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OBJECTIVE: The Clock Drawing Test (CDT) is a widely used test for cognitive screening as its execution taps into a large number of cognitive functions. Because of the involvement of visuospatial abilities, the CDT is also commonly used to assess hemispatial neglect. In the present study, we introduce a new quantitative scoring method for the CDT that aims to measure the use of space for each half of the clock face and asymmetries of space use. METHOD: Two measures are introduced: the explored space (ES) and used space (US) for each half of the clock, as well as two derived asymmetry indices. Such new measures were applied to CDTs of four groups of participants: right brain-damaged patients without visuospatial neglect, two groups of right brain-damaged patients with varying degrees of visuospatial neglect, and a group of neurologically healthy participants. RESULTS: Analyses showed that only neglect patients explored and used the left clock half significantly less than the right one. This result was also confirmed by the asymmetry indices, where neglect patients showed a stronger rightward bias. For neglect patients, the US asymmetry index correlated with the patients' scores on the neuropsychological tests. The analyses of receiver operating characteristic curves showed that left US and left ES scores had good accuracy in categorizing neglect patients. CONCLUSIONS: The present work provides new quantitative indices of CDT space usage in hemispatial neglect. Cutoffs are provided for clinical practice.
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Introduction: Homonymous visual field defects (HVFDs) following acquired brain lesions affect independent living by hampering several activities of everyday life. Available treatments are intensive and week- or month-long. Transcranial Direct current stimulation (tDCS), a plasticity-modulating non-invasive brain stimulation technique, could be combined with behavioral trainings to boost their efficacy or reduce treatment duration. Some promising attempts have been made pairing occipital tDCS with visual restitution training, however less is knows about which area/network should be best stimulated in association with compensatory approaches, aimed at improving exploratory abilities, such as multisensory trainings. Methods: In a proof-of-principle, sham-controlled, single-blind study, 15 participants with chronic HVFDs underwent four one-shot sessions of active or sham anodal tDCS applied over the ipsilesional occipital cortex, the ipsilesional or contralesional posterior parietal cortex. tDCS was delivered during a compensatory multisensory (audiovisual) training. Before and immediately after each tDCS session, participants carried out a visual detection task, and two visual search tasks (EF and Triangles search tests). Accuracy (ACC) and response times (RTs) were analyzed with generalized mixed models. We investigated differences in baseline performance, clinical-demographic and lesion factors between tDCS responders and non-responders, based on post-tDCS behavioral improvements. Lastly, we conducted exploratory analyses to compare left and right brain-damaged participants. Results: RTs improved after active ipsilesional occipital and parietal tDCS in the visual search tasks, while no changes in ACC were detected. Responders to ipsilesional occipital tDCS (Triangle task) had shorter disease duration and smaller lesions of the parietal cortex and the superior longitudinal fasciculus. On the other end, on the EF test, those participants with larger damage of the temporo-parietal cortex or the fronto-occipital white matter tracts showed a larger benefit from contralesional parietal tDCS. Overall, the visual search RTs improvements were larger in participants with right-sided hemispheric lesions. Conclusion: The present result shows the facilitatory effects of occipital and parietal tDCS combined with compensatory multisensory training on visual field exploration in HVFDs, suggesting a potential for the development of new neuromodulation treatments to improve visual scanning behavior in brain-injured patients.
