Improvement in NART word reading in demented and normal older persons using the Cambridge Contextual Reading Test.

A test that assesses ability to pronounce correctly a list of irregular words (NART) has become widely used to estimate IQ particularly in elderly and demented subjects. This estimate relies on the assumption that words that are not pronounced correctly were not previously in the subject's vocabulary. This assumption was questioned by the results of a community study showing that older adults commonly mispronounced even simple NART words that were almost certainly in their vocabulary. The present study investigated the extent to which putting NART words into sentences facilitated correct pronunciation. Both normal and demented subjects substantially improved their performance when the words were seen in context. The improvement was most marked for demented subjects and for poor or average readers as compared with skilled readers. Since irregular words can only be pronounced correctly if they are in the individual's vocabulary, it appears that the NART underestimates reading ability and, hence, underestimates premorbid IQ in certain groups. We conclude that the Cambridge Contextual Reading Test (CCRT) provides a more accurate estimate of reading ability and IQ in elderly and demented subjects.