A regression based approach to estimating premorbid neuropsychological functioning in the older adult population using four tests of executive function
Objective: Build regression equations based on a combination of demographic variables and an estimate of premorbid IQ (National Adult Reading Test) for four tests of executive function: the Trail Making Test (TMT), the Modified Six Elements Test (SET) and the Hayling and Brixton tests. Method: 106 n...
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| Format: | Dissertation |
| Language: | English |
| Published: |
ProQuest Dissertations & Theses
01-01-2007
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| Online Access: | Get full text |
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| Summary: | Objective: Build regression equations based on a combination of demographic variables and an estimate of premorbid IQ (National Adult Reading Test) for four tests of executive function: the Trail Making Test (TMT), the Modified Six Elements Test (SET) and the Hayling and Brixton tests. Method: 106 neurologically stable community-dwelling older adults participated in the study. These volunteers completed all test measures. The data were analysed using descriptive statistics and correlation analysis. Hierarchical regression analysis was used to explore the relationship between potential predictor variables and test scores. Results: As expected, age was a significant predictor of test score on all four tests of executive function. The proportion of variance explained by age varied. For instance, age alone accounted for 40.2% of the variance in performance on the TMT Part B, but only 8.1% of the variance on the SET. The addition of estimated IQ and other demographic variables to the regression analysis significantly improved prediction accuracy of test scores. Conclusion: Advancing age was associated with poorer test performance on all outcome measures (all ps<0.01). Poorer test performance was also associated with fewer years of education, lower educational achievements, lower socio-economic status, and lower estimated IQ. Incorporating such information, the set of equations produced provide clinicians with a practical means of estimating a client’s executive function test performance. Clinicians can assess the abnormality of a client’s executive function test performance by comparing the difference between their predicted and obtained test scores against a table of critical values. An example of how to apply these equations in clinical practice was presented. The findings presented here appear to provide further support for the hypothesis that normal ageing is associated with a decline in frontal executive functioning. |
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