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BACKGROUND: This study aimed at developing and standardizing the Telephone Language Screener (TLS), a novel, disease-nonspecific, telephone-based screening test for language disorders. METHODS: The TLS was developed in strict pursuance to the current psycholinguistic standards. It comprises nine tasks assessing phonological, lexical-semantic and morpho-syntactic components, as well as an extra Backward Digit Span task. The TLS was administered to 480 healthy participants (HPs), along with the Telephone-based Semantic Verbal Fluency (t-SVF) test and a Telephone-based Composite Language Index (TBCLI), as well as to 37 cerebrovascular/neurodegenerative patients-who also underwent the language subscale of the Telephone Interview for Cognitive Status (TICS-L). An HP subsample was also administered an in-person language battery. Construct validity, factorial structure, internal consistency, test-retest and inter-rater reliability were tested. Norms were derived via Equivalent Scores. The capability of the TLS to discriminate patients from HPs and to identify, among the patient cohort, those with a defective TICS-L, was also examined. RESULTS: The TLS was underpinned by a mono-component structure and converged with the t-SVF (p < .001), the TBCLI (p < .001) and the in-person language battery (p = .002). It was internally consistent (McDonald's ω = 0.67) and reliable between raters (ICC = 0.99) and at retest (ICC = 0.83). Age and education, but not sex, were predictors of TLS scores. The TLS optimally discriminated patients from HPs (AUC = 0.80) and successfully identified patients with an impaired TICS-L (AUC = 0.92). In patients, the TLS converged with TICS-L scores (p = 0.016). DISCUSSION: The TLS is a valid, reliable, normed and clinically feasible telephone-based screener for language impairment.
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Trastornos del Conocimiento , Trastornos del Desarrollo del Lenguaje , Humanos , Trastornos del Conocimiento/diagnóstico , Sensibilidad y Especificidad , Reproducibilidad de los Resultados , Teléfono , Estándares de Referencia , Pruebas NeuropsicológicasRESUMEN
BACKGROUND: The goal of this study was to monitor the microbial biodiversity in beach sand that is heavily visited by tourists during the summer, and to determinate whether the high presence of bathers (around 5000 per day) can modify sand microbial composition. METHODS: Between 2016 and 2020, 150 sand samples were collected from nine different points at La Pelosa beach in Sardinia, Italy. Non-culturing methods were used; DNA extraction and meta-barcode sequencing were performed. All samples were analyzed with sequencing methods for 16S and ITS sequences. RESULTS: Fungal genera differ on the three beaches and in the winter/summer zones. The ITS sequence showed the most common presence of Candida during summer and Paradendryphiella in the winter. The greatest diversity was found in the dune during winter, while in other parts of the beach, there are differences between bacteria and fungi, particularly in the wash zone during the winter, with high diversity for 16S sequences but low diversity for ITS sequences. CONCLUSIONS: It appears reasonable that the sands, even on non-urban beaches, should be included in health monitoring programs in addition to the waters, and that access to them should be regulated by limiting the number of bathers with the aim of reducing the presence of pathogenic fungal species.
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Arena , Microbiología del Agua , Estaciones del Año , Bacterias/genética , Hongos/genética , Playas , Monitoreo del Ambiente/métodosRESUMEN
Motor interactions require observing and monitoring a partner's performance as the interaction unfolds. Studies in monkeys suggest that this form of social monitoring might be mediated by the activity of the ventral premotor cortex (vPMc), a critical brain region in action observation and motor planning. Our previous fMRI studies in humans showed that the left vPMc is indeed recruited during social monitoring, but its causal role is unexplored. In three experiments, we applied online anodal or cathodal transcranial direct current stimulation over the left lateral frontal cortex during a music-like interactive task to test the hypothesis that neuromodulation of the left vPMc affects participants' performance when a partner violates the agent's expectations. Participants played short musical sequences together with a virtual partner by playing one note each in turn-taking. In 50% of the trials, the partner violated the participant's expectations by generating the correct note through an unexpected movement. During sham stimulation, the partner's unexpected behavior led to a slowdown in the participant's performance (observation-induced posterror slowing). A significant interaction with the stimulation type showed that cathodal and anodal transcranial direct current stimulation induced modulation of the observation-induced posterror slowing in opposite directions by reducing or enhancing it, respectively. Cathodal stimulation significantly reduced the effect compared to sham stimulation. No effect of neuromodulation was found when the partner behaved as expected or when the observed violation occurred within a context that was perceptually matched but noninteractive in nature. These results provide evidence for the critical causal role that the left vPMc might play in social monitoring during motor interactions, possibly through the interplay with other brain regions in the posterior medial frontal cortex.
