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BACKGROUND: The current COVID-19 pandemic has abruptly catalysed a shift towards remote assessment in neuropsychological practice (tele-neuropsychology, t-NPs). Although the validity of t-NPs diagnostics is gaining recognition worldwide, little is known about its implementation in Italy. The present review by the Italian working group on tele-neuropsychology (TELA) aims at describing the availability, psychometric properties, and feasibility of t-NPs tools currently available in Italy. METHODS: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. This work was pre-registered on the Prospective Register of Systematic Reviews (PROSPERO; CRD42021239687). Observational studies reporting telephone-, videoconference- or web-based assessment of cognition/behaviour in Italian both healthy participants (HPs) and patients were included. Bias assessment was performed through ad hoc scales. RESULTS: Fourteen studies were included from an initial N = 895 (4 databases searched). Studies were subdivided into those focused on psychometric properties and those characterized by a predominant applied nature. The majority of studies addressed either adult/elderly HPs or neurological/internal patients. Multi-domain screening tools for cognition, behaviour, mood/anxiety and quality of life were the most represented. Findings regarding validity, reliability, sensitivity, specificity and clinical usability were reported for cognitive screenings - the telephone- and videoconference-based Mini-Mental State Examination and the Telephone Interview for Cognitive Status. DISCUSSION: Positive albeit preliminary evidence regarding psychometric properties and feasibility in both clinical and non-clinical populations of Italian t-NPs brief screening tools are herewith provided. Further studies exploring clinical usability of t-NPs and psychometric properties/feasibility of tests for the in-depth assessment of specific cognitive domains are necessary.
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COVID-19 , Calidad de Vida , Anciano , Humanos , Pandemias , Psicometría , Reproducibilidad de los Resultados , SARS-CoV-2RESUMEN
OBJECTIVE: Patients with unilateral stroke commonly show hemispatial neglect or milder contralesional visuoattentive deficits, but spatially non-lateralized visuoattentive deficits have also been reported. The aim of the present study was to compare spatially lateralized (i.e., contralesional) and non-lateralized (i.e., general) visuoattentive deficits in left and right hemisphere stroke patients. METHOD: Participants included 40 patients with chronic unilateral stroke in either the left hemisphere (LH group, n = 20) or the right hemisphere (RH group, n = 20) and 20 healthy controls. To assess the contralesional deficits, we used a traditional paper-and-pencil cancellation task (the Bells Test) and a Lateralized Targets Computer Task. To assess the non-lateralized deficits, we developed a novel large-screen (173 × 277 cm) computer method, the Ball Rain task, with moving visual stimuli and fast-paced requirements for selective attention. RESULTS: There were no contralesional visuoattentive deficits according to the cancellation task. However, in the Lateralized Targets Computer Task, RH patients missed significantly more left-sided than right-sided targets in bilateral trials. This omission distribution differed significantly from those of the controls and LH patients. In the assessment of non-lateralized attention, RH and LH patients missed significantly more Ball Rain targets than controls in both the left and right hemifields. CONCLUSIONS: Computer-based assessment sensitively reveals various aspects of visuoattentive deficits in unilateral stroke. Patients with either right or left hemisphere stroke demonstrate non-lateralized visual inattention. In right hemisphere stroke, these symptoms can be accompanied by subtle contralesional visuoattentive deficits that have remained unnoticed in cancellation task.
