herself and then to move in the environment using a language-based strategy. At the end of the treatment, the patient was able to navigate in the environment by adopting several cognitive strategies useful for orientation. This result was maintained at the one-year follow-up, at which time the patient was also able to reach locations she had never been to alone. These results suggest that even patients who have never developed the ability to orient themselves in the environment can still achieve very good functional recovery if they are accurately assessed and submitted to a specific rehabilitation intervention.
 
Representational neglect and navigation in real space.
(Guariglia C, Piccardi L, Iaria G, Nico D, Pizzamiglio L.) 
 
Topographical orientation relies on several cognitive strategies adopted by humans to move within the environment. In the present study, we investigate whether mental representation disorders affect specific cognitive mechanisms subserving human orientation. In order to differentiate distinct cognitive mechanisms involved in topographical orientation, we created a human version of the well-known "Morris Water Maze" and tested left and right brain damaged patients in a place-learning task. The test required the subjects to explore an experimental room in which no visual cues were present, find a target location, and then reach it in different conditions. The ability to memorize target locations in short- and long-term memory was also assessed. We found that all participants were able to reach the target location by using idiothetic cues (vestibular inputs, motor efferent copy, etc.). On the other hand, when starting position changed and re-orientation was necessary to reach the target location, in order to compute a new trajectory, only patients affected by representational neglect got lost. These results provide the first neuropsychological evidence of involvement of mental representation in a specific cognitive process allowing humans to reach a target place from any location in the environment.
 
Landmark based navigation in brain-damaged patients with neglect.
(Nico D, Piccardi L, Iaria G, Bianchini F, Zompanti L, Guariglia C.)
 
We tested navigational abilities of brain-damaged patients suffering from representational or perceptual neglect asking them to retrieve a location according to salient spatial cues included in a rectangular empty room. Both groups of patients showed difficulties in learning the spatial definition of the target location in relation to two landmarks. However in a delayed attempt performed after several trials the group of patients with perceptual neglect proved able to easily retrieve the target location. In this condition they performed as controls showing a spared ability to navigate according to a stable representation of the room in long-term memory. In contrast the difficulty of patients with representational neglect remained unchanged across experimental conditions. At variance with clinical assessment, in which patients show asymmetrical performances in describing a well-known environment from memory, this latter result depicts a behavioural counterpart of the disorder, namely the inability to orient in a new environment according to an inner representation. Data are further discussed in order to provide a description of the cognitive mechanisms required for space representation for navigation.
 
Pure representational neglect and navigational deficits in a case with preserved visuo-spatial working memory.
(Piccardi L, Bianchini F, Zompanti L, Guariglia C.)
 
We describe a patient who, after right hemisphere damage, showed severe, persistent, pure representational neglect but no evidence of perceptual neglect and no deficits in spatial working memory when evaluated with a traditional clinical test (Corsi Block Tapping test). This finding provides evidence against a full explanation of representational neglect within the context of visuo-spatial working memory. Indeed, this patient showed a peculiar deficit in navigational tasks requiring re-orientation in a novel environment by means of his mental representation of the environment. Since no representational neglect was observed in tests requiring mental representation of single or multiple objects (i.e., o'clock test) we suggest that in our patient representational neglect is caused by damage to the cognitive system involved in coding and storing environmental information to be used during navigation.
 
Environment and object mental images in patients with representational neglect: Two case reports.
(Palermo L, Nori R, Piccardi L, Giusberti F, Guariglia C.)
 
