It is estimated that up to half of all stroke survivors have persistent attention problems. Attention problems manifest themselves in everyday tasks where an individual has to concentrate, do two or more things at once or not get distracted, and this can have a knock on effect on their ability to engage in rehabilitation programmes.
Loetscher and Lincoln set out to review the studies that had evaluated whether stroke survivors receiving attentional therapy had better outcomes than those who did not, and if the therapy benefitted independence in activities, mood and quality of life.
The Cochrane Stroke Group Trials Register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL, PsycINFO, PsycBITE, REHABDATA, and ongoing trials registers were searched. Reference lists and citations were also tracked. Studies that met the following criteria were included:
- RCTs in which an attentional treatment was compared with a control that received either an alternative form of treatment or no attentional treatment
- Stroke survivors with attentional deficits
- Studies that assessed global attentional functions, specific domains of attention, functional abilities, mood and quality of life
- Subjective measures of attention and objective tests of attention were eligible for inclusion
Following the search one author excluded all articles that were not relevant. The remaining studies were reviewed independently by the two authors to identify those for inclusion.
2785 articles were screened with 2721 being excluded. Sixty-four articles underwent an in-depth assessment for possible inclusion with 53 being excluded due to an ineligible population, not rehabilitation for attention impairments, not RCTs, duplicate records and individuals awaiting assessment. This left six studies being included in the review.
Of the Included Studies:
- The six studies included a total of 223 participants, number of participants varied from 18 to 78 participants
- In all studies participants and therapists were aware of the treatment being given
- Participants were recruited two months (two studies), within one year (three studies) and up to four years post-stroke (one study)
- Interventions aimed to restore attentional functions or provide compensatory strategies
- Interventions lasted from three weeks to eleven weeks
- The number of treatment sessions varying between 13 and 55 sessions for the restorative approach and 10 hours for the compensatory approach
- Thirty psychometric tests with more than 40 variables as attentional outcome measures were used in the studies
Effectiveness of cognitive rehabilitation
- A statistically significant effect was found for cognitive rehabilitation improving divided attention in the short-term only
- No statistically significant effects of cognitive rehabilitation improving global measures of attention, standardized attention assessments or functional outcomes
There was limited evidence that cognitive rehabilitation improves aspects of attention, functional outcomes, mood or quality of life irrespective of the phase of recovery due to a lack of studies.
The authors also reported that the methodological quality of the studies was poor, that greater consistency is needed in terms of outcome choice and there was a paucity of RCTs addressing the effectiveness of cognitive rehabilitation for attention deficits post-stroke.
The Stroke Elf’s View
Many stroke survivors are living with attentional impairments in everyday life and need adequate treatment to address their attentional problems.
Thus, Cochrane reviews like this by Loetscher and Lincoln are valued as knowledge of the effectiveness of cognitive rehabilitation for attention deficits is elusive. However, the results from the present review do not paint a clearer picture as there is still uncertainty surrounding how best to treat attentional problems.
One issue the Stroke Elf has with this review is the inclusion of only RCTs. Of course these types of studies are considered gold standard for good reason but with RCTs it is the general applicability of the findings that are assessed. Therefore, it is perplexing as to why this methodology is viewed as paramount in a population that is heterogeneous. The authors of the review did comment that they were aiming to do sub-group analyses but could not due to insufficient data. However, stroke research samples are typically small so fractioning the data is likely to lead to spurious results.
Rather than going down the RCT path it may be worthwhile considering alternative methodologies such as single-case designs. Historically, single-case methods have been weak due to poorly designed studies and a lack of statistical techniques to support the method. However, with the advancement of statistic approaches and knowledge of how to conduct single-case studies at the standard required, better quality studies can be implemented at the individual level.
At the moment there is limited evidence supporting the effectiveness of cognitive rehabilitation for attentional deficits post-stroke. This is due to a lack of good quality research studies in this area irrespective of whether they are RCTs or single-case designs. As research outcomes impact on policy and practice it is vitally important that attention is paid to this gap in the literature and the necessary research is carried out.
Loetscher T, Lincoln NB. Cognitive rehabilitation for attention deficits following stroke. Cochrane Database of Systematic Reviews 2013, Issue 5. Art. No.: CD002842. DOI: 10.1002/14651858.CD002842.pub2.
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