The Box Task: A tool to design experiments for assessing visuospatial working memory

Visuospatial working memory in behavioural variant frontotemporal dementia: a comparative analysis with Alzheimer's disease using the box task

OBJECTIVE

This study investigated the visuospatial working memory profiles of behavioural variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD) using a novel computerised test of visuospatial working memory: the Box Task.

METHODS

Twenty-eight bvFTD and 28 AD patients, as well as 32 age-matched control participants were recruited. All participants completed the Box Task and conventional neuropsychological tests of working memory, episodic memory, and visuospatial function.

RESULTS

Both the bvFTD and AD groups exhibited significantly more Box Task between-search errors than the control group across all set sizes. Notably, the AD group demonstrated a significantly higher error rate compared to the bvFTD group. Regression analysis revealed that whilst episodic memory impairment significantly predicted Box Task error performance in AD, this was not the case for bvFTD. Additionally, a noticeable trend was observed for attention in predicting Box Task errors in both bvFTD and AD groups. The Box Task demonstrated high utility in differentiating between bvFTD and AD, with a decision tree correctly classifying 82.1% of bvFTD patients and 75% of AD patients.

CONCLUSIONS

Our findings reveal significant visuospatial working memory impairments in bvFTD, albeit of lesser severity compared to disease-matched AD patients. The Box Task, a novel measure of visuospatial working memory, proved effective in differentiating between bvFTD and AD, outperforming many traditional neuropsychological measures. Overall, our findings highlight the utility of assessing visuospatial memory when differentiating between bvFTD and AD in the clinical setting.

A virtual reality platform for memory evaluation: Assessing effects of spatial strategies

Human spatial memories are usually evaluated using computer screens instead of real arenas or landscapes where subjects could move voluntarily and use allocentric cues to guide their behavior. A possible approach to fill this gap is the adoption of virtual reality, which provides the opportunity to create spatial memory tasks closer to real-life experience. Here we present and evaluate a new software to create experiments using this technology. Specifically, we have developed a spatial memory task that is carried out in a computer-assisted virtual environment where participants walk around a virtual arena using a joystick. This spatial memory task provides an immersive environment where the spatial component is constantly present without the use of virtual reality goggles. The design is similar to that of tasks used for animal studies, allowing a direct comparison across species. We found that only participants who reported using spatial cues to guide their behavior showed significant learning and performed significantly better during a memory test. This tool allows evaluation of human spatial memory in an ecological environment and will be useful to develop a wide range of other tasks to assess spatial cognition.

The Box Task: A novel tool to differentiate the primary progressive aphasias

OBJECTIVE

Differentiating the primary progressive aphasia (PPA) variants in clinical settings remains complex and challenging, especially for the logopenic (lv-PPA) and non-fluent variants (nfv-PPA). Recent studies suggest that visuospatial memory is more compromised in lv-PPA than in nfv-PPA and is relatively spared in the semantic variant (sv-PPA). Accordingly, assessment of visuospatial memory performance may assist in the differential diagnosis of PPA variants. Here, we investigated the utility of a novel computerised visuospatial working memory test-the Box Task-to differentiate the three PPA variants and typical Alzheimer's disease (AD).

METHODS

Eighteen lv-PPA, 14 nfv-PPA, 23 sv-PPA, 33 AD patients, and 32 healthy controls matched for age and education were recruited. All participants completed the computerised Box Task and WMS-III Spatial Span as measures of visuospatial working memory.

RESULTS

The lv-PPA group made significantly more Box Task between-search errors than nfv-PPA, sv-PPA and control groups. The AD group, however, displayed the greatest impairments on this measure relative to the PPA variants. Logistic regression analyses in lv-PPA and nfv-PPA demonstrated that the combination of Box Task between-search error variables (i.e., 4- and 6-box levels) could correctly classify 72% of lv-PPA patients and nearly 79% of nfv-PPA patients. Area under the receiver operator characteristics curve (AUC) analyses revealed the Box Task was more sensitive than Spatial Span at differentiating lv-PPA from nfv-PPA.

CONCLUSIONS

Our findings suggest that a simple, computerised measure of visuospatial working memory-the Box Task-shows potential diagnostic utility in differentiating lv-PPA from the other PPA variants.

Visual working memory capacity in Korsakoff's amnesia

Introduction: Despite the interest in memory functioning in Korsakoff's syndrome (KS), visual working memory capacity in KS is still poorly understood. Results from the last decades on working memory limitations in KS appear to be mixed, clearly calling for further investigations.Method: We investigated visual working memory storage capacity of patients diagnosed with KS using a change detection paradigm. Nine patients diagnosed with KS and thirty age- and education- matched healthy controls were presented twice with 2, 3, 4, or 6 bars with different orientations and had to detect whether the orientation of the target bar had changed.Results: As a group, KS patients performed significantly worse than controls on all set sizes, with an average capacity of 1.13 items, compared to 1.75 items in the control participants. In case study analysis, 4 out of 9 patients performed significantly worse than control participants, while 5 had relatively intact visual working memory capacity. In patients, deficits in visual working memory could not be explained by other cognitive deficits.Conclusion: Based on these results, we conclude that visual working memory deficits are a prominent characteristic in some, but not all KS patients. Training visual working memory capacity could possibly optimize other cognitive difficulties in this population.

Improving precision in neuropsychological assessment: Bridging the gap between classic paper-and-pencil tests and paradigms from cognitive neuroscience

OBJECTIVE

In cognitive neuroscience, well-controlled and highly specific paradigms have been developed to measure cognitive processes over the last decades, often using computer-assisted presentation and response registration. This approach is in contrast with the traditional paper-and-pencil tests used in clinical neuropsychology, which typically assess cognitive function in a less specific manner, often even at the level of a cognitive domain. As a result, important aspects of cognitive (dys)function may be missed during a neuropsychological assessment. This paper focuses on the main challenges that need to be overcome in order to successfully integrate experimental paradigms from cognitive neuroscience into the clinical practice of neuropsychologists.

METHOD

Six challenges are discussed: (i) experimental paradigms are often lengthy and may be overly specific; (ii) technical limitations even today hamper their application in clinics; (iii) the psychometric properties of methods used in cognitive neuroscience are under-examined or poor; (iv) many paradigms from cognitive neuroscience rely on reaction times rather than accuracy, limiting their use in the many brain-injured patients with processing speed deficits; (v) the predictive and ecological validity of these paradigms often unclear; (vi) technological progress (e.g. Moore's law) seriously affects the continuous availability of experimental computerized assessment methods.

CONCLUSION

Both cognitive neuroscientists and clinical neuropsychologists should work together to develop and validate novel paradigms for use in clinical assessments that are platform-independent, reliable and valid, user friendly and easy to use in clinical practice.