The free and cued selective reminding test: Validation for mild cognitive impairment and Alzheimer's disease

The International Working Group on Alzheimer's disease (AD) suggested the free and cued selective reminding test (FCSRT) to assess memory, as it showed high sensitivity and specificity in the differentiation of AD from healthy controls and other dementias. The FCSRT involves the use of selective reminding with semantic cueing in memory assessment. This study aims to validate the FCSRT for mild cognitive impairment (MCI) and AD through the analysis of the diagnostic accuracy and the suggestion of cut‐off scores. Patients were classified into two groups according to standard criteria: MCI (n = 100) and AD (n = 70). A matched control group (n = 101) of cognitively healthy subjects was included. The reliability and the validity of the FCSRT were analysed on the immediate (IR) and delayed (DR) recalls. The Cronbach's alpha was 0.915 for the IR and 0.879 for the DR. The total recall measures revealed good areas under the curve for MCI (IR: .818; DR: .828) and excellent for AD (IR: .987; DR: .991). Furthermore, the MCI group was subdivided with respect to a non‐similar/similar AD pattern of impairment, with almost half of the subjects showing an AD‐like decline. This analysis represents a novel contribution regarding the properties of the FCSRT in illustrating the heterogeneity of MCI at baseline. The FCSRT has proved to be a very useful tool in the characterization of the memory impairment of the AD spectrum.     

Working memory and situation model updating

Situation model updating requires managing the availability of information as a function of its relevance to the current situation. This is thought to involve some aspect of working memory. The present study assesses the relation between updating ability and various measures of working memory span or capacity. In addition, a primitive general measure of situation model processing, a situation model identification test, and its relation to updating ability was also assessed. The present experiment used a version of a paradigm developed by Glenberg, Meyer, and Lindem (1987) to assess updating. Although updating was observed in both anaphoric reading time and recognition test accuracy measures, the reading time measure was relatively weak. Importantly, the updating effect on the recognition test was unrelated to working memory capacity. In contrast, updating was related to performance on the situation model identification task. Specifically, people who were good at model processing were better able to keep associated objects available than were people who were less adept. There were no differences in the maintenance of dissociated objects. These results suggest that the relationship between situation model processing and working memory capacity is relatively weak.     

The orienting response,and future directions of its development

The orienting response (OR) is a specific behavioral act directed towards extraction of information from the environment. Head and eye movements represent only the tip of the iceberg of internal responses, which includes vascular modifications, EEG changes, and event-related potentials. Two mechanisms of the OR have to be differentiated: voluntary and involuntary. In the event-related potential, such a differentiation is expressed in mismatch negativity (involuntary effect) and processing negativity (voluntary effect). Single unit studies have shown that hippocampal neurones are simulating specific features of the OR as a response to novelty. Repeated presentation of stimuli results in a selective habituation of novelty detectors in hippocampus and of the OR. The trace of a standard stimulus formed at the level of hippocampal neurones matches the features of the standard stimulus and can be called a “neuronal model of the stimulus.” The OR is triggered by mismatch between the test stimulus and the elaborated neuronal model, and is activated by verbal instruction, by reinforcement during the initial stage of conditioned reflex elaboration, and by differentiation of signal and non-signal stimuli. A promising new area of practical application of the OR lies in the evaluation of a corridor of optimal functional state for efficient computer-based learning. Registration of the OR and defensive responses can be used for an objective evaluation of the functional state of the student, or, in a wider sense, of the industrial operator. New avenues of OR research are opened by recent techniques that isolate single-trial event related potentials, and their correlation with autonomic and behavioral manifestations of the OR. The combination of single unit recording with such isolated event related potentials can elucidate the neuronal basis of OR generation. Intracellular recording combined with dye injection can be used for analysis of the synaptic contacts involved in generation of the OR. Integration of macro and micro levels of OR organization can be achieved in a computerized model that can be used for simulation and planning of experiments. A step-by-step improvement of the model will accumulate knowledge about the OR as an important mechanism of information processing.     

