Introduction
Dementia is an umbrella term for a number of progressive and chronic syndromes, with underlying neurological causes and varying patterns of impairment in cognitive function, as well as emotional and behavioural changes (World Health Organization
2016). It is estimated that 46.8 million people worldwide are living with the condition (Prince et al.
2015). The economic cost of the condition is high (estimated at £26.3 billion a year in the UK alone (Prince et al.
2014)), as is the biopsychosocial impact on people living with dementia and those who care for them. In addition to cognitive impairment, people with dementia experience depression at far higher rates than the non-dementia population (Winblad et al.
2004, cited in Enache et al.
2011; Kales et al.
2005), with damaging effects (González-Salvador et al.
1999; Kunik et al.
2003; Orgeta et al.
2015; Rapp et al.
2011; Shin et al.
2005; Suh and Yeon
2005)
.
Given the evidence that mindfulness-based interventions can reduce current depressive symptoms, reduce risk of future depression and enhance cognition in those without dementia (Chiesa et al.
2011; Piet and Hougaard
2011; Strauss et al.
2014), there has been increasing interest in the application of mindfulness-based interventions to those with dementia. The most recent and rigorously conducted trial in people already diagnosed with dementia suggested that an adapted mindfulness-based stress reduction intervention can improve self-reported quality of life in those living with dementia in care homes (Churcher Clarke et al.
2017). However, the mechanism by which this improvement was obtained was unclear, as there was no improvement in mindfulness skills over the course of the intervention. We know that stimulating structured group activity may produce similar results to those found in Churcher Clarke et al. (Spector et al.
2003), thus it may be that any such activity (rather than mindfulness practice in particular) would produce the same benefits.
It is also possible that the cognitive deficits present in dementia may preclude or at least affect the ability to practice mindfulness, rather than to engage in structured activity per se. The issue of whether such deficits do affect mindfulness ability has not previously been investigated. It is important to understand both theoretically and practically, as mindfulness-based stress reduction is a highly specialised intervention requiring expert facilitation with consequent cost and resource implications, whereas other structured group interventions are not (mindfulnessteachersuk.org.uk
2011; Spector et al.
2003). In particular, the ability to attend (and to self-regulate attention) has been identified as one of the core components of mindfulness practice and the related construct of cognitive flexibility is empirically associated with mindfulness ability (Bishop et al.
2006; Moore and Malinowski
2009). Cognitive flexibility and attentional regulation are also affected early in the disease process of the two most common forms of dementia, Alzheimer’s disease and vascular dementia (World Health Organization
2016).
Consequently, in the current study, we aimed to compare ability on a mindful attention task in a group of people with dementia and in an older adult comparison group. To enhance ecological validity, we did this using an experience sampling measure (Napa Scollon et al.
2009), the Meditation Breath Attention Score (MBAS) (Frewen et al.
2008). The MBAS task has been used in a dementia sample previously (Churcher Clarke et al.
2017) and was selected in order to minimise the memory load which exacerbates issues with retrospective self-report of skills in this population, while still replicating core elements of the common meditation practice of mindfulness of breathing. Our primary prediction was that having dementia would have a large effect size impact on mindful attentional ability. Given that we expected this effect to be due to cognitive deficits we made a secondary prediction that, within the dementia sample, levels of overall cognition and cognitive flexibility would be correlated with mindful attention skill levels, and that if these correlations were present, it would be expected that overall cognition and cognitive flexibility predicted mindfulness performance over and above mood and premorbid IQ.
Results
Demographic characteristics of the samples are presented in Table
1. Those with dementia were older and less educated than those in the comparison group (
p < 0.001). Other demographic characteristics did not differ between groups.
Table 1
Demographic characteristics and results of between group analyses for people with dementia (PWD) and older adult (OA) participants
Variable | | M (SD) | M (SD) | Test statistic |
Age | | 82.84 (6.58) | 72.96 (6.30) | t = 7.06* |
Years of education | | 11.91a (3.82) | 16.07 (3.59) | t = 5.14* |
| | n (%)b | n (%)b | |
Gender | Male | 17 (50) | 21 (38) | χ2 = 0.83 |
Female | 17 (50) | 34 (63) | |
Ethnicity | White | 28 (82) | 54 (98) | χ2 = 7.27 |
BME | 6 (18) | 1 (2) |
Marital status | Single | 5 (15) | 7 (13) | χ2 = 3.62 |
Married | 12 (35) | 29 (53) |
Separated | 0 (0) | 1 (2) |
Divorced | 6 (18) | 7 (13) |
Widowed | 11 (32) | 11 (20) |
Diagnosis (ICD 10 code)c | Alzheimer’s disease—early onset (F00.0) | 1 (3) | | |
Alzheimer’s disease—late onset (F00.1) | 20 (59) | | |
Alzheimer’s disease—atypical/mixed type (F00.2) | 5 (15) | | |
Alzheimer’s disease—unspecified type (F00.9) | 4 (12) | | |
Dementia in Parkinson’s disease (F02.3) | 1 (3) | | |
Dementia—type unspecified (F0.3) | 3 (9) | | |
Data for neuropsychological and mood variables are shown in Table
2. For the dementia group, there was a small amount of missing data on some variables (one participant’s response in each case). Given the low level of missing data, which were missing completely at random (Little’s MCAR
p > 0.05), data were deleted listwise (Graham
2009). For the MBAS task, there was a greater percentage of missing/ambiguous responses. Twenty-four percent (8/34) of participants had appeared to respond impulsively (raising their hand before the instructions were given), incongruently (raising the hand indicating attention to the breath when the bell rang, but commenting later that they had not been attending), ambiguously (half raising a hand then putting it down), or not at all. It was felt that listwise deletion, excluding these eight cases from all analyses involving the MBAT, was likely to have too great an effect on the power of the study and would further increase the risk of Type II error. Therefore for this variable only, missing/ambiguous responses were imputed. While several methods for doing this were considered (Gelman and Hill,
2006; Higgins and Green,
2011), the final decision was to impute assumed scores of ‘0’, equivalent to participants having indicated they were not attending to the breath at the bell.