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Trastornos de la Percepción , Accidente Cerebrovascular , Computadores , Lateralidad Funcional , Humanos , Trastornos de la Percepción/etiología , Tiempo de Reacción , Accidente Cerebrovascular/complicaciones , Percepción VisualRESUMEN
Can cognitive load enhance concentration on task-relevant information and help filter out distractors? Most of the prior research in the area of selective attention has focused on visual attention or cross-modal distraction and has yielded controversial results. Here, we studied whether working memory load can facilitate selective attention when both target and distractor stimuli are auditory. We used a letter n-back task with four levels of working memory load and two levels of distraction: congruent and incongruent distractors. This combination of updating and inhibition tasks allowed us to manipulate working memory load within the selective attention task. Participants sat in front of three loudspeakers and were asked to attend to the letter presented from the central loudspeaker while ignoring that presented from the flanking ones (spoken by a different person), which could be the same letter as the central one (congruent) or a different (incongruent) letter. Their task was to respond whether or not the central letter matched the letter presented n (0, 1, 2, or 3) trials back. Distraction was measured in terms of the difference in reaction time and accuracy on trials with incongruent versus congruent flankers. We found reduced interference from incongruent flankers in 2- and 3-back conditions compared to 0- and 1-back conditions, whereby higher working memory load almost negated the effect of incongruent flankers. These results suggest that high load on verbal working memory can facilitate inhibition of distractors in the auditory domain rather than make it more difficult as sometimes claimed.
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Cognición , Memoria a Corto Plazo , Humanos , Tiempo de ReacciónRESUMEN
OBJECTIVE: Neuropsychological studies suggest that the ability to compensate for the presence of spatial neglect highly depends on the attentional resources a patient can rely on. The present research aimed to study neglect in situations where attentional resources are limited due to multitasking. METHOD: We examined two patients more than 3 years after a right-hemispheric stroke. Both had received neuropsychological rehabilitation for left neglect and did not show any impairment in standard tests. We used a dual-task paradigm combining a peripheral target detection task with a central shape recognition task. Peripheral targets could appear in left/right positions but also in lower/upper positions. RESULTS: In patient #1, dual-task condition exacerbated left neglect and extinction. Patient #2 did not show any sign of neglect along the horizontal axis, but omitted half of the lower targets when they were presented simultaneously with upper targets under dual-task condition. This behavior reflects altitudinal extinction as the detection of single targets appearing either in upper or lower position was preserved. CONCLUSION: The present findings show that dual-tasking is a sensitive tool for the quantitative and qualitative assessment of spatial attention deficits, which are often overlooked by standard methods, especially in chronic stage. (JINS, 2019, 25, 644-653).
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Atención/fisiología , Función Ejecutiva/fisiología , Reconocimiento Visual de Modelos/fisiología , Trastornos de la Percepción/fisiopatología , Percepción Espacial/fisiología , Accidente Cerebrovascular/fisiopatología , Anciano , Enfermedad Crónica , Percepción de Forma/fisiología , Humanos , Masculino , Persona de Mediana Edad , Trastornos de la Percepción/etiología , Accidente Cerebrovascular/complicaciones , Campos Visuales/fisiologíaRESUMEN
Voluntary orienting of spatial attention is typically investigated by visually presented directional cues, which are called predictive when they indicate where the target is more likely to appear. In this study, we investigated the nature of the potential link between cue predictivity (the proportion of valid trials) and the strength of the resulting covert orienting of attention. Participants judged the orientation of a unilateral Gabor grating preceded by a centrally presented, non-directional, color cue, arbitrarily prompting a leftwards or rightwards shift of attention. Unknown to them, cue predictivity was manipulated across blocks, whereby the cue was only predictive for either the first or the second half of the experiment. Our results show that the cueing effects were strongly influenced by the change in predictivity. This influence differently emerged in response speed and accuracy. The speed difference between valid and invalid trials was significantly larger when cues were predictive, and the amplitude of this effect was modulated at the single trial level by the recent trial history. Complementary to these findings, accuracy revealed a robust effect of block history and also a different time-course compared with speed, as if it mainly mirrored voluntary processes. These findings, obtained with a new manipulation and using arbitrary non-directional cueing, demonstrate that cue-target contingencies strongly modulate the way attention is deployed in space.