Visual associations to retrieve episodic memory across healthy elderly,mild cognitive impairment,and patients with Alzheimer’s disease

Episodic memory tests need to determine the degree to which patients with moderate to severe memory deficits can still benefit from retrieval support. Especially in the case of Alzheimer’s disease (AD), this may support health care to be more closely aligned with patients’ memory capacities. We investigated whether the different measures of episodic memory of the Visual Association Test-Extended (VAT-E) can provide a more detailed and informative assessment on memory disturbances across a broad range of cognitive decline, from normal to severe impairment as seen in AD, by examining differences in floor effects. The VAT-E consists of 24 pairs of black-and-white line drawings. In a within-group design, we compared score distributions of VAT-E subtests in healthy elderly controls, mild cognitive impairment (MCI), and AD (n = 144), as well as in relation to global cognitive impairment. Paired associate recall showed a floor effect in 41% of MCI patients and 62% of AD patients. Free recall showed a floor effect in 73% of MCI patients and 84% of AD patients. Multiple-choice cued recognition did not show a floor effect in either of the patient groups. We conclude that the VAT-E covers a broad range of episodic memory decline in patients. As expected, paired associate recall was of intermediate difficulty, free recall was most difficult, and multiple-choice cued recognition was least difficult for patients. These varying levels of difficulty enable a more accurate determination of the level of retrieval support that can still benefit patients across a broad range of cognitive decline.     

Personally-significant information affects performance only within the focus of attention: a direct manipulation of attention

It has been suggested that personally significant (PS) information interferes with performance only when presented within the focus of attention. However, this claim was never tested by a systematic manipulation of attention, but only by using correlative measures of its locus. We addressed this issue in two experiments, utilizing a cued visual search paradigm that allowed us to directly manipulate attention and to measure behavioral and physiological responses. One of the stimuli in the search display had a higher luminance value (i.e., was cued), and, orthogonally, one of the stimuli could be a PS or neutral name. When the cue did not predict target location, PS distractors mildly interfered with task performance, regardless of the cue's location. However, when the cue predicted target location, responses were facilitated for cued targets, indicating that attention was shifted to the cue. Importantly, PS distractors interfered with task performance and elicited enhanced orienting responses only when they were cued. This implies that PS information affects performance only when presented within but not outside the focus of attention.     

Using experiential optimization to build lexical representations

To account for natural variability in cognitive processing, it is standard practice to optimize a model’s parameters by fitting it to behavioral data. Although most language-related theories acknowledge a large role for experience in language processing, variability reflecting that knowledge is usually ignored when evaluating a model’s fit to representative data. We fit language-based behavioral data using experiential optimization, a method that optimizes the materials that a model is given while retaining the learning and processing mechanisms of standard practice. Rather than using default materials, experiential optimization selects the optimal linguistic sources to create a memory representation that maximizes task performance. We demonstrate performance on multiple benchmark tasks by optimizing the experience on which a model’s representation is based.

     

They saw a movie: long-term memory for an extended audiovisual narrative

We measured long-term memory for a narrative film. During the study session, participants watched a 27-min movie episode, without instructions to remember it. During the test session, administered at a delay ranging from 3 h to 9 mo after the study session, long-term memory for the movie was probed using a computerized questionnaire that assessed cued recall, recognition, and metamemory of movie events sampled ~20 sec apart. The performance of each group of participants was measured at a single time point only. The participants remembered many events in the movie even months after watching it. Analysis of performance, using multiple measures, indicates differences between recent (weeks) and remote (months) memory. While high-confidence recognition performance was a reliable index of memory throughout the measured time span, cued recall accuracy was higher for relatively recent information. Analysis of different content elements in the movie revealed differential memory performance profiles according to time since encoding. We also used the data to propose lower limits on the capacity of long-term memory. This experimental paradigm is useful not only for the analysis of behavioral performance that results from encoding episodes in a continuous real-life-like situation, but is also suitable for studying brain substrates and processes of real-life memory using functional brain imaging.     

Processing speed in normal aging: Effects of white matter hyperintensities and hippocampal volume loss

Changes in cognitive functioning are said to be part of normal aging. Quantitative MRI has made it possible to measure structural brain changes during aging which may underlie these decrements which include slowed information processing and memory loss. Much has been written on white matter hyperintensities (WMH), which are associated with cognitive deficits on tasks requiring processing speed and executive functioning, and hippocampal volume loss, which is associated with memory decline. Here we examine volumetric MRI measures of WMH and hippocampal volume loss together in relation to neuropsychological tests considered to be measures of executive functioning and processing speed in 81 non-demented elderly individuals, aged 75–90. Correlational analysis showed that when controlling for age, both greater WMH volume and smaller hippocampal volume were correlated with slower performances on most tests with the exception of a battery of continuous performance tests in which only WMH was correlated with slower reaction time (RT). We then performed a series of hierarchical multiple regression analyses to examine the independent contributions of greater WMH volume and reduced hippocampal volume to executive functioning and processing speed. The results showed that for the four measures requiring executive functioning and speed of processing, WMH volume and hippocampal volume combined predicted between 21.4% and 37% of the explained variance. These results suggest that WM integrity and hippocampal volume influence cognitive decline independently on tasks involving processing speed and executive function independent of age.     

