According to the latest report by Global Burden of Diseases (GBD) 2019 Stroke Collaborators, stroke is still one of the two most common causes of death and the third most common cause of death and disability combined (Feigin et al., 2021). The most challenging long-term sequelae affecting stroke survivors include physical, emotional, and cognitive impairments (Intercollegiate Stroke Working Party, 2012).

Post-stroke cognitive impairment (PSCI) is a significant complication and affects over 40% of stroke survivors (Lo et al., 2019). Due to the unlimited variation of brain lesions and diffuse vascular brain injuries among stroke patients, PSCI is heterogeneous (Moore and Demeyere, 2022). Aphasia syndromes arising from lesions in language networks, impairments in memory systems, executive and attention deficits, and visuospatial dysfunction are typical domain-specific impairments in PSCI patients (Corbetta et al., 2005; Jokinen et al., 2015; Dichgans and Leys, 2017). Despite this pervasiveness, there is no easy way to screen for and monitor PSCI other than the traditional paper and pencil cognitive assessment tools (Khaw et al., 2021). Assessment difficulty and heterogeneity of cognitive deficits are likely the major contributing factors to the widespread underdiagnosis of PSCI (Quinn et al., 2021) and are a hindrance to its successful management. The most widely used cognitive assessment tests/scales, such as ACE-R, Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), and Montreal Cognitive Assessment (MoCA), are time-consuming taking ∼10–30 min to administer, which is manageable in research settings but can be challenging in routine clinical settings. Other extensively utilized tests which take a relatively shorter time to administer, such as the Mini-Cog and mini-mental state examination (MMSE), screen fewer cognitive domains (Bartos and Fayette, 2018). All the above tests have limitations with poor test-retest stability and with the floor effect not being considered for those with lower education (Gottesman and Hillis, 2010). Clinicians need assessment tools that can screen for PSCI sensitively, quickly, and cost-effectively. Furthermore, attention and executive function deficits are two of the major features of PSCI, which processing speed or reaction time is often used to measure (Khaw et al., 2021), but none of the above-mentioned paper and pencil assessment tools measure reaction/response time.

Due to the dynamic and temporal features of the cognitive function changes after stroke, longitudinal and continuous follow-up of cognitive function is recommended for all stroke patients (Rost et al., 2022). For the convenience of physicians and patients, telemedicine has developed widely and effectively in the past decade (Duffy and Lee, 2018). And during the COVID-19 pandemic, patient management and healthcare delivery have faced unique challenges with limits on traditional in-person visits (Hollander and Carr, 2020). Alternatively, online screening and brief, but comprehensive, computerized cognitive assessment are valuable options for tracking cognitive function (Ashford et al., 2022). Therefore, there is an urgent need for a better cognitive screening tool that is simple and easy to implement and has high sensitivity and specificity to screen for PSCI.

We have recently cross-validated a 1.5 to 2-min online digital cognitive assessment tool, the MemTrax (MTx) “continuous recognition task” (Bergeron et al., 2020). MTx specifically assesses information processing and storage in episodic memory, including processing speed via response time, for the estimation of mild cognitive impairment (MCI) associated with early and mild Alzheimer’s disease (AD) (Chen et al., 2021). Based on the well-known features of PSCI (Khaw et al., 2021), we hypothesized that MTx could validly screen for PSCI. Therefore, we designed a study to test the effectiveness and reliability of MTx to distinguish cognitive deficits among patients after ischemic stroke.

In this cross-sectional study based on a post-stroke cohort, we demonstrated the clinical utility of MTx in screening PSCI in patients with ischemic stroke. It complements earlier research findings on mild cognitive impairment and dementia due to AD or vascular dementia in a group of Chinese participants where cognitive impairment and severity were detected (Chen et al., 2021; Liu et al., 2021).

Our previous study on the utility of MTx in AD recommended MTx-%C as the best metric to screen for MCI, with the optimal MTx-%C cut-off being 81% (Liu et al., 2021). In this study, the optimized cut-off value was < 78%, with sensitivity and specificity of detecting PSCI, at 90.0 and 84.1%, respectively. Further, our current study found that both MTx-RT and MTx-Cp are also valuable metrics when screening for PSCI.

A positive LR of 10 or more suggests that a positive test will be very good at ruling the disorder in. A negative LR of 0.1 or less suggests that a negative test will be very good at ruling the disorder out (Davidson, 2002). In our findings, 46.3% as a cut-off value for MTx-Cp had the highest LR+ of 11.73, which means those whose MTx-Cp was lower than this cut-off point might be considered to have PSCI. Meanwhile, when 78% was used as the cut-off value of MTx-%C, LR− was 0.12, which means those whose MTx-%C was greater than this cutoff point might not be considered to have PSCI. Thus, it is recommended to apply MTx-%C to assist in ruling out PSCI, whereas MTx-Cp can be more effective to screen for PSCI at the follow-up points.

