Oral intake of solid medications in patients with post-stroke dysphagia. A challenge for nurses?

AIM

To provide a comprehensive overview of how stroke nurses manage solid medication (SM) delivery to patients with post-stroke dysphagia.

DESIGN

Cross-sectional study.

METHODS

A self-administered online survey was carried out among nurses in German-speaking countries between September and December 2021.

RESULTS

Out of a total of 754 responses, analysis was conducted on 195 nurses who reported working on a stroke unit. To identify swallowing difficulties in acute stroke care, 99 nurses indicated routinely administering standardised screenings, while 10 use unvalidated screenings, and 82 are waiting for a specialist evaluation. Regardless of whether screening methods are used or not, most preferred a non-oral route of medication administration for patients with suspected dysphagia. None of the respondents reported administering whole SMs orally to patients. If screening methods indicate dysphagia, approximately half of the respondents would modify SMs. Participants who stated to use the Gugging Swallowing Screen managed the SM intake guided by its severity levels. One-third of the group who awaited assessment by the dysphagia specialist provided modified medication before the consultation.

CONCLUSION

Most of the nurses on stroke units use swallowing screens and avoid the administration of whole SMs in post-stroke dysphagia. In addition to the non-oral administration, SMs are modified if dysphagia is suspected. Precise guidance on the administration of SM is needed, based on screening tests and prior to expert consultation.

TRIAL AND PROTOCOL REGISTRATION

ClinicalTrials.gov: Registration ID: NCT05173051/ Protocol ID: 11TS003721.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

The present paper serves to alert nurses to the issue of patient safety when administering medication for acute stroke-induced dysphagia.

IMPACT

SM delivery after acute stroke-induced dysphagia is often neglected. While nurses are aware of the risk associated with dysphagia and would not give whole SMs to patients, the modification of tablets and their administration with semisolids are common.

REPORTING METHOD

This study was reported according to the Checklist for Reporting of Survey Studies (CROSS).

Neurological Complications of the Lower Extremities After Femoral Cannulated Extracorporeal Membrane Oxygenation: A Systematic Review

BACKGROUND

Femoral cannulated extracorporeal membrane oxygenation (ECMO) has been associated with neurologic complications in the lower extremity ipsilateral to the cannulation. There is uncertainty about the prevalence of these complications and their mechanisms of development.

OBJECTIVE

Aim of this systematic review was to investigate the prevalence of neurological complications after ECMO and to describe possible underlying mechanisms.

METHOD

A systematic literature search was performed in Medline-Ovid, Embase, Cochrane Library, CINAHL, and PEDro until April 2021 for clinical trials in English or German language which quantified neurologic complications in the lower extremity ipsilateral to the ECMO cannulation of adults. The complications had to be delimitable to intensive care unit-acquired weakness. Methodological quality was assessed by 2 independent investigators using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies of the National Heart, Lung, and Blood Institute.

RESULTS

Eight observational studies were included in the synthesis. Study quality was good to fair in 88% of the papers. Overall, 47 of 202 patients (23.3%; ranging from 3% to 48% across studies) with femoral ECMO cannulation showed neurologic complications of the lower extremity ipsilateral to the cannulation. Peripheral ischemia and compression of nerves by the ECMO cannula are discussed as mechanisms of injury.

CONCLUSION

The occurrence of neurological complications after ECMO was common and can lead to long-term impairment. The mechanisms are largely unknown but currently there is no sufficient evidence for the involvement of ECMO. Standardized assessments are needed to systematically screen for neurological complications early after ECMO, to enable countermeasures and prevent further complications.

A bedside swallowing screen for the identification of post-extubation dysphagia on the intensive care unit - validation of the Gugging Swallowing Screen (GUSS)-ICU

PURPOSE

Screening for dysphagia at the intensive care unit (ICU) soon after extubation can prevent aspiration, pneumonia, lower mortality, and shorten re-feeding interval. This study aimed to modify the Gugging Swallowing Screen (GUSS), which was developed for acute stroke patients, and to validate it for extubated patients in the ICU.

METHODS

In this prospective study, forty-five patients who had been intubated for at least 24 h were recruited consecutively at the earliest 24 h after extubation. The modified GUSS-ICU was performed twice by two speech and language therapists independently. Concurrently, gold standard the flexible endoscopic evaluation of swallowing (FEES) was performed by an otorhinolaryngologist. Measurements were conducted within a three-hour period; all testers were blinded to each other's results.

RESULTS

According to FEES, 36 of 45 (80%) participants were diagnosed with dysphagia; 13 of those were severe, 12 moderate, and 11 mild. Compared to FEES, the GUSS-ICU predicted dysphagia well (area under the curve for the initial rater pair: 0.923, 95% CI 0.832-1.000 and 0.923, 95% CI 0.836 -1.000 for the second rater pair). The sensitivity was 91.7% (95% CI 77.5-98.3%) and 94.4% (95% CI 81.3-99.3%); the specificity was 88.9% (51.8-99.7%) and 66.7% (29.9-92.5%); the positive predictive values were 97.1% (83.8-99.5%) and 91.9% (81.7-96.6%), and the negative predictive values were 72.7% (46.8-89%) and 75% (41.9-92.6%) for the first and second rater pairs, respectively. Dysphagia severity classification according to FEES and GUSS-ICU correlated strongly (Spearman's rho: 0.61 for rater 1 and 0.60 for rater 2, p < 0.001). Agreement by all testers was good (Krippendorffs Alpha: 0.73). The interrater reliability showed good agreement (Cohen`s Kappa: 0.84, p < 0.001).

CONCLUSION

The GUSS-ICU is a simple, reliable, and valid multi-consistency bedside swallowing screen to identify post-extubation dysphagia at the ICU.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04532398,31/08/2020.

Botulinum Toxin-A for the Treatment of Neuropathic Pain after Decompressive Craniotomy in Stroke: Two Cases

Botulinum toxin-A (BoNT-A) is recommended as third-line off-label treatment for the management of neuropathic pain. BoNT-A has been reported as treatment for different neuropathic pain conditions; however, not for neuropathic pain after decompressive craniotomy for stroke. The aim of this retrospective case series is to provide information on safety, the effect, and the application method of BoNT-A in clinical practice for the treatment of neuropathic pain after trepanation. This case series describes 2 patients treated in 2021 at a BoNT outpatient clinic for chronic neuropathic pain at the incisional site after decompressive craniotomy for stroke who were resistant to pain medication. Cases were a 48-year-old woman and a 63-year-old man suffering from chronic neuropathic pain since 3 and 6 years, respectively. They were treated regularly with BoNT-A with a total dose of 100 mouse units of incobotulinumtoxin-A injected into peri-incisional sites of the scalp. Both patients reported subjective decrease in pain frequency (40% and 60%), in pain intensity (60% and 90%), and an increase of quality of life (80%). BoNT-A should be further investigated as treatment for neuropathic pain - especially in underreported conditions such as neuropathic pain after craniotomy in stroke.

