Numeracy skills in patients with degenerative disorders and focal brain lesions: A neuropsychological investigation.

Abstract

Objective: To characterize the numerical profile of patients with acquired brain disorders. Method: We investigated numeracy skills in 76 participants—40 healthy controls and 36 patients with neurodegenerative disorders (Alzheimer dementia, frontotemporal dementia, semantic dementia, progressive aphasia) and with focal brain lesions affecting parietal, frontal, and temporal areas as in herpes simplex encephalitis (HSE). All patients were tested with the same comprehensive battery of paper-and-pencil and computerized tasks assessing numerical abilities and calculation. Degenerative and HSE patients also performed nonnumerical semantic tasks. Results: Our results, based on nonparametric group statistics as well as on the analysis of individual patients, and all highly significant, show that: (a) all patients, including those with parietal lesions—a key brain area for numeracy processing—had intact processing of number quantity; (b) patients with impaired semantic knowledge had much better preserved numerical knowledge; and (c) most patients showed impaired calculation skills, with the exception of most semantic dementia and HSE patients. Conclusion: Our results allow us, for the first time, to characterize the numeracy skills in patients with a variety of neurological conditions and to suggest that the pattern of numerical performance can vary considerably across different neurological populations. Moreover, the selective sparing of calculation skills in most semantic dementia and HSE suggest that numerical abilities are an independent component of the semantic system. Finally, our data suggest that, besides the parietal areas, other brain regions might be critical to the understanding and processing of numerical concepts.

Anatomical substrates and neurocognitive predictors of daily numerical abilities in mild cognitive impairment

“…Lack of sufficient variance in the scores of controls might explain this negative result. There is, however, some recently published evidence of significant associations between GM volume and measures of performance on number/arithmetic in the right interparietal sulcus, cuneus, and temporoparietal junction (Cappelletti et al, 2012). Based on this evidence it seems that numerical abilities in MCI patients are associated with regions that are not typically associated with numerical representations.…”

Arithmetic in the Child and Adult Brain

“…However, they use increasingly basic, inflexible strategies to retrieve multiplication 'facts', and in multi-digit calculations they made procedural errors that pointed to a failure to understand the differential weighting of left and right hand columns (Julien, Thompson, Neary, & Snowden, 2008). The findings are noteworthy because they challenge the notion that arithmetic knowledge is a totally separate semantic domain, and instead suggest that anterior lateral temporal cortex, which is known to be impacted in semantic dementia also plays an important role in arithmetic understanding (Cappelletti, Butterworth, & Kopelman, 2012). Paradoxically, although this brain system has not yet been directly examined in neurotypical adults using functional neuroimaging techniques, recent studies (reviewed below) in children point to its differential engagement in relation to different types of strategies used to solve arithmetic problems (Cho, Ryali, Geary, & Menon, 2011).…”

Origins of the brain networks for advanced mathematics in expert mathematicians

“…Only a small part of our arithmetic knowledge, namely the rote memory for arithmetic facts, encoded in linguistic form (16,21). The bulk of number comprehension and even algebraic manipulations can remain preserved in patients with global aphasia or semantic dementia (22)(23)(24). Contrary to intuition, brain-imaging studies of the processing of nested arithmetic expressions show little or no overlap with language areas (25)(26)(27).…”