Ian W. Turnbull

Deglutitive laryngeal closure in stroke patients

Background: Dysphagia has been reported in up to 70% of patients with stroke, predisposing them to aspiration and pneumonia. Despite this, the mechanism for aspiration remains unclear. Aims: To determine the relationship between bolus flow and laryngeal closure during swallowing in patients with stroke and to examine the sensorimotor mechanisms leading to aspiration. Methods: Measures of swallowing and bolus flow were taken from digital videofluoroscopic images in 90 patients with stroke and 50 healthy adults, after repeated volitional swallows of controlled volumes of thin liquid. Aspiration was assessed using a validated Penetration–Aspiration Scale. Oral sensation was also measured by electrical stimulation at the faucial pillars. Results: After stroke, laryngeal ascent was delayed (mean (standard deviation (SD)) 0.31 (0.06) s, p<0.001), resulting in prolongation of pharyngeal transit time (1.17 (0.07) s, p<0.001) without a concomitant increase in laryngeal closure duration (0.84 (0.04) s, p = 0.9). The delay in laryngeal elevation correlated with both the severity of aspiration (r = 0.5, p<0.001) and oral sensation (r = 0.5, p<0.001). Conclusions: After stroke, duration of laryngeal delay and degree of sensory deficit are associated with the severity of aspiration. These findings indicate a role for sensorimotor interactions in control of swallowing and have implications for the assessment and management of dysphagia after stroke.

Evaluating Oral Stimulation as a Treatment for Dysphagia after Stroke

Deglutitive aspiration is common after stroke and can have devastating consequences. While the application of oral sensory stimulation as a treatment for dysphagia remains controversial, data from our laboratory have suggested that it may increase corticobulbar excitability, which in previous work was correlated with swallowing recovery after stroke. Our study assessed the effects of oral stimulation at the faucial pillar on measures of swallowing and aspiration in patients with dysphagic stroke. Swallowing was assessed before and 60 min after 0.2-Hz electrical or sham stimulation in 16 stroke patients (12 male, mean age = 73 ± 12 years). Swallowing measures included laryngeal closure (initiation and duration) and pharyngeal transit time, taken from digitally acquired videofluoroscopy. Aspiration severity was assessed using a validated penetration-aspiration scale. Preintervention, the initiation of laryngeal closure, was delayed in both groups, occurring 0.66 ± 0.17 s after the bolus arrived at the hypopharynx. The larynx was closed for 0.79 ± 0.07 s and pharyngeal transit time was 0.94 ± 0.06 s. Baseline swallowing measures and aspiration severity were similar between groups (stimulation: 24.9 ± 3.01; sham: 24.9 ± 3.3, p = 0.2). Compared with baseline, no change was observed in the speed of laryngeal elevation, pharyngeal transit time, or aspiration severity within subjects or between groups for either active or sham stimulation. Our study found no evidence for functional change in swallow physiology after faucial pillar stimulation in dysphagic stroke. Therefore, with the parameters used in this study, oral stimulation does not offer an effective treatment for poststroke patients.

Arterial ischemic stroke in HIV: Defining and classifying etiology for research studies.

HIV infection, and potentially its treatment, increases the risk of an arterial ischemic stroke. Multiple etiologies and lack of clear case definitions inhibit progress in this field. Several etiologies, many treatable, are relevant to HIV-related stroke. To fully understand the mechanisms and the terminology used, a robust classification algorithm to help ascribe the various etiologies is needed. This consensus paper considers the strengths and limitations of current case definitions in the context of HIV infection. The case definitions for the major etiologies in HIV-related strokes were refined (e.g., varicella zoster vasculopathy and antiphospholipid syndrome) and in some instances new case definitions were described (e.g., HIV-associated vasculopathy). These case definitions provided a framework for an algorithm to help assign a final diagnosis, and help classify the subtypes of HIV etiology in ischemic stroke.

