Cognitive Estimation Task: Sensitivity and specificity to frontal lobe lesions

1. Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK
2. Department of Psychology, University of Edinburgh, Edinburgh, UK
3. Department of Neuropsychology, National Hospital for Neurology and Neurosurgery, London, UK
4. Institute of Cognitive Neuroscience, University College London, UK
5. International School for Advanced Studies (SISSA-ISAS), Trieste, Italy
6. Institute of Neurology, UCL, London, UK
7. Dipartimento di Scienze Psicologiche, Pedagogiche e della Formazione, Università degli Studi di Palermo, Palermo, Italy

The Cognitive Estimation Test (CET: Shallice & Evans, 1978) is widely used in clinical and research settings to assess the ability to produce reasonable estimates to items that individuals would not know the exact answer to (e.g., “How fast do race horses run?”). Successful CET performance is considered to rely upon processes such as reasoning, the development and application of appropriate strategies, response plausibility checking as well as general knowledge and numeracy. Despite its use clinically to assess frontal executive dysfunction, it remains unknown whether the CET is sensitive and specific to frontal lobe lesions. Thirty-eight patients with focal, unilateral frontal lobe lesions, 22 patients with focal, unilateral nonfrontal lesions and 39 healthy controls were assessed on the CET-A and CET-B (MacPherson et al., 2014). We investigated their overall performance and conducted an error analysis in terms of estimate bizarreness. We found that frontal patients’ performance was impaired compared to healthy controls on both CET-A and CET-B demonstrating that CET-A and CET-B are sensitive to frontal lobe damage. However, frontal patients only generated significantly poorer estimates than posterior patients on CET-A, suggesting that only CET-A is specific to frontal lobe damage. In addition, while extreme and very extreme responses were sensitive to frontal lobe damage, only very extreme responses were specific. These findings suggest that only CET-A is suitable for assessing frontal-executive impairment in clinical practice and research.

References

MacPherson, S.E., Wagner, G.P., Murphy, P., Bozzali, M., Cipolotti, L., & Shallice, T. (2014). Bringing the Cognitive Estimation Task into the 21st Century: Normative Data on Two New Parallel Forms. PLoS One, 9(3), e92554.

Shallice, T. & Evans, M.E. (1978). The involvement of the frontal lobes in cognitive estimation. Cortex, 14, 294-303.