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Corteza Motora , Estimulación Transcraneal de Corriente Directa , Humanos , Corteza Motora/diagnóstico por imagen , Corteza Motora/fisiología , Movimiento/fisiología , EncéfaloRESUMEN
OBJECTIVE: The study explored the change in handwritten signature in neurodegenerative diseases by using of a rater-based approach. METHODS: Four independent observers were required to compare a pair of signatures (on average, 5 years elapsed between the two signatures) made by 103 patients (mean age 72 years) with Alzheimer's disease (AD) or frontotemporal dementia (FTD) and by 31 healthy participants (HC; mean age 73 years), judging their change according to a 0-1 rating scale (0 = similar or 1 = different). If a signature change was detected, the rater had also to report which signature features (spatial layout, omitted/added/switched letters or names, shape of letter, pen-flow) changed on the same 0-1 scale. For the AD and FTD groups, one signature was collected prior to the diagnosis of dementia, the other subsequent. RESULTS: A signature change was reported by raters in 36% of AD patients, 44% of FTD, and 17% of HC, with significant differences between both clinical groups and HC (vs. AD, p = .01; vs. FTD, p = .001). There was not a distinctive marker of the signature change (i.e., feature change) in patients with dementia. Moreover, the signature changes in neurological patients were unrelated to their clinical and demographic characteristics (age, sex, education, time elapsed between the two signatures, Mini-mental State Examination score). CONCLUSION: The findings suggest a resistance of handwritten signature in neurodegenerative diseases and in physiological aging, also suggesting that the signature may be an unreliable indicator of the cognitive status in AD and FTD, at least if subjectively evaluated.
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Enfermedad de Alzheimer , Disfunción Cognitiva , Demencia Frontotemporal , Humanos , Anciano , Demencia Frontotemporal/diagnóstico , Enfermedad de Alzheimer/diagnóstico , Pruebas NeuropsicológicasRESUMEN
BACKGROUND: SARS-COV-2 infection has been associated to long-lasting neuropsychiatric sequelae, including cognitive deficits, that persist after one year. However, longitudinal monitoring has been scarcely performed. Here, in a sample of COVID-19 patients, we monitor cognitive, psychological and quality of life-related profiles up to 22 months from resolution of respiratory disease. METHODS: Out of 657 COVID-19 patients screened at Manzoni Hospital (Lecco, Italy), 22 underwent neuropsychological testing because of subjective cognitive disturbances at 6 months, 16 months, and 22 months. Tests of memory, attention, and executive functions were administered, along with questionnaires for depressive and Post-traumatic stress disorder (PTSD) symptoms, psychological well-being and quality of life. Cross-sectional descriptives, correlational, as well as longitudinal analyses considering COVID19-severity were carried out. A preliminary comparison with a sample of obstructive sleep apneas patients was also performed. RESULTS: Around 50% of COVID-19 patients presented with cognitive deficits at t0. The most affected domain was verbal memory. Pathological scores diminished over time, but a high rate of borderline scores was still observable. Longitudinal analyses highlighted improvements in verbal and non-verbal long term memory, as well as attention, and executive functioning. Depression and PTSD-related symptoms were present in 30% of patients. The latter decreased over time and were associated to attentional-executive performance. CONCLUSIONS: Cognitive dysfunctions in COVID-19 patients may extend over 1 year, yet showing a significant recovery in several cases. Cognitive alterations are accompanied by a significant psychological distress. Many patients displaying borderline scores, especially those at higher risk of dementia, deserve clinical monitoring.
