Neuropsychological asymmetry in Alzheimer's disease: Verbal versus visuoconstructional deficits across stages of dementia

Abstract

The incidence of clinically apparent asymmetric profiles of neuropsychological deficits in Alzheimer's disease (AD) patients similar to those reported in the PET literature is currently unclear. This study investigated lateral neuropsychological asymmetry using principal component factor analysis in a sample of 153 patients diagnosed with probable AD. Using factor scores, patients were classified into groups exhibiting asymmetric or symmetric profiles of neuropsychological deficits. In the analysis of lateral asymmetry, 27.5% of patients were classified as asymmetric (10% verbally and 17% visuospatially). Consistent with reports of continued asymmetry beyond the mild dementia stage, asymmetry was exhibited in the mild, moderate, and severely demented groups. These findings of neuropsychological asymmetry across stages of dementia are consistent with the picture of significant neuropsychological heterogeneity in AD that has been emerging in the decade. (JINS, 1997, 3, 420–427.)

The emergence of cognitive discrepancies in preclinical Alzheimer's disease: A six-year case study

“…Several of our previous studies examining cognitive discrepancies in older adults have shown that only 10–20% of older adults (over age 65) who do not have an increased genetic risk for AD (ApoE-e4 allele) show a greater than 1 SD discrepancy between verbal/spatial tasks or complex/basic-level tasks. In contrast, 40–55% of those with increased ApoE-e4 genetic risk had large discrepancies (Houston et al, 2005; Jacobson et al, 2005a,b; Wetter et al, 2005), a ratio that is consistent with other studies of AD subjects with asymmetric cognitive functioning (Massman & Doody, 1996; Strite et al, 1997). A significant caveat to the use of cognitive discrepancies is the possibility of premorbid asymmetries in individual examinees.…”

“…We have suggested that inconsistent findings in the search for preclinical cognitive markers could reflect the use of central-tendency analyses of single test scores that were not sensitive to the presence of subgroups within the larger, at-risk elderly group. For example, both AD and Pre-AD subgroups have been identified with disproportionate impairment in verbal relative to spatial skills (or vice versa) (Albert, Duffy, & McAnulty, 1990; Demadura, Delis, Jacobson, & Salmon, 2001; Finton et al, 2003; Martin, 1990; Massman & Doody, 1996; Strite, Massman, Cooke, & Doody, 1997). It follows that cognitive-discrepancy analyses contrasting two domains may be superior to central-tendency analyses of each task individually for identifying asymmetric deficits, particularly in Pre-AD.…”

The Influence of Handedness on the Clinical Presentation and Neuropsychology of Alzheimer Disease

“…Functional neuroimaging may provide a means to test these hypotheses, as neurocognitive asymmetries are common in AD and may have pathophysiological significance. 24 Further studies are necessary to confirm and extend our results. Although we used a large database of patients with AD to identify left-handers, the low prevalence of left-handedness in general, which may be compounded in AD, 1 still resulted in a small number of lefthanded subjects.…”

Visuospatial Memory in Healthy Elderly, AD and MCI: A Review

“…For example, many researchers use constructional tasks that require participants to copy or to remember complex figures such as the Rey-Osterrieth test [4,[111][112][113][114][115], the most used in the literature. Similarly, the Block Construction from the Performance subtests of the Wechsler Adult Intelligence Scale-Revised [116,117] requires to arrange painted wooden blocks in order to copy a design formed by the examiner or shown on a diagram. Both tests make demands on several cognitive components, including planning and praxis, as well as visuospatial abilities; this complexity does not allow to separate the relative contribution of visuospatial and executive components.…”