The Brixton Spatial Anticipation Test as a test for executive function: Validity in patient groups and norms for older adults

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INTRODUCTION

Executive functions refer to the ability to respond in an adaptive manner to novel situations and are the basis of many cognitive, emotional, and social skills. Executive functions include volition, planning, purposive action, and effective performance, each of which involves a set of activity-related behaviors (Lezak, Howieson, & Loring, 2004) that can be referred to as "cognitive control." Deficits in executive functions frequently occur after acquired brain injury, particularly after damage to the dorsolateral prefrontal circuit that connects the lateral convexity or the frontal lobe to subcortical structures, such as the dorsolateral portions of the caudate nucleus, and distinct areas of the globus pallidus, substantia nigra, and the thalamus (Cummings, 1995). Decreased executive functioning is also linked to age-related cognitive decline (Brennan, Welsh, & Fisher, 1997), possibly in relation to impairment of (parts of) the supervisory attentional system (SAS) and largely independent of a more general decline in processing speed (Andres & Van der Linden, 2000). Furthermore, impaired executive functioning has been reported in several psychiatric disorders, for example, schizophrenia (Kerns, Nuechterlein, Braver, & Barch, 2008) and major depressive disorder (Channon & Green, 1999).

Several measures have been developed to tap crucial aspects of executive functioning, such as rule detection, concept shifting, and sorting, in clinical populations. Well-known tests that are used in clinical practice are the Wisconsin Card Sorting Test (WCST; Heaton, 1981), the Tower of London (ToL; Shallice, 1982), and the Trail Making Test, Part B (TMT-B; Reitan, 1956). Although frequently used, these tests typically only tap single aspects of executive functioning (e.g., either planning or rule detection) and a patient's performance on one executive function test may thus have little predictive value for performance on another test, let alone in complex real-world situations ("ecological validity"; see also Burgess, Alderman, Evans, Emslie, & Wilson, 1998; Chan, Shum, Toulopoulou, & Chen, 2008; Odhuba, van den Broek, & Johns, 2005). Tests that resemble "real-world" tasks, such as the Behavioural Assessment of the Dysexecutive Syndrome (BADS; Wilson, Alderman, Burgess, Emslie, & Evans, 1996) may help to overcome this issue, but are usually time-consuming as part of a full neuropsychological examination. Accurate and valid assessment of executive functions in clinical populations is also hampered by the paradoxical need to structure...