Acalculia

Acalculia (or acquired dyscalculia) represents the acquired loss of the ability to perform simple arithmetic tasks secondary to CNS pathology. It is not to be confused with developmental dyscalculia, which is a different entity and represents developmental disturbance of computational ability. 

As computational tasks necessitate an orchestrated interplay between visuospatial, verbal and conceptual cognitive functions, dyscalculias can have significantly variable symptoms. Impairments in some patients can, for example, solely affect recognition, or production of numbers, or inability to carry out simple arithmetic tasks despite ample knowledge of the principles of arithmetics ¹. 

Major forms of acalculia:

• primary acalculia (anarithmetria): inability to understand numerical concepts and to perform basic arithmetic tasks
  • often occurs in combination with aphasia, alexia, and agraphia ¹
  • in the eponymous Gerstmann syndrome acalculia co-occurs with agraphia, right-left disorientation, and finger agnosia ² 
• secondary acalculia: impaired computational performance secondary to other cognitive functional damage (memory, language, or visuospatial deficits, etc.)