The aim of this study was to shed light on the nature of the imagery deficits in two patients with representational neglect and to determine whether representational neglect is affected by the content of the mental images the patients have to generate, inspect and manipulate. In particular, we submitted two patients with different types of representational neglect to a battery of visual mental imagery tests to assess the different kinds of imagery processes. We found that Patient 1, whose performance was asymmetrical on the O'Clock Test, performed poorly on tasks involving the mental generation, inspection and manipulation of objects but showed no deficit on tasks involving the mental generation, inspection and manipulation of environments. On the other hand, Patient 2, whose performance was asymmetrical on the Familiar Squares Description Test, performed poorly on tasks involving the mental generation, inspection and manipulation of environments, but not on tasks involving the mental generation, inspection and manipulation of objects. Our results demonstrate that environments and objects in the imagery domain can be represented separately and can be selectively affected by damage following brain lesions.
 
Representational neglect and navigation in virtual space.
(Piccardi L.)
 
Previous studies have shown that mental representational disorders affect specific mechanisms that subserve human orientation. Specifically, representational neglect impairs the ability to reorient oneself in a new environment. Apparently, the inability of patients with this disorder to manipulate a mental representation of the environment prevents them from using their previous navigational experience. In this study, we compared representational neglect patients' performance with the performance of other groups of brain-damaged patients (left and right lesions) without representational disorders and healthy participants during navigation in a virtual maze with and without local landmarks. The virtual environment allows to observe navigation ruling out vestibular and proprioceptive information about linear and angular movements that could explain results of previous studies and to shed some light on navigational disorders shown by perceptual and representational neglect patients. We found that brain-damaged patients without neglect and healthy participants showed no deficits in navigation. Further perceptual and representational neglect patients performed poorly across experimental conditions. Finally, only the representational neglect patients group was unable to build or retrieve the mental representation of a new environment.
 
Mental imagery skills and topographical orientation in humans: a correlation study.
(Palermo L, Iaria G, Guariglia C.)
 
Several studies provide evidence that mental imagery is critical for human navigation. However, the contribution of different mental imagery abilities to the individuals' skill of using specific orientation strategies remains unclear. In the present study we assessed a variety of mental imagery skills and investigated their contribution in relationship with the selective individuals' ability of forming and using a mental representation of the environment, namely a cognitive map. Indeed, despite the use of alternative strategies that individuals may adopt while moving along the same well-known route, cognitive maps are critical for orientation since they allow individuals to reach any target location from any place in the environment. We found that the ability to form a cognitive map was related to the specific ability of performing mental rotations of simple geometrical shapes, and the ability to imaging ourselves moving on a map. Other imagery skills such as the ability to generate mental images from memory or the ability of mentally manipulate objects were not correlated with the individuals' performance in forming the cognitive map. Moreover, we revealed gender differences in forming a cognitive map, as well as in performing some of the mental imagery tests. We discuss these findings in order to shed more light on the specific role of mental imagery in human topographical orientation.
 
Walking in the Corsi test: which type of memory do you need?
(Piccardi L, Iaria G, Ricci M, Bianchini F, Zompanti L, Guariglia C.)
 
Sex differences are often reported in spatial abilities. However, some studies show conflicting results, which can be ascribed to the complexity of the variables involved in the visuo-spatial domain. Until a few years ago, it was widely accepted that men outperformed women on almost all spatial tasks. However, recently some studies [A. Postma, G. Jager, R.P.C. Kessels, H.P.F. Koppeschaar, J. van Honk, Sex differences for selective forms of spatial memory, Brain Cogn. 54 (2004) 24-34; D.H. McBurney, S.J.C. Gaulin, T. Devineni, C. Adams, Superior spatial memory of women: stronger evidence for the gathering hypothesis, Evol. Hum. Behav. 18 (1997) 165-174; Q. Rahman, G.D. Wilson, S. Abrahams, Sexual orientation related differences in spatial memory, J. Int. Neuropsychol. Soc. 9 (2003) 376-383] found sex differences for selective forms of spatial memory and described a female advantage in specific spatial abilities. In this paper, we studied sex differences by testing object locations and route memories with the Corsi Block-Tapping test (CBT), one of the non-verbal tasks most used in clinical settings, and its modified, large-scale version. Our results showed a performance advantage for males in both tests and a more homogeneous pattern of memory in females.

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