Dual Impairment in Cognition and Physical Performance After Stroke: Prevalence, Pathogenesis and Prediction of Function

Dual impairment of physical performance and cognition has been reported to increase the risk of dementia, falls, and functional dependency. However, this coexistence of impairments has to a little extent been explored in stroke populations; instead, these impairments have been studied, diagnosed, and treated as distinct entities. As a result, further knowledge is needed to delineate the underlying pathological mechanisms of dual impairment and their consequences for long-term function in stroke survivors. The overall aim of this thesis was to investigate both the synergistic relationship between physical performance and cognition after stroke and the associations between functional outcomes and brain pathology. This thesis was based on data from baseline and 3- and 18-month follow-ups of the Norwegian Cognitive Impairment After Stroke (Nor-COAST) study, a prospective multicenter cohort study including 815 participants admitted to stroke units with acute stroke in five Norwegian hospitals between May 2015 and March 2017. Performance-based assessments included the Montreal Cognitive Assessment (MoCA) and Short Physical Performance Battery (SPPB) at baseline and 3-month follow-up. In addition, executive function, memory, grip strength, and dual task cost were assessed at 3-month follow-up. Instrumental activities of daily living (IADL) were assessed at 3-and 18-month follow-up with the Nottingham Extended ADL (NEADL) questionnaire. Approximately half of the Nor-COAST participants were included in an MRI sub-study in which information was obtained on markers of cerebrovascular and neurodegenerative pathology, as well as on stroke lesion location and volume. Results from Paper 1 showed that every third participant in our sample showed impairment in either cognitive or physical function at 3 months post-stroke, with rates of concurrent impairment ranging from 10% to 23%, depending on which combination of assessments was applied. Impairments in physical performance and grip strength were associated with impaired global cognition, executive dysfunction, and impaired memory. Higher dual-task cost was only associated with executive dysfunction. In Paper 2, combining measures of physical performance and cognition was found to be superior to assessing one domain exclusively in the prediction of change in IADL from 3 to 18 months post-stroke; however, cognition appeared to be a stronger predictor than physical performance when applied in combination within the same model. Overall, a stable level of IADL function was found among participants, but high scores on measures of both physical performance and cognition at 3 months post-stroke were associated with a statistically significant improvement in function over the ensuing 15 months. Results from Paper 3 showed that a larger stroke lesion volume was associated with dual impairment in cognition and physical performance at the time of stroke. Pre-existing pathology was found in two-thirds of the participants; however, associations with dual impairment were not significant when adjusting for age, whereas the association with stroke lesion volume remained significant. Participants with dual impairment were older, had poorer pre-stroke function, and suffered more severe stroke, on average, than participants with only one or no impaired domain. To summarize, this thesis found that impairments in cognition and physical performance are observed in a substantial number of stroke patients, and that performance-based testing of dual impairment at 3 months post-stroke is useful for predicting IADL function at 18 months. These results contribute to increased knowledge of the interplay between post-stroke cognition and physical performance, their associations with brain pathology at the time of stroke, and their role in the prediction of long-term function. The identification of dual impairments at 3 months post-stroke may be relevant for preventing functional decline and supports the adoption of a holistic treatment approach for this patient group. Further research is needed to refine the methods for identifying risk profiles and developing personalized rehabilitation that targets especially vulnerable populations following stroke

Assiciation between in-hospital frailty and health related quality of life three months after stroke: the Nor-COAST study

Background Stroke survivors are known to have poorer health-related quality of life (HRQoL) than the general population, but less is known about characteristics associated with HRQoL decreasing through time following a stroke. This study aims to examine how in-hospital frailty is related to HRQoL from 3 to 18 months post stroke. Method Six hundred twenty-five participants hospitalised with stroke were included and followed up at 3 and/or 18 months post stroke. Stroke severity was assessed the day after admission with the National Institutes of Health Stroke Scale (NIHSS). A modified Fried phenotype was used to assess in-hospital frailty; measures of exhaustion, physical activity, and weight loss were based on pre-stroke status, while gait speed and grip strength were measured during hospital stay. HRQoL at 3- and 18-months follow-up were assessed using the five-level version of the EuroQol five-dimensional descriptive system (EQ-5D-5L) and the EuroQol visual analogue scale (EQ-5D VAS). We conducted linear mixed effect regression analyses unadjusted and adjusted for sex, age, and stroke severity to investigate the association between in-hospital frailty and post-stroke HRQoL. Results Mean (SD) age was 71.7 years (11.6); mean NIHSS score was 2.8 (4.0), and 263 (42.1%) were female. Frailty prevalence was 10.4%, while 58.6% were pre-frail. The robust group had EQ-5D-5L index and EQ-5D VAS scores at 3 and 18 months comparable to the general population. Also at 3 and 18 months, the pre-frail and frail groups had significantly lower EQ-5D-5L indices than the robust group (p <  0.001), and the frail group showed a larger decrease from 3 to 18 months in the EQ-5D-5L index score compared to the robust group (− 0.056; 95% CI − 0.104 to − 0.009; p = 0.021). There were no significant differences in change in EQ-5D VAS scores between the groups. Conclusion This study on participants mainly diagnosed with mild strokes suggests that robust stroke patients have fairly good and stable post-stroke HRQoL, while post-stroke HRQoL is impaired and continues to deteriorate among patients with in-hospital frailty. This emphasises the importance of a greater focus on frailty in stroke units

