Arithmetic in the adult deaf signing brain

Abstract

We have previously shown that deaf signers recruit partially different brain regions during simple arithmetic compared to a group of hearing non-signers, despite similar performance. Specifically, hearing individuals show more widespread activation in brain areas that have been related to the verbal system of numerical processing, i.e., the left angular and inferior frontal gyrus, whereas deaf individuals engaged brain areas that have been related to the quantity system of numerical processing, i.e., the right horizontal intraparietal sulcus. This indicates that compared to hearing non-signers, deaf signers can successfully make use of processes located in partially different brain areas during simple arithmetic. In this study, which is a conceptual replication and extension of the above-presented study, the main aim is to understand similarities and differences in neural correlates supporting arithmetic in deaf compared to hearing individuals. The primary objective is to investigate the role of the right horizontal intraparietal gyrus, the left inferior frontal gyrus, the hippocampus, and the left angular gyrus during simple and difficult arithmetic and how these regions are connected to each other. A second objective is to explore what other brain regions support arithmetic in deaf signers. Up to 34 adult deaf signers and the same amount of hearing non-signers will be enrolled in an functional magnetic resonance imaging study that will include simple and difficult subtraction and multiplication. Brain imaging data will be analyzed using whole-brain analysis, region of interest analysis and connectivity analysis. This is the first study to investigate neural underpinnings of arithmetic of different difficulties in deaf individuals. K E Y W O R D Sarithmetic, deafness, functional magnetic resonance imaging, RRID:SCR_009550, sign language

Different Language Modalities Yet Similar Cognitive Processes in Arithmetic Fact Retrieval

“…These have shown to be solved through different procedures [ 41 ], rely on distinct brain networks [ 26 , 28 ] and modulate ERP components differently [ 23 , 25 ]. So far, one study investigated language modality and arithmetic processing using the fMRI [ 42 ]. Our study is unique as it is the first to investigate the impact of language modality on the time course of arithmetic processing.…”

Deafness and early language deprivation influence arithmetic performances

“…While Andin et al (2019) failed to find behavioural group differences in reaction time and accuracy on their arithmetic task, they nevertheless highlighted differences in the neural networks deaf signers and hearing non-signers engage to calculate (but see Andin et al, 2022;Berteletti et al, 2022). Whereas language related brain regions in the left cerebral hemisphere are usually recruited for arithmetic fact retrieval (Dehaene et al, 2003), stronger activation of the right horizontal intraparietal sulcus was found in deaf signers compared to hearing non-signers.…”

“…It is finally worth mentioning that only single-digit operations were included in this study. This level of arithmetic reasoning might have not been sufficient enough to highlight group differences in adults ( Andin et al, 2022 ).…”

“…Mixed conclusions can also be found at the brain level. While an fMRI study showed that the right horizontal intraparietal sulcus was more activated in deaf signers as compared to hearing during multiplication operations ( Andin et al, 2019 ), more recent studies ( Andin et al, 2022 ; Berteletti et al, 2022 ) highlighted a comparable dissociation between the brain networks supporting multiplication and subtraction in deaf and hearing participants. There is therefore an urgent need to better characterise the impact deafness and its related language experience may have on arithmetic processing.…”

Numerical Magnitude Processing in Deaf Adolescents and Its Contribution to Arithmetical Ability

“…Mathematical knowledge and ability play an important role in the successes of our social life (Ritchie and Bates, 2013), but most deaf individuals have some difficulty in acquisition of arithmetical skills even if they have the approximately same level of nonverbal intelligence as hearing peers (Braden, 1994;Moreno, 2000). Many studies have shown the close association between numerical magnitude processing and mathematical ability (LeFevre et al, 2010;De Smedt et al, 2013;Sasanguie et al, 2013;Fazio et al, 2014;Linsen et al, 2015), although few studies on the arithmetical abilities of deaf individuals (Masataka, 2006;Andin et al, 2014Andin et al, , 2020. It has been found in many studies that the poorer performance of deaf individuals in mathematics has generally been associated with their reduced language abilities (Kelly and Gaustad, 2007;Wu et al, 2013;Huber et al, 2014;Vitova et al, 2014).…”