Luria's fist-edge-palm test: A small change makes a big difference

Slight modifications in the instructions or administration of neuropsychological tests could result in noticeable differences in performance. A good example is offered by a test devised by Luria to assess executive functioning in motor planning, the three-step fist-edge-palm (FEP) test, which is still frequently employed in clinical settings and features in several neuropsychological test batteries such as the Frontal Assessment Battery (FAB). While Luria described the orientation of the fist as horizontal to the testing desk (hFEP), recent versions of the task indicate the fist should be vertical to the testing desk (vFEP). The current study examined whether administering the hFEP or the vFEP tests results in different performance in healthy people, and whether one version is better than the other at detecting impairments in a patient population. The hFEP proved more challenging for healthy adults than the vFEP, and people with brain damage committed more errors on the hFEP than the vFEP. Both versions correlated with executive measures but also with several other cognitive variables, indicating that the test is not a specific marker of executive functions. Although performance on the FEP is sensitive to articulatory suppression, faster pace, and the number of sequences performed, none of these conditions fully account for the differences between the hFEP and vFEP. The additional demand of the hFEP appears to be due to the less natural (i.e., automatic) orientation of the horizontal fist. In conclusion, a small change in the administration of the test, eluding Luria's instructions, grossly modified its sensitivity. Clinicians and researchers should be wary of modifying instructions or testing procedures without considering the possible consequences of such modifications.

Locations of objects are better remembered than their identities in naturalistic scenes: An eye-tracking experiment in mild cognitive impairment

OBJECTIVE

Retaining the identity or location of decontextualized objects in visual short-term working memory (VWM) is impaired by healthy and pathological ageing, but research remains inconclusive on whether these two features are equally impacted by it. Moreover, it is unclear whether similar impairments would manifest in naturalistic visual contexts.

METHOD

30 people with mild cognitive impairment (MCI) and 32 age-matched control participants (CPs) were eye-tracked within a change detection paradigm. They viewed 120 naturalistic scenes, and after a retention interval (1 s) asked whether a critical object in the scene had (or not) changed on either: identity (became a different object), location (same object but changed location), or both (changed in location and identity).

RESULTS

MCIs performed worse than CP but there was no interaction with the type of change. Changes in both were easiest while changes in identity alone were hardest. The latency to first fixation and first-pass duration to the critical object during successful recognition was not different between MCIs and CPs. Objects that changed in both features took longer to be fixated for the first time but required a shorter first pass compared to changes in identity alone which displayed the opposite pattern.

CONCLUSIONS

Locations of objects are better remembered than their identities; memory for changes is best when involving both features. These mechanisms are spared by pathological ageing as indicated by the similarity between groups besides trivial differences in overall performance. These findings demonstrate that VWM mechanisms in the context of naturalistic scene information are preserved in people with MCI. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Short-term memory conjunctive binding in Alzheimer's disease: A systematic review and meta-analysis

OBJECTIVE

Short-term memory (STM) binding tests assess the ability to temporarily hold conjunctions between surface features, such as objects and their colors (i.e., feature binding condition), relative to the ability to hold the individual features (i.e., single feature condition). Impairments in performance of these tests have been considered cognitive markers of Alzheimer's disease (AD). The objective of the present study was to conduct a meta-analysis of results from STM binding tests used in the assessment of samples mapped along the AD clinical continuum.

METHOD

We searched PubMed, Scopus, and Web of Science for articles that assessed patients with AD (from preclinical to dementia) using the STM binding tests and compared their results with those of controls. From each relevant article, we extracted the number of participants, the mean and standard deviations from single feature and of feature binding conditions. Results across studies were combined using standardized mean differences (effect sizes) to produce overall estimates of effect.

RESULTS

The feature binding condition of the STM binding showed large effects in all stages of AD. However, small sample sizes across studies, the presence of moderate to high heterogeneity and cross-sectional, case-controls designs decreased our confidence in the current evidence.

CONCLUSIONS

To be considered as a cognitive marker for AD, properly powered longitudinal designs and studies that clearly relate conjunctive memory tests with biomarkers (amyloid and tau) are still needed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The time course of planar and non-planar rotations in a letter rotation task