Post-stroke Cognitive Impairment—Impact of Follow-Up Time and Stroke Subtype on Severity and Cognitive Profile: The Nor-COAST Study

Background: Post-stroke cognitive impairment (PSCI) is common, but evidence of cognitive symptom profiles, course over time, and pathogenesis is scarce. We investigated the significance of time and etiologic stroke subtype for the probability of PSCI, severity, and cognitive profile. Methods: Stroke survivors (n = 617) underwent cognitive assessments of attention, executive function, memory, language, perceptual-motor function, and the Montreal Cognitive Assessment (MoCA) after 3 and/or 18 months. PSCI was classified according to DSM-5 criteria. Stroke severity was assessed with the National Institutes of Health Stroke Scale (NIHSS). Stroke subtype was categorized as intracerebral hemorrhage (ICH), large artery disease (LAD), cardioembolic stroke (CE), small vessel disease (SVD), or un-/other determined strokes (UD). Mixed-effects logistic or linear regression was applied with PSCI, MoCA, and z-scores of the cognitive domains as dependent variables. Independent variables were time as well as stroke subtype, time, and interaction between these. The analyses were adjusted for age, education, and sex. The effects of time and stroke subtype were analyzed by likelihood ratio tests (LR). Results: Mean age was 72 years (SD 12), 42% were females, and mean NIHSS score at admittance was 3.8 (SD 4.8). Probability (95% CI) for PSCI after 3 and 18 months was 0.59 (0.51–0.66) and 0.51 (0.52–0.60), respectively and remained constant over time. Global measures and most cognitive domains were assessed as impaired for the entire stroke population and for most stroke subtypes. Executive function and language improved for the entire stroke population (LR) = 9.05, p = 0.003, and LR = 10.38, p = 0.001, respectively). After dividing the sample according to stroke subtypes, language improved for ICH patients (LR = 18.02, p = 0.003). No significant differences were found in the severity of impairment between stroke subtypes except for attention, which was impaired for LAD and CE in contrast to no impairment for SVD (LR = 56.58, p < 0.001). Conclusions: In this study including mainly minor strokes, PSCI is common for all subtypes, both early and long-term after stroke, while executive function and language improve over time. The findings might contribute to personalizing follow-up and offer new insights into underlying mechanisms. Further research is needed on underlying mechanisms, PSCI prevention and treatment, and relevance for rehabilitation

Post-stroke Cognitive Impairment—Impact of Follow-Up Time and Stroke Subtype on Severity and Cognitive Profile: The Nor-COAST Study

Background: Post-stroke cognitive impairment (PSCI) is common, but evidence of cognitive symptom profiles, course over time, and pathogenesis is scarce. We investigated the significance of time and etiologic stroke subtype for the probability of PSCI, severity, and cognitive profile. Methods: Stroke survivors (n = 617) underwent cognitive assessments of attention, executive function, memory, language, perceptual-motor function, and the Montreal Cognitive Assessment (MoCA) after 3 and/or 18 months. PSCI was classified according to DSM-5 criteria. Stroke severity was assessed with the National Institutes of Health Stroke Scale (NIHSS). Stroke subtype was categorized as intracerebral hemorrhage (ICH), large artery disease (LAD), cardioembolic stroke (CE), small vessel disease (SVD), or un-/other determined strokes (UD). Mixed-effects logistic or linear regression was applied with PSCI, MoCA, and z-scores of the cognitive domains as dependent variables. Independent variables were time as well as stroke subtype, time, and interaction between these. The analyses were adjusted for age, education, and sex. The effects of time and stroke subtype were analyzed by likelihood ratio tests (LR). Results: Mean age was 72 years (SD 12), 42% were females, and mean NIHSS score at admittance was 3.8 (SD 4.8). Probability (95% CI) for PSCI after 3 and 18 months was 0.59 (0.51–0.66) and 0.51 (0.52–0.60), respectively and remained constant over time. Global measures and most cognitive domains were assessed as impaired for the entire stroke population and for most stroke subtypes. Executive function and language improved for the entire stroke population (LR) = 9.05, p = 0.003, and LR = 10.38, p = 0.001, respectively). After dividing the sample according to stroke subtypes, language Aam et al. Post-stroke Cognitive Impairment improved for ICH patients (LR = 18.02, p = 0.003). No significant differences were found in the severity of impairment between stroke subtypes except for attention, which was impaired for LAD and CE in contrast to no impairment for SVD (LR = 56.58, p < 0.001). Conclusions: In this study including mainly minor strokes, PSCI is common for all subtypes, both early and long-term after stroke, while executive function and language improve over time. The findings might contribute to personalizing follow-up and offer new insights into underlying mechanisms. Further research is needed on underlying mechanisms, PSCI prevention and treatment, and relevance for rehabilitation

