Poster F109, Tuesday, March 28, 8:00 – 10:00 am, Pacific Concourse
The National Adult Reading Test and Wechsler Test of Adult Reading as measures of premorbid IQ: Comparison and Restandardisation against the Wechsler Adult Intelligence Scale – Fourth Edition.
Peter Bright1, Ian van der Linde1; 1Anglia Ruskin University, Cambridge
The National Adult Reading Test (NART; Nelson, 1982; NART–R; Nelson & Willison, 1991) and Wechsler Test of Adult Reading (WTAR; Wechsler, 2001) are widely adopted methods for estimating premorbid IQ in neurological patients. However, neither test has been standardised against the most recent revision of the Wechsler Adult Intelligence Scale (WAIS-IV; Wechsler, 2008). Our objective, therefore, was to produce reliable standardised estimates of WAIS-IV IQ from the NART and WTAR. Assessments were conducted on 92 neurologically healthy British participants (mean age 40 years; range 18-70; SD 16.78). Regression equations were extracted from the data and used to produce population estimates of WAIS-IV full-scale IQ (FSIQ) and constituent index scores. Strong NART/WAIS-IV and WTAR/WAIS-IV FSIQ correlations were observed with more moderate correlations observed between NART/WTAR error and WAIS-IV constituent index scores. Combining NART and WTAR data did not improve predictive accuracy. Demographically-based equations provided comparatively inaccurate estimates, and the combination of demographic data with NART/WTAR scores did not provide a more accurate measure of IQ than either test alone. Estimates were markedly discrepant with published WAIS-R/WAIS-III FSIQ estimates at the lower end of the performance distribution, and we therefore advise caution in the use of published WAIS and/or WAIS-R estimates for estimating premorbid WAIS-IV FSIQ, particularly for those with low scores. In conclusion, the present findings indicate that continued use of the NART or WTAR as important clinical tools for estimating premorbid levels of intellectual ability is justified, despite the availability of more recently developed measures.
Topic Area: METHODS: Other