Mental rotation (MR) of character letters requires participants to mentally rotate the letter in their minds' eyes through a process akin to the physical rotation of the stimulus. It has been suggested that different cognitive processes are engaged during such MR of both canonical and mirror-reversed letters. In addition to the planar rotation of the canonical letters, an additional "flip-over" process (non-planar rotation) has been assumed during the MR of mirror-reversed letters. However, the temporal relationship between planar and non-planar rotation has not been systematically investigated. In this study, the occurrence of both planar and non-planar rotations were examined through the analysis of the event-related brain potentials (ERPs) elicited by canonical or mirror-reversed letters presented at different rotation angles between 300 and 1000 ms post-stimulus onset over consecutive 50ms time-windows. For smaller rotation angles (30° and 60°), non-planar rotation preceded planar rotation. For letters rotated by 90°, planar and non-planar rotation occurred at the same time. For larger angles (120° and 150°), the letter was first rotated within the plane (planar rotation) and afterwards it was also rotated out-of-the-plane (non-planar rotation) until it was fully canonicalized. Thus, the temporal relationship between planar and non-planar rotation differed for each rotation angle, with the non-planar rotation occurring at increasingly later intervals for different points in time for progressively larger rotation angles. These findings have relevant methodological implications for studies investigating the psychophysiological correlates of the mental rotation of mirror letters.

Forgetting Rates of Prose Memory in Mild Cognitive Impairment

BACKGROUND

Some authors report steeper slopes of forgetting in early Alzheimer's disease (AD), while others do not. Contrasting findings are thought to be due to methodological inconsistencies or variety of testing methods, yet they also emerge when people are assessed on the same testing procedure.

OBJECTIVE

We aimed to assess if forgetting slopes of people with mild cognitive impairment due to AD (MCI-AD) are different from age-matched healthy controls (HC) by using a prose paradigm.

METHODS

Twenty-nine people with MCI-AD and twenty-six HC listened to a short prose passage and were asked to freely recall it after delays of 1 h and 24 h.

RESULTS

Generalized linear mixed modelling revealed that, compared to HC, people with MCI-AD showed poorer encoding at immediate recall and steeper forgetting up to 1 h in prose memory as assessed by free recall and with repeated testing of the same material. Forgetting rates between groups did not differ from 1 h to 24 h.

CONCLUSION

The differences observed in MCI-AD could be due to a post-encoding deficit. These findings could be accounted either by a differential benefit from retrieval practice, whereby people with MCI-AD benefit less than HC, or by a working memory deficit in people with MCI-AD, which fails to support their memory performance from immediate recall to 1 h.

Skill and self-knowledge: empirical refutation of the dual-burden account of the Dunning-Kruger effect

For many intellectual tasks, the people with the least skill overestimate themselves the most, a pattern popularly known as the Dunning-Kruger effect (DKE). The dominant account of this effect depends on the idea that assessing the quality of one's performance (metacognition) requires the same mental resources as task performance itself (cognition). Unskilled people are said to suffer a dual burden: they lack the cognitive resources to perform well, and this deprives them of metacognitive insight into their failings. In this Registered Report, we applied recently developed methods for the measurement of metacognition to a matrix reasoning task, to test the dual-burden account. Metacognitive sensitivity (information exploited by metacognition) tracked performance closely, so less information was exploited by the metacognitive judgements of poor performers; but metacognitive efficiency (quality of metacognitive processing itself) was unrelated to performance. Metacognitive bias (overall tendency towards high or low confidence) was positively associated with performance, so poor performers were appropriately less confident-not more confident-than good performers. Crucially, these metacognitive factors did not cause the DKE pattern, which was driven overwhelmingly by performance scores. These results refute the dual-burden account and suggest that the classic DKE is a statistical regression artefact that tells us nothing much about metacognition.

Righteous Adam, Sinister Eve

The symbolism of laterality in images implies that the virtuous figure is represented on the right of the scene whereas the sinful character is depicted on the left. In portraits of male and female characters this has reflected and reinforced stereotypes and inequalities down the ages. Given these premises, we hypothesized that the prototypical representations of Adam and Eve, as a man and a woman conflated with notions of virtue and vice, would show a non-random arrangement. We tested this hypothesis, sampling artistic depictions of the Garden of Eden, from the twelth century to the present day in three separately-collected series of 100, 99, and 142 images respectively. Eve is depicted to Adam's left significantly more often than chance (between 70% and 83%), particularly in pre-1600 artworks. We interpret this asymmetry as reflecting the perceived lesser status of women in relation to men, since the allegorical incipit of humankind. We also provide experimental evidence that this asymmetry, although pervasive, has not been internalized by modern viewers. Cognitive sciences account for this spatial asymmetry in terms of preference for figures placed within the left visual field of the observer, i.e., within the right space of the objective scene.

Memory markers in the continuum of the Alzheimer's clinical syndrome

BACKGROUND

The individual and complementary value of the Visual Short-Term Memory Binding Test (VSTMBT) and the Free and Cued Selective Reminding Test (FCSRT) as markers to trace the AD continuum was investigated. It was hypothesised that the VSTMBT would be an early indicator while the FCSRT would inform on imminent progression.

