Use of a modified spatial-context memory test to detect amnestic mild cognitive impairment

Suite test. A virtual reality based neuropsychological assessment tool for memory. A normative study on immediate, short-term and delayed memory tasks

OBJECTIVE

To collect normative data for the Suite test, a virtual reality (VR) tool designed to assess memory processes.

METHOD

The normative sample included 676 subjects (49.7% female), aged from 12 to 85 years. The Suite test comprises a 360-degree VR environment designed as a furniture shop, in which participants must group specific sets of furniture items (ordered by different families of customers) by clicking on the furniture to be packed following instructions from a voice-over.

RESULTS

Core variables provided were grouped into immediate, short-term and long-term delayed recall. Cluster analyses established five age groups (12 years old, 13 to 26, 27 to 44, 45 to 58, and 59 to 85) with gender differentiated norms only deemed necessary for those transitioning from adolescence to adulthood (13 to 26) and from middle age to older adulthood (45 to 58). No statistically significant differences were found for additional gender × age normative groups, or for any group differentiated by educational level. A confirmatory factor analysis raised the existence of two differentiated factors, one associated to encoding processes (immediate memory trials) and the other to retrieval processes (both short term and long-term delayed recall trials grouping into the same factor). Additional results on the test reliability and internal consistency are presented.

CONCLUSIONS

Suite Test can help explore memory deficits across the life span and differentiate between visual and verbal memory strategies. Further research is required to study the test sensitivity and specificity, as well as convergent validity studies with well-established memory assessment tools.

Assessing mild cognitive impairment using object-location memory in immersive virtual environments

Pathological changes in the medial temporal lobe (MTL) are found in the early stages of Alzheimer's disease (AD) and aging. The earliest pathological accumulation of tau colocalizes with the areas of the MTL involved in object processing as part of a wider anterolateral network. Here, we sought to assess the diagnostic potential of memory for object locations in iVR environments in individuals at high risk of AD dementia (amnestic mild cognitive impairment [aMCI] n = 23) as compared to age-related cognitive decline. Consistent with our primary hypothesis that early AD would be associated with impaired object location, aMCI patients exhibited impaired spatial feature binding. Compared to both older (n = 24) and younger (n = 53) controls, aMCI patients, recalled object locations with significantly less accuracy (p < .001), with a trend toward an impaired identification of the object's correct context (p = .05). Importantly, these findings were not explained by deficits in object recognition (p = .6). These deficits differentiated aMCI from controls with greater accuracy (AUC = 0.89) than the standard neuropsychological tests. Within the aMCI group, 16 had CSF biomarkers indicative of their likely AD status (MCI+ n = 9 vs. MCI- n = 7). MCI+ showed lower accuracy in the object-context association than MCI- (p = .03) suggesting a selective deficit in object-context binding postulated to be associated with anterior-temporal areas. MRI volumetric analysis across healthy older participants and aMCI revealed that test performance positively correlates with lateral entorhinal cortex volumes (p < .05) and hippocampus volumes (p < .01), consistent with their hypothesized role in binding contextual and spatial information with object identity. Our results indicate that tests relying on the anterolateral object processing stream, and in particular requiring successful binding of an object with spatial information, may aid detection of pre-dementia AD due to the underlying early spread of tau pathology.

The challenge of neuropsychological assessment of visual/visuo-spatial memory: A critical, historical review, and lessons for the present and future

A proliferation of tests exists for the assessment of auditory-verbal memory processes. However, from a clinical practice perspective, the situation is less clear when it comes to the ready availability of reliable and valid tests for the evaluation of visual/visuo-spatial memory processes. While, at face value, there appear to be a wide range of available tests of visual/visuo-spatial memory, utilizing different types of materials and assessment strategies, a number of criticisms have been, and arguably should be, leveled at the majority of these tests. The criticisms that have been directed toward what are typically considered to be visual/visuo-spatial memory tests, such as (1) the potential for verbal mediation, (2) over-abstraction of stimuli, (3) the requirement of a drawing response, and (4) the lack of sensitivity to unilateral brain lesions, mean that, in reality, the number of readily available valid tests of visual/visuo-spatial memory is, at best, limited. This article offers a critical, historical review on the existing measures and resources for the neuropsychological assessment of visual/visuo-spatial memory, and it showcases some examples of newer tests that have aimed to overcome the challenges of assessing these important aspects of memory. The article also identifies new trends and examples of how technological advances such as virtual reality may add value to overcome previous obstacles to assessment, thereby offering professionals more reliable, accurate means to evaluate visual/visuo-spatial memory in clinical practice.