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Atención/fisiología , Señales (Psicología) , Orientación Espacial/fisiología , Tiempo de Reacción/fisiología , Adulto , Femenino , Humanos , Masculino , Estimulación LuminosaRESUMEN
Recent research has led to the hypothesis that events which unfold in time might be spatially represented in a left-to-right fashion, resembling writing direction. Here we studied fourteen right-hemisphere damaged patients, with or without neglect, a disorder of spatial awareness affecting contralesional (here left) space processing and representation. We reasoned that if the processing of time-ordered events is spatial in nature, it should be impaired in the presence of neglect and spared in its absence. Patients categorized events of a story as occurring before or after a central event, which acted as a temporal reference. An asymmetric distance effect emerged in neglect patients, with slower responses to events that took place before the temporal reference. The event occurring immediately before the reference elicited particularly slow responses, closely mirroring the pattern found in neglect patients performing numerical comparison tasks. Moreover, the first item elicited significantly slower responses than the last one, suggesting a preference for a left-to-right scanning/representation of events in time. Patients without neglect showed a regular and symmetric distance effect. These findings further suggest that the representation of events order is spatial in nature and provide compelling evidence that ordinality is similarly represented within temporal and numerical domains.
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Atención/fisiología , Lateralidad Funcional/fisiología , Trastornos de la Percepción/fisiopatología , Percepción Espacial/fisiología , Percepción Visual/fisiología , Adulto , Anciano , Encéfalo/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Movimiento/fisiología , Pruebas NeuropsicológicasRESUMEN
The prevalence of neurodegenerative disorders, particularly dementia, is on the rise across many countries worldwide. This negative trend calls for improving our understanding of cognitive aging. While motor-cognitive dual-task approaches have already been proven valuable for clinical diagnosis, comparatively less research is available on the application of Cognitive-Cognitive Dual-Tasking (CCDT), across several cognitive domains. Moreover, there is limited understanding about how healthy aging affects performance in such dual-tasks in the general population. CCDT entails engaging individuals in multiple cognitive tasks simultaneously and holds promise for remote e-Health interventions. In this cross-sectional study, our objective was to evaluate the suitability of a newly developed, self-administered, online tool for examining age-related differences in memory performance under dual-tasking. 337 healthy adults aged 50-90 underwent a visual memory test (Memo) under both single and dual-task conditions (attend to auditory letters). Additional measures included questionnaires on subjective memory complaints (MAC-Q), on cognitive reserve (CR), and a cognitive screening (auto-GEMS). As expected, the accuracy of visual memory performance exhibited a negative correlation with age and MAC-Q, and a positive correlation with CR and auto-GEMS scores. Dual-tasking significantly impaired performance, and its detrimental effect decreased with increasing age. Furthermore, the protective effect of cognitive reserve diminished with advancing age. These findings suggest that the commonly observed age-related increase in dual-task costs is not universally applicable across all tasks and cognitive domains. With further refinement, a longitudinal implementation of this approach may assist in identifying individuals with a distinct cognitive trajectory and potentially at a higher risk of developing cognitive decline.
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Envejecimiento , Cognición , Humanos , Estudios Transversales , Anciano , Masculino , Femenino , Persona de Mediana Edad , Cognición/fisiología , Anciano de 80 o más Años , Envejecimiento/fisiología , Envejecimiento/psicología , Pruebas Neuropsicológicas , Memoria/fisiología , Reserva Cognitiva/fisiología , Envejecimiento Cognitivo/fisiologíaRESUMEN
A theoretical perspective on grandiose narcissism suggests four forms of it (sanctity, admiration, heroism, rivalry) and states that these forms conduce to different ways of thinking and acting. Guided by this perspective, we examined in a multinational and multicultural study (61 countries; N = 15,039) how narcissism forms are linked to cognitions and behaviors prompted by the COVID-19 pandemic. As expected, differences in cognitions and behaviors across narcissism forms emerged. For example, higher narcissistic rivalry predicted lower likelihood of enactment of COVID-19 prevention behaviors, but higher narcissistic sanctity predicted higher likelihood of enactment of COVID-19 prevention behaviors. Further, whereas the heroism, admiration, and rivalry narcissism forms acted in a typically antisocial manner, with high narcissism predicting greater endorsement of unfounded health beliefs, the sanctity form acted in a prosocial manner, with higher narcissism being linked to lower endorsement of unfounded COVID-19 health beliefs. Thus, the findings (a) support the idea of four narcissism forms acting differently, and (b) show that these differences reflect a double-edged sword, sometimes linking to an anti-social orientation, and sometimes linking to a pro-social orientation.
