University of Tasmania

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Estimation of premorbid intelligence in traumatic brain injury : NART and AUSNART performance in an Australian sample

posted on 2023-05-27, 20:18 authored by Dean, TA
The National Adult Reading Test (NART: Nelson, 1982; Nelson & Willison, 1991) is the most commonly used method for estimating premorbid intelligence in neuropsychological practice and research. It has been used extensively in dementia research (Brayne & Beardsall, 1990; Nelson & O'Connell, 1978) and to a lesser degree in traumatic brain injury (TBI) research (Crawford, Parker & Besson, 1988a). Recent findings suggest NART scores may be sensitive to TBI (Riley & Simmonds, 2003), although available studies are limited by small, mixed injury severity samples and ill-defined severity criteria and assessment time post-injury. Concerns have also been raised regarding the applicability of the NART for Australians as it was developed with a British sample. The Australian National Adult Reading Test (AUSNART: Hennessey & McKenzie, 1994) was developed to address these concerns; however norms were small and limited to Psychology Undergraduate students. There is no published research examining AUSNART in an Australian TBI population. The aims of the current research were to examine the effects of TBI on NART and AUSNART performance, investigate the influence of demographic variables and compare performance on the two tests. Participants were from a large TBI population study and a longitudinal repeated measures design was implemented. Study 1 examined the NART performance of 194 participants at 1, 6 and 12 months post-injury. A significant reduction in NART error score was observed by 6 months post-injury, indicating NART scores are sensitive to TBI. A highly significant effect of education was also noted, with higher level of education providing protection from NART 'impairment'. Age, socio-economic status (SES) and TBI severity also significantly influenced NART scores. Study 2 examined AUSNART performance of 92 participants and was found to be less sensitive to TBI than NART. There was no significant change in AUSNART performance at 6 months, though a significant reduction in error score was noted by 12 months. Age, severity and SES did not significantly affect AUSNART performance but education remained highly influential. AUSNART produced significantly higher estimates of IQ than NART. Study 3 examined two methods for predicting NART performance following TBI: a Multiple Regression equation using initial NART score and a mean NART change score method based on education and age. Tables are provided for each method to assist clinicians. Overall, the results indicate caution is necessary when using the NART to estimate premorbid IQ in an Australian TBI population. AUSNART may eventually provide a more valid estimate than NART, although larger normative studies are required before it can be used with confidence.


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Copyright 2009 the Author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s) CD-ROM contains appendices. Thesis (DPsych (Clin))--University of Tasmania, 2009. Includes bibliographical references

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