Differential Effect of Retroactive Interference on Object and Spatial Memory in the Course of Healthy Aging and Neurodegeneration

Objective: In subjects with mild cognitive impairment (MCI), interference during memory consolidation may further degrade subsequent recall of newly learned information. We investigated whether spatial and object memory are differentially susceptible to interference. Method: Thirty-nine healthy young subjects, 39 healthy older subjects, and 12 subjects suffering from MCI encoded objects and their spatial position on a 4-by-5 grid. Encoding was followed by either: (i) a pause; (ii) an interference task immediately following encoding; or (iii) an interference task following encoding after a 6-min delay. Type of interference (no, early, delayed) was applied in different sessions and order was counterbalanced. Twelve minutes after encoding, subjects saw objects previously presented or new ones. Subjects indicated whether they recognized the object, and if so, the objects' position during encoding. Results: Interference during consolidation provoked a negative effect on spatial memory in young more than older controls. In MCI, object but not spatial memory was affected by interference. Furthermore, a shift from fine- to coarse-grained spatial representation was observed in MCI. No differential effect of early vs. late interference (EI vs. LI) in either of the groups was detected. Conclusions: Data show that consolidation in healthy aging and MCI differs from consolidation in young controls. Data suggest differential processes underlying object and spatial memory and that these are differentially affected by aging and MCI.

Comparison of Computerized and Paper-and-Pencil Memory Tests in Detection of Mild Cognitive Impairment and Dementia: A Systematic Review and Meta-analysis of Diagnostic Studies

OBJECTIVES

To compare the diagnostic performance of computerized and paper-and-pencil memory tests in detection of mild cognitive impairment (MCI) and dementia.

DESIGN

Diagnostic studies comparing computerized or paper-and-pencil memory tests with the standard diagnostic criterion for MCI or dementia were identified from OVID databases. The primary outcome was the diagnostic performance of memory tests for detection of MCI, and detection of dementia was the secondary outcome. Risk of bias and reporting quality in included studies was assessed.

SETTING AND PARTICIPANTS

Participants with MCI and dementia in any kind of setting.

MEASURES

Bivariate random-effects models were used to combine the diagnostic performance of memory tests and presented with a summary receiver-operating characteristic curve.

RESULTS

A total of 58 studies with 18,450 participants with mean age ranging from 55 to 84 years were included. For the verbal memory tests on patients with MCI, computerized tests showed diagnostic accuracy of 0.89 sensitivity (95% confidence interval [CI] 0.69-0.97) and 0.82 specificity (95% CI 0.70-0.90), whereas paper-and-pencil tests showed diagnostic accuracy of 0.86 sensitivity (95% CI 0.82-0.90) and 0.82 specificity (95% CI 0.76-0.86). For the visual memory tests on MCI patients, computerized tests showed diagnostic accuracy of 0.79 sensitivity (95% CI 0.71-0.84) and 0.80 specificity (95% CI 0.71-0.86), whereas paper-and-pencil tests showed diagnostic accuracy of 0.80 sensitivity (95% CI 0.67-0.89) and 0.68 specificity (95% CI 0.51-0.81). The findings were also comparable to those with dementia.

CONCLUSIONS/IMPLICATIONS

Both verbal and visual computerized memory tests showed comparable diagnostic performance to the paper-and-pencil tests. Computerized cognitive tests show a great potential to use as an alternative to paper-and-pencil tests. When the records can be digitalized, long-term monitoring of cognitive function will be feasible for better management of dementia.

Diagnostic Accuracy of Memory Measures in Alzheimer's Dementia and Mild Cognitive Impairment: a Systematic Review and Meta-Analysis

With an increasing focus on biomarkers in dementia research, illustrating the role of neuropsychological assessment in detecting mild cognitive impairment (MCI) and Alzheimer's dementia (AD) is important. This systematic review and meta-analysis, conducted in accordance with PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) standards, summarizes the sensitivity and specificity of memory measures in individuals with MCI and AD. Both meta-analytic and qualitative examination of AD versus healthy control (HC) studies (n = 47) revealed generally high sensitivity and specificity (≥ 80% for AD comparisons) for measures of immediate (sensitivity = 87%, specificity = 88%) and delayed memory (sensitivity = 89%, specificity = 89%), especially those involving word-list recall. Examination of MCI versus HC studies (n = 38) revealed generally lower diagnostic accuracy for both immediate (sensitivity = 72%, specificity = 81%) and delayed memory (sensitivity = 75%, specificity = 81%). Measures that differentiated AD from other conditions (n = 10 studies) yielded mixed results, with generally high sensitivity in the context of low or variable specificity. Results confirm that memory measures have high diagnostic accuracy for identification of AD, are promising but require further refinement for identification of MCI, and provide support for ongoing investigation of neuropsychological assessment as a cognitive biomarker of preclinical AD. Emphasizing diagnostic test accuracy statistics over null hypothesis testing in future studies will promote the ongoing use of neuropsychological tests as Alzheimer's disease research and clinical criteria increasingly rely upon cerebrospinal fluid (CSF) and neuroimaging biomarkers.