METHODS

Healthy older adults (n=70) and patients with mild cognitive impairment (MCI) (n=80) were recruited and followed up between 2012 and 2017. Participants with at least two assessment points entered the study. Using baseline and follow-up assessments four groups were defined: Older adults who were healthy (HOA), with very mild cognitive but not functional impairment (eMCI), and with MCI who did and did not convert to dementia (MCI converters and non-converters).

RESULTS

Only the VSTMBT predicted group membership in the very early stages (HOA vs eMCI). As the disease progressed, the FCSRT became a strong predictor excluding the VSTMB from the models. Their complementary value was high during the mid-prodromal stages and decreased in stages closer to dementia.

DISCUSSION

The study supports the notion that neuropsychological assessment for AD needs to abandon the notion of one-size-fits-all. A memory toolkit for AD needs to consider tools that are early indicators and tools that suggest imminent progression. The VSTMBT and the FSCRT are such tools.

EXPRESS: Rate of forgetting is independent from initial degree of learning across different age groups

It is well established that the more we learn, the more we remember. It is also known that our ability to acquire new information changes with age. An important remaining issue for debate is whether the rate of forgetting depends on initial degree of learning. In two experiments, following the procedure used by Slamecka and McElree (1983, Exp 3), we investigated the relationship between initial degree of learning and rate of forgetting in both younger and older adults. A set of 36 (Exp 1) and a set of 30 (Exp 2) sentences was presented four times. Forgetting was measured via cued recall at three retention intervals (30s, 1hr and 24hr). A different third of the original sentences was tested at each delay. The results of both experiments showed that initial acquisition is influenced by age. However, the rate of forgetting proved to be independent from initial degree of learning. The conclusion is that rates of forgetting are independent from initial degree of learning.

Similar mechanisms of temporary bindings for identity and location of objects in healthy ageing: an eye-tracking study with naturalistic scenes

The ability to maintain visual working memory (VWM) associations about the identity and location of objects has at times been found to decrease with age. To date, however, this age-related difficulty was mostly observed in artificial visual contexts (e.g., object arrays), and so it is unclear whether it may manifest in naturalistic contexts, and in which ways. In this eye-tracking study, 26 younger and 24 healthy older adults were asked to detect changes in a critical object situated in a photographic scene (192 in total), about its identity (the object becomes a different object but maintains the same position), location (the object only changes position) or both (the object changes in location and identity). Aging was associated with a lower change detection performance. A change in identity was harder to detect than a location change, and performance was best when both features changed, especially in younger adults. Eye movements displayed minor differences between age groups (e.g., shorter saccades in older adults) but were similarly modulated by the type of change. Latencies to the first fixation were longer and the amplitude of incoming saccades was larger when the critical object changed in location. Once fixated, the target object was inspected for longer when it only changed in identity compared to location. Visually salient objects were fixated earlier, but saliency did not affect any other eye movement measures considered, nor did it interact with the type of change. Our findings suggest that even though aging results in lower performance, it does not selectively disrupt temporary bindings of object identity, location, or their association in VWM, and highlight the importance of using naturalistic contexts to discriminate the cognitive processes that undergo detriment from those that are instead spared by aging.

EXPRESS: Long-term learning and forgetting of feature binding in verbal free recall

Temporary feature bindings can be learned under specific experimental conditions. However, how this learning occurs and how it is forgotten over long intervals is unclear. We addressed this question with repeated presentation of an array of coloured shapes followed by verbal free recall after delays of one day, one week, and one month. A total of 120 participants viewed 24 repetitions of the same study array of six objects each with two features (shape and colour). After 24 trials, 61 participants reported becoming aware of the repetition while 59 reported being unaware. Memory performance improved across trials, with aware participants showing faster learning than unaware participants whose performance appeared to reflect the capacity of short-term visual memory across all repetitions.Both aware and unaware participants recalled some of the array after their allocated delay, showing that learning had occurred during repetition trials, even for unaware participants who showed little or no improvement across 24 repetition trials. Memory for binding showed no change after one day compared to performance on the 24th repetition trial, was significantly lower for participants tested after one-week, and was lower still for those tested after one-month. Findings are interpreted as consistent with both a short-term, limited capacity visual cache that supports performance during early repetition trials, before learning can have occurred, and gradual strengthening across trials of an episodic long-term memory trace that supports learning. If the episodic trace exceeds the threshold of awareness, this accelerates learning.

