Comparison of NART and Barona demographic equation premorbid IQ estimates in Alzheimer's disease

Abstract

Two methods of estimating premorbid WAIS-R intelligence were compared in matched samples of normal and AD persons. The NART and Barona 1984 demographic equations accurately predicted the IQs of the normal group and overestimated the IQs of the AD subjects. When the AD group was divided into mild and moderately impaired subgroups, the more severely demented subjects displayed lower WAIS-R IQs and NART estimated IQs, revealing that NART performance is sensitive to dementia severity. However, the NART estimated IQs for the mild and moderately impaired AD subgroups were larger than the WAIS-R IQs, suggesting that while the NART is sensitive to dementia severity, it may still provide relevant clinical information.

Cognitive Reserve Is a Determinant of Health-related Quality of Life in Patients With Cirrhosis, Independent of Covert Hepatic Encephalopathy and Model for End-Stage Liver Disease Score

“…14 The Barona index is an optimal method for testing pre-morbid intelligence that tracks subject cognitive performance. 15 Occupations can be broadly categorized as blue collar, white collar and a category comprising of retired/homemaker and disabled persons. The Barona IQ is divided into the verbal IQ (VIQ), performance IQ (PIQ), and the full scale IQ (FSIQ); we used the FSIQ as our measure for cognitive reserve.…”

Estimating Premorbid Intelligence among Older Adults: The Utility of the AMNART

“…This approach can be useful because the data are gained without lengthy or invasive testing and independent of the patient's current cognitive functioning and therefore remain constant throughout the patient's adult life without being affected by any cognitive decline that may occur [2]. The use of demographic variables has been shown in some studies to be a good estimate of premorbid intelligence among healthy controls [3] and has been recommended over other premorbid estimates for those with Alzheimer's disease [4]. Demographic variables have been found in some cases to improve the accuracy of alternative approaches [5].…”

“…The NART appears to be a good estimate for healthy older adults [12] and has been shown to be more resistant to the effects of age than the WAIS Vocabulary subtest [13–15]. Although some researchers have found the NART to be a good premorbid estimate among those with dementia [12, 15–17], others have found that it actually declines in dementia, therefore implying that it is not impervious to the effects of cognitive impairment [4, 18–20]. Similarly, while some researchers recommend that the NART should not be used among all adult populations, particularly those with organic conditions such as schizophrenia, Korsakoff psychosis, or Huntington's disease [13, 21], others have not found any declines related to these conditions [16].…”

Severity of Alzheimer's disease and effect on premorbid measures of intelligence

“…Recent research has questioned whether pronunciation of irregular words genuinely remains unaffected by Alzheimer's Disease (AD). Several studies have found that reading ability becomes compromised with increasing severity in AD (Cockburn, Keene, Hope, & Smith, 2000; Paolo, Tröster, Ryan, & Koller, 1997; Taylor, 1999). These findings raised the possibility that the NART provides an underestimation of premorbid ability in more cognitively impaired individuals.…”