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COVID-19 , Disfunción Cognitiva , Humanos , Calidad de Vida , Estudios Transversales , COVID-19/complicaciones , SARS-CoV-2 , Disfunción Cognitiva/epidemiología , Disfunción Cognitiva/etiología , Pruebas Neuropsicológicas , CogniciónRESUMEN
The COVID-19 pandemic has outlined the need to strengthen the resilience of healthcare systems. It has cost millions of human lives and has had indirect health impacts too. Hospital buildings have undergone extensive modifications and adaptations to ensure infection control and prevention measures, and, as it is happened following past epidemics, the COVID-19 experience might change the design of hospital buildings in the future. This paper aims to capitalise on the knowledge developed by the stakeholders directly involved with the hospital response during the pandemic to generate new evidence that will enhance resilience of hospital buildings to pandemics. The research adopted qualitative research methods, namely literature review and interviews with Italian experts including doctors and facility managers to collect data which were analysed through a thematic analysis. The findings include the identification of new needs for hospital buildings and the related actions to be taken or already performed at hospital building and service level which are viable for long term implementation and are aimed at improving hospital resilience to pandemics. The results specify how to improve resilience by means of structural modifications (e.g. placing filter zones among different wards, ensuring the presence of airborne infection isolation rooms at least in the emergency departments), technological changes (e.g. oversizing capacity such as medical gases, information technology improvement for delivering healthcare services remotely), and operational measures (e.g. assessing the risk of infection before admission, dividing acute-care from low-care assets). The needs discussed in this paper substantiate the urge to renovate the Italian healthcare infrastructures and they can be considered useful elements of knowledge for enhancing hospital resilience to pandemics in the extended and in the post-COVID-19 era.
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Background: This study aimed at standardizing and providing preliminary evidence on the clinical usability of the Italian telephone-based Verbal Fluency Battery (t-VFB), which includes phonemic (t-PVF), semantic (t-SVF) and alternate (t-AVF) verbal fluency tasks. Methods: Three-hundred and thirty-five Italian healthy participants (HPs; 140 males; age range = 18-96 years; education range = 4-23 years) and 27 individuals with neurodegenerative or cerebrovascular diseases were administered the t-VFB. Switch number and cluster size were computed via latent semantic analyses. HPs underwent the telephone-based Mental State Examination (MMSE) and Backward Digit Span (BDS). Construct validity, factorial structure, internal consistency, test-retest and inter-rater reliability and equivalence with the in-person Verbal Fluency tasks were assessed. Norms were derived via Equivalent Scores. Diagnostic accuracy against clinical populations was assessed. Results: The majority of t-VFB scores correlated among each other and with the BDS, but not with the MMSE. Switch number correlated with t-PVF, t-SVF, t-AVF scores, whilst cluster size with the t-SVF and t-AVF scores only. The t-VFB was underpinned by a mono-component structure and was internally consistent (Cronbach's α = 0.91). Test-retest (ICC = 0.69-0.95) and inter-rater reliability (ICC = 0.98-1) were optimal. Each t-VFB test was statistically equivalent to its in-person version (equivalence bounds yielding a p < 0.05). Education predicted all t-VFB scores, whereas age t-SVF and t-AVF scores and sex only some t-SVF scores. Diagnostic accuracy against clinical samples was optimal (AUC = 0.81-0.86). Discussion: The t-VFB is a valid, reliable and normed telephone-based assessment tool for language and executive functioning, equivalent to the in-person version; results show promising evidence of its diagnostic accuracy in neurological populations.
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BACKGROUND: Despite the relevance of telephone-based cognitive screening tests in clinical practice and research, no specific test assessing executive functioning is available. The present study aimed at standardizing and providing evidence of clinical usability for the Italian telephone-based Frontal Assessment Battery (t-FAB). METHODS: The t-FAB (ranging 0-12), comprising two subtests, has two versions: one requiring motor responses (t-FAB-M) and the other verbal responses (t-FAB-V). Three hundred and forty-six Italian healthy adults (HPs; 143 males; age range = 18-96 years; education range = 4-23 years) and 40 participants with neurological diseases were recruited. To HPs, the t-FAB was administered along with a set of telephone-based tests: MMSE, verbal fluency (VF), backward digit span (BDS). The in-person version of the FAB was administered to both HPs and clinical groups. Factorial structure, construct validity, inter-rater and test-retest reliability, t-FAB-M vs. t-FAB-V equivalence and diagnostic accuracy were assessed. Norms were derived via Equivalent Scores. RESULTS: In HPs, t-FAB measures yielded high inter-rater/test-retest reliability (ICC = .78-.94), were internally related (p ≤ .005) and underpinned by a single component, converging with the telephone-based MMSE, VF, BDS (p ≤ .0013). The two t-FAB versions were statistically equivalent in clinical groups (ps of both equivalence bounds < .001). Education predicted all t-FAB scores (p < .001), whereas age only the t-FAB-M score (p ≤ .004). t-FAB scores converge with the in-person FAB in HPs and clinical groups (rs = .43-.78). Both t-FAB versions were accurate in discriminating HPs from the clinical cohort (AUC = .73-.76). DISCUSSION: The t-FAB is a normed, valid, reliable and clinically usable telephone-based cognitive screening test to adopt in both clinical and research practice.
