Living in a noisy area increases the risk of suffering a more serious stroke

Dec 6, 2019

First published on ScienceDaily.com

The high levels of environmental noise we are subjected to in large cities can increase both the severity and consequences of an ischaemic stroke. More precisely, researchers from the Hospital del Mar Medical Research Institute (IMIM) and doctors from Hospital del Mar, together with researchers from the Barcelona Institute for Global Health (ISGlobal), CIBER in Epidemiology and Public Health (CIBERESP), and Brown University, in the United States, put the increased risk at 30% for people living in noisier areas. In contrast, living close to green areas brings down this risk by up to 25%. This is the first time that these factors have been analysed in relation to stroke severity. The study has been published in the journal Environmental Research.

The researchers looked at the influence of noise levels, air pollution (particularly suspended particles smaller than 2.5 microns; PM2.5), and exposure to green areas on nearly 3,000 ischaemic stroke patients treated at Hospital del Mar between 2005 and 2014. To do this, they used data from the Cartographic Institute of Catalonia, as well as models to analyse atmospheric pollutant levels, the noise map of Barcelona, and satellite images to define areas with vegetation. Also taken into account was the socioeconomic level of the place the patients lived.

Dr. Rosa María Vivanco, from the IMIM’s Neurovascular Research Group and first author of the study, points out that the study gives us initial insight into how noise levels and exposure to green spaces influences the severity of ischaemic stroke. “We have observed a gradient: the more green spaces, the less serious the stroke. And the more noise, the more serious it is. This suggests that factors other than those traditionally associated with stroke may play an independent role in the condition,” she explains. At the same time, Dr. Xavier Basagaña, one of the authors of the study and a researcher at ISGlobal, a centre supported by “la Caixa,” stresses that “exposure to green spaces can benefit human health through various mechanisms. For example, it can reduce stress, encourage social interaction, and increase levels of physical activity.” However, in this study no link was seen with atmospheric pollution. The researchers warn that one of the limitations of the work was the lack of variability in pollutant concentrations to which the study population is exposed. This made it difficult to draw conclusions, and they point out that more studies are needed in this field.

More noise, greater stroke severity

“Previous studies have demonstrated that living in places with high levels of air pollution or noise, or with fewer green areas, exposes the population to a higher risk of suffering an ischaemic stroke. This work broadens our knowledge in this field, showing that the place where we live affects not only the risk of suffering a stroke, but also its severity if it occurs,” explains Dr Gregory A. Wellenius, from the Epidemiology Department at Brown University and final author of the study. In this sense, the results indicate that patients living in noisier areas presented more severe strokes on arrival at hospital.

You can read the full article here.

More aggressive blood pressure control benefits brains of older adults

Dec 5, 2019

First published on ScienceDaily.com

A major UConn School of Medicine study published in the American Heart Association’s flagship journal Circulation shows that more aggressively controlling daily blood pressure in older adults can improve brain health.

It’s been estimated that approximately two-thirds of people over the age of 75 may have damaged small blood vessels in the brain which are visible as bright white lesions on brain imaging. Prior research evidence has linked increased amounts of these white matter lesions in the brain with cognitive decline, limited mobility such as a slower walking speed, increased incidence of falls and even increased stroke risk.

The clinical trial, led by Drs. William B. White of the Calhoun Cardiology Center and Leslie Wolfson of the Department of Neurology, followed 199 hypertension patients 75 years of age and older for 3 years.

Throughout that time, researchers tracked the potential benefits of using an intensive anti-hypertensive medication treatment regimen to garner a 24-hour systolic blood pressure target of less than 130 mmHg compared to standard control (approximately 145 mmHg).

As part of the INFINITY (Intensive Versus Standard Ambulatory Blood Pressure Lowering to Prevent Functional Decline In the Elderly) study, researchers assessed the older adults’ mobility, cognitive function, their brain’s white matter progression with magnetic resonance imaging (MRI), and tracked the occurrence of any adverse events.

While the researchers did not identify any significant differences in cognitive outcomes or walking speed between the two study groups, they did observe a significant reduction in the accumulation of brain white matter disease in those receiving the intensive treatment for blood pressure control.

“The results of INFINITY demonstrate that a lower ambulatory blood pressure goal for older adults is likely to conserve future brain function and health,” said Wolfson, professor of neurology and former chair of the Department of Neurology at UConn Health.

In fact, after three years, the accrual of white matter lesions in the brain were reduced by up to 40% in the those patients receiving the intensive blood pressure therapy compared to those who were on standard therapy.

You can read the full article here.

Dynamic reorganization of brain circuit with post-stroke rehabilitation

Dec 3, 2019

First published on ScienceDaily.com

Nagoya City University (NCU) researchers have revealed an interaction between cortico-brainstem pathways during training-induced recovery in stroke model rats, providing valuable insights for improving rehabilitation methods.

Upper limb hemiparesis often occurs after ischemic or hemorrhagic stroke. Unilateral upper extremity impairment can substantially disturb patients’ ability to complete activities of daily living. Therefore, continuous improvement of rehabilitation methods is needed to achieve more positive long-term outcomes among survivors.

Researchers at NCU have identified the dynamic recruitment of the “cortex-to-brainstem” pathways via post-stroke intensive rehabilitation and its contribution to the recovery of impaired forelimb function in intracerebral hemorrhage (ICH) model rats. This crucial finding could provide new insights enabling the improvement of rehabilitative methods for humans.

Stroke often affects the primary network from the cortex to the spinal cord, causing severe ongoing motor deficits. Rehabilitation promotes the recovery of impaired motor function, which is believed to be due to reorganization of the residual neural circuits. However, how the circuits are recruited in rehabilitation-induced recovery remains unclear.

To investigate the mechanisms underlying these phenomena, the NCU team used an ICH rat model in which almost 90% of the cortico-spinal tract is destroyed, causing changes in other motor-related circuits. “We previously found abundant newly formed connections from the motor cortex to the red nucleus in rehabilitated rats,” first author Akimasa Ishida explains. “Interestingly, we also uncovered an increase in the “cortex-to-reticular formation” pathway in trained rats when the “cortico-to-red nucleus” pathway failed to function, using a double-viral infection technique during rehabilitation.”

You can read the full article here.