OptiCogs Online is a complex multicomponent intervention comprising of cognitive, physical activity and educational components.

OptiCogs Online was developed in accordance with the MRC framework for the development and evaluation of complex interventions. Given the known interactions and interconnectivity of cognitive domains required for optimal cognitive functioning post-stroke, a systematic review of 64 studies addressing all types of non-pharmacological rehabilitation interventions which may improve multiple cognitive domains in people post-stroke was conducted. Within this review, rehabilitation interventions were categorised as multicomponent interventions, physical activity interventions, cognitive rehabilitation interventions, NIBS protocols, occupational-based interventions and other interventions. The most consistent evidence in our systematic review and meta-analysis supported multicomponent interventions, with significant improvement demonstrated for general cognitive function and memory outcomes. Specifically, multicomponent interventions wherein a form of cognitive rehabilitation was conducted in conjunction with a form of physical activity were shown to improve cognitive functioning in people post-stroke.

As well as meta-analytic evidence, we drew from qualitative findings which explored the perspectives of PpS, caregivers and healthcare professionals on the design and delivery of an intervention to improve cognitive functioning in PpS. Qualitative findings and input from clinical experts emphasised the importance of information provision, peer support and meaningful engagement. As such, each component of OptiCogs Online is supplemented with an educational or 'cognitive education' session wherein group discussion covers different aspects of cognitive functioning. As well as drawing on findings from our qualitative study, this 'cognitive education' component is underpinned by the Bridges stroke self-management package and based on self-efficacy principles.

To this end, a complex multicomponent intervention comprising of cognitive, physical activity and educational components was developed in line with the MRC framework.

Inclusion Criteria:

• People with a physician-confirmed diagnosis of stroke. Stroke may be ischaemic or haemorrhagic in nature.
• People aged ≥18 years old; with confirmed mild to moderate cognitive impairment using the Oxford Cognitive Screen (OCS) (in accordance with cut-offs for impairment for OCS-plus subtasks (Demeyere et al. 2021a) and the Addenbroke's Examination III (ACE III) with a cut-off score of 88/100 (Takenoshita et al. 2019).
• People post-stroke who have a Modified Rankin Scale (MRS) score of 0-3
• Capacity to provide informed consent
• People post-stroke who are able to express their basic needs, verbally or not
• Have access to a smartphone, laptop or tablet with an internet connection
• Willingness/ interest in participating in an online intervention
• Physician-confirmed suitability to partake in this intervention

Exclusion Criteria:

• Physician-confirmed contraindications for undertaking physical activity e.g., safety, presence of unstable heart disease
• People with diagnosed TIA will be excluded
• People post-stroke with known active delirium or dementia will be excluded
• People post-stroke with a diagnosis of known pre-stroke cognitive impairment
• People post-stroke with moderate or severe visuospatial neglect