Non-interpersonal planning and multitasking measures

Attempts to design real-life-type planning and multitasking measures are considered separately below. While multitasking measures are thought to include planning components, they are also thought to rely on additional processes as described below.

3.1.2.3.1 Planning

There have been some attempts to develop more ecologically valid planning measures. One o f these described a financial planning task (Goel, Grafman, Tajik, Sheldon & Danto, 1997) in which the performance o f ten participants with brain lesions including areas o f the frontal lobe was compared with that o f ten age- and education-matched healthy volunteers. Participants were asked to help a fictional couple to achieve four goals. These were all associated with their finances, but had different time-frames ranging from balancing their budget in the immediate term, to planning to have enough money to retire in 35 years. Participants were asked to plan out loud, and all their responses were recorded, and later coded, using a complex system. The authors argued that the anterior group did not have one ‘planning’ impairment, but instead showed a range o f deficits including structuring the problem, allocating their time appropriately across the demands o f the task, judging when they had achieved their goals, and looking beyond the immediate information o f the task in order to apply their real-world experience. They conceptualised the difficulties in terms o f a theory o f ‘structured event complexes’ (Grafman, 1995). In essence, they argued that the further away the fruition o f a plan is in time, the more difficult the planning will be for patients with frontal lobe lesions because the hypothetical future situation will come to differ more and more from their current situation, which will make it more difficult for the patient to retrieve information to the plan. This bears similarities with other theories regarding the role o f the frontal lobes in novel situations (e.g. Shallice & Burgess, 1993). Goel et al argue that the conceptual difference between these theoretical viewpoints is whether memory traces are thought to be damaged (Goel et al, 1997), or the executive control processes, as proposed in the Shallice and Burgess model.

The same authors reported on a single case study, examining a patient’s planning ability in a hypothetical problem that was similar to those he would have encountered in his previous profession as an architect (Goel & Grafman, 2000). The patient showed a range o f marked deficits in his planning ability. O f note is that his knowledge o f the task, based on his experience, was intact, but he was unable to apply it efficiently to the task demands. Thus, like EVR, he showed a

dissociation between having knowledge and being able to apply it. His deficit was conceptualised primarily in terms of his inability to cope with the ill-structured nature o f the task. This was manifested in an excessively long period o f planning time before he was able to begin solving the problem, and an erratic approach to the various elements o f the task, which he was then unable to develop effectively.

Another test o f planning that was designed to have greater ecological validity was the ‘Virtual Planning Test’ (Miotto & Morris, 1998). This task was presented in the form o f a board game, and required participants to choose a range o f target activities from a set including distractor items. There were time constraints on most o f the activities, and some necessitated other items to be carried out prior to their execution. They tested a group with mixed unilateral and bilateral lesions, and found that, relative to a healthy control group, they chose fewer o f the target items, and were less efficient at selecting the tasks within the time constraints. They argued that the deficits were consistent with a model o f disruption to the supervisory attentional system (Shallice & Burgess, 1993; 1996).

Another study looking at more ecologically valid types o f planning, compared participants on their ability to describe plans verbally and then their ability to carry out their plans (Zalla, Plassiart, Pillon, Grafman & Sirigu, 2001). They noted that some o f the behaviours shown by the participants with frontal lobe lesions during the execution o f their plans, such as failing to fulfil goals, missing out important steps, could not have been picked up by the verbal generation phase, but required the participants to attempt to actually carry out the tasks. This clearly has importance for the development of ecologically valid measures.

3.1.2.3.2 Multitasking

‘M ultitasking’ refers to situations in which a range o f tasks have to be prioritised, planned and carried out within a specified period o f time. Shallice and Burgess (1991) described three patients with frontal lobe lesions, who showed intact performance on most standardised measures in the context o f everyday dysexecutive problems. They described two measures that were designed to be sensitive to these patients’ impairments. The first o f these was termed the ‘Multiple

Errands’ Test, which was carried out in a real-life setting, a shopping precinct, rather than in a laboratory. Participants were requested to carry out a range o f real- life tasks such as buying items from shops, whilst not breaking a set o f rules. The patients performed fewer tasks than the controls, and showed qualitative impairments in terms o f rule breaks and inefficient performance. They also showed impairments on the second specially designed measure, the Six Elements Test (SET), which was intended to be a standardised laboratory analogue o f the Multiple Errands Test. The results were interpreted within the context o f the model of supervisory attentional functions in the frontal lobes (Norman & Shallice, 1986; Shallice, 1988). They argued that the results were consistent with a fractionated system, in which processes such as goal development, forming and monitoring plans, and prospective memory are separate, and they outlined how this accounted for the types o f deficits shown in the patients.

Support for the sensitivity o f the Multiple Errands Test was provided in a case study o f a patient with a unilateral left sided lesion, who also demonstrated a range o f difficulties on the test (Goldstein et al, 1993). Thus, there is some evidence that systematic, formal studies of ‘real-life’ behaviour can demonstrate the nature o f the everyday difficulties shown by these patients. However, this test is clearly limited in terms o f practical application by the length o f time o f administration, practical complexity and qualitative scoring system. By contrast, the Six Elements Test is a possible means o f assessing these difficulties in a standardised setting, and a modified version is included in the BADS (Wilson et al, 1996).

Similar principles to the Six Elements test were employed in a later study, to look further at multitasking (Burgess et al, 2000). The task had a more complex set of rules than that governing the SET, and participants’ ability to make and follow plans was incorporated into the procedure. Patients with lesions to the frontal lobe performed more poorly than control participants. However, the purpose o f the study was to investigate whether lesions to particular areas to the frontal lobe were associated with particular types o f deficits, thus providing evidence for a fractionated system; this was supported. It was argued that there are three factors involved in this task, retrospective memory, planning and prospective memory.

Anterior cingulate lesions were associated with impairments in retrospective memory. Planning was linked with right dorsolateral lesions, and prospective memory impairments with medial left hemisphere lesions, including area 10. The findings that deficits can occur separately in retrospective and prospective memory and planning demonstrates that real-life problem-solving should not be considered to be a unitary concept. Burgess (2000a, 2000b) argues that many o f the everyday deficits seen in people with strategy application disorder are in situations where ‘multitasking’ is required. It is argued that situations involving multitasking share a range o f characteristics, including having a number o f discrete tasks with varying characteristics, which have to be carried out one at a time. Participants have to decide for themselves when they have achieved their goals, and they are given no immediate feedback. By contrast, many highly-structured standardised measures have one type of task, with a clear externally-provided goal, and feedback from an experimenter regarding the quality o f performance. Thus, the challenge is to contribute further to the development o f measures which are more open-ended and less structured than standard measures, and which contain multiple dimensions of problem-solving, in order to enhance knowledge o f the types o f processes which people with frontal lobe lesions find difficult.