Magnetic Resonance Imaging of Cerebral Malaria Patients Reveals Distinct Pathogenetic Processes in Different Parts of the Brain

The pathophysiology and molecular mechanisms underlying cerebral malaria (CM) are still poorly understood. Recent neuroimaging studies demonstrated that brain swelling is a common feature in CM and a major contributor to death in pediatric patients. Consequently, determining the precise mechanisms responsible for this swelling could open new adjunct therapeutic avenues in CM patients. Using an MRI scanner with a higher resolution than the ones used in previous reports, we identified two distinct origins of brain swelling in both adult and pediatric patients from India, occurring in distinct parts of the brain. Our results support the hypothesis that both endothelial dysfunction and microvascular obstruction by Plasmodium falciparum-infected erythrocytes make independent contributions to the pathogenesis of CM, providing opportunities for novel therapeutic interventions. ABSTRACT The mechanisms underlying the rapidly reversible brain swelling described in patients with cerebral malaria (CM) are unknown. Using a 1.5-Tesla (T) magnetic resonance imaging (MRI) scanner, we undertook an observational study in Rourkela, India, of 11 Indian patients hospitalized with CM and increased brain volume. Among the 11 cases, there were 5 adults and 6 children. All patients had reduced consciousness and various degrees of cortical swelling at baseline. The latter was predominately posterior in distribution. The findings on diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps were consistent with vasogenic edema in all cases. Reversibility after 48 to 72 h was observed in >90% of cases. DWI/ADC mismatch suggested the additional presence of cytotoxic edema in the basal nuclei of 5 patients; all of these had perfusion parameters consistent with vascular engorgement and not with ischemic infarcts. Our results suggest that an impairment of the blood-brain barrier is responsible for the brain swelling in CM. In 5 cases, vasogenic edema occurred in conjunction with changes in the basal nuclei consistent with venous congestion, likely to be caused by the sequestration of Plasmodium falciparum-infected erythrocytes. While both mechanisms have been individually postulated to play an important role in the development of CM, this is the first demonstration of their concurrent involvement in different parts of the brain. The clinical and radiological characteristics observed in the majority of our patients are consistent with posterior reversible encephalopathy syndrome (PRES), and we show for the first time a high frequency of PRES in the context of CM. IMPORTANCE The pathophysiology and molecular mechanisms underlying cerebral malaria (CM) are still poorly understood. Recent neuroimaging studies demonstrated that brain swelling is a common feature in CM and a major contributor to death in pediatric patients. Consequently, determining the precise mechanisms responsible for this swelling could open new adjunct therapeutic avenues in CM patients. Using an MRI scanner with a higher resolution than the ones used in previous reports, we identified two distinct origins of brain swelling in both adult and pediatric patients from India, occurring in distinct parts of the brain. Our results support the hypothesis that both endothelial dysfunction and microvascular obstruction by Plasmodium falciparum-infected erythrocytes make independent contributions to the pathogenesis of CM, providing opportunities for novel therapeutic interventions.

Bilateral extradural hematoma extending from the foramen magnum to the vertex

We present a 35-year-old man with an extradural hematoma extending bilaterally across the midline from the foramen magnum to the vertex who completely recovered following surgery. Because of the extent of the fluid collection, computed tomographic scanning proved invaluable in facilitating the planning of our surgical approach. He had a long history of alcohol abuse and there were features suggesting preexisting alcoholic brain atrophy in his postoperative computed tomography scan. The possible relationship of this finding to the size of the hematoma and the outcome is discussed.

Reliability of a Semi-Automated Technique of Cerebral Infarct Volume Measurement with CT

Background: A reliable method of infarct volume measurement is needed if infarct volume is to be used as an outcome measure in clinical stroke trials. We investigated the reproducibility of a semi-automated method of computed tomography (CT) infarct volume measurement amongst three stroke research fellows with no formal neuroradiology training and two consultant neuroradiologists. Methods: CT brain scans for volumetric analysis were performed at 5 to 7 days in 34 patients with acute ischaemic stroke, of which 28 scans showed visible recent infarction. Five observers independently traced the infarct boundary on digitised images with a cursor. Volumetric analysis incorporated pixel thresholding with preset Hounsfield thresholds. One of the observers repeated the analyses on 21 of the scans in order to assess intraobserver variation. Results: Median infarct volume was 35.7 cm3 (range 0.2–318 cm3). The closest limits of observed agreement (mean ± 1.96 SD) between pairs of observers were between a research fellow and neuroradiologist (–29 to 21 cm3). The widest limits of agreement were between a different research fellow and the same neuroradiologist (–39.1 to 41.4 cm3). The limits of agreement between infarct volumes measured on two separate occasions by one of the research fellows were –7 to 8 cm3. Conclusions: Intraobserver reliability of CT infarct volume measurements performed by a stroke research fellow was superior to interobserver reliability between any pair of observers. The wide limits of agreement between different observers using manual tracing may not be acceptable in multicentre trials of acute ischaemic stroke treatment, but volume measurement by a single observer appears to be more reliable.