Think-aloud protocols and the selection task: Evidence for relevance effects and rationalisation processes

Two experiments are reported that employed think-aloud methods to test predictions concerning relevance effects and rationalisation processes derivable from Evans' (1996) heuristic-analytic theory of the selection task. Evans' account proposes that card selections are triggered by relevance-determining heuristics, with analytic processing serving merely to rationalise heuristically cued decisions. As such, selected cards should be associated with more references to both their facing and their hidden sides than rejected cards, which are not subjected to analytic rationalisation. Experiment 1 used a standard selection-task paradigm, with negative components permuted through abstract conditional rules. Support was found for all heuristic-analytic predictions. This evidence was shown to be robust in Experiment 2, where “select - don't select” decisions were enforced for all cards. Both experiments also clarify the role played by secondary heuristics in cueing the consideration of hidden card values during rationalisation. We suggest that whilst Evans' heuristic-analytic model and Oaksford and Chater's (e.g., 2003) optimal data selection model can provide compelling accounts of our protocol findings, the mental models theory fares less well as an explanation of our full dataset.     

The Microanalysis of Memory Span and Its Development in Childhood

It is not clear from the literature why, as children develop, there are important increases in memory span, the number of just-presented items that the participant can repeat in the correct serial order. To understand this, some recent results on capacity limits and processing rates were re-analyzed. We first describe results using a conventional measure of performance in immediate memory tasks that is affected by the list length (proportion correct). Next we describe results using a less conventional measure (number correct) that is unaffected by list length under circumstances in which attention to the list during its presentation is curtailed. This measure can estimate an individual's limited-capacity storage ability. Last, we examine measures of spoken response timing that do and do not change with list length. We show that unconventional measures that do not change with list length, but do change with development, are especially useful in assessing basic changes in information processing parameters, including increases in memory capacity and processing speed.     

Precue effects in visual search: Data or resource limited?

Precuing an observer as to where a target is more likely to occur in a subsequent visual array can increase the detectability (d′) of a target at that location. This is often attributed to the observer’s increased allocation of some limited cognitive resource (“attention”) to the cued location. Two experiments are reported which are difficult to interpret in this way even though they involve similar cue effects. The first involves postcuing a location well after the array but before the observer responds, so that the cue can influence the response but not the observation. The second involves precuing, but with slow sequential presentation of array elements prior to the response, so the observer need not share any limited resource while processing each element in turn. Enhanced detectability similar to that produced with precues and simultaneous presentation of elements is shown to occur in each experiment. An alternative data-limited (rather than resource-limited) interpretation of these effects is provided by a mathematical model in which the observer integrates equally noisy or degraded internal representations of the array elements, but gives more weight to cued elements in selecting a response. Theoretical parameters of the model are shown to provide separate measures of both an observer’s overall sensitivity and precue effects in cost-benefit analyses of cuing data.     

Spatial distribution of visual attention: Perceptual sensitivity and response latency

Studies of the spatial distribution of visual attention have shown that attentional facilitation monotonically decreases in a graded fashion with increasing distance from an attended location. However, reaction time (RT) measures have typically shown broader gradients than have signal detection (SD) measures of perceptual sensitivity. It is not clear whether these differences have arisen because the stages of information processing indexed by RT measures are different from those indexed by SD measures, or whether these differences are due to methodological confounds in the SD studies. In the present set of experiments, the spatial distribution of attention was studied by using a luminance detection task in an endogenous cuing paradigm that was designed to permit accurate calculations of SD and RT measures for targets at cued and uncued locations. Subjects made target-present/absent decisions at one of six possible cued or uncued upper visual hemifield locations on each trial. The results from three experiments suggest that the differences between broad and focal attentional distributions are not the result of different stages of information processing indexed by RT measures as opposed to SD measures. Rather, the differing distributions appear to reflect variations in attentional allocation strategies induced by the perceptual requirements typical of RT paradigms as opposed to SD paradigms. These findings support numerous prior studies showing that spatial attention affects perceptual sensitivity and that the strategic allocation of attention is a highly flexible process.     