Working memory impairment is found in 75% of stroke survivors (Riepe et al., 2004), and additional impairment in executive function is common in patients after stroke (Chung et al., 2013). Attentional deficits are commonly observed within the acute phase and at discharge from the hospital (Loetscher et al., 2019). Cognitive slowing is a common complaint after stroke (Cumming et al., 2013), and the processing speed of information can also be impaired in 20 to 50% of stroke survivors for years (Barker-Collo et al., 2010). Thus, in clinical practice, cognitive assessment to screen for PSCI should include the following five core domains: executive function, attention, memory, language, and visuospatial function (Iadecola et al., 2019). Previous research showed that both the MTx-%C and MTx-RT gave reasonably accurate estimates of the MoCA score. Nevertheless, the MemTrax scores also related highly to the subscores of the MoCA, indicating the breadth of relevance to the cognitive domains (van der Hoek et al., 2019). Based on its design, MTx performance depends on the functioning of these cognitive domains, and its impairment non-specifically reflects dysfunction in these areas. While the primary MTx output metrics primarily assess performance in recognition memory (MTx-%C) and reaction/response time (MTx-RT), these measures are also affected by attention/executive function, as well as visuospatial and motor function. Our findings of lower MTx-%C and longer MTx-RT in the PSCI group compared to those in the Non-PSCI lend support to our hypothesis that the MTx test would be a useful and practical tool for detecting and monitoring PSCI.

Findings in our present study are consistent with reported cognitive impairment incidence of 25–75% in stroke victims (Patel et al., 2002), which results in poorer recovery, more significant functional impairment, increased stroke recurrence, and mortality (Swartz et al., 2016; Rost et al., 2022). The cognitive impairment may occur at the very beginning of the post-stroke period (McClure et al., 2012), or it may appear after 3 months (Patel et al., 2002), 1, 2, or 3 years following the stroke event (Patel et al., 2003). Therefore, detecting and providing therapy for cognitive impairment is crucial in the long-term follow-up and welfare of stroke survivors. These observations suggest that an extended follow-up plan for stroke patients with simple, feasible approaches to routinely screen for PSCI is vitally important (Swartz et al., 2016). Two widely used tools to assess cognition, MoCA and ACE-R, require face-to-face administration and a comparatively long time burden to the patient and healthcare provider, with questions of test-retest validity, learning, and stability (van der Hoek et al., 2019). Accordingly, MTx provides an advantageous and viable alternative as a screening tool to identify and initially select patients for a more comprehensive cognitive assessment.

The COVID-19 pandemic prompted an unintended though necessary widespread transformation to digital and virtual healthcare services (Hachinski, 2022). And with a recognizably prevalent unsatisfactory provider follow-up rate combined with the broad impact and related restrictions resulting from the pandemic (Cadilhac et al., 2022), a remote digital tool that can readily and validly evaluate cognitive status would be an effective solution to monitor complications of post-stroke patients. The 2-min MTx memory test has demonstrated advantages for this population, including the capacity to connect patients to providers more regularly and meet the needs of cognitive screening for PSCI. Furthermore, due to its large sets of unique tests, MTx can be repeatedly used at a regular frequency without compromising accuracy in differentiating cognitive health or losing the interest of patients to perform repeated tests. There are an increasing number of clinical trials focusing on the prevention or treatment of PSCI, such as secondary prevention (Yaffe, 2019), pharmaceutical interventions (Lim et al., 2021), or non-pharmaceutical treatments (Yun et al., 2015). MTx may also be useful for tracking post-stroke cognitive status during the recovery period to assist in determining if the cognitive impairment trend is improving, stable, or deteriorating, as well as evaluating treatment efficacy. In the future, we will explore the value of MTx in predicting PSCI through a cohort study.

The current study has several limitations. First, the sample size was small. Therefore, these results may be viewed as only preliminary, pending confirmation from further larger studies. Additional research focused on a larger group of different patients should be carried out to verify the findings from this study. Second, in this study, the NIHSS scores of patients who voluntarily returned for follow-up were relatively mild, and the screening point was only at D90. In the next research phase, we will include more patients with severe NIHSS scores and extend the follow-up period. Third, this is a cross-sectional study. Future efforts should include implementing a prospective longitudinal study to evaluate stroke patients across different time periods to evaluate the flexibility and effectiveness of MTx for tracking changes of cognitive function. MTx is currently under continuous development. With further comprehensive analyses from MTx to date and ongoing usage in cognitive screening, we anticipate there will be informed updates and variations to the MTx paradigm that will support multi-dimensional testing and assessments to cover broader aspects of cognitive function.

Our study proved MemTrax was effective in screening for PSCI in AIS patients. This user-friendly computerized could be valuable for managing post-stroke patients, particularly in detecting and monitoring PSCI. Future studies will evaluate MemTrax’s utility in tracking cognitive health and assessing the effectiveness of interventions in post-stroke patients.

The original contributions presented in this study are included in the article/Supplementary material, further inquiries can be directed to the corresponding authors.

This study was performed according to the Helsinki declaration of 1975 and was approved by the Ethical Committee of the First Affiliated Hospital of Kunming Medical University in Kunming, Yunnan, China (2020-L-56). All participants voluntarily signed an informed consent document.

XL, JZ, and JA designed study. SD, XZha, and XL wrote the main manuscript text. XZha, RZ, XC, and MZ collected data. JZ and LZ analyzed data. SD, XZha, and JZ prepared figures and tables. MB, JA, XL, and XZho edited the manuscript. All authors contributed to the article and approved the submitted version.