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Función Ejecutiva , Enfermedades del Sistema Nervioso , Anciano , Anciano de 80 o más Años , Humanos , Masculino , Enfermedades del Sistema Nervioso/diagnóstico , Pruebas Neuropsicológicas , Estándares de Referencia , Reproducibilidad de los Resultados , TeléfonoRESUMEN
BACKGROUND: Telephone-based cognitive screening (TBCS) is crucial to telehealth care of neurological patients, prevention campaigns, and epidemiological studies on cognitive impairment. The Telephone Interview for Cognitive Status (TICS) is one of the most widespread and psychometrically/diagnostically sound TBCS test, with several versions developed worldwide (e.g., with and without a delayed recall item). In Italy, only attempts of adaptation and preliminary evidence of its statistical features have been provided so far. This study thus aimed at (1) developing an Italian version of the TICS and assessing its (2) psychometric and (3) diagnostic properties. METHODS: A back-translated and culturally adapted version of the TICS was developed. Three-hundred and sixty-five healthy individuals from different regions of Italy (147 males, 216 females; age: 53.2 ± 16 years; education: 13 ± 4.5 years) were administered the TICS and the Italian telephone-based Mini-Mental State Examination (Itel-MMSE). Validity was tested by convergence and at the structure level, whereas reliability as internal consistency, test-retest, and inter-rater. Diagnostic accuracy, item difficulty, and discrimination were also examined. RESULTS: The TICS featured a single component and its score converged with that of the Itel-MMSE (rs = .37). Reliability was excellent as inter-rater (ICC = .94), good as test-retest (ICC = .78), and acceptable as internal consistency (Cronbach's α = .63). Accuracy was high as tested against the Itel-MMSE (AUC = .83) and did not improve when adding the delayed recall. Backward subtraction was the most difficult and discriminative task. DISCUSSION: The Italian TICS is a valid, reliable, and diagnostically accurate TBCS test. The original format of the TICS can be thus adopted in both clinical and research settings.
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Cognición , Teléfono , Adulto , Anciano , Femenino , Humanos , Italia , Masculino , Persona de Mediana Edad , Psicometría , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Encuestas y CuestionariosRESUMEN
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
BACKGROUND: Up to 50% of motor neuron disease (MND) patients show neuropsychological deficits which negatively affect prognosis and care. However, disability-related logistical issues and uneven geographical coverage of healthcare services may prevent MND patients from accessing neuropsychological evaluations. This study thus aimed to standardize for the Italian population the ALS Cognitive Behavioral Screen-Phone Version (ALS-CBS™-PhV), an MND-specific, telephone-based screening for frontotemporal dysfunction. METHODS: The cognitive section of the ALS-CBS™-PhV, the Italian telephone-based Mini-Mental State Examination (Itel-MMSE), and the Telephone Interview for Cognitive Status (TICS) was administered to 359 healthy individuals (143 males, 216 females; age, 52.7 ± 15.8; education, 13.1 ± 4.4). Norms were derived through equivalent scores. Validity, factorial structure, reliability, diagnostic accuracy, and item difficulty and discrimination were examined. Statistical equivalence between the telephone-based and in-person versions was tested. RESULTS: ALS-CBS™-PhV measures were predicted by age and education. The ALS-CBS™-PhV reflected a mono-component structure, converged with Itel-MMSE and TICS scores (rs = .23-.51) and was equivalent to its in-person format (t = .37; p = .72). Good internal (Cronbach's α = .61), test-retest (ICC = .69), and inter-rater (ICC = .96) reliability was detected. High accuracy was found when tested against both the Itel-MMSE and the TICS (AUC = .82-89). Backward digit span items were the most discriminative. DISCUSSION: The ALS-CBS™-PhV is a statistically solid screening test for frontotemporal disorders featuring MND. Its standardization allows for (1) improvements in tele-healthcare for MND patients, (2) epidemiological applications, and (3) effective assessments in decentralized clinical trials. The ALS-CBS™-PhV can be also suitable for assessing bedridden and visually impaired patients with motor disorders.
