Reading Test Predicts Pre-Dementia IQ
Test Helps Determine Toll of Alzheimer's and Other Forms of Dementia
April 12, 2004 -- A simple reading test that involves pronouncing 50 unusual English words can help measure the toll that Alzheimer's and other forms of dementia take on the mind.
A new study shows scores on the National Adult Reading Test (NART) do not differ between people with and without dementia, and the test still serves as an accurate predictor of pre-dementia intelligence.
Diagnosing Alzheimer's disease and other forms of dementia is often difficult without knowing the person's previous mental abilities. But researchers say NART provides such a measure of pre-dementia intelligence, despite recent concerns raised about validity of the test.
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Reading Test Measures Pre-Dementia Intelligence
The NART assesses the pronunciation of 50 English words that do not follow normal speech patterns, such as "ache" and "thyme."
Since the test was introduced in 1982, it has frequently been used to estimate pre-dementia mental abilities in people with Alzheimer's disease because these pronunciation abilities are unaffected by dementia and closely related to earlier intelligence.
But some recent studies have suggested that mild to moderate dementia may reduce NART scores and have questioned whether the test is an accurate indicator of pre-disease intelligence.
In the study, published in the April issue of Neurology, researchers looked at the relationship between NART scores at about age 80 and childhood intelligence in adults with and without mild to moderate dementia.
The study showed adults with dementia who scored lower on the reading test also had lower IQ (intelligence quotient) scores at age 11. Researchers say this is consistent with previous studies linking lower childhood IQ to dementia in old age.
But when researchers took into account childhood IQ scores, they found no overall difference in NART scores between the adults with and without dementia.
They found there was a consistent relationship between childhood intelligence and NART performance, which validates the reading test as a predictor of pre-dementia intelligence in people with mild to moderate dementia.