Table 2
Data for neuropsychological and mood variables by group
Variable | M (SD) Min-Max | M (SD) Min-Max | Test statistic | Effect size (d) |
ACE (/100) | 74a (10.84) 45–98 | 95.11 (4.42) 82–100 | t = 10.67* | 2.55 |
Estimated IQ | 101.92a, b (14.00) 75.90–126.40 | 118.70 (9.02) 93.30–132.60 | t = 6.16* | 1.42 |
TMT difference score | 166.58a (76.36) 38–274 | 42.98 (35.94) 4–155 | t = 8.80* | 2.07 |
HADS (anxiety) (/21) | 4.94 (2.76) 1–12 | 4.55 (2.89) 0–12 | t = 0.64 | 0.14 |
HADS (depression) (/21) | 5.35 (3.88) 0–14 | 2.47 (1.82) 0–7 | t = 4.21* | 0.95 |
The analysis for the primary prediction (that there would be a large effect size difference on MBAS performance between groups, with better performance in healthy older adults than in those with dementia) was then run twice: once with imputed data included (N = 34), and once with listwise deletion of participants who had given missing/ambiguous MBAS task responses (N = 26). MBAS data for the healthy comparison group were complete (N = 55).
Full results for the primary prediction are given in Table
3. No statistically significant difference was found between the groups (
p = 0.38), and this difference remained insignificant whether or not participants with imputed MBAS data were included in the analysis (
p = 0.79). Therefore the null hypothesis (that people with dementia and those without would not differ on MBAS performance and that the groups had come from a population with the same median score) could not be rejected. The effect sizes of both calculations (
r = 0.09,
r = 0.03) were below the accepted conventional cut-off for a ‘small’ effect size of 0.1 (Cohen
1992).
Table 3
Results of Mann-Whitney U tests with descriptive statistics for MBAS performance by group
Variable | Median | Mode | Min-Max | Median | Mode | Min-Max |
df
|
U
|
z
|
r
|
MBAS (with imputed data) | 3 | 5 | 0–5 | 4 | 4 | 0–5 | 87 | 1036.50* | 0.88 | 0.09 |
| PWD (N = 26) | OA (N = 55) | | | | |
MBAS (without imputed data) | 4 | 5 | 0–5 | 4 | 4 | 0–5 | 79 | 689.50** | − 0.27 | 0.03 |
The secondary prediction was that MBAS performance would positively correlate with measures of executive function and overall cognition. If these correlations were present, it would be expected that performance on these measures predicted mindfulness performance over and above mood and premorbid IQ.
Where possible, further exploratory analyses were carried out for the dementia sample, to assess any associations between MBAS performance and the two putatively associated neurocognitive variables of overall cognition and cognitive flexibility (plus the potential nuisance variates of anxiety, depression and estimated premorbid IQ). Results reported include imputed MBAS data, though interpretations were unchanged when these data were excluded.
Spearman’s rank order correlation was performed to assess the relationship between the MBAS and the TMT difference score. The correlation was statistically non-significant, with a medium effect size (
rs(31) = 0.323,
p = 0.067). The same analysis was performed to assess the relationship between MBAS and HADS (anxiety) scores, and again, the resulting correlation was statistically non-significant, with a small to medium effect size (
rs(32) = 0.181,
p = 0.306). Interpretations of effect sizes were based on Cohen’s framework (
1988,
1992), where
r = 0.10 represents a small effect size,
r = 0.30 a medium effect size and
r = 0.50 a large effect size. Correlational analyses for the MBAS task and the ACE, HADS (depression) and premorbid IQ were not performed, as assessment of bivariate scatterplots indicated the test’s assumption of a monotonic relationship between variables was not met in these cases.