The Mannheim Declaration of Stroke in Eastern Europe

Accessible online at: www.karger.com/ced Stroke is the most devastating cause of morbidity and mortality in the Eastern European countries. In this region, stroke is more frequent and the victims are younger than in Western Europe. Moreover, the incidence of stroke is significantly higher in social classes with low income, which represents a higher percentage of the Eastern European populations. Stroke is still one of the most important contributors to the mortality gap between East and West. The socioeconomic impact of stroke further weakens the economic development of these societies. The frequency of stroke is partly dependent on modifiable risk factors. In Eastern Europe, relatively more high-risk patients (hypertension + diabetes + smoking) live in worse environmental conditions compared with Western individuals. The positive tendency of decreasing mortality and morbidity could not be seen in the majority of Eastern countries, therefore urgent and efficient steps should be done to improve the situation. To avoid death and permanent disability caused by stroke in Eastern Europe, a specialised action plan has been established. This action plan is based on the Helsingborg Declaration and the 10-Point Action Plan to Tackle Stroke summarised by the European Parliament in June, 2003. The governments of these countries should elaborate a countryspecific programme based on the following elements. 1 Highlight the link between stroke and risk factors to physicians, emergency medical personnel, other health care professionals and the general public by facilitating education programmes. Recognition of symptoms of stroke is the cornerstone of successful stroke management. 2 Health care budgets should be allocated considering stroke prevention and therapy as a priority. 3 In specialised stroke units, widespread application of diagnostic interventions, pharmacological and surgical treatments should be available for all patients with stroke. The prevention and treatment of stroke should be based on the principle of evidence-based medicine. There is a pressing need for further randomised and placebo-controlled trials. 4 Stroke patients should receive an individual, patient-centred rehabilitation treatment carried out by an interdisciplinary team and involving the family. 5 Ensure the timely prevention of stroke by adequately treated modifiable risk factors such as hypertension, diabetes, hyperlipidaemia and atrial fibrillation by helping physicians making their treatment decisions using swiftly adoptable guidelines. 6 Because stroke is an emergency and efficient therapy is possible only in a limited time window, simplify the transport of acute stroke patients from their home to the stroke units and try to shorten the stroke-to-needle time. 7 Persuade people of the importance of changing their lifestyle including smoking, heavy alcohol and calorie intake, lack of physical activity, mental and emotional stress, which are very common, but also modifiable risk factors of stroke in Eastern Europe. 8 Encourage active and establish new patients’ associations. Patient groups play an important role in health policy and are able to coordinate actions to promote better rehabilitation and social support for people with stroke and their families. 9 Set realistic, time-based targets for stroke management and produce population-based monitoring systems covering incidence, prevalence, mortality and disability to provide an Eastern European picture of stroke management. 10 Foundation of an East and West European Stroke Forum to share all information between Western and Eastern European stroke professionals by identifying and disseminating the best practices in stroke prevention and treatment.

The Role of Human Immunodeficiency Virus–Associated Vasculopathy in the Etiology of Stroke

Manuscript Number: 61556R2 Full Title: The role of HIV-associated vasculopathy in the etiology of ischemic stroke Short Title: Etiology of HIV ischemic stroke Article Type: Major Article Section/Category: HIV/AIDSSummary The etiologic spectrum of stroke is different in those with HIV infection compared to those without. HIV-associated vasculopathy was the commonest mechanism found. We describe an immune reconstitution syndrome–like vasculopathy among those starting antiretroviral therapy.