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COVID-19 , Narcisismo , Humanos , COVID-19/psicología , COVID-19/epidemiología , Masculino , Femenino , Adulto , Pandemias , SARS-CoV-2 , Persona de Mediana Edad , Adulto JovenRESUMEN
The stop signal task is widely adopted to assess motor inhibition performance in both clinical and non-clinical populations. Several recent studies explored the influence of strategic approaches to the task. In particular, response slowing seems to be a strategic approach commonly adopted to perform the task. In the present study, we compared a standard version with a strategic version of the task, in which participants were explicitly instructed to slow down responses. Results showed that the instructed slowing did not affect the main inhibition measure, thus confirming the robustness of the stop signal index. On the other hand, it apparently changed the nature of the task, as shown by the lack of correlation between the standard and the strategic versions. In addition, we found a specific influence of individual characteristics on slowing strategies. In the standard version, adherence to task instructions was positively correlated with compliant traits of personality. Despite instructions to maximize response speed, non-compliant participants preferred to adopt a slowing strategy in the standard version of the task, up to a speed level similar to the strategic version, where slowing was required by task instructions. Understanding the role of individual approach to the task seems to be crucial to properly identify how participants cope with task instructions.
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Inhibición Psicológica , Pruebas Neuropsicológicas/normas , Personalidad/fisiología , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Adulto , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
The cognitive impairments shown by brain-damaged patients emphasize the role of task difficulty as a major determinant for performance. We discuss the proposal of Kurzban et al. in light of our findings on right-hemisphere-damaged patients, who show increasing awareness deficits for the contralesional hemispace when engaged with resource-consuming dual tasks. This phenomenon is readily explained by the assumption of unspecific depletable resources.
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Fatiga Mental/psicología , Modelos Psicológicos , HumanosRESUMEN
Performing multiple tasks in parallel is detrimental to performance, a phenomenon generically referred to as dual-task interference (DTi). Several variables can modulate DTi at the individual level, and increasing age is typically described as negatively affecting response costs. In this study, we investigated, in 252 healthy adults aged between 50 and 89 years, how age modulates the detrimental effect of DTi during the encoding of images. We combined a visual memory task and a sustained attention task (i.e., an auditory version of the continuous performance task, ACPT) in three separate blocks. In the first block, participants had to perform a four-alternative forced-choice recognition of previously memorized images without having attended to ACPT sounds during the encoding. In the second block, during memorization, participants had to press a response key when detecting the letter "X" within a stream of letters (Low Load). In the third block, they had to respond only when the letter "X" was preceded by the letter "A" (High Load). The results showed that overall performance linearly decreased with age. In contrast with our predictions, DTi was stable across different ages. Finally, using a cluster-based approach, we found that participants who paid the highest costs when dual-tasking also demonstrated, on a self-administered cognitive screening significantly lower scores than peers. These new types of tests, which ask for concurrent task performance, might become useful for detecting outlier performance that might anticipate or correlate with aging-related cognitive decline.