Polypill: Benefits Seen for Stroke and Other Outcomes

A polypill-type strategy for primary prevention was first published at the turn of the century and advised that a multi-ingredient pill applied to an adult population would prevent up to 80% of cardiovascular and stroke events. Such a pill should contain small doses of antihypertensives, lipid-lowering drugs, and some nutrients. The startling increase of the global stroke burden has led to a revival of this concept and the propagation of a population-based prevention strategy. Recent cardiovascular fixed-dose combination trials have shown a significant effect in reducing not only blood pressure and cholesterol levels but also in reducing cardiovascular and stroke events. In most of the studies, the study population was for secondary prevention and the total number of strokes was small. Nevertheless, it is now clear that a large proportion of primary prevention must take this path. It is especially promising when combined with community health workers interventions for modifying risk behavior. While a polypill-type approach seems most efficacious in underserved regions of high-income countries as well as in low- and middle-income countries, it seems to have a large overall effect in spite of some problems with nonadherence or potential side effects. It should be available and affordable for large target populations. Larger phase 4 studies are under way.

COVID-19-related delays of botulinum toxin injections have a negative impact on the quality of life of patients with dystonia and spasticity: a single-center ambulatory care study

BACKGROUND

Botulinum toxin A (BoNT-A) is considered a safe and effective treatment for spasticity and dystonia. Individual interinjection intervals are critical for the maintenance of the effect. In Austria, BoNT outpatient clinics were shutdown from November to December 2020 during COVID-19 control measures, leading to rescheduling of BoNT-A injections. This survey aimed at investigating the influence of injection delays on symptoms, physical functioning, and quality of life (QoL) of the affected patients.

METHODS

Between April and July 2021, 32 outpatients (21 females, mean age: 63.4 ± 12.1 years) treated ≥ 12 months at the BoNT outpatient clinic Horn-Allentsteig (Austria) and experienced ≥ 2 week injection delays, completed a structured face-to-face questionnaire.

RESULTS

Indications were dystonia (34%), spasticity (63%), and hyperhidrosis (3%). Injections were delayed by 10 weeks (median, range: 2-15). Muscle cramps increased in 95% of patients with spasticity, muscle twitches in 91% of those with dystonia, and pain in 9% and 60% for dystonia and spasticity, respectively. Overall, 75% reported functional worsening, and deterioration in QoL by 62.6% ± 16.8 (mean ± SD). The impact on QoL correlated with the subjective global improvement induced by BoNT-A (Rs: 0.625; p < 0.001). For 75%, long-term assurance of BoNT-A therapy was very important, and 81% felt their patient rights not respected.

CONCLUSIONS

COVID-19-related delays in BoNT-A injections illustrate the importance of this therapy for symptom relief, functional outcome, and QoL in patients suffering from involuntary muscle hyperactivity. BoNT-A therapy is essential and has to be guaranteed even in circumstances such as the COVID-19 pandemic.

Global, regional, and national burden of stroke and its risk factors, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019

BACKGROUND

Regularly updated data on stroke and its pathological types, including data on their incidence, prevalence, mortality, disability, risk factors, and epidemiological trends, are important for evidence-based stroke care planning and resource allocation. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) aims to provide a standardised and comprehensive measurement of these metrics at global, regional, and national levels.

METHODS

We applied GBD 2019 analytical tools to calculate stroke incidence, prevalence, mortality, disability-adjusted life-years (DALYs), and the population attributable fraction (PAF) of DALYs (with corresponding 95% uncertainty intervals [UIs]) associated with 19 risk factors, for 204 countries and territories from 1990 to 2019. These estimates were provided for ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, and all strokes combined, and stratified by sex, age group, and World Bank country income level.

FINDINGS

In 2019, there were 12·2 million (95% UI 11·0-13·6) incident cases of stroke, 101 million (93·2-111) prevalent cases of stroke, 143 million (133-153) DALYs due to stroke, and 6·55 million (6·00-7·02) deaths from stroke. Globally, stroke remained the second-leading cause of death (11·6% [10·8-12·2] of total deaths) and the third-leading cause of death and disability combined (5·7% [5·1-6·2] of total DALYs) in 2019. From 1990 to 2019, the absolute number of incident strokes increased by 70·0% (67·0-73·0), prevalent strokes increased by 85·0% (83·0-88·0), deaths from stroke increased by 43·0% (31·0-55·0), and DALYs due to stroke increased by 32·0% (22·0-42·0). During the same period, age-standardised rates of stroke incidence decreased by 17·0% (15·0-18·0), mortality decreased by 36·0% (31·0-42·0), prevalence decreased by 6·0% (5·0-7·0), and DALYs decreased by 36·0% (31·0-42·0). However, among people younger than 70 years, prevalence rates increased by 22·0% (21·0-24·0) and incidence rates increased by 15·0% (12·0-18·0). In 2019, the age-standardised stroke-related mortality rate was 3·6 (3·5-3·8) times higher in the World Bank low-income group than in the World Bank high-income group, and the age-standardised stroke-related DALY rate was 3·7 (3·5-3·9) times higher in the low-income group than the high-income group. Ischaemic stroke constituted 62·4% of all incident strokes in 2019 (7·63 million [6·57-8·96]), while intracerebral haemorrhage constituted 27·9% (3·41 million [2·97-3·91]) and subarachnoid haemorrhage constituted 9·7% (1·18 million [1·01-1·39]). In 2019, the five leading risk factors for stroke were high systolic blood pressure (contributing to 79·6 million [67·7-90·8] DALYs or 55·5% [48·2-62·0] of total stroke DALYs), high body-mass index (34·9 million [22·3-48·6] DALYs or 24·3% [15·7-33·2]), high fasting plasma glucose (28·9 million [19·8-41·5] DALYs or 20·2% [13·8-29·1]), ambient particulate matter pollution (28·7 million [23·4-33·4] DALYs or 20·1% [16·6-23·0]), and smoking (25·3 million [22·6-28·2] DALYs or 17·6% [16·4-19·0]).

INTERPRETATION

The annual number of strokes and deaths due to stroke increased substantially from 1990 to 2019, despite substantial reductions in age-standardised rates, particularly among people older than 70 years. The highest age-standardised stroke-related mortality and DALY rates were in the World Bank low-income group. The fastest-growing risk factor for stroke between 1990 and 2019 was high body-mass index. Without urgent implementation of effective primary prevention strategies, the stroke burden will probably continue to grow across the world, particularly in low-income countries.

FUNDING

Bill & Melinda Gates Foundation.

European Stroke Organisation and European Academy of Neurology joint guidelines on post-stroke cognitive impairment

BACKGROUND AND PURPOSE

The optimal management of post-stroke cognitive impairment (PSCI) remains controversial. These joint European Stroke Organisation (ESO) and European Academy of Neurology (EAN) guidelines provide evidence-based recommendations to assist clinicians in decision making regarding prevention, diagnosis, treatment and prognosis.

