Cognitive intervention in semantic dementia: maintaining words over time.

Patients with semantic dementia (SD) can improve their naming ability through cognitive intervention, with good retention 1 month later. Beyond this time, improvements often fade, yet no studies have investigated how to maintain performance. Nine SD patients completed a 2-month word training program and were then monitored over 6 months: firstly for 2 months without training, followed by a further 4 months, where additional training was provided to revise words, if required. All patients improved their naming immediately postintervention (P<0.001). After 2 months without practice, significant declines occurred in 4 patients. To sustain at least 80% of their postintervention performance 6 months later, 4 patients required minimal revision (<10 sessions over the period), 2 required regular weekly or biweekly revision sessions, with the remaining 3 patients requiring no revision sessions. During this period, group results indicated some decline in words that were initially known, but were not trained. Improvements in naming can be sustained in SD patients, with the support of less intense, but ongoing revision. Training words that are still known appears to help prolong memory of these words.