Cognitive testing following transient ischaemic attack: A systematic review of clinical assessment tools

Cognitive deficits are prevalent after transient ischaemic attack (TIA) and result in loss of function, poorer quality of life and increased risks of dependency and mortality. This systematic review aimed to synthesise the available evidence on cognitive assessment in TIA patients to determine the prevalence of cognitive deficits, and the optimal tests for cognitive assessment. Medline, Embase, PsychINFO and CINAHL databases were searched for relevant articles. Articles were screened by title and abstract. Full-text analysis and quality assessment was performed using the National Institute of Health Tool. Data were extracted on study characteristics, prevalence of TIA deficits, and key study findings. Due to significant heterogeneity, meta-analysis was not possible. Twenty-five full-text articles met the review inclusion criteria. There was significant heterogeneity in terms of cognitive tests used, definitions of cognitive impairment and TIA, time points post-event, and analysis methods. The majority of studies used the Mini-Mental State Examination (MMSE) or Montreal Cognitive Assessment (MoCA) (n = 23). Prevalence of cognitive impairment ranged from 2% to 100%, depending on the time-point and cognitive domain studied. The MoCA was more sensitive than the MMSE for identifying cognitive deficits. Deficits were common in executive function, attention, and language. No studies assessed diagnostic test accuracy against a reference standard diagnosis of cognitive impairment. Recommendations on cognitive testing after TIA are hampered by significant heterogeneity between studies, as well as a lack of diagnostic test accuracy studies. Future research should focus on harmonising tools, definitions, and time-points, and validating tools specifically for the TIA population.

The Cognition and Flow Study (CogFlowS): A Mixed Method Evaluation of a Randomized Feasibility Trial of Cognitive Training in Dementia

Background: Cognitive training (CT) may be beneficial in delaying the onset or slowing dementia progression. CT has been evaluated quantitatively and qualitatively, but none have used mixed methods approaches. Objective: The aim of this study was to use a mixed methods approach to identify those who may selectively benefit from CT. Methods: This was an explanatory sequential mixed methods study involving a quantitative randomized trial of 12 weeks multi-domain CT in healthy older adults (HC, n = 20), and people living with mild cognitive impairment (MCI; n = 12) and dementia (n = 24). Quantitative outcomes included: cognition, mood, quality of life, and activities of daily living. 28 (10 HC, 6 MCI, 12 dementia) training participants completed semi-structured interviews with their carer. Quantitative and qualitative data were integrated using joint displays. Results: Three participants dropped out from the training early-on, leaving 25 participants with follow-up data for full integration (10 HC, 6 MCI, 9 dementia). Dropouts and lower adherence to training were more common in dementia participants with greater non-modifiable barriers. High adherers were more resilient to negative emotions, and poorer or fluctuating performance. Integrated analysis found the majority of participants (n = 24) benefited across outcomes, with no clear profile of individuals who benefited more than others. Participants made a number of key recommendations to improve adherence and minimize dropout to CT. Conclusion: Reasons for dropout and low adherence were identified, with recommendations provided for the design of CT for dementia. An individual approach to training should be adopted and low adherence should not preclude engagement with CT.

Qualitative Analysis of the Cognition and Flow (CoGFlowS) Study: An Individualized Approach to Cognitive Training for Dementia Is Needed

BACKGROUND

Cognitive training (CT) may have benefits for both healthy older adults (HC) and those with early cognitive disorders [mild cognitive impairment (MCI) and dementia]. However, few studies have qualitatively evaluated home-based, computerized CT programs.

OBJECTIVE

We present the qualitative arm of a feasibility randomized controlled trial evaluating a CT program for HC and people living with MCI or dementia.

METHODS

Participants underwent semi-structured interviews after 12 weeks of CT. Where possible, participants were interviewed with their carers. The interview schedule and analysis were underpinned by the health belief model. Interviews were audio-recorded, transcribed, open-coded, and categorized into themes. The analytical framework was developed, and themes were condensed under five major categories: benefits, barriers, threat, self-efficacy, and cues to action.