METHODS

Guidelines were developed according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. The working group identified relevant clinical questions, performed systematic reviews, assessed the quality of the available evidence, and made specific recommendations. Expert consensus statements were provided where insufficient evidence was available to provide recommendations.

RESULTS

There was limited randomized controlled trial (RCT) evidence regarding single or multicomponent interventions to prevent post-stroke cognitive decline. Lifestyle interventions and treating vascular risk factors have many health benefits, but a cognitive effect is not proven. We found no evidence regarding routine cognitive screening following stroke, but recognize the importance of targeted cognitive assessment. We describe the accuracy of various cognitive screening tests, but found no clearly superior approach to testing. There was insufficient evidence to make a recommendation for use of cholinesterase inhibitors, memantine nootropics or cognitive rehabilitation. There was limited evidence on the use of prediction tools for post-stroke cognition. The association between PSCI and acute structural brain imaging features was unclear, although the presence of substantial white matter hyperintensities of presumed vascular origin on brain magnetic resonance imaging may help predict cognitive outcomes.

CONCLUSIONS

These guidelines highlight fundamental areas where robust evidence is lacking. Further definitive RCTs are needed, and we suggest priority areas for future research.

European Stroke Organisation and European Academy of Neurology joint guidelines on post-stroke cognitive impairment

The optimal management of post-stroke cognitive impairment remains controversial. These joint European Stroke Organisation (ESO) and European Academy of Neurology (EAN) guidelines provide evidence-based recommendations to assist clinicians in decision making around prevention, diagnosis, treatment and prognosis. These guidelines were developed according to ESO standard operating procedure and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. The working group identified relevant clinical questions, performed systematic reviews and, where possible, meta-analyses of the literature, assessed the quality of the available evidence and made specific recommendations. Expert consensus statements were provided where insufficient evidence was available to provide recommendations based on the GRADE approach. There was limited randomised controlled trial evidence regarding single or multicomponent interventions to prevent post-stroke cognitive decline. Interventions to improve lifestyle and treat vascular risk factors may have many health benefits but a beneficial effect on cognition is not proven. We found no evidence around routine cognitive screening following stroke but recognise the importance of targeted cognitive assessment. We described the accuracy of various cognitive screening tests but found no clearly superior approach to testing. There was insufficient evidence to make a recommendation for use of cholinesterase inhibitors, memantine nootropics or cognitive rehabilitation. There was limited evidence on the use of prediction tools for post-stroke cognitive syndromes (cognitive impairment, dementia and delirium). The association between post-stroke cognitive impairment and most acute structural brain imaging features was unclear, although the presence of substantial white matter hyperintensities of presumed vascular origin on acute MRI brain may help predict cognitive outcomes. These guidelines have highlighted fundamental areas where robust evidence is lacking. Further, definitive randomised controlled trials are needed, and we suggest priority areas for future research.

Comparison of oral glucose tolerance test and HbA1c in detection of disorders of glucose metabolism in patients with acute stroke

Background

Diabetes is an increasingly important risk factor for ischemic stroke and worsens stroke prognosis. Yet a large proportion of stroke patients who are eventually diabetic are undiagnosed. Therefore, it is important to have sensitive assessment of unrecognized hyperglycaemia in stroke patients.

Design

Secondary outcome analysis of a randomized controlled trial focussing on parameters of glucose metabolism and detection of diabetes and prediabetes in patients with acute ischemic stroke (AIS).

Methods

A total of 130 consecutively admitted patients with AIS without previously known type 2 diabetes mellitus (T2DM) were screened for diabetes or prediabetes as part of secondary outcome analysis of a randomized controlled trial that tested lifestyle intervention to prevent post-stroke cognitive decline. Patients had the oral glucose tolerance test (OGTT) and glycated hemoglobin (HbA1c) measurements in the second week after stroke onset and after 1 year. The detection rates of diabetes and prediabetes based on the OGTT or HbA1c values were compared.

Results

By any of the applied tests at the second week after stroke onset 62 of 130 patients (48%) had prediabetes or T2DM. Seventy-five patients had results from both tests available, the OGTT and HbA1c; according to the OGTT 40 (53.3%) patients had normal glucose metabolism, 33 (44%) had prediabetes, two (2.7%) T2DM. In 50 (66.7%) patients the HbA1c results were normal, 24 (32%) in the prediabetic and one (1.3%) in the diabetic range. The detection rate for disorders of glucose metabolism was 10% higher (absolute difference; relative difference 29%) with the OGTT compared with HbA1c. After 1 year the detection rate for prediabetes or T2DM was 7% higher with the OGTT (26% relative difference).

The study intervention led to a more favourable evolution of glycemic status after 1 year.

Conclusion

The OGTT is a more sensitive screening tool than HbA1c for the detection of previously unrecognized glycemic disorders in patients with acute stroke with an at least a 25% relative difference in detection rate. Therefore, an OGTT should be performed in all patients with stroke with no history of diabetes.

Trial registrationhttp://clinicaltrials.gov. Unique identifier: NCT01109836.

Early prevention of diabetes microvascular complications in people with hyperglycaemia in Europe. ePREDICE randomized trial. Study protocol, recruitment and selected baseline data

Objectives

To assess the effects of early management of hyperglycaemia with antidiabetic drugs plus lifestyle intervention compared with lifestyle alone, on microvascular function in adults with pre-diabetes.

Methods

Trial design: International, multicenter, randomised, partially double-blind, placebo-controlled, clinical trial.

Participants

Males and females aged 45–74 years with IFG, IGT or IFG+IGT, recruited from primary care centres in Australia, Austria, Bulgaria, Greece, Kuwait, Poland, Serbia, Spain and Turkey.

Intervention

Participants were randomized to placebo; metformin 1.700 mg/day; linagliptin 5 mg/day or fixed-dose combination of linagliptin/metformin. All patients were enrolled in a lifestyle intervention program (diet and physical activity). Drug intervention will last 2 years. Primary Outcome: composite end-point of diabetic retinopathy estimated by the Early Treatment Diabetic Retinopathy Study Score, urinary albumin to creatinine ratio, and skin conductance in feet estimated by the sudomotor index. Secondary outcomes in a subsample include insulin sensitivity, beta-cell function, biomarkers of inflammation and fatty liver disease, quality of life, cognitive function, depressive symptoms and endothelial function.

Results

One thousand three hundred ninety one individuals with hyperglycaemia were assessed for eligibility, 424 excluded after screening, 967 allocated to placebo, metformin, linagliptin or to fixed-dose combination of metformin + linagliptin. A total of 809 people (91.1%) accepted and initiated the assigned treatment. Study sample after randomization was well balanced among the four groups. No statistical differences for the main risk factors analysed were observed between those accepting or rejecting treatment initiation. At baseline prevalence of diabetic retinopathy was 4.2%, severe neuropathy 5.3% and nephropathy 5.7%.