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Films, compared with emotional static pictures, represent true-to-life dynamic stimuli that are both ecological and effective in inducing an emotional response given the involvement of multimodal stimulation (i.e., visual and auditory systems). We hypothesized that a direct comparison between the two methods would have shown greater efficacy of movies, compared to standardized slides, in eliciting emotions at both subjective and neurophysiological levels. To this end, we compared these two methods of emotional stimulation in a group of 40 young adults (20 females). Electroencephalographic (EEG) Alpha rhythm (8-12 Hz) was recorded from 64 scalp sites while participants watched (in counterbalanced order across participants) two separate blocks of 45 slides and 45 clips. Each block included three groups of 15 validated stimuli classified as Erotic, Neutral and Fear content. Greater self-perceived arousal was found after the presentation of Fear and Erotic video clips compared with the same slide categories. sLORETA analysis showed a different lateralization pattern: slides induced decreased Alpha power (greater activation) in the left secondary visual area (Brodmann Area, BA, 18) to Erotic and Fear compared with the Neutral stimuli. Instead, video clips elicited reduced Alpha in the homologous right secondary visual area (BA 18) again to both Erotic and Fear contents compared with Neutral ones. Comparison of emotional stimuli showed smaller Alpha power to Erotic than to Fear stimuli in the left precuneus/posterior cingulate cortex (BA 7/31) for the slide condition, and in the left superior parietal lobule (BA 7) for the clip condition. This result matched the parallel analysis of the overlapped Mu rhythm (corresponding to the upper Alpha band) and can be interpreted as Mu/Alpha EEG suppression elicited by greater motor action tendency to Erotic (approach motivation) compared to Fear (withdrawal motivation) stimuli. Correlation analysis found lower Alpha in the left middle temporal gyrus (BA 21) associated with greater pleasantness to Erotic slides (r 38 = -0.62, p = 0.009), whereas lower Alpha in the right supramarginal/angular gyrus (BA 40/39) was associated with greater pleasantness to Neutral clips (r 38 = -0.69, p = 0.012). Results point to stronger emotion elicitation of movies vs. slides, but also to a specific involvement of the two hemispheres during emotional processing of slides vs. video clips, with a shift from the left to the right associative visual areas.
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Coronavirus disease (COVID-19) has been a source of fear around the world. We asked whether the measurement of this fear is trustworthy and comparable across countries. In particular, we explored the measurement invariance and cross-cultural replicability of the widely used Fear of COVID-19 scale (FCV-19S), testing community samples from 48 countries (N = 14,558). The findings indicate that the FCV-19S has a somewhat problematic structure, yet the one-factor solution is replicable across cultural contexts and could be used in studies that compare people who vary on gender and educational level. The validity of the scale is supported by a consistent pattern of positive correlations with perceived stress and general anxiety. However, given the unclear structure of the FCV-19S, we recommend using latent factor scores, instead of raw scores, especially in cross-cultural comparisons. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
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COVID-19 , Miedo , Humanos , Psicometría , Reproducibilidad de los Resultados , SARS-CoV-2RESUMEN
The mental representation of brief temporal durations, when assessed in standard laboratory conditions, is highly accurate. Here we show that adding or subtracting temporal durations systematically results in strong and opposite biases, namely over-estimation for addition and under-estimation for subtraction. The difference with respect to a baseline temporal reproduction task changed across durations in an operation-specific way and survived correcting for the effect due to operation sign alone, indexing a reliable signature of arithmetic processing on time representation. A second experiment replicated these findings with a different set of stimuli. This novel behavioral marker conceptually mirrors in the time domain the representational momentum found with motion, whereby the estimated spatial position of a visual target is displaced in the direction of motion itself. This momentum effect in temporal arithmetic suggests a striking analogy between time processing and visuospatial processing, which might index the presence of common computational principles.
