Anarithmetia is also know as primary acalculia and is a basic inability to perform computations. 

It is important to recognize that it is distinct from secondary acalculia (aphasic, alexic, agraphic, frontal and spatial). 

Some patients preserve some parts of their original numerical knowledge but still fail in quantity comparisons and simple arithmetic calculations in both oral and written forms (Dehaene and Cohen, 1997).


Observed Symptoms


Suggested Neuroanatomical Damage

It is suspected that the angular gyrus is responsible for the defects seen in primary acalculia.  It is involved in a large number of processes for language and general cognition.

The angular gyrus. (


(Ardila, 2008)


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