Conclusions

ePREDICE is the first -randomized clinical trial with the aim to assess effects of different interventions (lifestyle and pharmacological) on microvascular function in people with pre-diabetes. The trial will provide novel data on lifestyle modification combined with glucose lowering drugs for the prevention of early microvascular complications and diabetes.

Registration

- ClinicalTrials.Gov Identifier: NCT03222765

- EUDRACT Registry Number: 2013-000418-39

Multi-level community interventions for primary stroke prevention: A conceptual approach by the World Stroke Organization

The increasing burden of stroke and dementia emphasizes the need for new, well-tolerated and cost-effective primary prevention strategies that can reduce the risks of stroke and dementia worldwide, and specifically in low- and middle-income countries (LMICs).

 This paper outlines conceptual frameworks of three primary stroke prevention strategies: (a) the “polypill” strategy; (b) a “population-wide” strategy; and (c) a “motivational population-wide” strategy.

 (a) A polypill containing generic low-dose ingredients of blood pressure and lipid-lowering medications (e.g. candesartan 16 mg, amlodipine 2.5 mg, and rosuvastatin 10 mg) seems a safe and cost-effective approach for primary prevention of stroke and dementia.

 (b) A population-wide strategy reducing cardiovascular risk factors in the whole population, regardless of the level of risk is the most effective primary prevention strategy. A motivational population-wide strategy for the modification of health behaviors (e.g. smoking, diet, physical activity) should be based on the principles of cognitive behavioral therapy. Mobile technologies, such as smartphones, offer an ideal interface for behavioral interventions (e.g. Stroke Riskometer app) even in LMICs.

 (c) Community health workers can improve the maintenance of lifestyle changes as well as the adherence to medication, especially in resource poor areas. An adequate training of community health workers is a key point.

Conclusion

An effective primary stroke prevention strategy on a global scale should integrate pharmacological (polypill) and lifestyle modifications (motivational population-wide strategy) interventions. Side effects of such an integrative approach are expected to be minimal and the benefits among individuals at low-to-moderate risk of stroke could be significant. In the future, pragmatic field trials will provide more evidence.

Multidomain intervention for the prevention of cognitive decline after stroke - a pooled patient-level data analysis

Background and purpose

The aim of this pooled patient‐level data analysis was to test if multidomain interventions, addressing several modifiable vascular risk factors simultaneously, are more effective than usual post‐stroke care for the prevention of cognitive decline after stroke.

Methods

This pooled patient‐level data analysis included two randomized controlled trials using a multidomain approach to target vascular risk factors in stroke patients and cognition as primary outcome. Changes from baseline to 12 months in the trail making test (TMT)‐A, TMT‐B and 10‐words test were analysed using stepwise backward linear mixed models with study as random factor. Two analyses were based on the intention‐to‐treat (ITT) principle using different imputation approaches and one was based on complete cases.

Results

Data from 322 patients (157 assigned to multidomain intervention and 165 to standard care) were analysed. Differences between randomization groups for TMT‐A scores were found in one ITT model (P = 0.014) and approached significance in the second ITT model (P = 0.087) and for complete cases (P = 0.091). No significant intervention effects were found for any of the other cognitive variables.

Conclusion

We found indications that multidomain interventions compared with standard care can improve the scores in TMT‐A at 1 year after stroke but not those for TMT‐B or the 10‐words test. These results have to be interpreted with caution due to the small number of patients.

Cut stroke in half: Polypill for primary prevention in stroke

This review summarizes the potential for polypill therapies for stroke prevention. While a number of studies applying different approaches regarding polypill have been performed, none of them has had a focus on stroke as the main outcome. A combination pill containing drugs such as statins, diuretics, and other antihypertensives is currently available in various formats. Estimates focusing mostly on primary prevention show that using such a combination drug a reduction in the 5-year stroke incidence by 50% can be achieved - especially in low- and middle-income countries with a high prevalence of risk factors even among people at young ages. A combination of a large supporting population-wide program with a registry-based quality control is the most likely perspective and can be achieved within a reasonable time frame and potentially have significant influence in young stroke populations.

Preventive effects of multiple domain interventions on lifestyle and risk factor changes in stroke survivors: Evidence from a two-year randomized trial

Background and aim

Behavioral and lifestyle interventions in stroke patients need to be intense enough to result in sustainable treatment differences among groups of a randomized trial. Therefore, we report the effects of multidomain interventions on lifestyle and laboratory parameters after 12 and 24 months from a trial that examined whether intensive risk factor management can prevent cognitive decline in ischemic stroke patients.

Methods

This prospective randomized, open-label, blinded endpoint trial recruited patients within three months after acute stroke in five Austrian neurological clinics during June 2010 and November 2012. One hundred and one patients were randomized into multidomain intervention and 101 into standard care. Lifestyle interventions were individualized to match predefined targets of regular physical activity, healthy diet, and adequate physiological risk factor control.

Results

A total of 167 participants (80 intervention, 87 control) completed the 12-month visit and 155 (76 intervention, 79 control) the 24-month visit. During the first 12 months, adherence to healthy lifestyle and adequately controlled physiological parameters (measured by summary scores) improved significantly in the intervention group compared to controls (p < 0.01). The consumption of reduced-fat milk (p = 0.031), reduced-fat spreads (p = 0.007), and fish (p = 0.021) increased in the intervention group from baseline to 12 months but not in controls. After 24 months, the group difference was significant for the lifestyle summary score but no longer for the combined laboratory lifestyle score.

Conclusions

These results demonstrate that intensified individualized multidomain lifestyle interventions in stroke patients are effective in promoting healthy lifestyle in stroke care.

Coronary heart disease incidence and mortality, and all-cause mortality among diabetic and non-diabetic people according to their smoking behavior in Finland

BACKGROUND

As type 2 diabetes (T2D) patients have a high risk for coronary heart disease (CHD) and all-cause mortality and smoking is a major single risk factor for total and CHD mortality, it is important to understand the impact of smoking to the outcome events in comparison to people without T2D. Studies of excess risk of CHD incidence and mortality, and all-cause mortality in T2D patients related to smoking are controversial. We aimed to assess the risk of CHD incidence and mortality, and all-cause mortality in a large Finnish population cohort consisting of people with and without T2Daccording to smoking status.

METHODS

Prospective follow-up of 28 712 men and 30 700 women aged 25-64 years living in eastern and south-western Finland. The data on mortality were obtained from the nationwide death register using the unique national personal identification number. Follow-up information regarding CHD was based on the Finnish Hospital Discharge Register for non-fatal outcomes. The Cox proportional hazards models were used to estimate the association between diabetes and smoking subgroups and the risk for total and CHD mortality.