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Percepción Espacial , Sesgo , Humanos , MatemáticaRESUMEN
Objective: Traditionally, asymmetric spatial processing (i.e., hemispatial neglect) has been assessed with paper-and-pencil tasks, but growing evidence indicates that computer-based methods are a more sensitive assessment modality. It is not known, however, whether simply converting well-established paper-and-pencil methods into a digital format is the best option. The aim of the present study was to compare sensitivity in detecting contralesional omissions of two different computer-based methods: a "digitally converted" cancellation task was compared with a computer-based Visual and Auditory dual-tasking approach, which has already proved to be very sensitive. Methods: Participants included 40 patients with chronic unilateral stroke in either the right hemisphere (RH patients, N = 20) or the left hemisphere (LH patients, N = 20) and 20 age-matched healthy controls. The cancellation task was implemented on a very large format (173 cm × 277 cm) or in a smaller (A4) paper-and-pencil version. The computer-based dual-tasks were implemented on a 15'' monitor and required the detection of unilateral and bilateral briefly presented lateralized targets. Results: Neither version of the cancellation task was able to show spatial bias in RH patients. In contrast, in the Visual dual-task RH patients missed significantly more left-sided targets than controls in both unilateral and bilateral trials. They also missed significantly more left-sided than right-sided targets only in the bilateral trials of the Auditory dual-task. Conclusion: The dual-task setting outperforms the cancellation task approach even when the latter is implemented on a (large) screen. Attentionally demanding methods are useful for revealing mild forms of contralesional visuospatial deficits.
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OBJECTIVE: Transcranial direct current stimulation (tDCS) provides a way to modulate spatial attention by enhancing the ratio of neural activity between the left and right hemispheres, with a potential benefit for the rehabilitation of visual neglect. METHODS: We tested the effect of bilateral tDCS in healthy individuals performing a visual detection task. This protocol consists in the positioning of the anode and cathode on mirror positions over the left and right parietal areas. The stimulation was repeated over three days to maximize the chance to observe a bias to the hemispace controlateral to the anode. RESULTS: Compared to a sham treatment, left anodal - right cathodal stimulation enhanced attention across the full range of space, since the first day with no build-up effect on the next days, and modified the balance of left-right omissions when stimuli appeared at the same time. CONCLUSION: Bilateral tDCS improved detection in both visual fields, with no privileged processing of one side, except when concurrent stimuli were presented. The results provide partial support to the hemispheric rivalry hypothesis. SIGNIFICANCE: The technique has the potential to boost attention in neglect patients but should be used as an adjuvant rather than as an alternative to functional rehabilitation.
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Atención/fisiología , Percepción Espacial/fisiología , Estimulación Transcraneal de Corriente Directa , Percepción Visual/fisiología , Adulto , Femenino , Lateralidad Funcional/fisiología , Humanos , Masculino , Trastornos de la Percepción/etiología , Trastornos de la Percepción/fisiopatología , Trastornos de la Percepción/rehabilitación , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/fisiopatología , Rehabilitación de Accidente Cerebrovascular/métodos , Adulto JovenRESUMEN
Multitasking is ubiquitous in everyday life. It can have a detrimental effect on several cognitive abilities including spatial processing in both brain-damaged and healthy participants. The present study investigated, in healthy adults, the electrophysiological mechanisms associated with correct detection vs. misdetection of peripheral visual target(s) while processing concurrent visual or auditory stimuli. Correct responses were coupled with increased N1 amplitude under visual (i.e., intra-modal) load but not under auditory (i.e., cross-modal) load. Under visual load, error responses were associated to opposite patterns on N1/N2 components for unilateral and bilateral stimuli. In particular, errors were marked by significantly reduced N1 and N2 amplitude for the left and right visual field, respectively, whereas higher N1 amplitude was found for errors to bilateral targets. This suggests that early negative components represent the biological marker of target awareness under visual load, whereby correct target detection is grounded on a threshold criterion. These results provide an electrophysiological correlate for the allocation of capacity-limited cognitive resources during the concurrent processing of multiple and heterogeneous visual stimuli.