RESULTS

37 participants underwent interviews. CT was feasible and acceptable to participants. Benefits included: enjoyment, improved awareness, benchmarking cognitive function, reassurance of abilities and giving back control. Barriers were more prevalent among those with dementia: problems with technology, frustration, conflict between patients and carers, apathy and lack of insight, anxiety or low mood, and lack of portability. HC and MCI perceived the severity of dementia risk as high, partially mitigated by CT. Participants living with dementia valued a more individualized approach to training, accounting for baseline characteristics.

CONCLUSION

CT was a feasible intervention for HC and people living with dementia and MCI. Benefits were present, but the identified barriers need to be addressed for CT to be implemented successfully.

407 QUALITATIVE ASSESSMENT OF COGNITIVE TRAINING FOR PEOPLE LIVING WITH DEMENTIA: AN INDIVIDUALISED APPROACH IS NEEDED AUTHORS

Background

Cognitive training (CT) may be beneficial in mild cognitive impairment (MCI) and early dementia. However, few studies have qualitatively evaluated CT programmes in dementia. The aim of this analysis was to explore the benefits and barriers to a home-based computerised CT programme for healthy older adults, and people living with MCI or dementia.

Methods

This was a nested qualitative study within a larger feasibility randomised trial of CT. Participants underwent semi-structured interviews after 12 weeks of CT. Where possible, participants were interviewed with their carers. The interview schedule and analysis were underpinned by the health belief model. Interviews were audio-recorded, transcribed, open-coded, and categorised into themes. The analytical framework was developed, and themes were condensed under four major categories: benefits and efficacy, barriers, threat, and behaviour.

Results

37 participants underwent interviews (10 healthy older adults, 4 MCI, 5 dementia, 9 patient-carer dyads [2 MCI, 7 dementia]). CT was feasible and acceptable to participants. Benefits included: enjoyment, improved awareness, benchmarking cognitive function, reassurance of abilities, and giving back control. Barriers were more prevalent amongst those with dementia: problems with technology, frustration, conflict between patients and carers, apathy and lack of insight, anxiety or low mood, and lack of portability. Perceived risk susceptibility of dementia varied between participants. Healthy older adults and MCI perceived the severity of dementia risk as high, which was only partially mitigated by CT. Participants living with dementia valued a more individualised approach to training, accounting for baseline characteristics. For people living with dementia, maintenance was as valued as improvement of cognitive function.

Conclusions

CT was a feasible intervention for healthy older adults, and people living with dementia and MCI. Benefits were present, but the identified barriers need to be addressed for CT to be implemented successfully.

Driving in Parkinson's disease: a retrospective study of driving and mobility assessments

BACKGROUND

To guide decision-making about driving ability, some patients with Parkinson's disease (PD) undergo specialist driving assessment. However, decisions about driving safety in most patients need to be made without this definitive test. There is no consensus on what predicts unsafe driving in PD nor a validated prediction tool to guide clinician decision-making and the need to refer for further assessment.

OBJECTIVES

To describe the characteristics of patients with PD assessed at a Driving Mobility Centre and investigate factors that predict driving assessment outcome.

METHODS

Retrospective cohort study of patients with PD assessed between 2012 and 2016. Descriptive analyses and logistic models to determine factors predicting a negative outcome.

RESULTS

There were 86 assessments of patients with PD. The mean age was 70 years (±9.2), 86% were male, median disease duration 7 years (interquartile range 5-12.5 years) and 59% were referred by the Driver and Vehicle Licensing Agency. In total, 62% had a negative 'not drive' outcome. The Rookwood Driving Battery (RDB), depth of vision deficit, usual driving frequency, age, duration license held and response time were all predictors in univariable analysis. The RDB was the best predictor of assessment failure, conditional on other variables in a backward stepwise model (odds ratio 1.29; 95% confidence interval 1.05, 1.60; P = 0.015).

CONCLUSIONS

This is the first study to describe patients with PD undergoing driving assessments in the UK. In this population, RDB performance was the best predictor of outcome. Future prospective studies are required to better determine predictors of driving ability to guide development of prediction tools for implementation into clinical practice.

Chasing the evidence: the influence of data segmentation on estimates of dynamic cerebral autoregulation

OBJECTIVE

Transfer function analysis (TFA) of dynamic cerebral autoregulation (dCA) requires smoothing of spectral estimates using segmentation of the data (S_D). Systematic studies are required to elucidate the potential influence of S_D on dCA parameters.

