Bringing words back to mind - improving word production in semantic dementia

Patients with semantic dementia (SD) have significant impairments in naming and comprehension, but demonstrate relatively intact attention, everyday memory, and visuospatial skills. Given these preserved skills, attempts have been made to help re-build vocabulary in SD patients, with promising results. Such reports, however, are generally based upon only one or two cases and have employed variable retraining methods. It is thus unclear which elements of practice are crucial to success. Over two studies, we assessed four patients undergoing a word training program, who ranged in severity from mild to severe impairments to semantic knowledge. All four participants showed significant improvements in their ability to name trained items, with no changes in untrained items over the same time period. Improvements were evident within 3weeks of practice, and could be established from a simple, repetitive practice of word-picture pairing, carried out at the participant's home. Strong effect sizes of the treatment were found in patients with severe deficits. Maintenance of learning was observed on some follow-up assessments, although continued practice is likely to be needed to sustain naming performance. Incorporating generation tasks into the practice may be assistive, but was not essential to success. These data support the utility of implementing simple home-practice programs even for patients with significant language deficits.