The effect of selective retrieval practice on forgetting rates in younger and older adults

Recent findings demonstrate that selective retrieval practice (SRP), specifically the retrieval of subparts of material, not just retrieval of the entire encoded material, can enhance later memory performance. We present two experiments that investigated whether SRP enhances memory performance among older adults. We also examined to what extent this effect is enhanced by the level of integration of the studied material. We used a design that contrasts the performance of the groups in conditions with and without SRP. This design also allowed us to examine whether older adults present with faster forgetting compared to younger individuals when assessed over a long delay. In both experiments, participants were exposed to a learning phase in which they had to achieve a criterion of 70% correct recall and were then tested at 1 month. The SRP for the experimental group occurred 1 day and 1 week after the learning phase (the control group received no SRP). None of the items at 1-month delay was probed in the retrieval practice. Experiment 1 used integrated material (four short stories). Experiment 2 used less integrated material (16 sentences). Both age groups showed a decline in memory performance over 1 month, however, groups tested repeatedly showed better performance (irrespective of age or material). (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Preserved Extra-Foveal Processing of Object Semantics in Alzheimer's Disease

Alzheimer's disease (AD) patients underperform on a range of tasks requiring semantic processing, but it is unclear whether this impairment is due to a generalised loss of semantic knowledge or to issues in accessing and selecting such information from memory. The objective of this eye-tracking visual search study was to determine whether semantic expectancy mechanisms known to support object recognition in healthy adults are preserved in AD patients. Furthermore, as AD patients are often reported to be impaired in accessing information in extra-foveal vision, we investigated whether that was also the case in our study. Twenty AD patients and 20 age-matched controls searched for a target object among an array of distractors presented extra-foveally. The distractors were either semantically related or unrelated to the target (e.g., a car in an array with other vehicles or kitchen items). Results showed that semantically related objects were detected with more difficulty than semantically unrelated objects by both groups, but more markedly by the AD group. Participants looked earlier and for longer at the critical objects when these were semantically unrelated to the distractors. Our findings show that AD patients can process the semantics of objects and access it in extra-foveal vision. This suggests that their impairments in semantic processing may reflect difficulties in accessing semantic information rather than a generalised loss of semantic memory.

Distance assessment of cognitive deficits in older immigrants

BACKGROUND

In European memory clinics, requests for assessing people with cognitive complaints in a foreign language are becoming frequent. Currently, over one million people living in EU are older migrants presenting with possible cognitive deterioration. The assessments of cognitive functions is the gateway to diagnosis, and the main tool for monitoring progression of neurocognitive disorders. However, the limitations of older migrants in the language of the host country add hurdles to the diagnostic process. This represents an emerging problem for the EU healthcare systems. In several EU countries, the current best approach is to involve a translator, who assists the healthcare personnel with the assessment. This practice is far from perfect.

METHODS

We convened a multidisciplinary and international team, including experts in neurocognitive disorders and in digital tools, to develop a user-friendly process aimed at connecting clinicians dealing with the diagnosis of people affected by cognitive deficits in different languages or countries. The initial network included countries with great prevalence of immigrants (DE, F, I, UK) and referents from partner specialists from the main immigrant nationalities. This network is planned to expand.

RESULTS

This preliminary network convened on a reference procedure to be supported with digital tools. The procedure includes referral of migrants with cognitive complaints to a colleague from the established network, for remote assessment in their mother-tongue using tools appropriate for their cultural background. The outcome of the referral is sent to the clinicians in the adopted country who could take a better informed decision on the diagnosis and handling of the symptoms presented by the migrant.

DISCUSSION

The proposed procedure overcomes several limitations of the current assessment of migrants via a translator, relative to time, languages availability, linguistic and cultural specificity of materials and norms used for the assessment. Assessment would improve thank to greater empathy allowed through the process, and the specific medical background will allow to detect issues that could emerge during the interview or the formal testing. The proposed process solves several problems identified within the current practice, with considerable benefit on detection of neurocognitive disorders in a heterogeneous population.

Challenges to recruitment of participants with MCI in a multicentric neuropsychological study

BACKGROUND

Data on recruitment of Mild Cognitive Impairment (MCI) samples are seldom reported and this issue can be an important source of research waste.

AIM

To describe the recruitment challenges and reasons for non-eligibility faced during a bi-centre clinical study assessing the predictive value of a neuropsychological battery of the progression to dementia.

METHODS

Potential MCI participants were identified from databases of the two memory clinics based in Milan (Italy) and invited to the screening assessment.

RESULTS

About 50% of the cases initially identified were ineligible according to inclusion/exclusion criteria and the two sites took 22 months to recruit the planned 150 people. The main reasons for non-eligibility were the MMSE score (41%), age (14%), presence of cerebrovascular disorders (9%), perceptual deficits (6%), neurological (6%) or psychiatric (4%) comorbidities and low education (5%).