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Esclerosis Amiotrófica Lateral , Adulto , Anciano , Esclerosis Amiotrófica Lateral/diagnóstico , Cognición , Atención a la Salud , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Psicometría , Reproducibilidad de los Resultados , TeléfonoRESUMEN
When humans visually explore an image, they typically tend to start exploring its left side. This phenomenon, so-called pseudoneglect, is well known, but its time-course has only sparsely been studied. Furthermore, it is unclear whether age influences pseudoneglect, and the relationship between visuo-spatial attentional asymmetries in a free visual exploration task and a classical line bisection task has not been established. To address these questions, 60 healthy participants, aged between 22 and 86, were assessed by means of a free visual exploration task with a series of naturalistic, colour photographs of everyday scenes, while their gaze was recorded by means of a contact-free eye-tracking system. Furthermore, a classical line bisection task was administered, and information concerning handedness and subjective alertness during the experiment was obtained. The results revealed a time-sensitive window during visual exploration, between 260 and 960 ms, in which age was a significant predictor of the leftward bias in gaze position, i.e., of pseudoneglect. Moreover, pseudoneglect as assessed by the line bisection task correlated with the average gaze position throughout a time-window of 300-1490 ms during the visual exploration task. These results suggest that age influences visual exploration and pseudoneglect in a time-sensitive fashion, and that the degree of pseudoneglect in the line bisection task correlates with the average gaze position during visual exploration in a time-sensitive manner.
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Percepción Espacial , Percepción del Tiempo , Adulto , Anciano , Anciano de 80 o más Años , Atención , Sesgo , Lateralidad Funcional , Humanos , Persona de Mediana Edad , Adulto JovenRESUMEN
Transcranial Direct Current Stimulation (tDCS) has been employed to modulate visuo-spatial attentional asymmetries, however, further investigation is needed to characterize tDCS-associated variability in more ecological settings. In the present research, we tested the effects of offline, anodal conventional tDCS (Experiment 1) and HD-tDCS (Experiment 2) delivered over the posterior parietal cortex (PPC) and Frontal Eye Field (FEF) of the right hemisphere in healthy participants. Attentional asymmetries were measured by means of an eye tracking-based, ecological paradigm, that is, a Free Visual Exploration task of naturalistic pictures. Data were analyzed from a spatiotemporal perspective. In Experiment 1, a pre-post linear mixed model (LMM) indicated a leftward attentional shift after PPC tDCS; this effect was not confirmed when the individual baseline performance was considered. In Experiment 2, FEF HD-tDCS was shown to induce a significant leftward shift of gaze position, which emerged after 6 s of picture exploration and lasted for 200 ms. The present results do not allow us to conclude on a clear efficacy of offline conventional tDCS and HD-tDCS in modulating overt visuospatial attention in an ecological setting. Nonetheless, our findings highlight a complex relationship among stimulated area, focality of stimulation, spatiotemporal aspects of deployment of attention, and the role of individual baseline performance in shaping the effects of tDCS.
