Is math lateralised on the same side as language? Right hemisphere aphasia and mathematical abilities

• Published in: Neuroscience letters Vol. 406; no. 3; pp. 285 - 288
• Main Authors: Semenza, Carlo, Delazer, Margarete, Bertella, Laura, Granà, Alessia, Mori, Ileana, Conti, Fabio M., Pignatti, Riccardo, Bartha, Lisa, Domahs, Frank, Benke, Thomas, Mauro, Alessandro
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 09.10.2006; Elsevier
• Subjects: Acalculia; Aphasia - physiopathology; Biological and medical sciences; Crossed aphasia; Disorders of higher nervous function. Focal brain diseases. Central vestibular syndrome and deafness. Brain stem syndromes; Female; Functional Laterality - physiology; Fundamental and applied biological sciences. Psychology; Humans; Language; Male; Math abilities; Mathematics; Medical sciences; Nervous system (semeiology, syndromes); Neurology; Neuropsychological Tests - statistics & numerical data; Recursion; Right hemisphere; Vertebrates: nervous system and sense organs; Math abilities; Right hemisphere; Acalculia; Recursion; Crossed aphasia; Nervous system diseases; Mathematics; Language disorder; Cerebral disorder; Communication disorder; Language; Cerebral hemisphere; Central nervous system disease; Aphasia; Neurological disorder
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2006.07.063

The main purpose of the present study was to learn how mathematical abilities are located and develop in the brain with respect to language. Mathematical abilities were assessed in six right-handed patients affected by aphasia following a lesion to their non-dominant hemisphere ( crossed aphasia) and in two left-handed aphasics with a right-sided lesion. Acalculia, although in different degrees, was found in all cases. The type of acalculia depended on the type of aphasia, following patterns that have been previously observed in the most common aphasias resulting from left hemisphere lesions. No sign of right hemisphere or spatial acalculia (acalculia in left lateralised right-handed subjects) was detected. These results suggest that, as a rule, language and calculation share the same hemisphere. A primitive computational mechanism capable of recursion may be the precursor of both functions.