Detection of visuoperceptual deficits in preclinical and mild Alzheimer's disease

Alegret, Montserrat; Boada-Rovira, Mercè; Vinyes-Junqué, Georgina; Valero, Sergi; Espinosa, Ana; Hernández, Isabel; Modinos, Gemma; Rosende-Roca, Maiteé; Mauleón, Ana; Becker, James T.; Tárraga, Lluís

doi:10.1080/13803390802595568

Cited by 61 publications

(54 citation statements)

References 32 publications

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“…The test battery includes common neuropsychological instruments whose utility have been demonstrated in research studies. In addition, we used the 15-Objects Test because it is easy to administer and provides information regarding the overall severity of cognitive impairment and visual perception abilities (Alegret et al, 2009; Alegret et al, 2010). We report here the psychometric characteristics of these tests, as well as the normative ranges and percentile scores for specific age and/or education subgroups.…”

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Normative data of a brief neuropsychological battery for Spanish individuals older than 49

Alegret

Espinosa

Vinyes-Junqué

et al. 2012

Journal of Clinical and Experimental Neuropsychology

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There is an increasing need for standardized assessment of cognition in older patients that is relatively brief, easy to administer, and has normative data adjusted for age and educational attainment. We tested 332 literate, cognitively normal, Spanish persons older than 49 years from the Memory Clinic of Fundació ACE, Institut Català de Neurociències Aplicades (Barcelona, Spain) with measures of cognitive information processing speed, orientation, attention, verbal learning and memory, language, visuoperception, praxis, and executive functions. Several of the tests were affected by age, education, and/or gender, but the language of administration (i.e., Spanish or Catalan) did not affect the test scores. Standardized scores and percentile ranks were calculated for each age and/or education group for use by clinical neuropsychologists.

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confidence: 99%

Normative data of a brief neuropsychological battery for Spanish individuals older than 49

Alegret

Espinosa

Vinyes-Junqué

et al. 2012

Journal of Clinical and Experimental Neuropsychology

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“…MCI patients who later convert to Alzheimer's disease show damage to the MTL (Bell-McGinty et al, 2005), including to the PRC (Mitchell et al, 2002). Interestingly, evidence suggests that MCI and Alzheimer's disease patients show impairments on perceptual tasks, especially when those tasks require complex visuoperceptual processing of objects (e.g., Alegret et al, 2009Alegret et al, , 2010. Alegret et al found that MCI and Alzheimer's disease patients have visuoperceptual deficits that may be more subtle than standard visuoperceptual tests can pick up, yet no study The representational-hierarchical theory.…”

Section: Introductionmentioning

confidence: 99%

Reducing perceptual interference improves visual discrimination in mild cognitive impairment: Implications for a model of perirhinal cortex function

2012

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ABSTRACT:Memory loss resulting from damage to the medial temporal lobes (MTL) is traditionally considered to reflect damage to a dedicated, exclusive memory system. Recent work, however, has suggested that damage to one MTL structure, the perirhinal cortex (PRC), compromises complex object representations that are necessary for both memory and perception. These representations are thought to be critical in shielding against the interference caused by a stream of visually similar input. In this study, we administered a complex object discrimination task to two memory-impaired populations thought to have brain damage that includes the PRC [patients diagnosed with amnestic mild cognitive impairment (MCI), and older adults at risk for MCI], as well as agematched controls. Importantly, we carefully manipulated the level of interference: in the High Interference condition, participants completed a block of consecutive perceptually similar complex object discriminations, whereas in the Low Interference condition, we interspersed perceptually dissimilar objects such that there was less buildup of visual interference. We found that both memory-impaired populations were impaired on the High Interference condition compared with controls, but critically, by reducing the degree of perceptual interference, we were largely able to improve their performance. These findings, when taken together with convergent evidence from animals with selective PRC lesions and amnesic patients with focal damage to the PRC, provide support for a representational-hierarchical model of PRC function and suggest that memory loss following PRC damage may reflect a heightened vulnerability to perceptual interference. V

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“…None of the patients exhibited significant global-related activation within the borders of the TPA region. Without correction for multiple comparisons (p B 0.05 uncorrected) global-related cortical activation was observed in one patient within a parietal region located laterally and anterior to the known TPA (62, 37,34). In one patient, there was no global-or local-related activation, while for the other three patients, activity in the temporoparietal area was greater when attending the local versus the global attributes of the Navon letters.…”

Section: Cortical Activation Corresponds To the Behavioral Deficits Smentioning

confidence: 97%

“…Compared with adult norms, patients had lower results on the Hooper test (9.5 ± 7.58 items were recognized vs. adult norms of 15.75 ± 5.89 [36]); the Gollin visual closure test (3.29 ± 1.44 attributes needed to identify the object vs. average adult norms of 1.95 ± 0.62 [16]); and the ''15 Object Test'' of overlapping figures (5.71 ± 4.16 different items were recognized in a tangled image vs. average adult norms of 13.82 ± 1.08 [37]). In this test, patients tended to focus on a local attribute resulting in misidentification of the entire object (see example in Fig.…”

Section: Routine Visual Functions Revealed Impaired Peripheral Visualmentioning

confidence: 99%

Functional neural substrates of posterior cortical atrophy patients

2015

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Posterior cortical atrophy (PCA) is a neurodegenerative syndrome in which the most pronounced pathologic involvement is in the occipito-parietal visual regions. Herein, we aimed to better define the cortical reflection of this unique syndrome using a thorough battery of behavioral and functional MRI (fMRI) tests. Eight PCA patients underwent extensive testing to map their visual deficits. Assessments included visual functions associated with lower and higher components of the cortical hierarchy, as well as dorsal- and ventral-related cortical functions. fMRI was performed on five patients to examine the neuronal substrate of their visual functions. The PCA patient cohort exhibited stereopsis, saccadic eye movements and higher dorsal stream-related functional impairments, including simultant perception, image orientation, figure-from-ground segregation, closure and spatial orientation. In accordance with the behavioral findings, fMRI revealed intact activation in the ventral visual regions of face and object perception while more dorsal aspects of perception, including motion and gestalt perception, revealed impaired patterns of activity. In most of the patients, there was a lack of activity in the word form area, which is known to be linked to reading disorders. Finally, there was evidence of reduced cortical representation of the peripheral visual field, corresponding to the behaviorally assessed peripheral visual deficit. The findings are discussed in the context of networks extending from parietal regions, which mediate navigationally related processing, visually guided actions, eye movement control and working memory, suggesting that damage to these networks might explain the wide range of deficits in PCA patients.

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Detection of visuoperceptual deficits in preclinical and mild Alzheimer's disease

Cited by 61 publications

References 32 publications

Normative data of a brief neuropsychological battery for Spanish individuals older than 49

Normative data of a brief neuropsychological battery for Spanish individuals older than 49

Reducing perceptual interference improves visual discrimination in mild cognitive impairment: Implications for a model of perirhinal cortex function

Functional neural substrates of posterior cortical atrophy patients

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