CONCLUSION

Awareness of the reasons for exclusion and of the time needed to recruit the planned sample would provide hints for the planning of future studies on MCI.

Semantic interference mechanisms on long-term visual memory and their eye-movement signatures in mild cognitive impairment

OBJECTIVE

Long-term visual memory representations, measured by recognition performance, degrade as a function of semantic interference, and their strength is related to eye-movement responses. Even though clinical research has examined interference mechanisms in pathological cognitive aging and explored the diagnostic potential of eye-movements in this context, little is known about their interaction in long-term visual memory.

METHOD

An eye-tracking study compared a Mild Cognitive Impaired group with healthy adults. Participants watched a stream of 129 naturalistic images from different semantic categories, presented at different frequencies (1, 6, 12, 24) to induce semantic interference (SI), then asked in a 2-Alternative Forced Choice paradigm to verbally recognize the scene they remembered (old/novel).

RESULTS

Recognition accuracy of both groups was negatively impacted by SI, especially in healthy adults. A wider distribution of overt attention across the scene predicted better recognition, especially by the Mild Cognitive Impaired (MCI) participants, although these fixation patterns were influenced by SI. MCI compensated the detrimental effect of SI by focusing overt attention during encoding and so accruing distinctive details of the scene. During recognition, MCI participants widened overt attention to boost retrieval. Independently of the group: (a) the re-instatement of fixations indicated a more successful recall and increased as a function of SI; and (b) attending visually salient regions negatively impacted on recognition accuracy, although the reliance on such regions grew as SI increased.

CONCLUSIONS

Effects of SI on long-term memory were reduced in MCI participants. They used different oculomotor strategies compared to healthy adults to compensate for its detrimental effects. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

A reappraisal of acute doses of benzodiazepines as a model of anterograde amnesia

OBJECTIVE

Acute administration of benzodiazepines is considered a pharmacological model of general organic anterograde amnesias (OAA). We sought to determine which type of amnesia these drugs best model by comparing the effects of diazepam with those reported in amnesiacs regarding working memory capacity (WMC), susceptibility to retroactive interference (RI), and accelerated forgetting.

METHODS

In this double-blind, parallel-group design study, 30 undergraduates were randomly allocated to acute oral treatments with 15 mg diazepam or placebo. WMC and story recall were assessed pre- and post-treatment. Story presentation was succeeded by 10 min of RI (spotting differences in pictures) or minimal RI (doing nothing in a darkened room). Delayed story recall was assessed under diazepam and 7 days later in a drug-free session to assess accelerated forgetting.

RESULTS

Recall of stories encoded under diazepam, whether reactivated or not, was severely impaired (anterograde amnesia). However, diazepam did not impair WMC, increase susceptibility to RI, or accelerate forgetting.

CONCLUSIONS

Diazepam's amnestic effects mirror those in patients with probable severe medial temporal damage, mostly restricted to initial consolidation and differ from other OAA (Korsakoff syndrome, frontal, transient epileptic, posttraumatic amnesia, and most progressive amnesias) in terms of WMC, susceptibility to RI and accelerated forgetting.

Alzheimer's Disease and Parkinson Dementia Distinguished by Cognitive Marker

BACKGROUND

Temporary memory binding (TMB) has been shown to be specifically affected by Alzheimer's disease (AD) when it is assessed via free recall and titrating the task demands to equate baseline performance across patients.

METHODS

Patients with Parkinson's disease (PD) were subdivided into patients with and without cognitive impairment and compared with AD and amnestic mild cognitive impairment (aMCI) patients on their performance on the TMB.

RESULTS

The results show that only patients with AD dementia present with impaired TMB performance. Receiver operating characteristic curve analyses showed that TMB holds high sensitivity and specificity for aMCI and AD relative to PD groups and healthy controls.

CONCLUSION

The TMB is sensitive to the neurodegenerative mechanisms leading to AD dementia but not to those underpinning PD dementia. As such, TMB task can aid the differential diagnosis of these common forms of dementia.

Profiles of cognitive impairment in the continuum from normal cognition to Alzheimer's clinical syndrome: Contributions of the short-term memory binding tests

BACKGROUND

Short-term memory binding (STMB) tests assess conjunctive binding, in which participants should remember the integration of features, such as shapes (or objects) and colors, forming a unique representation in memory. In this study, we investigated two STMB paradigms: change detection (CD) and free recall (FR).