APPROACH

Healthy subjects (HS, n = 237) and acute ischaemic stroke patients (AIS, n = 98) were included. Cerebral blood flow velocity (CBFV, transcranial Doppler ultrasound) was recorded supine at rest with continuous arterial blood pressure (BP, Finometer) for a minimum of 5 min. TFA was performed with durations S_D = 100, 50 or 25 s and 50% superposition to derive estimates of coherence, gain and phase for the BP-CBFV relationship. The autoregulation index (ARI) was estimated from the CBFV step response. Intrasubject reproducibility was expressed by the intraclass correlation coefficient (ICC).

MAIN RESULTS

In HS, the ARI, coherence, gain, and phase (low frequency) were influenced by S_D, but in AIS, phase (very low frequency) and ARI were not affected. ICC was excellent (>0.75) for all parameters, for both HS and AIS. For S_D = 100 s, ARI was different between HS and AIS (mean ± sdev: 5.70 ± 1.61 vs 5.1 ± 2.0; p < 0.01) and the significance of this difference was maintained for S_D = 50 s and 25 s. Using S_D = 100 s as reference, the rate of misclassification, based on a threshold of ARI ⩽ 4, was 6.3% for S_D = 50 s and 8.1% for S_D = 25 s in HS, with corresponding values of 11.7% and 8.2% in AIS patients, respectively.

SIGNIFICANCE

Further studies are warranted with S_D values lower than the recommended standard of S_D = 100 s, to explore possibilities of improving the reproducibility, sensitivity and prognostic value of TFA parameters used as metrics of dCA.

100 Prevalence of Cognitive Impairment in Vascular Surgery Patients: Preliminary Results of A Systematic Review and Meta-Analysis

Introduction

Single-centre studies have shown a high prevalence of undiagnosed cognitive impairment in patients undergoing vascular surgery. The aim of this meta-analysis was to estimate the pooled prevalence of cognitive impairment in vascular surgery patients.

Methods

A systematic review and meta-analysis was performed of studies reporting cognitive impairment in vascular surgery patients (PROSPERO registration: CRD42019134684). Databases searched included: Medline, Embase, Emcare, CINAHL, PsychINFO and Scopus. Studies were excluded if they: did not use a validated cognitive assessment tool, included patients with asymptomatic or sub-threshold (for treatment) disease, or excluded patients with cognitive impairment. Quality of included studies was assessed using Newcastle-Ottawa scores (NOS), risk of bias was assessed using the ROBINS-E tool, and quality of evidence assessed using GRADE criteria. A pooled estimate of prevalence was calculated using the inverse-variance method separately for carotid artery disease (CAD), lower extremity arterial disease (LEAD), and studies including patients with multiple vascular surgery presentations. Data were pooled using random effects models and estimated prevalence presented with 95% confidence intervals (95%CI). Subgroup analyses were performed by cognitive assessment tool used.

Authors of 24 studies meeting inclusion criteria that did not report numbers of cognitively impaired patients were contacted to enable inclusion: responses are awaited.

Results

After de-duplication of search results, 7,169 records were screened and 11 studies (911 patients) included in the meta-analysis. Nine studies were deemed high quality (NOS ≥7) however 8 studies had a serious risk of bias. Only one study explicitly stated provision for recruiting patients without capacity. Six different tools were used to assess cognitive function (MoCA, MMSE, ACE-R, HDS-R, Mini-Cog and a global cognitive score). Two studies found an association of cognitive impairment with post-op delirium whilst one did not, and a further study showed an association with increased length of stay.

Pooled estimate of prevalence of cognitive impairment in CAD patients was 38% (95%CI 17%, 62%; 7 studies), and in “vascular surgery patients” was 61% (95%CI 47%, 74%, 3 studies). Only one study reported prevalence of cognitive impairment in LEAD patients alone of 19% (95%CI 14%, 24%). Quality of evidence was moderate to very low.

Conclusions

Cognitive impairment is highly prevalent in vascular surgery patients highlighting the need for close collaboration between vascular surgeons and geriatricians.

