Neurocognitive mechanisms of collaborative recall.

Research on collaborative memory shows that people recalling in groups rarely achieve optimal performance. Collaborative groups typically recall less than nominal groups, where performance for the latter is derived by pooling the non-overlapping information recalled by the same number of individuals working alone. While behavioural evidence has widely replicated this collaborative inhibition in free recall, little evidence speaks to the neurophysiological signatures of this counterintuitive phenomenon. Behavioural evidence also indicates that disruption to one's preferred recall strategy, resulting from processing others' recalled information, is a key mechanism underlying this effect. We aimed to identify the neural signatures indexing the recollection process and their disruption during collaborative recall. In three experiments, we replicated the standard collaborative inhibition effect with an EEG-adapted procedure (Experiment 1), and recorded EEG while people recalled in groups or in isolation (Experiments 2a, 2b). Comparisons showed increments in N400 and theta power, the neurophysiological components associated with interference, at shorter intervals for the collaborative compared to the nominal groups. Stronger theta power for collaborative than nominal recall, and for speakers than non-speakers in collaborative groups, were also evident at longer intervals and suggest demanding reinstatement of memory associated with collaborative recall. Together, the results suggest distinct neural processes underlying collaborative inhibition, with neural responses at shorter intervals signaling processes that are consistent with strategy disruption (stronger interference signaled by N400 and theta power increments), and further increments in theta at later times suggesting more demanding reinstatement processes during collaborative remembering.

The Cognitive Scale of Basic and Instrumental Activities of Daily Living for Multidomain Mild Cognitive Impairment and Dementia Patients: Validation of its Extended Version.

OBJECTIVE: To validate an informant-based tool - the extended version of the Cognitive Scale of Basic and Instrumental Activities of Daily Living (BADL and IADL) or Ext. Cog-ADL Scale - in a larger sample and with a broader range of cognitive-functional items related to activities of daily living (ADL). METHOD: The Ext. Cog-ADL Scale was administered to family informants of 42 patients with dementia, 43 patients with multidomain mild cognitive impairment (mdMCI), and 23 healthy control participants. We analyzed the convergent and concurrent validity and external validity of this scale. RESULTS: The Ext. Cog-ADL Scale demonstrated good psychometric properties. Episodic and working memory tests were the main predictors of most cognitive-functional items of the scale. While patients with dementia obtained lower scores in most error categories of the scale, affecting both BADL and IADL, mdMCI patients showed a more specific pattern of difficulties. Apart from the typical alterations in IADL, mdMCI patients also showed difficulties in several error categories related to BADL (i.e., error detection, problem solving, task self-initiation, distraction inhibition, and restore). CONCLUSIONS: The Ext. Cog-ADL Scale seems to be an adequate tool to capture the specific pattern of cognitive alterations related to IADL and BADL that differentiates dementia from mdMCI and healthy aging; it shows that mdMCI can involve specific cognitive difficulties that affect even BADL.

Positive and Negative Consequences of Making Coffee among Breakfast Related Irrelevant Objects: Evidence from MCI, Dementia, and Healthy Ageing.

OBJECTIVES: Previous studies have reported impairments in activities of daily living (ADL) performance in the presence of irrelevant but physically/functionally related objects in dementia patients. The aim of the present study was to increase our knowledge about the impact of the presence of contextually related non-target objects on ADL execution in patients with multi-domain mild cognitive impairment (MCI) and dementia. METHODS: We compared ADL execution in patients with MCI, dementia, and healthy elderly participants under two experimental conditions: One in which the target objects were embedded with contextually related non-target items that constituted the object set necessary to complete two additional (but unrequired) ADL tasks related to the target task, and a second, control condition where target objects were surrounded by isolated objects (they never constituted a whole set needed to complete an alternative ADL task). RESULTS: Separate analysis of ADL errors associated with the target task versus errors involving the non-target objects revealed that, although the presence of contextually related objects facilitated the accomplishment of the target task, such a condition also led to errors involving the use of irrelevant objects in dementia and MCI. CONCLUSIONS: The presence of contextually related non-target items produces both positive and negative effects on ADL performance. These types of non-target objects might help to cue the retrieval of the action schema related to the target task, particularly in patients with MCI. In contrast, the presence of these objects might also lead to distraction in dementia and MCI. (JINS, 2017, 23, 481-492).

Preliminary cognitive scale of basic and instrumental activities of daily living for dementia and mild cognitive impairment.

In the present study we explored cognitive and functional deficits in patients with multidomain mild cognitive impairment (MCI), patients with dementia, and healthy age-matched control participants using the Cognitive Scale for Basic and Instrumental Activities of Daily Living, a new preliminary informant-based assessment tool. This tool allowed us to evaluate four key cognitive abilities-task memory schema, error detection, problem solving, and task self-initiation-in a range of basic and instrumental activities of daily living (BADL and IADL, respectively). The first part of the present study was devoted to testing the psychometric adequateness of this new informant-based tool and its convergent validity with other global functioning and neuropsychological measures. The second part of the study was aimed at finding the patterns of everyday cognitive factors that best discriminate between the three groups. We found that patients with dementia exhibited impairment in all cognitive abilities in both basic and instrumental activities. By contrast, patients with MCI were found to have preserved task memory schema in both types of ADL; however, such patients exhibited deficits in error detection and task self-initiation but only in IADL. Finally, patients with MCI also showed a generalized problem solving deficit that affected even BADL. Studying various cognitive processes instantiated in specific ADL differing in complexity seems a promising strategy to further understand the specific relationships between cognition and function in these and other cognitively impaired populations.