OBJECTIVE

To investigate the cognitive profile in the CD and FR tasks of three diagnostic groups: cognitively unimpaired (CU), mild cognitive impairment (MCI), and Alzheimer's clinical syndrome (ACS). In addition, we aimed to calculate and compare the accuracy of the CD and FR tasks to identify MCI and ACS.

METHODS

Participants were 24 CU, 24 MCI, and 37 ACS. The cognitive scores of the clinical groups were compared using analysis of variance (ANOVA) and receiver-operating characteristic (ROC) analyses were carried out to verify the accuracy of the STMB tasks.

RESULTS

In the CD task, CU was different from MCI and ACS (CU > MCI = ACS), while in the FR task all groups were different (CU > MCI > ACS). The ROC analyses showed an area under the curve (AUC) of 0.855 comparing CU with MCI for the CD task and 0.975 for the FR. The AUC comparing CU and ACS was 0.924 for the CD and 0.973 for the FR task. The FR task showed better accuracy to identify MCI patients, and the same accuracy to detect ACS.

CONCLUSION

The present findings indicate that impairments in CD and FR of bound representations are features of the cognitive profiles of MCI and ACS patients.

The effects of source expertise and trustworthiness on recollection: the case of vaccine misinformation

Designing effective communication strategies for correcting vaccines misinformation requires an understanding of how the target group might react to information from different sources. The present study examined whether erroneous inferences about vaccination could be effectively corrected by a perceived credible (i.e. expert or trustworthy) source. Two experiments are reported using a standard continued influence paradigm, each featuring two correction conditions on vaccine misinformation. Participants were presented with a story containing a piece of information that was later retracted by a perceived credible or not so credible source. Experiment 1 showed that providing a correction reduced participants' use of the original erroneous information, yet the overall reliance on misinformation did not significantly differ between the low- and high-expertise correction groups. Experiment 2 revealed that a correction from a high-trustworthy source decreased participants' reliance on misinformation when making inferences; nonetheless, it did not positively affect the reported intent to vaccinate one's child. Overall, source trustworthiness was more relevant than source expertise.

Wakeful rest benefits before and after encoding in anterograde amnesia

Objective: Studies have shown that patients with anterograde amnesia forget less episodic information after a delay if encoding is immediately followed by an unfilled period of wakeful rest. This benefit has been attributed to the reduced interference with the consolidation process. However, this account cannot directly explain improved retention in healthy adults resulting from pre-encoding rest. While benefits resulting from pre- and post-encoding rest can be alternatively explained via improved distinctiveness at retrieval, it has yet to be established whether both benefits are observable in amnesics. The aim of the current study was to assess whether amnesic patients showed improved retention of prose material after 10 min following both pre- and post-encoding unfilled intervals of wakeful rest. Method: Twelve patients with anterograde amnesia were recruited. Participants completed four conditions. A short prose passage was aurally presented in each condition. Prose presentation was preceded and followed by a 9-min delay interval. Delay intervals were either filled (spot-the-difference task) or unfilled (wakeful rest). Prose retention was assessed immediately after presentation and after 10 min. Results: Prose retention was consistently better when wakeful rest followed prose encoding in comparison to a condition where an effortful task was encountered both before and after encoding. Conclusions: Post-encoding wakeful rest alone substantially improves retention in amnesic patients. While pre-encoding wakeful rest elicits inconsistent benefits in amnesics, reduced retention following both pre- and post-encoding task engagement suggests that pre-encoding activity may still be relevant. Overall, our findings support consolidation interference explanations of forgetting in anterograde amnesia. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Forgetting in Alzheimer's disease: Is it fast? Is it affected by repeated retrieval?

OBJECTIVES

Whether people with Alzheimer's Disease present with accelerated long term forgetting compared to healthy controls is still debated. Typically, accelerated long term forgetting implies testing the same participants repeatedly over several delays. This testing method raises the issue of confounding repetition effects with forgetting rates. We used a novel procedure to disentangle the two effects.

METHODS

Four short stories were presented during an initial in-person assessment of 40 patients with Alzheimer's Disease and 42 age-matched healthy controls. Our aim was for participants to reach a score of 70% correct (9 out of 13 questions) at encoding. If this criterion was not achieved after the first trial, the four stories were presented again (in a different order); participants took the 1 min filler task again and were then retested. We repeated this process until participants reached the 70% criterion or to a maximum of four trials. Cued recall memory tests were completed during follow-up telephone call(s) at different delay intervals. Study material was presented only at encoding, then probed with different question sets on all other delays. Each question set tested different sub-parts of the material. The experiment employed a mixed design. Participants were randomly allocated to either a condition without retrieval practice or a condition with retrieval practice. Participants in the condition without retrieval practice were only tested at two delays: post encoding filled delay and at one month. Participants in the condition with retrieval practice were tested at four delays: post encoding filled delay, one day, one week and one month. Our methodological design allowed us to separate the effects of retesting from the effects of delay.