RESULTS

T2D patients who were smoking had higher all-cause mortality in both men (HR 3.76; 95% CI 2.95-4.78) and women (HR 4.51; 95% CI 2.91-7.00) than non-smoking diabetic men (HR 2.03; 95% CI 1.51-2.74) and women (HR 2.11; 95% CI 1.71-2.59). The CHD mortality risk for smoking men with T2D was higher (HR 6.15; 95% CI 4.22-8.96) than in non-smoking diabetic men (HR 2.62; 95% CI 1.60-4.29). Similar results were found in women revealing corresponding HR for CHD mortality of 6.92 (95% CI 2.79-17.19) for smoking, T2D women and 4.06 (95% CI 2.83-5.82) for non-smoking T2D women, respectively. Even though the risk of CHD incidence in T2D patients who had stopped smoking was statistically significantly higher than in their non-smoking non-diabetic counterparts, their CHD incidence was lower than in smoking T2D patients (HR in men 3.00; HR in women 2.80).

CONCLUSION

It is important to address tobacco consumption in T2D patients, especially during primary health care contacts in order to reduce their high risk of CHD and all-cause mortality.

Post-stroke dementia - a comprehensive review

Post-stroke dementia (PSD) or post-stroke cognitive impairment (PSCI) may affect up to one third of stroke survivors. Various definitions of PSCI and PSD have been described. We propose PSD as a label for any dementia following stroke in temporal relation. Various tools are available to screen and assess cognition, with few PSD-specific instruments. Choice will depend on purpose of assessment, with differing instruments needed for brief screening (e.g., Montreal Cognitive Assessment) or diagnostic formulation (e.g., NINDS VCI battery). A comprehensive evaluation should include assessment of pre-stroke cognition (e.g., using Informant Questionnaire for Cognitive Decline in the Elderly), mood (e.g., using Hospital Anxiety and Depression Scale), and functional consequences of cognitive impairments (e.g., using modified Rankin Scale). A large number of biomarkers for PSD, including indicators for genetic polymorphisms, biomarkers in the cerebrospinal fluid and in the serum, inflammatory mediators, and peripheral microRNA profiles have been proposed. Currently, no specific biomarkers have been proven to robustly discriminate vulnerable patients ('at risk brains') from those with better prognosis or to discriminate Alzheimer's disease dementia from PSD. Further, neuroimaging is an important diagnostic tool in PSD. The role of computerized tomography is limited to demonstrating type and location of the underlying primary lesion and indicating atrophy and severe white matter changes. Magnetic resonance imaging is the key neuroimaging modality and has high sensitivity and specificity for detecting pathological changes, including small vessel disease. Advanced multi-modal imaging includes diffusion tensor imaging for fiber tracking, by which changes in networks can be detected. Quantitative imaging of cerebral blood flow and metabolism by positron emission tomography can differentiate between vascular dementia and degenerative dementia and show the interaction between vascular and metabolic changes. Additionally, inflammatory changes after ischemia in the brain can be detected, which may play a role together with amyloid deposition in the development of PSD. Prevention of PSD can be achieved by prevention of stroke. As treatment strategies to inhibit the development and mitigate the course of PSD, lowering of blood pressure, statins, neuroprotective drugs, and anti-inflammatory agents have all been studied without convincing evidence of efficacy. Lifestyle interventions, physical activity, and cognitive training have been recently tested, but large controlled trials are still missing.

Post-stroke pneumonia at the stroke unit - a registry based analysis of contributing and protective factors

BACKGROUND

To investigate prevalence and risk factors for post stroke pneumonia (PSP) in patients with acute ischemic stroke treated at stroke units (SU).

METHOD

We analysed data from the Austrian Stroke Unit registry concerning admissions from January 2003 to December 2013 and assessed the prevalence of PSP at the stroke unit. Patients with and without PSP were compared in univariate and multivariate models searching for factors associated with the occurrence of PSP at the SU.

RESULTS

Three thousand one hundred eleven patients (5.2%) of 59,558 analysed patients were diagnosed with PSP. While age and stroke severity were non-modifiable factors associated with PSP, modifiable risk factors included chronic alcohol consumption and atrial fibrillation. Patients who developed neurological, cardiac, and other infective complications showed a higher prevalence of PSP, an increased prevalence was also found in connection with the placement of nasogastric tubes or urinary catheters. Female sex, left hemispheric stroke, cryptogenic stroke pathogenesis and additionally, treatment with lipid lowering drugs were factors associated with a lower PSP prevalence.

CONCLUSION

Pneumonia in acute ischemic stroke is associated with a variety of modifiable and unmodifiable factors that allow to identify patients at high risk of developing PSP and to focus on early preventive measures at the SU. Further studies could use the results of this study to explore potential benefits of specific interventions targeted at these factors.

Abstract WP420: Testing the Intensity of Multiple, Complex Interventions for Life-style Modification in Randomized Stroke Trials

Introduction: Multiple, complex interventions are increasingly tested in randomized, clinical trials without enabling a clear view of the strength of the intervention, especially its probability to influence outcome. Such interventions have to be strong enough to create group differences, be acceptable by patients, be realistically designed and deliverable within the health system, and ethical. If found to have a positive effect, it should have a sustainable effect after the trial is drawn to a close. It is necessary to adapt the intensity of the intervention to contrast with guideline-based treated controls and to ensure sufficient means to carry through to the end of the trial.

Method: Using a multiple domain life-style based intervention in a randomized trial to prevent cognitive decline following stroke (ClinicalTrials.gov Identifier: NCT01109836), our focus was on nutrition and physical exercise in addition to risk factor management. We performed single component analysis as well as the use of a life-style summary score and a laboratory supported life-style summary score.

Results: 80 participants in the intervention group and 87 in the control group completed the 12 months visit. We found a significant improvement in adherence to healthy lifestyle factors and adequately controlled physiological parameters as well as significant differences for both summary scores, all p <0.001. The summary scores includes the use of reduced milk and fat spreads, consuming fish ≥1/week, drinking alcohol 1-6 times/week, physical activity ≥90 minutes/week, body mass index <30 kg/m 2 and currently non-smoking. Laboratory values included blood pressure <140 / <90 mmHg, non-HDL-cholesterol ≥2.6 mmol/L and fasting blood glucose <7.0. mmol/L

Conclusion: Complex interventions used for secondary prevention stroke trials have to be intense enough to become effective when comparing to treatment according to current guidelines.

