The number processing and calculation system: evidence from cognitive neuropsychology.
INTRODUCTION
Cognitive neuropsychology focuses on the concepts of dissociation and double dissociation. The performance of number processing and calculation tasks by patients with acquired brain injury can be used to characterise the way in which the healthy cognitive system manipulates number symbols and quantities. The objective of this study is to determine the components of the numerical processing and calculation system.


METHODS
Participants consisted of 6 patients with acquired brain injuries in different cerebral localisations. We used Batería de evaluación del procesamiento numérico y el cálculo, a battery assessing number processing and calculation. Data was analysed using the difference in proportions test.


RESULTS
Quantitative numerical knowledge is independent from number transcoding, qualitative numerical knowledge, and calculation. Recodification is independent from qualitative numerical knowledge and calculation. Quantitative numerical knowledge and calculation are also independent functions.


CONCLUSIONS
The number processing and calculation system comprises at least 4 components that operate independently: quantitative numerical knowledge, number transcoding, qualitative numerical knowledge, and calculation. Therefore, each one may be damaged selectively without affecting the functioning of another. According to the main models of number processing and calculation, each component has different characteristics and cerebral localisations.
['Salguero-Alcañiz|M P|MP|', 'Alameda-Bailén|J R|JR|']
D000328:Adult D000368:Aged D001930:Brain Injuries D003071:Cognition D005260:Female D006801:Humans D008297:Male D055641:Mathematical Concepts D008875:Middle Aged D009483:Neuropsychological Tests D009484:Neuropsychology
Number processing Calculation Cognitive neuropsychology Double dissociation Brain injury Cálculo Acalculia Daño cerebral Doble disociación Neuropsicología cognitiva Procesamiento numérico.