ABSTRACT
In his excellent book, The Executive Brain, Goldberg tells us that the brain’s chief executive is the frontal lobes. This is so often the area damaged after traumatic brain injury (TBI), and so often the cause of bewilderment to relatives of the survivors of TBI, not to mention the frustration of rehabilitation staff trying to remediate executive deficits.We have known formany years that frontal lobe damage can lead to devastating social consequences, one of the earliest case descriptions being that of the famous Phineas Gage (Harlow, 1868). Although Gage survived after an iron rod had been blown through his frontal lobes in a dynamiting accident, he became a changed character who suffered dire consequences, many of which are described in scholarly detail by Macmillan (2000). Treatment for damage to the frontal lobes has continued to develop since those early attempts to come to terms with such a disabling condition, andmuch of this treatment has benefited by a growth in understanding among scientists and researchers, some of whom have built their own models to explain a number of its complexities. Neuropsychologists have drawn help from these models of executive functioning and brain-behavior relationships and it is the aim of this chapter to focus on those models that seem to be most relevant to neuropsychological rehabilitation. A model is a representation that can help us understand and predict related
phenomena. Models range from simple analogies such as that of the faulty switch to explain distractibility, through to complex computer models to explain how
damaged systems learn new information. In rehabilitation, models are useful for facilitating thinking about assessment and treatment, for explaining deficits to therapists, relatives and patients, and for enabling us to conceptualize outcomes. There are several models that can guide our choice of rehabilitation strategy and among these perhaps the three most relevant for understanding deficits of executive functioning are (a) the Working Memory Model (WM; Baddeley, 1986; Baddeley & Hitch, 1974); (b) the Supervisory Attentional System Model (SAS; Norman & Shallice, 1986; Shallice & Burgess, 1996); and (c) Duncan’s Model of Goal Neglect (Duncan, 1986; Duncan, Burgess, & Emslie, 1995). These will be described below and evaluated in terms of their contribution to rehabilitation. Before doing this, however, it is perhaps timely here to remind ourselves that in
rehabilitation we address a wide range of issues and not simply a discrete problem that can be adequately explained by one particular model. Even for patients whose primary presenting disorder can be described as a Dysexecutive Syndrome, there will be other issues such as anxiety, stress, social and work related matters that must be addressed if rehabilitation is to improve functioning in everyday life. Consequently, we need to draw on a wide range of models including those that involve learning, behavior and emotion. Drawing upon a synthesis of several models is probably the best way to accomplish optimum effectiveness in rehabilitation and, in an attempt to achieve this goal, Wilson (2002) combined several current models to build an overarching framework of models to inform the complex everyday problems faced by survivors of brain injury, many of whom will experience executive impairments. A brief account of this broad and inclusive structure will therefore be offered in conclusion to this chapter.