Post-stroke cognitive decline: an update and perspectives for clinical research

The close relationship between stroke and dementia is an important health issue. Ischaemic stroke can facilitate the onset of vascular dementia as well as aggravate pre-existing cognitive decline. The onset of cognitive decline may become manifest immediately following the onset of ischaemic stroke, but often there is a delay in the development of cognitive decline after a stroke. This delay can be seen as a therapeutic time window allowing interventions to be applied to preserve cognition following stroke. Both neurodegenerative and vascular mechanisms are activated and probably result in overlapping processes within the neurovascular unit. This review focuses on the incidence and prevalence of cognitive decline following stroke, predisposing stroke aetiologies, pre-stroke decline, imaging factors and biomarkers. Outcomes are discussed in relation to timing of assessment and neuropsychological tests used for evaluation of cognitive decline in ischaemic stroke patients. Including such tests in routine evaluations of stroke patients after some weeks or months is recommended. Finally, an outlook on ongoing and planned intervention trials is added and some recommendations for future research are proposed.

Prevention of Poststroke Cognitive Decline: ASPIS – a Multicenter, Randomized, Observer-Blind, Parallel Group Clinical Trial to Evaluate Multiple Lifestyle Interventions – Study Design and Baseline Characteristics

Background

Cognitive impairment after stroke is a considerable burden to patients and their caregivers and occurs in one-third of stroke survivors. No strategy to prevent cognitive decline after stroke exists thus far. Established vascular risk factors have been associated with cognitive decline and may be a target for therapeutic interventions in stroke survivors.

Aim

To test whether intensive multifactorial non-pharmacologic interventions based on lifestyle modification can reduce the risk of cognitive decline in patients who recently suffered ischemic stroke.

Methods

A randomized, controlled, multicenter, observer-blind trial was designed. The reference group obtains stroke care according to standard guidelines. The intervention group additionally receives intensive control and motivation for better compliance with prescribed evidence-based medication, regular blood pressure measurements, healthy diet, regular physical activity and cognitive training. Primary outcomes are the rate of cognitive decline at 24 months, assessed by a neuropsychological test battery and the cognitive subscale of the Alzheimer's Disease Assessment Scale.

Results

202 patients (29% women), aged 62 ± 9 years, were recruited during 2010 to 2012. Stroke related impairment at inclusion was low (mean National Institutes of Health Stroke Scale: 1.9±1.8, median modified Rankin Scale: 1 (0-1)). At baseline, groups did not differ significantly in demographic, clinical or lifestyle characteristics.

Conclusion

The recruitment was successful and the groups are balanced regarding potential confounding variables. The study will provide essential data about the feasibility and efficacy of lifestyle intervention after stroke in order to develop a new approach to prevent cognitive decline in patients with mild ischemic stroke.

Diabetes and thrombolysis for acute stroke: a clear benefit for diabetics

BACKGROUND AND PURPOSE

Diabetes is a predictor for poor outcome after thrombolysis in stroke patients, and early post-stroke glycaemia is associated with higher rates of post-thrombolytic symptomatic intracerebral haemorrhages (SICHs). Diabetic stroke patients may nevertheless profit from thrombolysis. Here, we compared outcome data of matched thrombolysed and non-thrombolysed diabetic and non-diabetic stroke patients from a national database.

METHODS

The outcomes of 1079 matched quadruples, each consisting of a thrombolysed diabetic, a non-thrombolysed diabetic, a thrombolysed non-diabetic and a non-thrombolysed non-diabetic case (a total of 4316 cases), enrolled in the Austrian Stroke Unit Registry (2004-2013), were compared. Patients were matched according to sex, age, stroke severity, pre-stroke disability and prior stroke.

RESULTS

A regression model with improvement as depending variable found no effect of diabetes (P = 0.158) or the interaction diabetes × thrombolysis (P = 0.507), whereas the effect of thrombolysis itself was highly significant (P < 0.001). Functional outcome (modified Rankin Scale) was significantly better in thrombolysed than in non-thrombolysed diabetic patients at discharge from the stroke-unit (P < 0.001) and 3 months later (P = 0.006). No significant differences were found in the number of SICHs after thrombolytic treatment between diabetic (4.9%) and non-diabetic strokes (3.5%). Both groups had a higher risk of SICH compared with the non-thrombolysed groups (diabetics 2.6%, non-diabetics 2.5%). Due to lack of documentation, the effect of admission blood glucose on SICH was not investigated.

CONCLUSIONS

Data from this nationwide survey show that diabetic stroke patients receive a substantial benefit from thrombolysis, and therefore diabetic strokes should not be excluded from thrombolytic treatment.

Prevention of post-stroke cognitive decline: a review focusing on lifestyle interventions

BACKGROUND AND PURPOSE

Despite a high prevalence of post-stroke cognitive impairment, therapeutic possibilities are still limited. Stroke and dementia share the same cluster of modifiable risk factors. Thus, lifestyle interventions and strict adherence to medication may not only decrease the risk of recurrent stroke but also the risk of post-stroke cognitive decline.

METHODS

We performed a systematic literature search for randomized clinical trials (RCTs) targeting modifiable risk factors for the prevention of cognitive decline following stroke.

RESULTS

We identified 25 non-pharmacological interventions and eight multiple risk factor interventions in stroke patients using cognition as outcome measure. None of the published trials investigated interventions aimed at the prevention of post-stroke cognitive decline. However, a number of ongoing trials aim at risk factor reduction and include measures on cognition.

CONCLUSION

Evidence for risk factor modification for the prevention of cognitive decline after stroke is scarce and comes mainly from observational studies. There is a need for more RCTs targeting the prevention of post-stroke dementia using lifestyle interventions and a multiple risk factor approach.

Abstract 157: No Need To Exclude Diabetics From Thrombolysis: Diabetic And Non-diabetic Stroke Patients Profit Equally Well. Report From The Austrian National Stroke Unit Registry

Background: Diabetes has been known to be a predictor for poor outcome after thrombolysis in stroke patients, and early poststroke glycaemia is known to be associated with higher rates of postthrombolytic symptomatic intracerebral haemorrhages. Therefore, diabetic stroke patients are often excluded from thrombolytic treatment. Up to now comparisons exist only from clinical trials (e.g. VISTA collaboration) and registry data of thrombolysed paients (e.g. SITS registry). No nation-wide data have been investigated for the outcomes of thrombolysis in diabetics and non-diabetics.

Methods: National database of the Austrian Stroke Unit Registry, 2003-2010 , comprising 34 acute stroke units, comparison of outcome data of thrombolysed and non-thrombolysed diabetic and non-diabetic stroke. Stratification according to sex, age, stroke severity, functional impairment before stroke and recurrent stroke to non-thrombolysed diabetic strokes and to non-diabetic thrombolysed and non-thrombolysed controls. Improvement was defined as the difference between stroke severity at admission and at discharge.

Results: A modelled cohort of 1,988 r-tPA thrombolysed diabetic stroke patients from 13,246 ischaemic stroke patients were compared according to sex, age, stroke severity, and prestroke disability. A regression model with improvement as depending variable and age, sex, stroke severity, aetiology of stroke, risk factors (including diabetes) and treatment (including thrombolysis) found no effect of diabetes (p=0.854) or the interaction diabetes x thrombolysis (p=0.277), whereas the effect of thrombolysis itself was highly significant (p=0.0001). No differences were found in the number of symptomatic intracerebral haemorrhages after thrombolytic treatment between diabetic strokes (5.2%) and non-diabetic strokes (4.0%). Both groups had a higher risk of intracerebral haemorrhages compared to the non-thrombolysed groups (diabetic 2.9%, non-diabetic 2.6%).

