A Dissociation of Number Meanings

We report a study of a patient with selectively preserved sequence meaning of numbers, but impaired access to cardinal number meaning. This limited understanding of number meaning was associated with a severe impairment in calculation tasks, with the inability to apply arithmetic principles and with an inverse distance effect in a number comparison task. In the remission process, better numerical understanding was reflected by better arithmetical competence and a normal distance effect in number comparison. The dissociation of different aspects of number meaning and the gradual development of arithmetical skills is well known in developmental psychology. The present case study suggests that a similar pattern can occur after cerebral lesions.