Since its publication in 1982, the National Adult Reading Test
(NART; Revised Version, NART–R) has become a widely accepted
method for estimating premorbid levels of intelligence in
neuropsychological research. However, the assumption that
NART/NART–R performance is relatively independent of brain
damage has been increasingly challenged in recent years. In
a number of conditions, including Alzheimer dementia and
Korsakoff's syndrome, studies have indicated a deterioration
in reading ability, leading to an underestimated premorbid IQ.
In a reaction to these studies, some researchers have advocated
the use of demographic variables as a more suitable foundation
for accurately predicting premorbid intelligence. We addressed
this issue by calculating IQ estimates on the basis of
NART/NART–R, demographic variables, and a combination
of the two approaches and by comparing these with current
WAIS/WAIS–R IQ in patients with Korsakoff's syndrome,
Alzheimer dementia, frontal or temporal lobe lesions, and in
healthy controls. Estimated premorbid IQs did not differ across
groups, whether derived from NART/NART–R or demographic
variables. Those based on NART/NART–R demonstrated higher
correlations with current WAIS/WAIS–R IQ in controls and
patients than those derived from demographic variables. An equation
combining NART scores with demographic variables did not
significantly increase the amount of variance in IQ explained
by NART only, either in patients or controls. The data offer
reassurance regarding the continued use of NART as a valid estimate
of premorbid intelligence in a number of conditions.
(JINS, 2002, 8, 847–854.)
Dementia: The Estimation of Premorbid Intelligence Levels Using the New Adult Reading Test