Discussion
This study investigated whether having a diagnosis of dementia was associated with reduced ability on a task of mindful attention. Our finding of no significant difference between a dementia group and members of an older adult comparison group on a task measuring the ability to mindfully attend to the breath suggests that diagnosis may not have a large effect. This was in spite of statistically significant differences between the groups on measures of overall cognition, estimated premorbid IQ, and executive ability, with people with dementia performing worse.
Further analysis aimed at exploring possible mechanisms influencing MBAS performance in people with dementia found a non-significant positive correlation between cognitive flexibility (the TMT difference score) and MBAS in the dementia sample. The medium effect size (
r = 0.313) suggests that MBAS performance is also affected by or at least associated with other factors, and is insufficient strongly to support the construct validity of the MBAS task as previous papers have done (Frewen et al.
2011; Lai et al.
2015).
The expectation that people with dementia would perform significantly worse than the comparison group on the MBAS task was based in known and well-established differences (also reflected in the findings of the current study) between people with and without dementia, in areas which have a plausible theoretical link to the skills involved in optimal MBAS performance—cognition and cognitive flexibility. Given that the people with dementia group was a relatively high-functioning, community-dwelling sample, it is in fact possible that there was no underlying difference between the people with dementia and older adult group’s ability to pay sustained, mindful attention to the breath. If this was the case, since some higher functioning people with dementia are able to engage in a task incorporating core elements of a key mindfulness meditation practice, mindfulness may be seen as a potential mechanism of change for future clinical interventions with this population. Although Churcher Clarke et al. (
2017) did not find improvement on the MBAS task in those with dementia over the course of an intervention, it should be noted that the current study investigated a much higher functioning sample and it may be that in such a sample mindfulness ability is not affected in the same way. Further research would be needed to assess whether mindfulness abilities would improve in a similar sample over the course of a clinical intervention.
Limitations and Future Research Directions
Due to resource limitations, the first author was involved in administration of the test battery to the dementia group. She was not blinded to the status of these participants.
There was a period of time between initial diagnostic testing within the relevant memory services and subsequent identification and consenting of participants and their completion of the test battery; median (IQR) for the dementia sample were 291(525) days, respectively, and these lapses of time may have resulted in some participants’ dementia further deteriorating since diagnosis.
We used an experience sampling measure with high face validity in this population and good evidence for validity in other populations. However, social desirability (in this case, the idea that paying attention was the ‘correct’ response) could have influenced performance (Paulhus
1991; Tourangeau and Yan
2007 (cited in Kaminska and Foulsham
2013)). Furthermore, valid self-report in the MBAS task is based on successfully meeting a number of cognitive demands. In particular, it requires set-shifting between the required focus of attention (the breath) and the instructions being provided, (short-term) retention of these instructions, accurate delayed recall of one’s attentional state in the context of these instructions, and selection of the appropriate hand (left/right to indicate attention/distraction, depending on the condition). While delayed memory and other cognitive demands are reduced compared to a standard self-report task, they are by no means eliminated, and as can be seen from this brief summary, wider cognitive demands are fairly extensive.
Therefore, given that our samples differed significantly in cognitive abilities, these differences could have contributed to invalid responding in the dementia group. As detailed in the “
Method” section, use of a simplified version of the MBAS task, adapted for a more severely impaired nursing home dementia sample (Churcher Clarke et al.
2017), was considered but rejected after piloting.
Although the MBAS task has ecological validity in measuring performance on a common mindfulness practice, the wider testing situation was less representative of a naturalistic meditation setting. Care is taken in formal meditation settings to aid focus and concentration by reducing or removing sources of external distraction. Such a level of control was difficult to achieve in participants’ homes, where the majority of testing for the people with dementia sample took place. Sometimes family members/partners were present, occasionally presenting a distraction to the participant.
Finally, it is possible that there was a significant but small difference between groups on the MBAS which the study was underpowered to detect—scores between the groups did differ, with people with dementia having a lower median score. However, that difference was associated with a very small effect size of 0.09. Even if a higher-powered study had found this difference to be statistically significant, it is arguable that such a small effect size may not have clinical significance (Kazdin
1999; Shabbir and Sanders
2014).
Therefore, while the finding that there was no significant large effect size difference between those with dementia and those without on a measure of mindful attention may encourage further research on this area, interpretations of the study’s outcomes must necessarily be tentative. The paucity of research in this area necessitated an initial proof of concept study, with exploratory use of a measure not previously validated for people with dementia. It is possible (as acknowledged above) that aspects of the methodology, of the measure itself, and the low power of the study affected the outcomes, and complicate their interpretation. Future research could usefully replicate the current study with a larger dementia sample, and focus in greater depth on exploring the elements of the measure and its administration which may have affected its validity, as a basis for developing a better validated measure. Studies could also consider alternative approaches to assessing mindful attention in a dementia sample which might further obviate the self-report element, for example, use of neuroimaging (Tang et al.
2015). If a validated measure can be established, research would then usefully incorporate a longitudinal element, to explore the clinically relevant area of whether this population can increase its level of mindful attention through practice.
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