Conclusion: Data from this nation-wide survey show that diabetic stroke patients have a substantial benefit from thrombolysis and therefore diabetic strokes should not be excluded from thrombolysis treatment.

Helicopter Transport of Stroke Patients and Its Influence on Thrombolysis Rates

Background and Purpose—

Acute stroke management requires minimization of prehospital time. This study addresses the value of helicopter transport compared with other means of transportation to a stroke unit and compares their rates of thrombolysis on a nationwide basis.

Methods—

Prospective data collection and prespecified evaluation of data from 32 stroke units between 2003 and 2009 were used. We distinguished between patients transported either directly to a stroke unit or transferred indirectly via a peripheral hospital. Thus, there were 6 transport groups: helicopter emergency service (HEMS) direct and indirect, ambulance accompanied by an emergency physician direct and indirect, and ambulance without physician direct and indirect. Demographic and clinical factors, time delays, and rates of thrombolysis of patients transported by helicopter were compared with factors of patients transported otherwise.

Results—

Of 21 712 ischemic stroke patients, 905 patients (4.1%) were transported by helicopter. Of these, 752 patients (3.4%) were transported by direct HEMS, and 153 patients (0.7%) were transported by indirect HEMS. Thrombolysis rates were highest for HEMS (24% direct, 29% indirect) transport, followed by ambulance accompanied by an emergency physician (18% direct, 15% indirect). The probability of receiving thrombolysis was highest for indirect HEMS transport (OR 3.6, 2.2–6.0), followed by indirect ambulance accompanied by an emergency physician transport (OR 1.5, 1.1–1.9). The shortest times, 90 minutes or less from stroke onset to hospital arrival, were achieved with direct AMBP and direct HEMS transport.

Conclusions—

The shortest hospital arrival times and highest thrombolysis rates were seen in ischemic stroke patients transported by helicopter.

Stroke education: discrepancies among factors influencing prehospital delay and stroke knowledge

BACKGROUND

Time is essential for the treatment of acute stroke. Much time is lost outside the hospital, either due to failure in identifying stroke symptoms or due to a delay in notification or transport. We review studies reporting factors associated with better stroke knowledge and shorter time delays. We summarise the evidences for the effect of stroke knowledge and education on people's reaction in the acute situation of stroke.

METHODS

We searched MEDLINE for studies reporting factors associated with prehospital time of stroke patients, or knowledge of stroke symptoms. Further, we searched for studies reporting educational interventions aimed at increasing stroke symptom knowledge in the population.

FINDINGS

We included a total of 182 studies. Surprisingly, those factors associated with better stroke knowledge such as education and sociodemographic variables were not related to shorter time delays. Few studies report shorter time delays or better stroke knowledge in persons having suffered a previous stroke. Factors associated with shorter time delays were more severe stroke and symptoms regarded as serious, but not better knowledge about the most frequent symptoms such as hemiparesis or disorders of speech. Only 25-56% of patients recognised their own symptoms as stroke. While stroke education increases the knowledge of warning signs, a few population studies measured the impact of education on time delays; in such studies, time delays decreased after education. This may partly be mediated by better organisation of EMS and hospitals.

INTERPRETATION

There is a discrepancy between theoretical stroke knowledge and the reaction in an acute situation. Help-seeking behaviour is more dependent on the perceived severity of symptoms than on symptom knowledge. Bystanders play an important role in the decision to call for help and should be included in stroke education. Education is effective and should be culturally adapted and presented in a social context. It is unclear which educational concept is best suited to enhance symptom recognition in the acute situation of stroke, especially in view of discrepancies between knowledge and action.

Dysphagia Bedside Screening for Acute-Stroke Patients

Background and Purpose— Acute-onset dysphagia after stroke is frequently associated with an increased risk of aspiration pneumonia. Because most screening tools are complex and biased toward fluid swallowing, we developed a simple, stepwise bedside screen that allows a graded rating with separate evaluations for nonfluid and fluid nutrition starting with nonfluid textures. The Gugging Swallowing Screen (GUSS) aims at reducing the risk of aspiration during the test to a minimum; it assesses the severity of aspiration risk and recommends a special diet accordingly.

Methods— Fifty acute-stroke patients were assessed prospectively. The validity of the GUSS was established by fiberoptic endoscopic evaluation of swallowing. For interrater reliability, 2 independent therapists evaluated 20 patients within a 2-hour period. For external validity, another group of 30 patients was tested by stroke nurses. For content validity, the liquid score of the fiberoptic endoscopic evaluation of swallowing was compared with the semisolid score.

Results— Interrater reliability yielded excellent agreement between both raters (κ=0.835, P <0.001). In both groups, GUSS predicted aspiration risk well (area under the curve=0.77; 95% CI, 0.53 to 1.02 in the 20-patient sample; area under the curve=0.933; 95% CI, 0.833 to 1.033 in the 30-patient sample). The cutoff value of 14 points resulted in 100% sensitivity, 50% specificity, and a negative predictive value of 100% in the 20-patient sample and of 100%, 69%, and 100%, respectively, in the 30-patient sample. Content validity showed a significantly higher aspiration risk with liquids compared with semisolid textures ( P =0.001), therefore confirming the subtest sequence of GUSS.

Conclusions— The GUSS offers a quick and reliable method to identify stroke patients with dysphagia and aspiration risk. Such a graded assessment considers the pathophysiology of voluntary swallowing in a more differentiated fashion and provides less discomfort for those patients who can continue with their oral feeding routine for semisolid food while refraining from drinking fluids.

Is reduced female survival after mating a by-product of male-male competition in the dung fly Sepsis cynipsea?

BACKGROUND

In a number of species males damage females during copulation, but the reasons for this remain unclear. It may be that males are trying to manipulate female mating behaviour or their life histories. Alternatively, damage may be a side-effect of male-male competition. In the black scavenger or dung fly Sepsis cynipsea (Diptera: Sepsidae) mating reduces female survival, apparently because males wound females during copulation. However, this damage does not seem to relate to attempted manipulation of female reproduction by males. Here we tested the hypothesis that harming females during mating is an incidental by-product of characters favoured during pre-copulatory male-male competition. We assessed whether males and their sons vary genetically in their ability to obtain matings and harm females, and whether more successful males were also more damaging. We did this by ranking males' mating success in paired competitions across several females whose longevity under starvation was subsequently measured.

RESULTS

As previously reported, our results show mating is costly for female S. cynipsea. However, variance in female longevity was not explained by male identity, family, body size, number of previous copulations, or copulation duration. Nevertheless, there was a positive correlation between the harm fathers inflicted on their mates (affecting female longevity) and the harm sons inflicted on theirs. Additionally, family identity significantly influenced male copulation success.

