Development and Validation of a Model for Estimating Premorbid Verbal Intelligence in the Elderly

Abstract

In a preliminary effort to improve the early diagnosis of dementia, we developed a regression-based method for estimating premorbid intelligence measured by the ability to read irregular words from the American version of the Nelson Adult Reading Test (AMNART). Using errors on the AMNART and years of education, a model for predicting current verbal intelligence (VIQ) was developed in a sample of nondemented elderly. Double cross validation showed that the model had high accuracy and stability in estimating current VIQ in nondemented subjects. The model was then used to estimate premorbid VIQ in mildly demented subjects. Estimated premorbid IQ exceeded current IQ by at least 10 points and did not differ from that of nondemented subjects. Less than 10% of nondemented elderly had discrepancies that were as large. If intellectual decline predicts future functional loss and can be reliably measured using cross-sectional data, the requirement of functional impairment may be an unnecessary barrier to the early diagnosis of dementia.

Does expanded retrieval produce benefits over equal-interval spacing? Explorations of spacing effects in healthy aging and early stage Alzheimer's disease.

“…First, comparing young versus healthy controls, there was a significant Group ϫ Spacing interaction, F(2, 146) ϭ 11.65, MSE ϭ .321, p Ͻ .001, which, as shown in Figure 4, reflected the finding that there was a larger difference in the decrease in the equal-interval condition at retrieval attempt 3 for the healthy older adults compared with the younger adults. In addition, comparing healthy controls versus the DAT group, there also was a reliable Group ϫ Spacing interaction, F(2, 140) ϭ 3.80, MSE ϭ .196, p Ͻ .03, which indicated that there (Wechsler, 1955); AMNART ϭ American Version of the Nelson Adult Reading Test (Grober & Sliwinski, 1991). a Thurstone and Thurstone (1949).…”

“…As expected, there were highly reliable main effects of group, F(2, 100) ϭ 24.54, MSE ϭ .251, p Ͻ .001; spacing, F(2, 200) ϭ 81.84, MSE ϭ .086, p Ͻ .001; and retrieval attempt, F(4, 400) ϭ 143.78, MSE ϭ .022, p Ͻ .001. However, (Wechsler, 1955); AMNART ϭ American Version of the Nelson Adult Reading Test (Grober & Sliwinski, 1991). a Thurstone and Thurstone (1949).…”

Literacy, Cognitive Function, and Health: Results of the LitCog Study

“…On Day 2, patients were administered a cognitive battery to measure processing speed, working memory, inductive reasoning, long-term memory, prospective memory, and verbal ability (see Table 1). [33][34][35][36][37][38][39][40][41][42] Multiple tests were used for each cognitive domain, allowing a latent trait to be extracted. Northwestern University's Institutional Review Board approved the study.…”

Non-treatment-seeking heavy drinkers: Effects of chronic cigarette smoking on brain structure

“…From the LDH, we derived the number of drinks in the week prior to enrolment, and average number of drinks per month in the previous year and over lifetime, number of months of heavy drinking (i.e., total number of months over lifetime in which the participant drank in excess of 100 drinks per month), and cumulative ethanol consumption over lifetime in kilograms (total number of drinks over lifetime × 0.0136 kg ethanol/drink). General verbal intellectual functioning was predicted by the American version of the Nelson Adult Reading Task (AMNART; Grober and Sliwinski, 1991). The neurocognitive implications of chronic smoking in this HD cohort will be reported elsewhere.…”