RESULTS

Alzheimer's Disease patients showed a significant encoding deficit reflected in the higher number of trials required to reach criterion. Using Linear Mixed Models, we found no group by delay interactions between the post encoding filled delay retrieval and one month delays, with Alzheimer's Disease groups having a similar decline in performance to healthy controls, irrespective of testing condition. Significant condition by delay interactions were found for both groups (Alzheimer's Disease and healthy controls), with better performance at one month in the condition with retrieval practice.

CONCLUSIONS

Our data showed that Alzheimer's Disease is not characterised by accelerated long term forgetting, patients in our sample forgot at the same rate as healthy controls. Given the additional trials required by Alzheimer's patients to reach the 70% correct criterion, their memory impairment appears to be one of encoding. Moreover, Alzheimer's Disease patients benefited from repeated testing to the same extent as healthy controls. Due to our methodological design, we were also able to show that performance improved under repeated testing conditions, even with partial testing (sampling different features from each narrative on every test session/delay) in both healthy controls and Alzheimer's Disease.

Extra-foveal Processing of Object Semantics Guides Early Overt Attention During Visual Search

Eye-tracking studies using arrays of objects have demonstrated that some high-level processing of object semantics can occur in extra-foveal vision, but its role on the allocation of early overt attention is still unclear. This eye-tracking visual search study contributes novel findings by examining the role of object-to-object semantic relatedness and visual saliency on search responses and eye-movement behaviour across arrays of increasing size (3, 5, 7). Our data show that a critical object was looked at earlier and for longer when it was semantically unrelated than related to the other objects in the display, both when it was the search target (target-present trials) and when it was a target's semantically related competitor (target-absent trials). Semantic relatedness effects manifested already during the very first fixation after array onset, were consistently found for increasing set sizes, and were independent of low-level visual saliency, which did not play any role. We conclude that object semantics can be extracted early in extra-foveal vision and capture overt attention from the very first fixation. These findings pose a challenge to models of visual attention which assume that overt attention is guided by the visual appearance of stimuli, rather than by their semantics.

Unimodal and crossmodal working memory binding is not differentially affected by age or Alzheimer's disease

Working Memory Binding (WMB) entails the integration of multiple sources of information to form and temporarily store unique representations. Information can be processed through either one (i.e., Unimodal WMB) or separate sensory modalities (i.e., Crossmodal WMB).

OBJECTIVE

In this study, we investigated whether Crossmodal WMB is differentially affected by normal or pathological aging compared to Unimodal WMB.

METHOD

Experiment 1: 26 older and 26 younger adults recalled the target feature matching the test probe to complete a previously displayed color-shape binding (visually presented in the Unimodal condition; auditorily and visually presented in the Crossmodal condition). Experiment 2: 35 older and 35 younger adults undertook the same paradigm while carrying out articulatory suppression to limit verbal recoding. Experiment 3: 24 Alzheimer's disease (AD) patients and two groups of 24 healthy matched controls (tested respectively with the same and an increased memory load compared to the patients) were recruited to perform a similar task.

RESULTS

Results show no age-related additional cost in Crossmodal WMB in respect to Unimodal WMB. AD patients had poor attainment in both WMB tasks regardless of specific binding condition.

CONCLUSION

These findings provide evidence identifying WMB per se to be impaired in AD, regardless of the type of to-be-bound material. This supports the view that WMB is a suitable cognitive marker for AD. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Age-associated delay in mental rotation

Age-associated slowing in mental rotation (MR) process has been documented in the literature. Particularly, the intercept of the response times function of rotation angle has been consistently found to be larger in older than in younger adults. However, the intercept represents the speed of response in 2 distinct subprocesses of MR: the initial phase of stimulus encoding and the final phase of response selection and execution. Thus, it remains unclear which of these 2 subprocesses of MR is affected by age. To investigate this, we recorded event-related potentials in younger and older individuals during a letter rotation task. The onset of the rotation-related negativity (RRN), the electrophysiological correlate of MR, was delayed in older (n = 20; mean age = 20.1) as compared to younger participants (n = 20, mean age = 73.4). Consistent with this observation, additional analyses revealed that the RRN amplitude was modulated by rotation angle between 350 and 500 ms poststimulus in younger adults (n = 26, mean age = 21.0), while this modulation only emerged in the later time window (500-650 ms) in older participants (n = 26; mean age = 73.6). These results suggest that MR occurs later in older adults and demonstrate that the initial phase before MR proper is one source of the age-related slowing observed in MR tasks. Possible accounts for this age-associated delay include a prolonged phase of stimulus encoding and/or selective difficulties in directing attention away from the external stimulus toward its internal mental representation. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Free Recall of Bound Information Held in Short-Term Memory is Unimpaired by Age and Education

