Laura Zompanti

Walking in the Corsi test: which type of memory do you need?

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.

Developmental topographical disorientation in a healthy subject.

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.

Dissociated deficits of visuo-spatial memory in near space and navigational space: Evidence from brain-damaged patients and healthy older participants

ABSTRACT 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.

Pure representational neglect and navigational deficits in a case with preserved visuo-spatial working memory

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., oclock 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.

Landmark based navigation in brain-damaged patients with neglect.

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.

The Walking Corsi Test (WalCT): a normative study of topographical working memory in a sample of 4- to 11-year-olds.

We report normative data on topographical working memory collected through the Walking Corsi Test (WalCT; Piccardi et al., 2008) for developing a standard administration procedure to be used in clinical and educational practice. A total of 268 typically developing Italian children aged 4–11 years performed both WalCT and Corsi Block-Tapping Test (CBT; Corsi, 1972) a well-known visuo-spatial memory test. WalCT has already been validated in adults, demonstrating sensitivity in detecting topographical memory deficits even in individuals who have no other memory impairments. Our results showed that age, but not sex, affected performances. Both girls and boys had a larger span on the CBT than the WalCT. The youngest group did not differ in performing WalCT and CBT, but from 5.6 years of age children performed better on CBT than WalCT, suggesting that memory in reaching space develops before topographical memory. Only after 5 years of age do children learn to process specifically topographical stimuli, suggesting that this happens when their environmental knowledge becomes operational and they increase environmental independence. We also discuss the importance to introduce WalCT in the clinical assessment.

Women outperform men in remembering to remember

The study of gender differences in prospective memory (i.e., remembering to remember) has received modest attention in the literature. The few reported studies investigating either subjective or objective evaluations of prospective memory have shown inconsistent data. In this study, we aimed to verify the presence of gender differences during the performance of an objective prospective memory test by considering the weight of specific variables such as length of delay, type of response, and type of cue. We submitted a sample of 100 healthy Italian participants (50 men and 50 women) to a test expressly developed to assess prospective memory: The Memory for Intentions Screening Test. Women performed better than men in remembering to do an event-based task (i.e., prompted by an external event) and when the task required a physical response modality. We discuss the behavioural differences that emerged by considering the possible role of sociological, biological, neuroanatomical, and methodological variables.

Riconoscimento Delle Posizioni Prospettiche

Quando un individuo trova un ostacolo lungo un percorso, o deve trovare una scorciatoia, o nel caso in cui debba riprodurre al contrario un tragitto precedentemente effettuato, per orientarsi con successo deve essere in grado di riconoscere i landmark precedentemente incontrati, anche se questi vengono visualizzati secondo una prospettiva differente. La capacita di riconoscere una stessa immagine presentata da punti di vista diversi e quindi fondamentale per il buon esito della navigazione.

Orientamento topografico nell’uomo

Per mantenere l’orientamento nell’ambiente circostante, l’uomo deve aggiornare le proprie relazioni spaziali egocentriche (vale a dire le informazioni che provengono da se stesso in relazione con l’ambiente) al cambiare della sua posizione nello spazio. Tali aggiornamenti avvengono tramite l’integrazione di diverse fonti di informazioni (visiva, vestibolare, propriocettiva). In particolar modo l’informazione visiva gioca un ruolo fondamentale nell’aggiornamento sia della propria posizione sia di eventuali modifiche subite dall’ambiente (Farrell, Robertson, 2000). Inoltre, attraverso l’esperienza che deriva dal suo movimento nello spazio, l’individuo e in grado di elaborare un’informazione sia propriocettiva (cioe un’informazione sul senso di posizione e movimento degli arti e del corpo, che si ha indipendentemente dalle informazioni visive) sia locomotoria (un’informazione derivante dal proprio movimento indipendentemente dall’informazione visiva). Inoltre, gli studi condotti sui non vedenti ci insegnano che gli individui sono effettivamente in grado di aggiornare la propria posizione anche in assenza dell’informazione visiva (Rieser et al., 1986; Rieser 1989; Seemungal et al., 2007). Quando una persona si muove al buio ricava le informazioni sulla propria posizione basandosi su un processo definito path integration nel quale la posizione viene dedotta sulla base delle informazioni che derivano da segnali inerziali inviati dal sistema vestibolare e da informazioni tattili, attraverso un complicatissimo processo di integrazione che si avvale anche di veri e propri calcoli matematici per addizionare le informazioni vettoriali di movimento (Mittlestaedt, Mittlestaedt, 1980; Glasauer et al., 2002).

Prerequisiti Di Percezione Visuo-Spaziale

L’abilita di navigazione umana include diverse sottocomponenti che contribuiscono indipendentemente alla capacita di orientamento.