The benefits of errorless learning for people with amnestic mild cognitive impairment.

The aim of this study was to explore whether errorless learning leads to better outcomes than errorful learning in people with amnestic mild cognitive impairment (MCI), and to examine whether accuracy in error recognition relates to any observed benefit of errorless over errorful learning. Nineteen participants with a clinical diagnosis of amnestic MCI were recruited. A word-list learning task was used and learning was assessed by free recall, cued recall and recognition tasks. Errorless learning was significantly superior to errorful learning for both free recall and cued recall. The benefits of errorless learning were less marked in participants with better error recognition ability. Errorless learning methods are likely to prove more effective than errorful methods for those people with MCI whose ability to monitor and detect their own errors is impaired.

Functional Correlates of Midline Brain Volume Loss in Chronic Traumatic Brain Injury.

Traumatic brain injury (TBI) is associated with long-term changes in daily life functioning, yet the neuroanatomical correlates of these changes are poorly understood. This study related outcome assessed across several domains to brain structure derived from quantitative magnetic resonance imaging (MRI). Sixty individuals spanning a wide range of TBI severity participated 1-year post-injury as part of the Toronto TBI study. Volumetric data over 38 brain regions were derived from high resolution T1-weighted MRI scans. Functioning was assessed with a battery of self- and significant-other rated measures. Multivariate analysis (partial least squares) was used to identify shared variance between the neuroimaging and outcome measures. TBI was associated with item endorsement on outcome questionnaires without strong evidence for severity or focal lesion effects. Prefrontal midline, cingulate, medial temporal, right inferior parietal and basal ganglia/thalamic volumes were associated with measures of initiative, energization, and physical complaints. In the chronic stage of TBI, self-initiation, energization, and physical complaints related to a specific pattern of volume loss in midline and lateral regions known to be involved in motivation, apathy, and attention. These results suggest that crucial functional changes in chronic TBI may be associated with volume loss in established midline-frontal and attentional circuits.

Dynamic working memory performance in individuals with single-domain amnestic mild cognitive impairment.

Previous studies have observed poorer working memory performance in individuals with amnestic mild cognitive impairment than in healthy older adults. It is unclear, however, whether these difficulties are true only of the multiple-domain clinical subtype in whom poorer executive functioning is common. The current study examined working memory, as measured by the self-ordered pointing task (SOPT) and an n-back task, in healthy older adults and adults with single-domain amnestic mild cognitive impairment (aMCI). Individuals with single-domain aMCI committed more errors and required longer to develop an organizational strategy on the SOPT. The single-domain aMCI group did not differ from healthy older adults on the 1-back or 2-back, but had poorer discrimination on the 3-back task. This is, to our knowledge, the first characterization of dynamic working memory performance in a single-domain aMCI group. These results lend support for the idea that clinical amnestic MCI subtypes may reflect different stages on a continuum of progression to dementia and question whether standardized measures of working memory (span tasks) are sensitive enough to capture subtle changes in performance.

Recollection can support hybrid visual memory search.

On a daily basis, we accomplish the task of searching our visual environment for one of a number of possible objects, like searching for any one of our friends in a crowd, and we do this with ease. Understanding how attention, perception, and long-term memory interact to accomplish this process remains an important question. Recent research (Wolfe in Psychological Science 23:698-703, 2012) has shown that increasing the number of possible targets one is searching for adds little cost to the efficiency of visual search-specifically, that response times increase logarithmically with memory set size. It is unclear, however, what type of recognition memory process (familiarity or recollection) supports a hybrid visual memory search. Previous hybrid search paradigms create conditions that allow participants to rely on the familiarity of perceptually identical targets. In two experiments, we show that hybrid search remains efficient even when the familiarity of targets is minimized (Experiment 1) and when participants are encouraged to flexibly retrieve target information that is perceptually distinct from the information previously studied (Experiment 2). We propose that such efficient and flexible performance on a hybrid search task may engage a rapid from of recollection (Moscovitch in Canadian Journal of Experimental Psychology 62:62-79, 2008). We discuss possible neural correlates supporting simultaneous perception, comparison of incoming information, and recollection of episodic memories.

Self-generation amplifies the errorless learning effect in healthy older adults when transfer appropriate processing conditions are met.

Errorless learning improves memory for older adults by providing individuals with correct information from the onset, thereby minimizing the misleading influence of errors. Our previous research demonstrated that self-generation enhanced the errorless learning effect among older adults in cued recall when encoding encouraged processing of cue-target relationships, suggesting that transfer appropriate processing is necessary for this interactive effect ( Lubinsky, Rich, & Anderson, 2009 , Journal of the International Neuropsychological Society, 15, 704). The current study further tests this notion by investigating whether the interaction of errorless learning and self-generated learning is observed in free recall when study conditions foster encoding of inter-item associations. Healthy older adult participants studied related or unrelated words (manipulated between-subjects) under four within-subjects learning conditions representing the crossing of errorless/errorful learning and self-generated/experimenter-provided information. As predicted, self-generation enhanced the errorless learning advantage in free recall for related word lists but not unrelated word lists. The results are discussed in relation to the transfer appropriate processing view of generation effects.

Contributions of frontal and medial temporal lobe functioning to the errorless learning advantage.

Among individuals with episodic memory impairments, trial-and-error learning is less successful than when errors are avoided. This "errorless learning advantage" has been replicated numerous times, but its neurocognitive mechanism is uncertain, with existing evidence pointing to both medial temporal lobe (MTL) and frontal lobe (FL) involvement. To test the relative contribution of MTL and FL functioning to the errorless learning advantage, 51 healthy older adults were pre-experimentally assigned to one of four groups based on their neuropsychological test performance: Low MTL-Low FL, Low MTL-High FL, High MTL-Low FL, High MTL-High FL. Participants learned two word lists under errorless learning conditions, and two word lists under errorful learning conditions, and memory was tested via free recall, cued recall, and source recognition. Performance on all three tests was better for those with High relative to Low MTL functioning. An errorless learning advantage was found in free and cued recall, in cued recall marginally more so for those with Low than High MTL functioning. Participants with Low MTL functioning were also more likely to misclassify learning errors as target words. Overall, these results are consistent with a MTL locus of the errorless learning advantage. The results are discussed in terms of the multi-componential nature of neuropsychological tests and the impact of demographic and mood variables on cognitive functioning.

Process-specific interference effects during recognition of spatial patterns and words.

The authors examined recognition memory for words or visuospatial patterns under full (FA) or divided attention (DA) conditions with a distracting task requiring either phonological (rhyme) or visuospatial (curved-line) processing of letters, in 72 young adults. The authors found an interaction such that the curved-line distracting task had a more detrimental effect on corrected recognition, and discriminability measured by d', for spatial patterns than did the rhyme distracting task, whereas the reverse was true for memory of words. There was also a general effect of DA on response bias such that C increased under DA relative to FA conditions, regardless of the distracting task, and type of information being remembered. Results suggest memory interference from DA at retrieval is process-specific, and that DA at retrieval leads to a more conservative response strategy.