Objectives

It has been challenging to identify cognitive markers to differentiate healthy brain aging from neurodegeneration due to Alzheimer’s disease (AD) that are not affected by age and education. The Short-Term Memory Binding (STMB) showed not to be affected by age or education when using the change detection paradigm. However, no previous study has tested the effect of age and education using the free recall paradigm of the STMB. Therefore, the objective of this study was to investigate age and education effects on the free recall version of the STMB test under different memory loads.

Methods

126 healthy volunteers completed the free recall STMB test. The sample was divided into five age bands and into five education bands for comparisons. The STMB test assessed free recall of two (or three) common objects and two (or three) primary colors presented as individual features (unbound) or integrated into unified objects (bound).

Results

The binding condition and the larger set size generated lower free recall scores. Performance was lower in older and less educated participants. Critically, neither age nor education modified these effects when compared across experimental conditions (unbound v. bound features).

Conclusions

Binding in short-term memory carries a cost in performance. Age and education do not affect such a binding cost within a memory recall paradigm. These findings suggest that this paradigm is a suitable cognitive marker to differentiate healthy brain aging from age-related disease such as AD.

Which properties of the visual stimuli predict the type of representation used in mental rotation?

Two modes of internal representation, holistic and piecemeal transformation, have been reported as a means to perform mental rotation (MR) tasks. The stimulus complexity effect has been proposed as an indicator to disentangle between these two representation types. However, the complexity effect has not been fully confirmed owing to the fact that different performances could result from different types of stimuli. Moreover, whether the non-mirror foils play a role in forcing participants to encode all the information from the stimuli in MR tasks is still under debate. This study aims at testing the association between these two common types of representation with different stimuli in MR tasks. First, the numbers of segments and vertices in polygon stimuli were manipulated to test which property of the visual stimuli is more likely to influence the representation in MR tasks. Second, the role of non-mirror foils was examined by comparing the stimulus complexity effect in both with- and without-non-mirror foils conditions. The results revealed that the segment number affected the slope of the linear function relating response times to rotation angle, but the vertex number in the polygons did not. This suggests that a holistic representation was more likely to be adopted in processing integrated objects, whereas a piecemeal transformation was at play in processing multi-part objects. In addition, the stimulus complexity effect was observed in the with-non-mirror foils condition but not in the without-non-mirror foils one, providing a direct evidence to support the role of non-mirror foils in MR tasks.

Closing-In Behavior and Motor Distractibility in Persons with Brain Injury

OBJECTIVE

This study investigates closing-in behavior (CIB), a phenomenon observed in graphic copying tasks when responses encroach upon or overlap the model. The behavior is most common amongst individuals with dementia and amongst pre-school children. We explored the relationship between CIB and the 'distractor effect' in reaching, whereby salient visual stimuli can influence the spatial trajectory of the reach.

METHOD

A group of individuals with overlap-CIB (n = 9), without CIB (n = 9) and healthy controls (HC; n = 6) underwent a task-irrelevant and a task-relevant distractors and the deviation of the movement trajectory towards the distractor location was measured in both tasks.

RESULTS

Individuals with graphic CIB showed more distractor-directed veering during reaching than did individuals without CIB or HC, provided that the distractor was relevant for the reaching task.

CONCLUSIONS

These results strengthen the relationship between CIB and the distractor effect and reinforce the hypothesis that CIB represents a disinhibited tendency to act towards the focus of attention.

Theory of mind and the Ultimatum Game in healthy adult aging

BACKGROUND

The Ultimatum Game assesses decision-making involved in cooperative interactions with others. However, little is known about the role that the ability to understand other people's intentions plays in these interactions.

METHODS

This study examined performance on the Ultimatum Game and theory of mind (ToM) tasks in younger and older adults.

RESULTS

Age differences were not found on the ToM tasks, and a lack of variability in performance prevented analyses of the relationships between performance on the Ultimatum Game and ToM. However, age differences were found on the Ultimatum Game, with older adults accepting more unfair offers. Yet, the two age groups did not differ in their appreciation of fairness, as assessed using subjective fairness ratings.

CONCLUSIONS

These findings suggest that older adults are more rational in their behavior, accepting unfair offers even when they know they are unfair, as it is in their self-interest to accept small monetary values rather than nothing at all.