CONCLUSION

Our results indicate a heritable component of some yet unspecified male trait(s) that influence harm and mating success. However, there was no relationship between copulation success of fathers or sons and the mean longevity of their mates. We therefore found no support for harm being a side effect of traits favoured in pre-copulatory male-male competition.

Acute treatment and long-term management of stroke in developing countries

Developing countries have some of the highest stroke mortality rates in the world that account for over two-thirds of stroke deaths worldwide. Hospital-based studies suggest that the patterns of stroke types and causes of stroke differ between developing and developed countries, resulting in differing needs for acute and long-term care. Data on stroke care provision in developing countries are sparse and most of the available studies are biased towards urban settings in reasonably resourced health-care systems. A general overview shows that the quality and quantity of stroke care is largely patchy in low-income and middle-income countries, with areas of excellence intermixed with areas of severe need, depending upon patients' location, socioeconomic status, education, and cultural beliefs. Here we review the available literature on acute and long-term stroke management in developing countries. On the basis of available studies, largely from developed countries, we discuss the need to develop basic organised stroke-unit care in developing countries.

Correlated responses to artificial body size selection in growth, development, phenotypic plasticity and juvenile viability in yellow dung flies

Most life history traits are positively influenced by body size, whereas disadvantages of large body size are poorly documented. To investigate presumed intrinsic costs of large size in the yellow dung fly (Scathophaga stercoraria; Diptera: Scathophagidae), we established two replicates each of three body size laboratory selection lines (small, control and large; selection on males only), and subjected flies of the resulting extended body size range to various abiotic stresses. Response to selection was symmetrical in the small and large lines (realized h(2) = 0.16-0.18). After 24 generations of selection body size had changed by roughly 10%. Female size showed a correlated response to selection on male size, whereas sexual size dimorphism did not change. Development time also showed a correlated response as, similar to food limited flies, small line flies emerged earlier at smaller body size. At the lowest larval food limit possible, flies of all lines emerged at the same small body size after roughly the same development time; so overall phenotypic plasticity in body size and development time strongly increased following selection. Juvenile mortality increased markedly when food was extremely limited, large line flies showing highest mortality. Winter frost disproportionately killed large (line) flies because of their longer development times. Mortality at high temperatures was high but size-selective effects were inconsistent. In all environments the larger males suffered more. Initial growth rate was higher for males and at unlimited food. Small line individuals of both sexes grew slowest at unlimited larval food but fastest at limited larval food, suggesting a physiological cost of fast growth. Overall, extension of the natural body size range by artificial selection revealed some otherwise cryptic intrinsic juvenile viability costs of large size, mediated by longer development or faster growth, but only in stressful environments.

Sexual selection on morphological and physiological traits and fluctuating asymmetry in the black scavenger fly Sepsis cynipsea

Previous univariate studies of the fly Sepsis cynipsea (Diptera: Sepsidae) have demonstrated spatiotemporally variable and consequently overall weak sexual selection favouring large male size, which is nevertheless stronger on average than fecundity selection favouring larger females. To identify specific target(s) of selection on body size and additional traits possibly affecting mating success, two multivariate field studies of sexual selection were conducted. In one study using seasonal replicates from three populations, we assessed 15 morphological traits. No clear targets of sexual selection on male size could be detected, perhaps because spatiotemporal variation in selection was again strong. In particular, there was no (current) selection on male abdomen length or fore coxa length, the only traits for which S. cynipsea males are not smaller than females. Interestingly, copulating males had a consistently shorter fore femur base, a secondary sexual trait, and a wider clasper (hypopygium) gap, an external genital trait. In a second study using daily and seasonal replicates from one population, we included physiological measures of energy reserves (lipids, glucose, glycogen), in addition to hind tibia length and fluctuating asymmetry (FA) of all pairs of legs. This study again confirmed the mating advantage of large males, and additionally suggests independent positive influences of lipids (the long-term energy stores), with effects of glucose and glycogen (the short-term energy stores) tending to be negative. FA of paired traits was not associated with male mating success. Our study suggests that inclusion of physiological measures and genital traits in phenomenological studies of selection, which is rare, would be fruitful in other species.

Habitat and space use of European cuckoo females during the egg laying period

Abstract

In brood parasites, knowledge of spacing behaviour, habitat use and territoriality may reveal cues about how parasites find and use their hosts. To study the use of space and habitat of European cuckoos, Cuculus canorus, we radio-tagged 16 females during four consecutive reproductive seasons. We hypothesized that during the laying period cuckoo females should (1) use habitats selectively, and (2) attempt to monopolize potential egg laying areas to reduce competition for host nests. Our data are consistent with the first hypothesis: the use of pond edges compared to forest and transitional habitats was significantly greater than expected from the habitat availability in the total area and within individual female home ranges. All 26 directly observed egg layings and 27 nest visits without laying occurred at pond edges in nests of Acrocephalus spp. Females spent significantly more time at pond edges on egglaying days than on non-laying days. The second hypothesis was not supported: female home ranges overlapped similarly in all three major habitat categories of the potential egg laying areas, and only little aggression was observed between females. We discuss whether female cuckoos may lack territorial behaviour because they are not able to defend egg laying areas economically or because defence is not necessary due to sufficient availability of suitable host nests.

How do cuckoos find their hosts? The role of habitat imprinting

Although a number of hypotheses have been proposed for how European cuckoo, Cuculus canorus, females may find hosts belonging to their foster parents' species, clear evidence is lacking for any of them. Here, we propose 'habitat imprinting' as an alternative mechanism for host selection and provide evidence that cuckoos are able to remember acquired information about a familiar habitat. We hand-reared seven cuckoos in one of five different artificial habitats and tested them as adults in habitat choice experiments. In each test habitat, a pair of zebra finches, Taeniopygia guttuta, was presented as 'hosts'. We tested cuckoos of both sexes because the genotype of males may influence egg colour, and therefore egg mimicry; alternatively, habitat imprinting may be a general mechanism existing in both sexes but affecting egg mimicry only via females. Test cuckoos spent significantly more time looking at their respective familiar habitats than at other habitats in 1 of 2 test years. How long cuckoos were reared in the artificial habitats correlated positively with how long they spent in this habitat during the choice experiments. Additionally, test cuckoos remained longer with zebra finches that showed more nest-building behaviour but had lower levels of general activity, and they also observed these 'hosts' more frequently. If cuckoos choose to breed in habitats resembling those on which they were imprinted and search randomly for hosts in these habitats, they would increase their probability of parasitizing nests of their foster species. We propose that host specificity would be strengthened, however, if cuckoos use a sequence of several mechanisms, rather than just one, to find their hosts. (c) 1998 The Association for the Study of Animal Behaviour.