Abstract
This study was conducted to monitor picture naming longitudinally in a 59-yr.-old Down syndrome man with diagnosed dementia. On the test, the subject was shown a series of 40 pictures, and his task was to speak their names. Correct naming responses were followed by pennies. The test was repeated periodically over the course of 20 mo. The subject initially achieved 100% correct scores and maintained accuracy until the tenth month. Thereafter, his scores declined, gradually at first and then precipitously, until the subject scored less than 30% correct on the final test. Error analysis showed that low scores generally reflected loss of stimulus control by relevant characteristics of the test pictures; control apparently shifted to irrelevant features of the task. The results suggest that naming tests may ultimately prove useful in defining and documenting the nature of deterioration in Down dementia.