Previous MI Trial

The previous MI trial aimed to explore the impact on mood when MI was provided early stroke. A RCT was carried out in a single-centre with MI beginning within the first month post-stroke.

Four hundred and eleven patients following a stroke were recruited into the study,

participants were aged between 29-97 years old, (age: median 70, interquartile range: 61 to 77 years; 58.4% male). Participants were excluded if they had severe communication or cognitive difficulties; however some patients with mild to moderate communication difficulties were included.

Of the 411 consenting patients, 207 participants were randomised into the control group where participants received care as usual, and 204 participants received MI (as well as care as usual). Patients in the MI arm received up to one hour of MI each week for four weeks.

Measures were taken at baseline and three-months post-stroke.

Patients received a number of measures at baseline. Mood was measured using the General Health Questionnaire (GHQ-28, Goldberg and Hillier 1979) and the Yale single item (Mahoney et al. 1994). Cognition was measured using the Rivermead Behavioural Memory Test (RBMT, Wilson et al. 1989), communication was measured using the Frenchay Aphasia Screening Test (FAST, Enderby et al. 1987), and finally, physical dependence was measured using the Barthel Index (Wade and Collin 1988).

The primary outcome measure in this trial was mood, assessed using the GHQ-28, a 28 item self-administered questionnaire measuring emotional distress. The questionnaire aims to

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assess changes in normal function and detection of newly emerging symptoms of distress. The scale has four subscales; social dysfunction, anxiety and insomnia, somatic symptoms and severe depression. Each subscale has seven items, with a maximum score of seven. The scale measures responses on a four point Likert scale, with responses ranging from the least severe to most severe descriptor. The GHQ score is then calculated by assigning a two point score rating each problem as present or absent, coding a 0 score to those responding 0-1, with a code of 1 for those responding 2-3. This is referred to as the bimodal scoring system (Goldberg and Hillier 1979). Higher scores indicate increasing presence of psychological distress, however in the original RCT (Watkins et al. 2007), the total GHQ-28 score was dichotomised in to low mood (scores of ≥5) or normal mood (scores of <5).

A second measure of mood, the Yale single item (Mahoney et al. 1994) (“Do you often feel sad or depressed?”) was also taken at baseline. This requires patients to respond “yes” or “no”.

Cognition was measured using the Rivermead Behavioural Memory Test (RBMT) (Wilson et al.

1985). The RBMT is a short test of everyday memory problems including recalling a name, date, and details from a newspaper article. In total there are twelve areas which are tested with a point scored for a correct response, therefore allowing a maximum score of 12.

The FAST was used to measure communication. The tool is comprised of four subscales;

Comprehension, Expression, Reading, and Writing. Each subscale can be scored 0-5, with higher scores indicating greater communication ability. The maximum score on the FAST is 30, with participants being classified as having ‘communication difficulties’ (scoring ≤27 if under 59 or ≤25 if aged 60 and over). Patients scoring over these cut-points are classed as having

‘normal communication’.

The FAST is widely used and recognised as having strong psychometric properties which has been demonstrated in patients with aphasia (Enderby et al. 1987). The tool has excellent test-retest reliability. The Intra-rater reliability for patients with chronic aphasia who were tested at two separate time points by the same observer was excellent (Kendall’s coefficient of concordance=0.97), (Enderby et al. 1987). The FAST has also demonstrated excellent inter-rater reliability across three independent observers (Kendall’s coefficient of concordance

=0.97, p<0.001) (Enderby et al. 1987).

Convergent validity of the FAST has been shown against similar language assessments for example the Functional Communication Profile (FCP) (Sarno. 1969) and Minnesota Test for the shortened Differential Diagnosis of Aphasia (MTDDA) (Schuell; Enderby and Crow 1996).

Excellent positive correlations were found between the FAST and FCP (0.73, p<0.001) and

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MTDDA (0.91, p<0.001). The FAST has shown good sensitivity (100%) and specificity (79%) in acute stroke patients, when administered seven days post-stroke using a cut-off of 25/30 (O'Neill et al. 1990). Thus it is suitable for administration early post-stroke.

The Comprehension subscale consists of two parts, which will be referred to as

Comprehension A and Comprehension B. Comprehension A asks the participant to identify and point to certain objects on the riverboat scene picture card, for example, “point to the tallest tree”. Comprehension B asks participants to point to shapes on the alternative picture card, asking participants for example to, “Point to the cone”. The Expression subscale is also divided in to two parts which will be referred to as Expression A and Expression B. Expression A asks participants to describe the riverboat scene picture, with points awarded for objects named.

Expression B does not refer to the picture cards or visual clues to prompt responses, and asks participants to name as many animals as possible, with a point scored for each one correctly named. Reading is assessed by asking participants to read instructions. Writing is assessed by the patient’s ability to record responses in a written format.

The Barthel Index (Wade and Collins 1988) was used as a measure of stroke severity. This scale consists of ten items designed to measure an individual’s level of daily living, with items focusing on tasks of daily living and mobility. The scale has a maximum score of 20, with a higher score indicating greater independence.

The effects of intervention on mood were analysed using logistic regression. Mood at three-months was the dependent variable, and FAST subscales, age, sex, Barthel Index score, mood at baseline (GHQ-28), treatment group, location and FAST category interaction with treatment group were all independent variables. The results of this original trial indicated that there was a benefit in mood for those who received MI compared to those receiving usual care (p=0.03, OR 1.6, 95% CI 1.04 to 2.46).There was an indication that those with abnormal communication may have benefitted more in terms of mood compared to those with normal communication (p=0.07, OR: 2.42, 95% CI 0.93 to 6.32).

Summary

The original trial showed motivational interviewing has a beneficial effect on patients’ mood at three-months compared to those receiving usual care. A sub-group of patients with

communication difficulties appeared to benefit more in terms of mood after receiving MI. Not only was this study one of the first to report a benefit of mood following a talk-based

intervention, but it is also one of the first to report a benefit to mood in patients with communication difficulties after stroke.

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However, little information is reported on this sub-group of patients with communication difficulties in this trial. It may be that there are other differences in this patient group which influenced the mood outcome, and therefore this requires further exploration. In addition, more information is needed about the impact of communication ability on mood. It remains unknown whether a specific component of communication ability impacts on mood outcome.

In addition, while a benefit to mood was demonstrated for those receiving MI, it is unclear whether participants scoring within a particular sub-scale of the GHQ-28 benefit more than others. The next sections present findings from secondary analyses exploring these issues further.