Discussion
stroke, strokes, post-stroke, Fatigue
STROKE, STROKES, RECRUITMENT, ATTRITION
We demonstrated that it would be feasible and acceptable to conduct a definitive
trial of a rehabilitation intervention for stroke survivors with inattention,
delivered by NHS occupational therapists, beginning very early after stroke in the
inpatient usual care rehabilitation setting. We established realistic estimates of
recruitment (maximum 2 patients per site per month), retention, data completeness
and participant characteristics, and provided data to inform the primary outcome
measure and calculate sample size for future trials in this population.It was not possible for NHS research support staff to complete all outcome
assessments, nor for outcome assessors to remain blinded. Attrition in the study was
low. Treatment fidelity for prism adaptation training was good in terms of duration
and timing of delivery, however recording of the content of occupational therapy
sessions was incomplete and needs some revision. Study procedures and prism
intervention delivery were acceptable to patients, carers and therapists.Although the study was not powered to give a conclusion on the effectiveness of prism
adaptation training, none of the outcome measures showed any sign of benefit from
intervention. Furthermore, a proof-of-concept study (reported separately) did not
find evidence to suggest improved engagement in occupational therapy following one
session of prism adaptation training. Thus, we cannot justify taking prism
adaptation training, provided as per this study and with this early post-stroke
population, to a definitive trial.There are several potential explanations for our findings. There is no standard
protocol for prism adaptation delivery, for example, some studies delivered 10 or
more sessions per day over two weeksIn addition, time since stroke and physical ability early post-stroke may influence
the effect of prism adaptation. Fatigue early post-stroke may mean a higher
dose/intensity of prism adaptation is not well tolerated, particularly because
people with inattention often have more severe strokes and premorbid
difficulties.Although the sample size of this feasibility study lacks statistical power to
identify small but realistic and potentially worthwhile effects, our conclusions are
underpinned by our adequately powered proof of concept analysis (reported
separately) which ruled out a measurable effect on immediate patient engagement in
occupational therapy. The study targeted a potential sample size of 60–80
participants, which resulted in 53 eligible and consenting people. This demonstrated
it would be feasible to recruit to a definitive study in the post-acute stage with a
slightly longer recruitment window. Whilst our study reflects some existing
findings, most existing randomised controlled trials have small samples, many with
less than 50 participants, and therefore comparisons should be treated with
caution.Our choice of outcome assessments may provide limitations. Many participants assessed
at 12 weeks were still in hospital, limiting the number of activities of daily
living they could report completing on the primary outcome. This also impacted on
the relevance of collecting outcome data from carer participants. Despite training,
some assessments were not carried out in line with standardised instructions,
particularly at baseline (e.g. asking participants to cancel large rather than small
stars).Despite concluding that prism adaptation training, as provided by this study, is not
a candidate intervention for a definitive trial, we stress alternative
rehabilitation interventions for people with inattention early after stroke are
needed. We recommend exploring how patients assessed as physically or cognitively
unable to participate in the intervention might be able to benefit from future
interventions for inattention. We identified several methodological changes for a
future trial, including: choice or timing of most appropriate primary outcome early
post-stroke; facilities such as quiet space away from the bedside to facilitate
effective intervention delivery; and a need for outcome assessors employed as part
of the research team. Blinded assessors are expensive to achieve in rehabilitation
trials and trade-offs are required.