Different Measures of Structural Similarity Tap Different Aspects of Visual Object Processing

Naming in Older Adults: Complementary Auditory and Visual Assessment

OBJECTIVES

Naming difficulty is a common symptom of multiple age-related neurodegenerative disorders. As naming difficulty increases with age, valid, up-to-date naming assessment tools are crucial for differentiating between neurotypical changes in healthy aging and pathological naming difficulty. We aimed to develop and provide normative data for complementary auditory description naming and visual naming tests for older adults. Furthermore, these measures would include not only untimed accuracy, typically the sole naming performance measure, but also additional scores that incorporate features characteristic of actual word finding difficulty.

METHODS

A normative sample of 407 healthy older adults, aged 56-100 years, were administered the Auditory Naming Test (ANT) and Visual Naming Test (VNT), and other standardized measures.

RESULTS

Item analyses resulted in 36 stimuli for both tests. Age-stratified, education-based normative data are provided for accuracy, response time, tip-of-the-tongue (i.e., delayed, yet accurate responses plus correct responses following phonemic cueing), and multiple Summary Scores. Internal and test-retest reliability coefficients were reasonable (.59-.84). Untimed accuracy scores were high across age groups, seemingly reflecting stability of naming into late adulthood; however, time- and cue-based scores revealed reduced efficiency in word retrieval with increasing age.

CONCLUSIONS

These complementary auditory and visual naming test for older adults improve upon the current standard by providing more sensitive performance measures and the addition of an auditory-verbal component for assessing naming. Detection of subtle naming changes in healthy aging holds promise for capturing symptomatic naming changes during the early stages of neurocognitive disorders involving expressive language, potentially assisting in earlier diagnoses and more timely treatment.

Patterns of perceptual performance in developmental prosopagnosia: An in-depth case series

Developmental prosopagnosia (DP) is a syndrome characterized by lifelong impairment in face recognition in the absence of brain damage. A key question regarding DP concerns which process(es) might be affected to selectively/disproportionally impair face recognition. We present evidence from a group of DPs, combining an overview of previous results with additional analyses important for understanding their pattern of preserved and impaired perceptual abilities. We argue that for most of these individuals, the common denominator is a deficit in (rapid) processing of global shape information. We conclude that the deficit in this group of DPs is not face-selective, but that it may appear so because faces are more visually similar-and recognized at a more fine-grained level-than objects. Indeed, when the demand on perceptual differentiation and visual similarity are held constant for faces and objects, we find no evidence for a disproportionate deficit for faces in this group of DPs.

Object recognition and visual object agnosia

The term visual agnosia is used to refer to recognition disorders that are confined to the visual modality, that are not due to an impairment in sensory functions, and that cannot be explained by other cognitive deficits or by general reduction in intellectual ability. Here, we describe the different types of visual agnosia that have been reported (form agnosia, integrative agnosia, associative agnosia, transformational and orientation agnosia as well as category-specific impairments such as pure alexia and prosopagnosia) and how they relate to the current understanding of visual object recognition. Together with related disorders such as simultanagnosia, texture agnosia, aphantasia, and optic aphasia, these visual perceptual impairments can have severe consequences for those affected. We suggest how in-depth assessment can be carried out to determine the type and the extent of these impairments. In the context of clinical assessment, a step-by-step approach reflecting a posterior to anterior gradient in visual object recognition, from more perceptual to more memory-related processes, is suggested. Individually tailored interventions targeting the identified impairments can be initiated based on the results of the assessment.

Delayed processing of global shape information is associated with weaker top-down effects in developmental prosopagnosia

In previous studies we have shown that a group of individuals with developmental prosopagnosia (DP): (i) were impaired at recognizing objects when presented as silhouettes or fragmented forms; stimuli which place particular demands on global shape processing, (ii) that these impairments correlated with their face recognition deficit, (iii) that they showed a reduced global precedence effect in Navon's paradigm, and (iv) that the magnitude of their global precedence effect correlated with their face and object recognition performance. This pattern of deficits points towards a delay in the processing of global shape information; a delay that may weaken top-down influences on recognition performance. Here we show that the DPs show reduced real object superiority effects (faster responses to real objects than nonobjects) compared with controls. Given that real object superiority effects reflect top-down processing, these findings support the notion of impaired global shape based top-down processing in DP.

Navon's classical paradigm concerning local and global processing relates systematically to visual object classification performance

Forty years ago David Navon tried to tackle a central problem in psychology concerning the time course of perceptual processing: Do we first see the details (local level) followed by the overall outlay (global level) or is it rather the other way around? He did this by developing a now classical paradigm involving the presentation of compound stimuli; large letters composed of smaller letters. Despite the usefulness of this paradigm it remains uncertain whether effects found with compound stimuli relate directly to visual object recognition. It does so because compound stimuli are not actual objects but rather formations of elements and because the elements that form the global shape of compound stimuli are not features of the global shape but rather objects in their own right. To examine the relationship between performance on Navon’s paradigm and visual object processing we derived two indexes from Navon’s paradigm that reflect different aspects of the relationship between global and local processing. We find that individual differences on these indexes can explain a considerable amount of variance in two standard object classification paradigms; object decision and superordinate categorization, suggesting that Navon’s paradigm does relate to visual object processing.