Language and calculation within the parietal lobe: a combined cognitive, anatomical and fMRI study

Abstract

We report the case of a patient (ATH) who suered from aphasia, deep dyslexia, and acalculia, following a lesion in her left perisylvian area. She showed a severe impairment in all tasks involving numbers in a verbal format, such as reading aloud, writing to dictation, or responding verbally to questions of numerical knowledge. In contrast, her ability to manipulate nonverbal representations of numbers, i.e., Arabic numerals and quantities, was comparatively well preserved, as evidenced for instance in number comparison or number bisection tasks. This dissociated impairment of verbal and non-verbal numerical abilities entailed a dierential impairment of the four arithmetic operations. ATH performed much better with subtraction and addition, that can be solved on the basis of quantity manipulation, than with multiplication and division problems, that are commonly solved by retrieving stored verbal sequences. The brain lesion aected the classical language areas, but spared a subset of the left inferior parietal lobule that was active during calculation tasks, as demonstrated with functional MRI. Finally, the relative preservation of subtraction versus multiplication may be related to the fact that subtraction activated the intact right parietal lobe, while multiplication activated predominantly left-sided areas. 7

Event-related potentials of single-digit addition, subtraction, and multiplication

“…This hypothesis has been supported by several neuropsychological studies. Researchers have found that patients with lesions in the left perisylvian language region and those with low verbal fluency had more difficulty in single-digit multiplication than in addition and subtraction (e.g., Cohen, Dehaene, Chochon, Lehéricy, & Naccache, 2000;Dehaene & Cohen, 1997;Delazer & Benke, 1997;Lemer, Dehaene, Spelke, & Cohen, 2003;Pesenti, Seron, & van der Linden, 1994;van Harskamp, Rudge, & Cipolotti, 2002.…”

Performance of a Brazilian population in the EC 301 calculation and number processing battery: a pilot study

“…however, broad cortical injuries that also involve regions proximal to the left temporal cortex, left and right parietal and frontal lobe, are susceptible to conduct concomitant language disorders and numerical and calculating processing [13][14][15][16] .…”

Understanding economical outcomes with the mental number line

“…Authors reported that first-order and higher-order quantifiers both recruit right inferior parietal cortex, suggesting that a numerosity component contributes to quantifier comprehension. In fact, parietal activation was also widely reported in subjects asked to perform a simple number processing tasks [20,21,22,23,24] or arithmetic tasks [ 11,25,26].…”