Can we assess dynamic cerebral autoregulation in stroke patients with high rates of cardiac ectopicity?

It is unclear whether physiological recordings containing high numbers of ectopic heartbeats can be used to measure the cerebral autoregulation (CA) of blood flow. This study evaluated the utility of such data for assessing dynamic CA capacity. Physiological recordings of cerebral blood flow velocity, heart rate, end-tidal CO₂ and beat-to-beat blood pressure from acute ischaemic stroke (AIS) patients (n = 46) containing ectopic heartbeats of varying number (0.2 to 25 occurrences per minute) were analysed. Dynamic CA was determined using the autoregulation index (ARI) and the normalised mean square error (NMSE) was used to evaluate the fitting of the step response between BP and CBFV to Tiecks' model. We fitted linear mixed models on the CA variables incorporating ectopic burden, age, sex and hemisphere as predictor variables. Ectopic activity demonstrated an association with mean coherence (p = 0.006) but not with ARI (p = 0.162), impaired CA based on dichotomised ARI (p = 0.859) or NMSE (p = 0.671). Dynamic CA could be reliably assessed in AIS patients using physiological recordings with high rates of cardiac ectopic activity. This provides supportive data for future studies evaluating CA capability in AIS patients, with the potential to develop more individualised treatment strategies. Graphical Abstract.

Effects of brain training on brain blood flow (The Cognition and Flow Study-CogFlowS): protocol for a feasibility randomised controlled trial of cognitive training in dementia

INTRODUCTION

Cognitive training is an emerging non-pharmacological treatment to improve cognitive and physical function in mild cognitive impairment (MCI) and early Alzheimer's disease (AD). Abnormal brain blood flow is a key process in the development of cognitive decline. However, no studies have explored the effects of cognitive training on brain blood flow in dementia. The primary aim of this study is to assess the feasibility for a large-scale, randomised controlled trial of cognitive training in healthy older adults (HC), MCI and early AD.

METHODS AND ANALYSIS

This study will recruit 60 participants, in three subgroups of 20 (MCI, HC, AD), from primary, secondary and community services. Participants will be randomised to a 12-week computerised cognitive training programme (five × 30 min sessions per week), or waiting-list control. Participants will undergo baseline and follow-up assessments of: mood, cognition, quality of life and activities of daily living. Cerebral blood flow will be measured at rest and during task activation (pretraining and post-training) by bilateral transcranial Doppler ultrasonography, alongside heart rate (3-lead ECG), end-tidal CO2 (capnography) and beat-to-beat blood pressure (Finometer). Participants will be offered to join a focus group or semistructured interview to explore barriers and facilitators to cognitive training in patients with dementia. Qualitative data will be analysed using framework analysis, and data will be integrated using mixed methods matrices.

ETHICS AND DISSEMINATION

Bradford Leeds Research Ethics committee awarded a favourable opinion (18/YH/0396). Results of the study will be published in peer-reviewed journals, and presented at national and international conferences on ageing and dementia.

TRIALS REGISTRATION NUMBER

NCT03656107; Pre-results.

The Leicester cerebral haemodynamics database: normative values and the influence of age and sex

Normative values of physiological parameters hold significance in modern day clinical decision-making. Lack of such normative values has been a major hurdle in the translation of research into clinical practice. A large database containing uniform recordings was constructed to allow more robust estimates of normative ranges and also assess the influence of age and sex. Doppler recordings were performed on healthy volunteers in the same laboratory, using similar protocols and equipment. Beat-to-beat blood pressure, heart-rate, electrocardiogram, and end-tidal CO2 were measured continuously. Bilateral insonation of the middle cerebral arteries (MCAs) was performed using TCD following a 15 min stabilisation, and a 5 min baseline recording. Good quality Doppler recordings for both MCAs were obtained in 129 participants (57 female) with a median age of 57 years (range 20-82). Age was found to influence baseline haemodynamic and transfer function analysis parameters. Cerebral blood flow velocity and critical closing pressure were the only sex-related differences found, which was significantly higher in females than males. Normative values for cerebral haemodynamic parameters have been defined in a large, healthy population. Such age/sex-defined normal values can be used to reduce the burden of collecting additional control data in future studies, as well as to identify disease-associated changes.