Associations between post-stroke motor and cognitive function: a cross-sectional study

Background Motor and cognitive impairments are frequently observed following stroke, but are often managed as distinct entities, and there is little evidence regarding how they are related. The aim of this study was to describe the prevalence of concurrent motor and cognitive impairments 3 months after stroke and to examine how motor performance was associated with memory, executive function and global cognition. Methods The Norwegian Cognitive Impairment After Stroke (Nor-COAST) study is a prospective multicentre cohort study including patients hospitalized with acute stroke between May 2015 and March 2017. The National Institutes of Health Stroke Scale (NIHSS) was used to measure stroke severity at admission. Level of disability was assessed by the Modified Rankin Scale (mRS). Motor and cognitive functions were assessed 3 months post-stroke using the Montreal Cognitive Assessment (MoCA), Trail Making Test Part B (TMT-B), 10-Word List Recall (10WLR), Short Physical Performance Battery (SPPB), dual-task cost (DTC) and grip strength (Jamar®). Cut-offs were set according to current recommendations. Associations were examined using linear regression with cognitive tests as dependent variables and motor domains as covariates, adjusted for age, sex, education and stroke severity. Results Of 567 participants included, 242 (43%) were women, mean (SD) age was 72.2 (11.7) years, 416 (75%) had an NIHSS score ≤ 4 and 475 (84%) had an mRS score of ≤2. Prevalence of concurrent motor and cognitive impairment ranged from 9.5% for DTC and 10WLR to 22.9% for grip strength and TMT-B. SPPB was associated with MoCA (regression coefficient B = 0.465, 95%CI [0.352, 0.578]), TMT-B (B = -9.494, 95%CI [− 11.726, − 7.925]) and 10WLR (B = 0.132, 95%CI [0.054, 0.211]). Grip strength was associated with MoCA (B = 0.075, 95%CI [0.039, 0.112]), TMT-B (B = -1.972, 95%CI [− 2.672, − 1.272]) and 10WLR (B = 0.041, 95%CI [0.016, 0.066]). Higher DTC was associated with more time needed to complete TMT-B (B = 0.475, 95%CI [0.075, 0.875]) but not with MoCA or 10WLR. Conclusion Three months after suffering mainly minor strokes, 30–40% of participants had motor or cognitive impairments, while 20% had concurrent impairments. Motor performance was associated with memory, executive function and global cognition. The identification of concurrent impairments could be relevant for preventing functional decline

Associations between post-stroke motor and cognitive function: a cross-sectional study

Background Motor and cognitive impairments are frequently observed following stroke, but are often managed as distinct entities, and there is little evidence regarding how they are related. The aim of this study was to describe the prevalence of concurrent motor and cognitive impairments 3 months after stroke and to examine how motor performance was associated with memory, executive function and global cognition. Methods The Norwegian Cognitive Impairment After Stroke (Nor-COAST) study is a prospective multicentre cohort study including patients hospitalized with acute stroke between May 2015 and March 2017. The National Institutes of Health Stroke Scale (NIHSS) was used to measure stroke severity at admission. Level of disability was assessed by the Modified Rankin Scale (mRS). Motor and cognitive functions were assessed 3 months post-stroke using the Montreal Cognitive Assessment (MoCA), Trail Making Test Part B (TMT-B), 10-Word List Recall (10WLR), Short Physical Performance Battery (SPPB), dual-task cost (DTC) and grip strength (Jamar®). Cut-offs were set according to current recommendations. Associations were examined using linear regression with cognitive tests as dependent variables and motor domains as covariates, adjusted for age, sex, education and stroke severity. Results Of 567 participants included, 242 (43%) were women, mean (SD) age was 72.2 (11.7) years, 416 (75%) had an NIHSS score ≤ 4 and 475 (84%) had an mRS score of ≤2. Prevalence of concurrent motor and cognitive impairment ranged from 9.5% for DTC and 10WLR to 22.9% for grip strength and TMT-B. SPPB was associated with MoCA (regression coefficient B = 0.465, 95%CI [0.352, 0.578]), TMT-B (B = -9.494, 95%CI [− 11.726, − 7.925]) and 10WLR (B = 0.132, 95%CI [0.054, 0.211]). Grip strength was associated with MoCA (B = 0.075, 95%CI [0.039, 0.112]), TMT-B (B = -1.972, 95%CI [− 2.672, − 1.272]) and 10WLR (B = 0.041, 95%CI [0.016, 0.066]). Higher DTC was associated with more time needed to complete TMT-B (B = 0.475, 95%CI [0.075, 0.875]) but not with MoCA or 10WLR. Conclusion Three months after suffering mainly minor strokes, 30–40% of participants had motor or cognitive impairments, while 20% had concurrent impairments. Motor performance was associated with memory, executive function and global cognition. The identification of concurrent impairments could be relevant for preventing functional decline