Evidence for the substantia nigra pars compacta as an essential component of a memory system independent of the hippocampal memory system

The aim of the present study was to test if the nigrostriatal pathway is an essential component for a water maze cued task learning and if it works independently of the hippocampal memory system. This hypothesis was tested using an animal model of Parkinson's disease in which male Wistar rats were lesioned in the substantia nigra pars compacta (SNc) by the intranigral infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), thus causing a partial depletion of striatal dopamine. SNc-lesioned and sham-operated animals were implanted bilaterally with guide cannulae above the dorsal hippocampus in order to be tested after the administration of 0.4 microl 2% lidocaine or saline into this structure. The animals were tested in a spatial or in a cued version of the water maze, memory tasks previously reported to model hippocampal-dependent spatial/relational and striatal-dependent S-R learning, respectively. Hippocampal inactivation, but not SNc lesion, impaired learning and memory in the spatial version of the water maze. An opposite situation was observed with the cued version. No significant interaction was observed between the SNc lesion and hippocampal inactivation conditions affecting scores in the spatial or in the cued version of the water maze. These results suggest that the nigrostriatal pathway is an essential part of the memory system that processes S-R learning and that it works independently of the hippocampal memory system that processes spatial/relational memories.     

Multidimensional assessment of coping: a critical evaluation

Several existing self-report measures of coping and the relevant research using these instruments are reviewed. Many of these coping measures suffer from a variety of psychometric weaknesses. A self-report instrument, the Multidimensional Coping Inventory (MCI), was constructed that identifies 3 types of coping styles: task-oriented, emotion-oriented, and avoidance-oriented coping. Support for the multidimensional nature of the MCI is presented, along with support for the reliability of the MCI coping scales. Two studies are presented that assessed the validity of the MCI. The 1st study assessed the construct validity of the MCI by comparing it with the Ways of Coping Questionnaire. The 2nd study also assessed the criterion validity of the MCI by comparing it with measures of depression, anxiety, Type A behaviour, neuroticism, and extraversion. Overall, the results suggest that the MCI is a valid and highly reliable multidimensional measure of coping styles.     

A neural model of hippocampal–striatal interactions in associative learning and transfer generalization in various neurological and psychiatric patients

Building on our previous neurocomputational models of basal ganglia and hippocampal region function (and their modulation by dopamine and acetylcholine, respectively), we show here how an integration of these models can inform our understanding of the interaction between the basal ganglia and hippocampal region in associative learning and transfer generalization across various patient populations. As a common test bed for exploring interactions between these brain regions and neuromodulators, we focus on the acquired equivalence task, an associative learning paradigm in which stimuli that have been associated with the same outcome acquire a functional similarity such that subsequent generalization between these stimuli increases. This task has been used to test cognitive dysfunction in various patient populations with damages to the hippocampal region and basal ganglia, including studies of patients with Parkinson’s disease (PD), schizophrenia, basal forebrain amnesia, and hippocampal atrophy. Simulation results show that damage to the hippocampal region—as in patients with hippocampal atrophy (HA), hypoxia, mild Alzheimer’s (AD), or schizophrenia—leads to intact associative learning but impaired transfer generalization performance. Moreover, the model demonstrates how PD and anterior communicating artery (ACoA) aneurysm—two very different brain disorders that affect different neural mechanisms—can have similar effects on acquired equivalence performance. In particular, the model shows that simulating a loss of dopamine function in the basal ganglia module (as in PD) leads to slow acquisition learning but intact transfer generalization. Similarly, the model shows that simulating the loss of acetylcholine in the hippocampal region (as in ACoA aneurysm) also results in slower acquisition learning. We argue from this that changes in associative learning of stimulus–action pathways (in the basal ganglia) or changes in the learning of stimulus representations (in the hippocampal region) can have similar functional effects.     

Category Cued Recall Following Controlled Encoding as a Neuropsychological Tool in the Diagnosis of Alzheimer’s Disease: A Review of the Evidence

Aim of the present review paper was to evaluate the hypothesis (included in the proposal of new research criteria for Alzheimer’s disease; Dubois et al., Lancet Neurology, 6, 734–746, 2007) that a neuropsychological tool which provides support for the semantic encoding of memorandum at the time of study and supplies category cues at the time of retrieval (i.e. the Grober-Buschke paradigm) is more effective than traditional measures of free recall in 1) differentiating patients affected by the amnestic form of Mild Cognitive Impairment (MCI) or by mild to moderate forms of Alzheimer’s disease (AD) from healthy matches, 2) predicting the conversion of individuals with MCI to AD, and 3) differentiating AD patients from individuals affected by other forms of dementia. Results of the review are controversial regarding the superiority of the Grober-Buschke procedure in differentiating individuals affected by AD or MCI from healthy individuals. The only study that evaluated this issue directly found that the Grober-Buschke procedure was more sensitive and specific than more traditional memory tests in predicting the conversion of MCI patients to AD. Finally, two studies reported that patients affected by AD or other forms of dementia showed different performance patterns in the free and cued recall tasks of the Grober-Buschke procedure. In conclusion, although encouraging results are reported in the few studies that investigated the ability of this procedure to predict the evolution of individuals with amnestic MCI and to differentiate AD patients from patients with other forms of cortical and subcortical dementia, more experimental work is needed to confirm these positive findings.     