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Previous studies showed that the small leftward bias found in healthy humans' spatial judgments of lines ("pseudoneglect") shifts to the right with increasing distance between stimuli and observer. In this study, we investigated whether such a modulation of attentional asymmetry can also be observed in free visual exploration. Participants freely explored photographs of naturalistic scenes for 7â¯s in near (60â¯cm) and far (140â¯cm) space. After an initial leftward bias, followed by a compensatory rightward bias, gaze positions were significantly more leftward in near compared to far space (around 4â¯s from scene onset). Our results show that the modulation of attentional asymmetries by viewing distance previously reported for spatial judgments generalizes to free visual exploration, and we revealed the temporal dynamics of these asymmetries by fine-grained eye movement analysis. In contrast, an effect of viewing distance was reduced or absent when eye movements are under strong top-down control, as in systematic serial visual search (Sensitive Negelct Test). Finally, there was no effect of viewing distance in the landmark task (as also reported in a minority of other studies), suggesting that this effect may depend on specific, yet unidentified task characteristics.
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Atención , Movimientos Oculares , Percepción Espacial , Adulto , Sesgo , Femenino , Lateralidad Funcional , Humanos , Juicio , Masculino , Adulto JovenRESUMEN
Cross-modal spatial cueing can affect performance in a visual search task. For example, search performance improves if a visual target and an auditory cue originate from the same spatial location, and it deteriorates if they originate from different locations. Moreover, it has recently been postulated that multisensory settings, i.e., experimental settings, in which critical stimuli are concurrently presented in different sensory modalities (e.g., visual and auditory), may trigger asymmetries in visuospatial attention. Thereby, a facilitation has been observed for visual stimuli presented in the right compared to the left visual space. However, it remains unclear whether auditory cueing of attention differentially affects search performance in the left and the right hemifields in audio-visual search tasks. The present study investigated whether spatial asymmetries would occur in a search task with cross-modal spatial cueing. Participants completed a visual search task that contained no auditory cues (i.e., unimodal visual condition), spatially congruent, spatially incongruent, and spatially non-informative auditory cues. To further assess participants' accuracy in localising the auditory cues, a unimodal auditory spatial localisation task was also administered. The results demonstrated no left/right asymmetries in the unimodal visual search condition. Both an additional incongruent, as well as a spatially non-informative, auditory cue resulted in lateral asymmetries. Thereby, search times were increased for targets presented in the left compared to the right hemifield. No such spatial asymmetry was observed in the congruent condition. However, participants' performance in the congruent condition was modulated by their tone localisation accuracy. The findings of the present study demonstrate that spatial asymmetries in multisensory processing depend on the validity of the cross-modal cues, and occur under specific attentional conditions, i.e., when visual attention has to be reoriented towards the left hemifield.
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Atención , Señales (Psicología) , Análisis y Desempeño de Tareas , Estimulación Acústica/métodos , Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estimulación Luminosa/métodos , Tiempo de Reacción , Adulto JovenRESUMEN
Increasing time-on-task leads to fatigue and, as shown by previous research, differentially affects the deployment of visual attention towards the left and the right visual space. In healthy participants, an increasing rightward bias is commonly observed with increasing time-on-task. Yet, it is unclear whether specific mechanisms involved in the spatial deployment of visual attention are differentially affected by increasing time-on-task. The aim of the present study was to investigate whether prolonged time-on-task would affect a specific mechanism of visuospatial attentional deployment, namely attentional disengagement, in an asymmetrical fashion. For this purpose, we administered to healthy participants a prolonged gap/overlap saccadic paradigm, with left- and right-sided target stimuli. This oculomotor paradigm allowed to quantify disengagement costs according to the direction of the subsequent attentional shifts, and to evaluate the temporal development of disengagement costs with increasing time-on-task. Our results show that, with increasing time-on-task, participants demonstrated significantly lower disengagement costs for rightward compared to leftward saccades. These effects were specific, since concurring side differences of saccadic latencies were found for overlap trials (requiring attentional disengagement), but not for gap trials (requiring no or less attentional disengagement). Moreover, the results were paralleled by a non-lateralised decrease in saccadic peak velocity with increasing time-on-task, a common finding indicating an increasing level of fatigue. Our findings support the idea that non-spatial attentional aspects, such as fatigue due to increasing time-on-task, can have a substantial influence on the spatial deployment of visual attention, in particular on its disengagement, depending on the direction of the subsequent attentional shift.