Number processing after stroke: anatomoclinical correlations in oral and written codes

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurolinguistics

Background:

• Calculation abilities rely on complex cognitive functions.
• Vascular brain lesions can disrupt these functions, leading to calculation deficits.
• Understanding the neural basis of calculation is crucial for diagnosing and treating cognitive impairments.

Purpose of the Study:

• To investigate the impact of chronic single vascular brain lesions on calculation and number-processing abilities.
• To identify specific brain regions, particularly parietal areas, involved in different aspects of calculation.
• To explore the relationship between calculation, language, and other cognitive functions like working memory and attention.

Main Methods:

• A cohort of 49 patients with chronic single vascular brain lesions was assessed.
• A standardized multitask assessment battery (EC301) was employed.
• Additional tasks evaluated language, visuo-perceptive abilities, verbal and spatial working memory, planning, and attention.

Main Results:

• Lesions in parietal areas, especially the left, significantly impair calculation processing.
• Left parietal lesions affect both oral and digital number processing, while right parietal lesions primarily impact digital processing.
• Semantic number representations and rote arithmetical knowledge are also impaired by parietal damage.
• Calculation performance strongly correlates with language abilities, verbal working memory (oral calculation), and visuospatial working memory (written-digit calculation).

Conclusions:

• Parietal areas are critical for calculation, with distinct roles for left and right hemispheres in processing different number formats.
• Language and working memory are closely linked to calculation, but exhibit relative independence.
• Brain lesions reveal a dissociated sensitivity of oral and digital calculation processing, highlighting specific neural substrates.