Un giro en los ’70

Another laboratory measure that distinguishes event and time-based PM is the CAMPROMPT (Wilson et al., 2005). The CAMPROMPT is a more up-to-date

98 test battery that is sensitive to individual differences both within clinical and normal populations (Fleming et al., 2008; Groot et al., 2002; Wilson et al., 2005).

It is a standardised neuropsychological test that relates to Einstein and McDaniel’s (1990) paradigm (see Chapter 2). It consists of a total of six PM tasks, three cued by time and three cued by events. Participants are asked to work on some distractor tasks such as word-finder puzzles or a general knowledge quiz for a twenty minute period while they had to remember to perform the PM tasks. The participants are allowed to spontaneously use strategies, such as taking notes, to help them remember. Total scores are generated on both time-based and event-based subscales with higher scores reflecting better PM performance. The validity and reliability of the CAMPROMPT has been documented in a number of studies (i.e., Fleming et al., 2008; Groot et al., 2002; Wilson et al., 2005).

For instance, in a study by Groot, Wilson, Evans and Watson (2002) performance on an earlier version of the CAMPROMPT was found to be significantly poorer for a group of TBI patients in comparison to a control group. Groot et al. (2002) also found that the CAMPROMPT correlated significantly with measures of memory, attention and executive functioning. A later edition of the CAMPROMPT has since been published and is considered a highly valid tool for measuring PM in the TBI population. For example, Fish et al. (2007) used the CAMPROMPT to measure PM deficits in individuals with non-progressive brain injury and Fleming et al. (2008) assessed PM performance in adults with severe TBI using the CAMPROMPT’s time-based and event-based sub-scales as well as the incidence of note-taking. The authors concluded that patients with longer periods of post-traumatic amnesia (PTA) and EF impairment display poorer

99 PM. Additionally, the CAMPROMPT has also been used to measure PM deficits in individuals with bipolar disorder (BD; Lee et al. 2010).

In a more recent study Heffernan et al. (2010a) investigated whether persistent smoking leads to impairments in self-report and objective measures of PM.

Eighteen smokers and 22 non-smokers were assessed on the PRMQ questionnaire and on the CAMPROMPT. After controlling for ecstasy, cannabis and alcohol, results suggested that the two groups did not differ significantly in PM or RM as assessed by the PRMQ. Nevertheless, smokers were worse in terms of total recall on the CAMPROMPT recalling significantly fewer time-based, and event-based elements in comparison to the non- smoking group.

On the whole, these findings suggest that the CAMPROMPT is a more sensitive objective tool in detecting PM deficits than traditional self-report measures and demonstrates the importance of not relying solely on self-report measures, but the need to use laboratory tests to detect PM impairment. Nevertheless, the greatest advantage of the CAMPROMPT is that, as opposed to the RBMT, it is more sensitive in detecting PM problems in non-clinical population.

5.4 Chapter summary

It is evident from the literature that ecstasy/polydrug users are impaired on measures of PM. Most studies in the area have employed self-report measures to capture any possible PM deficits in recreational users of ecstasy (Heffernan et al., 2001a,b; Rodgers et al., 2001;2003; Montgomery and Fisk, 2008; Fisk and

100 Montgomery, 2008). Although self-report measures are found to be reliable in detecting PM difficulties it is possible that self-perceptions might be distorted. For instance, drug users may arrive at the laboratory with the expectation that they will underperform (Cole et al., 2006; Bedi & Redman, 2008). This expectation can affect their responses on self-report measures exaggerating the extent of any deficits present. Also, since the questionnaires assess memory, people experiencing memory impairment might not be able to remember and thus report memory lapses.

Furthermore, self-report measures of PM fail to capture the distinction between time-based and event-based PM tasks (retrieval phase) and concentrate on the storage/retention phase of PM i.e., action to be performed in the short or long-term. Although, objective measures such as the ‘virtual week’ have been employed in recent years to overcome this limitation, they have been rather artificial and contrived. In particular, the ‘virtual week’ paradigm although undoubtedly possessing a PM component, also involves associative learning in which ecstasy users are known to show impairment (Montgomery et al., 2005) making it unclear whether the deficits observed are due to the PM or learning aspects. Consequently, the need to employ more ecologically valid measures to assess PM is essential. In order to address some of these limitations this research will include simple laboratory measures of PM (event and time-based PM tasks as well as short-term and long-term PM tasks) that are designed to be more naturalistic and where the PM component is less obvious to the participant including the CAMPROMPT (see Chapter 7 and 8). Although CAMPROMPT

101 seems to be rather artificial as a laboratory measure, its main advantage is that it’s useful and reliable with non-clinical population as opposed to the RBMT.

As well as the obvious PM impairments in recreational users of ecstasy, neuropsychological evidence suggests that Executive Functions (EF) is also impaired in ecstasy/polydrug users (Fox et al., 2001; Fisk et al., 2004). In view of the potential role of EF in underpinning PM performance, the next chapter will evaluate the impact of the recreational use of ecstasy on measures of executive functioning.

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Chapter 6: Executive dysfunction