Estimation of verbal intelligence in an elderly community: a prediction analysis using a shortened NART.

Estimation of premorbid IQ is useful for estimating true cognitive decline in dementia. The National Adult Reading Test-NART (Nelson, 1982)-has been shown to estimate premorbid IQ in hospital patients. NART is potentially of use in epidemiological studies. However, asking community elderly people to read a list of irregular and difficult words can cause distress. This paper explores the possibility of administering only a part of the NART. On the basis of scores on the first half of the test from an elderly rural community sample (N = 316), a regression equation has been developed to predict performance on the second half of the test. It was built using the scores of half the population free from clinical diagnoses and tested on the other half. It was also applied to a demented group and a depressed group from the same population. Total NART scores predicted in this way were highly significantly correlated with the actual NART score for all groups. Recommendations about the use of this shortened test are made.