Explore mood outcome using a shortened version of the FAST communication screening tool

Previous analysis from Section 3.3.3 suggested that the FAST subscales of Reading and Writing may have less influence on mood outcome for those engaging in MI. In order to explore the impact of the remaining subscales on mood outcome, we will use the alternative FAST scoring system; the ‘mini-FAST’.

Aim

To explore communication ability and mood change at three-months using the shortened version of the FAST (Mini-FAST).

Method

The mini-FAST was created by removing Reading and Writing subscales from the overall score, as suggested in the original FAST study (Enderby et al. 1987). This scoring system creates a total FAST score by combining scores from the remaining subscales; Comprehension A, Comprehension B, Expression A and Expression B. Using this scoring system, participants can score a maximum of 20. Adjusted cut-off points defining abnormal or normal communication have been suggested, which are again stratified by age. These cut off points are 17 (age 20-60), 16 (age 61-70) or 15 (age 71+).

Analysis

Logistic regression analysis was performed to explore the impact of the Mini-FAST total score, as well as individual Mini-FAST subscale scores on mood at three-months for all participants.

Mood at three-months was the outcome variable, with age, sex, location, brain injury severity, mood at baseline, treatment group, communication subscale scores (comprehension a and b,

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expression a and b) inputted as explanatory variables. In addition, the interaction between treatment group and communication subscales scores was inputted as explanatory variables.

Communication subscales and their interaction with treatment group were input individually.

Interactions alone were interpreted using a 10% significance level.

Results

Using the Mini-FAST with alternative cut-points, fewer participants are classified as having abnormal communication (n=93), compared with the main FAST classifications (n=135). With the FAST communication subscales reduced to include only Comprehension A and B, and Expression A and B, it was expected that the effect might be stronger and therefore more powerful. However, despite the thought that the Mini-FAST, which measures comprehension and expression components, may be more relevant and therefore potentially more sensitive to the effectiveness of a talk-based therapy, no significant result was discovered. The logistic regression indicated that there was no longer a significant impact on the interaction of communication and MI on mood at three-months (p=0.47, OR 1.49, 95% CI 0.51 to 4.34 compared to the original FAST regression result of p=.07, OR 2.42 using a 10% significance level, CI 0.93 to 6.32). The comparison of the two results indicates that the odds ratio has reduced when the mini-FAST was used, therefore the result changed from significant to non-significant.

The individual subscales of the Mini-FAST were examined to explore whether mood outcomes at three-months could be accounted for by the subscales. However, no individual subscale could significantly predict the mood outcome at three-months as is shown below in Table 3.7.

Table 3.7: Logistic regression result for the Mini-FAST subscales

B p OR (CI 95%)

Comprehension A 0.01 0.97 1.01 (0.67-1.52)

Comprehension B -.12 0.36 0.83 (0.55-1.24)

Expression A 0.03 0.92 1.03 (0.65-1.61)

Expression B -.23 0.28 0.80 (0.53-1.20)

B=beta value, p=level of significance, OR= Odds Ratio, CI=Confidence Interval

In this analysis, using the Mini-FAST, communication no longer has a significant interaction with mood at three-months for those participating in MI, whereas in the main FAST it was identified that those with communication problems who participated in MI were more likely to have a reduced prevalence of low mood than those receiving usual care. Using the Mini-FAST although all participants benefit from MI, the difference between groups, particularly the

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difference between those with abnormal communication and normal communication is less prominent than when the full FAST was used. These results are displayed below in Table 3.8.

Table 3.8: Mini-FAST mood outcomes at three-months for communication groups and treatment groups

Abnormal Communication Normal Communication

MI Usual Care MI Usual Care

Poor outcome 52.3% n=23 65.3% n=32 53.5% n=76 58.9% n=83 Good outcome 47.7% n=21 34.7% n=17 46.5% n=66 41.1% n=58 FAST=Frenchay Aphasia Screening Test, ‘Abnormal communication’, ≤27 if under 59 or ≤25 if aged 60 and over. Scores over these cut-points indicate ‘normal communication’, ‘Good mood’ <5, ‘Poor mood’

≥5. MI=Motivational Interviewing.

The results in Table 3.8 suggest that when using the Mini-FAST tool to assess communication ability, communication does not have a significant interaction mood at three-months. Using the Mini-FAST, it appears that MI has no significant benefit on participants’ mood at three-months.

Summary

This analysis focused on exploring the use of the shortened FAST scale; the Mini-FAST, in assessing the potential impact of communication ability on mood outcome at three-months.

Due to the assumption that skills of reading and writing may be less relevant to engaging in a motivational interviewing session, it was felt suitable to remove these subscales and focusing the analysis on the remaining four subscales of comprehension and expression. This was not the case. Using the Mini-FAST, patients showed a benefit of MI, however the strength of this difference was smaller than when using the full FAST.

There are several explanations for this; it may be that the reading and writing subscales were skewing the results; it may be that there is no significant interaction with comprehension and expression elements. However, there is a lack of validation of the shortened version of the FAST tool, so until further validation studies are undertaken we are unsure of its psychometric properties and thus the degree to which it accurately identifies patients to have language difficulties. The mini-FAST may lack the sensitivity to detect changes which the full FAST may account for, therefore, this result must be interpreted with caution.

The lack of significant result may have been due to the smaller number of participants falling into the category of abnormal communication, the analysis was not powerful enough to detect a significant effect.

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Analysis using the Mini-FAST indicated no interaction of communication with mood; the mini-FAST may be less suitable due to its lack of validation. However, using the well validated full FAST in the original analysis detected a significant interaction. Yet it is unknown whether there are particular aspects of mood which interact with communication. The next analysis will focus on the measure of mood used in the previous MI trial, the GHQ-28.

3.3.5. Explore patterns in scoring of mood subscales of the GHQ-28 for those with