This treatment-effectiveness research study addresses these issues by examining the dose-response relationship for semantically-oriented naming treatment, and identifying cognitive, psycholinguistic and neuroanatomical predictors of treatment success. Study participants (n=60, over a 4-year period) will be recruited nationwide from Veterans enrolled in PIRATE. They will have their naming performance measured prior to PIRATE entry, during each week of treatment, and at program exit/follow-up. A battery of cognitive measures and structural magnetic resonance images of their brains will also be collected prior to treatment. Participants' performance on trained and untrained lexical items and a standardized measure of naming performance will be compared across time intervals to specify the therapy amounts for which maximum treatment benefits are achieved. Their treatment outcomes will also be correlated with specific cognitive test scores and the location and extent of their brain lesions to identify cognitive and neurological markers predictive of positive treatment response. Treatment response will also be compared across participants with different psycholinguistic profiles, to determine which groups of patients show greatest benefit from semantically-oriented naming treatment.