2.1 Research Ethics and Patient Consent
This study has been approved by the SingHealth Centralized Institutional Review Board (study reference number 201806-00133). Anonymized data will be shared upon reasonable request to the Corresponding Author from any qualified investigator. Informed consent was obtained from all participants.
2.2 Study Design
In this prospective observational cohort study, participants underwent a battery of assessments and questionnaires at baseline. Subsequently, participants attended the SMaRT program as a group. Participants were then assessed with the same test battery one week, three months and six months after completing program content (participant timeline summarized in Fig. 1) To cater to the multilingual Singaporean geriatric population, the program and assessments were conducted in English or Mandarin depending on participants’ preferred language.
2.3 Inclusion and Exclusion Criteria
Patients screened for eligibility included those admitted to a stroke ward in a hospital in Singapore from April 2018 to September 2019, or referred from other doctors in affiliated organizations. Inclusion criteria comprise (1) ischaemic stroke confirmed on MRI, (2) self-reported cognitive difficulties, (3) ages 18-80, (4) functional independence, defined as a score of 3 or lower on the Modified Rankin Scale (mRS), (5) basic literacy in English or Mandarin, (6) able to attend the program within 3 to 12 months of their stroke. This time frame accounts for the fact that many persons with stroke spontaneously recover some level of cognition or resolve acute symptoms such as psychosis and delirium within 3 months of their stroke, after which improvement plateaus9. However, beyond 12 months, PSCI is likely to have set in and stabilized10, making rehabilitation less beneficial. In sum, these criteria ensure that participants do not have cognitive and functional difficulties that might interfere with their comprehension of and participation in the program.
Exclusion criteria included pre-existing dementia prior to stroke, psychiatric conditions, behavioral symptoms, or physical difficulties that may impede participation in program activities.
2.4 Program Structure
The eight-week program was designed based on previous research highlighting common deficits in PSCI, potentially effective cognitive strategies, and lifestyle factors influencing PSCI and cognitive decline. The first and last sessions include pre- and post-rehabilitation assessments respectively. As persons with mild strokes have minimal difficulties with independent function and comprehension, they are likely to benefit from exposure to a large variety of PSCI-relevant topics and strategies, from which they can subsequently choose preferred strategies and lifestyle modifications. Further, as PSCI is multifactorial, a holistic program which discusses cognitive, lifestyle and emotional factors relevant to PSCI will be helpful 11,12. Finally, given the large proportion of persons who experience mild strokes, ensuring accessibility to such services within communities is paramount; hence, a manualized program which can be scaled to multiple centers will be best suited to this group. For these reasons, the program was designed to be multi-domain, to provide participants with a variety of PSCI-relevant strategies, and to have a structured curriculum scalable to multiple centers.
An overview of the program’s components is provided in Fig. 1. For each 8-week run, up to 12 participants could enroll, with a facilitator-participant ratio of at least 1:4. Program components are summarized in Table 1.
2.5 Ethics and Patient Consent
Approval for this study has been obtained from the SingHealth Centralised Institutional Review Board. Participant consent is obtained prior to the use of their data. All research was performed in accordance with relevant guidelines and regulations.
2.6 Statistical Analysis
Linear mixed models were performed separately for MoCA, VCAT, TMT-A, GDS, NEADL and Dem-QOL respectively. Outcome variables were changes in scores across timepoints, with intercepts for participants’ scores as a random effect and unstructured covariance matrix. Two models for each outcome variable were run with time as fixed effect: (1) to examine differences between each timepoint from baseline; (2) to estimate average change across timepoints from baseline.
To further understand possible individual differences in score changes across time, we computed the proportion of participants whose cognitive performance were maintained or improved at 6 months post-program, defined as a change in MoCA or VCAT scores greater than or equals to -1 between baseline to 6 months post-program.
To test whether trends of the scores may differ across demographic and stroke type variables, the respective interactions of time with age (dichotomized using median split), gender, ethnicity, stroke lacunarity, stroke lateralization and presence of stenosis were tested in separate linear mixed models.
All p-values are reported with Bonferroni adjustments for multiple comparisons of 6 outcome variables, with statistical significance set at p=.05. Statistical analysis was performed in STATA software (StataCorp. 2015. Stata Statistical Software: Release 14. College Station, TX: StataCorp LP.).