Abstract: Objective To investigate errors and mechanism of acalculia in patients with brain injury.Methods Forty patients with brain injury and forty-eight normal adults who were matched in age and years of education were tested with EC301 standardized battery. Patients were divided into the left-brain damaged (LBD) group (n=20), right-brain damaged (RBD) group (n=9) and bilateral brain damaged (BBD) group (n=11). The data of all subjects were statistical analyzed.Results Both total scores and scores of 27 out of 31 items were remarkable lower in patients than those in the normal control group ( P<0.05). The total scores and items' scores for number sequences, numerical transcodings were significantly lower in LBD group than those in RBD group ( P<0.05). Total scores and each items' score did not significantly differ between BBD group and LBD group, or between BBD group and RBD group ( P>0.05).Conclusion The abilities of number processing and calculation are impaired in patients with brain injury. There is either association or dissociation in terms of performance of acalculia and aphasia in LBD patients. Visuospatial impairment is related to performance of acalculia in RBD patients.

Key words: brain injury, acalculia, standardized tests, EC301 test, brain mechanism