Psychophysiologic chronometry: detection of facilitating and inhibiting processes in information processing using electroencephalographic and electromyographic data]

The objective of the present research was to tally the potential usefulness of psychophysiological measures in the systematic analysis of human information processing. Different context conditions were established in two cued choice-reaction time experiments. The context could either facilitate or inhibit the processing of an imperative stimulus. Event-related brain potentials (EEG-ERP) and event-related electromyograms (EMG-ERP) were recorded and from these biosignals latencies and duration times for different aspects of stimulus evaluation and movement execution were derived. The EEG-ERP provided measures for the time of primary stimulus categorization (N2), the time necessary to test actual stimulus information against stimulus expectancies (P3b), and the time necessary to check the decision about the stimulus-response mapping (pSW). From the EMG-ERP, processing times were derived which are related to the initiation of a motor program and to distinct sections of the movement trajectory. Results show that these latency measures react differently to different context manipulations. EEG-ERP measures, for example, reflected differences during stimulus evaluation which were not detectable in response- or EMG-derived movement times. The parallel analysis of EEG-ERPs and EMG-ERPs allowed delineation of processing modules which are responsible for particular context-dependent facilitation and inhibition effects. Moreover, the data revealed substantial overlap of evaluation times and movement times. This finding seems to be more compatible with a parallel processing model than with a strictly sequential model.     

Contributions of processing ability and knowledge to verbal memory tasks across the adult life-span

This study investigated the relationships of processing capacity and knowledge to memory measures that varied in retrieval difficulty and reliance on verbal knowledge in an adult life-span sample (N = 341). It was hypothesized that processing ability (speed and working memory) would have the strongest relationship to tasks requiring active retrieval and that knowledge (vocabulary ability) would be related to verbal fluency and cued recall, as participants relied upon verbal knowledge to retrieve category items (fluency) or develop associations (cued recall). Measurement and structural equation models were developed for the entire sample and separately for younger (aged 20-54 years, n = 168) and older (aged 55-92 years, n = 173) subgroups. In accordance with the hypotheses, processing ability was found to be most highly related to free recall, with additional significant relationships to cued recall, verbal fluency, and recognition. Knowledge was found to be significantly related only to verbal fluency and to cued recall. Moreover, knowledge was more important for older than for younger adults in mediating variance in cued recall, suggesting that older adults may use age-related increases in knowledge to partially compensate for processing declines when environmental support is available in memory tasks.     

Cognition and aided speech recognition in noise: Specific role for cognitive factors following nine-week experience with adjusted compression settings in hearing aids

The working memory model for Ease of Language Understanding (ELU) proposes that language understanding under taxing conditions is related to explicit cognitive capacity. We refer to this as the mismatch hypothesis, since phonological representations based on the processing of speech under established conditions may not be accessed so readily when input conditions change and a match becomes problematic. Then, cognitive capacity requirements may differ from those used for processing speech hitherto. In the present study, we tested this hypothesis by investigating the relationship between aided speech recognition in noise and cognitive capacity in experienced hearing aid users when there was either a match or mismatch between processed speech input and established phonological representations. The settings in the existing digital hearing aids of the participants were adjusted to one of two different compression settings which processed the speech signal in qualitatively different ways ("fast" or "slow"). Testing took place after a 9-week period of experience with the new setting. Speech recognition was tested under different noise conditions and with match or mismatch (i.e. alternative compression setting) manipulations of the input signal. Individual cognitive capacity was measured using a reading span test and a letter monitoring test. Reading span, a reliable measure of explicit cognitive capacity, predicted speech recognition performance under mismatch conditions when processed input was incongruent with recently established phonological representations, due to the specific hearing aid setting. Cognitive measures were not main predictors of performance under match conditions. These findings are in line with the ELU model.     

Extending the simultaneous-sequential paradigm to measure perceptual capacity for features and words

In perception, divided attention refers to conditions in which multiple stimuli are relevant to an observer. To measure the effect of divided attention in terms of perceptual capacity, we introduce an extension of the simultaneous-sequential paradigm. The extension makes predictions for fixed-capacity models as well as for unlimited-capacity models. We apply this paradigm to two example tasks, contrast discrimination and word categorization, and find dramatically different effects of divided attention. Contrast discrimination has unlimited capacity, consistent with independent, parallel processing. Word categorization has a nearly fixed capacity, consistent with either serial processing or fixed-capacity, parallel processing. We argue that these measures of perceptual capacity rely on relatively few assumptions compared to most alternative measures.