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Atención/fisiología , Encéfalo/fisiología , Potenciales Evocados/fisiología , Comportamiento Multifuncional/fisiología , Procesamiento Espacial/fisiología , Percepción Visual/fisiología , Electroencefalografía , Femenino , Humanos , Masculino , Estimulación Luminosa , Adulto JovenRESUMEN
Unilateral brain damage following stroke frequently hampers the processing of contralesional space. Whether and how it also affects the processing of stimuli appearing on the same side of the lesion is still poorly understood. Three main alternative hypotheses have been proposed, namely that ipsilesional processing is functionally (i) hyperefficient, (ii) impaired, or (iii) spared. Here, we investigated ipsilesional space awareness through a computerized paradigm that exploits a manipulation of concurrent information processing demands (i.e., multitasking). Twelve chronic right-hemisphere stroke patients with a total lack of awareness for the contralesional side of space were administered a task that required the spatial monitoring of two locations within the ipsilesional hemispace. Targets were presented immediately to the right of a central fixation point (3° eccentricity), or farther to the right toward the screen edge (17° eccentricity), or on both locations. Response to target position occurred either in isolation or while performing a concurrent visual or auditory task. Results showed that most errors occurred when two targets were simultaneously presented and patients were faced with additional task demands (in the visual or auditory modalities). In the context of concurrent visual load, ipsilesional targets presented at the rightmost location were omitted more frequently than those presented closer to fixation. This pattern qualifies ipsilesional processing in right-hemisphere stroke patients as functionally impaired, arguing against the notion of ipsilesional hyperperformance, especially when under visual load.
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Working memory refers to our ability to actively maintain and process a limited amount of information during a brief period of time. Often, not only the information itself but also its serial order is crucial for good task performance. It was recently proposed that serial order is grounded in spatial cognition. Here, we compared performance of a group of right hemisphere-damaged patients with hemispatial neglect to healthy controls in verbal working memory tasks. Participants memorized sequences of consonants at span level and had to judge whether a target consonant belonged to the memorized sequence (item task) or whether a pair of consonants were presented in the same order as in the memorized sequence (order task). In line with this idea that serial order is grounded in spatial cognition, we found that neglect patients made significantly more errors in the order task than in the item task compared to healthy controls. Furthermore, this deficit seemed functionally related to neglect severity and was more frequently observed following right posterior brain damage. Interestingly, this specific impairment for serial order in verbal working memory was not lateralized. We advance the hypotheses of a potential contribution to the deficit of serial order in neglect patients of either or both (1) reduced spatial working memory capacity that enables to keep track of the spatial codes that provide memorized items with a positional context, (2) a spatial compression of these codes in the intact representational space.
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Memoria a Corto Plazo , Trastornos de la Percepción/psicología , Anciano , Atención , Femenino , Humanos , Masculino , Persona de Mediana Edad , Desempeño Psicomotor , Percepción Espacial , Aprendizaje Verbal , Percepción VisualRESUMEN
In healthy individuals, increasing cognitive load induces an asymmetric deployment of visuospatial attention, which favors the right visual space. To date, the neural mechanisms of this left/right attentional asymmetry are poorly understood. The aim of the present study was thus to investigate whether a left/right asymmetry under high cognitive load is due to a shift in the interhemispheric balance between the left and right posterior parietal cortices (PPCs), favoring the left PPC. To this end, healthy participants completed a visuospatial attention detection task under low and high cognitive load, whilst undergoing biparietal transcranial direct current stimulation (tDCS). Three different tDCS conditions were applied in a within-subjects design: sham, anodal left/cathodal right, and cathodal left/anodal right stimulation. The results revealed a left/right attentional asymmetry under high cognitive load in the sham condition. This asymmetry disappeared during cathodal left/anodal right tDCS, yet was not influenced by anodal left/cathodal right tDCS. There were no left/right asymmetries under low cognitive load in any of the conditions. Overall, these findings demonstrate that attentional asymmetries under high cognitive load can be modulated in a polarity-specific fashion by means of tDCS. They thus support the assumption that load-related asymmetries in visuospatial attention are influenced by interhemispheric balance mechanisms between the left and right PPCs.