Too much to count on: Impaired very small numbers in corticobasal degeneration BRAIN AND COGNITION Halpern, C., Clark, R., Moore, P., Cross, K., Grossman, M. 2007; 64 (2): 144-149

Abstract

Patients with corticobasal degeneration (CBD) have calculation impairments. This study examined whether impaired number knowledge depends on verbal mediation. We focused particularly on knowledge of very small numbers, where there is a precise relationship between a cardinality and its number concept, but little hypothesized role for verbal mediation. We evaluated accuracy and reaction time (RT) for matching dot arrays and Arabic numerals involving smaller (2-4) and larger (5-9) cardinalities in non-aphasic patients with CBD (n=16), frontotemporal dementia (FTD; n=23), and healthy controls (n=15). CBD were less accurate and slowed at judging smaller Arabic numeral-dot array stimuli compared to FTD patients and controls. Moreover, only CBD showed longer RTs judging successively larger number-dot array pairs among the smaller cardinalities. Difficulty judging very small numbers is impaired in CBD, suggesting degraded representation of precise number knowledge that does not depend on language functioning.

View details for DOI 10.1016/j.bandc.2007.01.006

View details for Web of Science ID 000248255500004

View details for PubMedID 17397978

View details for PubMedCentralID PMC1986671