Numerical deficits in a single case of basal ganglia dysfunction.

The present investigation assesses specific numerical difficulties in a patient (SJ) with basal ganglia (BG) dysfunction. While previous studies on number processing in BG disorders typically tested arithmetic facts by production tasks, the present study uses production, recognition (verification, multiple-choice) and indirect (number-matching) arithmetic tasks. Patient SJ was severely impaired in production and to a lesser extent in verification and multiple-choice tasks. In number-matching, an abnormal latency pattern was found. This study extends previous research by indicating that BG dysfunction may not only affect production processes and sequencing, as was found in previous investigations, but may lead to a breakdown of semantic relationships of arithmetic facts.