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Showing posts with label Journal of the American Medical Association. Show all posts
Showing posts with label Journal of the American Medical Association. Show all posts

Wednesday, December 14, 2011

Autistic brains are heavier, with more neurons: study

Posted: 09 November 2011

WASHINGTON: A post-mortem analysis of half a dozen autistic boys showed that their brains were heavier and contained many more neurons than counterparts without the disorder, US researchers said Tuesday.

The study, while small, suggests that brain overgrowth may be occurring in the womb, according to the findings published in the November 9 issue of the Journal of the American Medical Association.

Researchers examined the brains of seven autistic boys, age two to 16, most of whom had died by drowning. The 16-year-old's cause of death was undetermined and one eight-year-old died of muscle cancer.

When they compared them to a control group of six boys without autism who died in accidents, they found that the brains of autistic boys had 67 percent more neurons in the prefrontal cortex and were nearly 18 percent heavier than normal brain weight for age.

"Because cortical neurons are not generated in postnatal life, this pathological increase in neuron numbers in autistic children indicates prenatal causes," the study said.

The researchers suggested that "faulty prenatal cell birth or maintenance may be involved in the development of autism."

The prefrontal cortex is where language and communication is based, as well as behaviors such as mood, attention, and social ability. Typically, autistic children have difficulty in these areas.

However, more research is needed to confirm the link, and to determine if and how brain differences may be tied to the severity of an autistic person's symptoms.

"Factors that normally organize the brain appear to be disrupted," said an accompanying editorial by Janet Lainhart of the University of Utah and Nicholas Lange of the Harvard University Schools of Medicine and Public Health.

Previous studies have suggested that clinical signs of autism tend to coincide with a period of abnormal brain and head growth that usually becomes apparent at nine to 18 months of age, according to the article.

Autism includes a wide spectrum of developmental differences and may range from mild social awkwardness to complete inability to communicate, repetitive movements, sensitivity to certain lights and sounds, and behavioral problems.

As many as one in 110 children is diagnosed with autism. The disorder is three to four times more common in boys than in girls, according to the advocacy group Autism Speaks which helped fund the study.

Other funding came from Cure Autism Now, The Emch Foundation, the Simons Foundation, the Thursday Club Juniors, and the University of California San Diego - National Institutes of Health Autism Center of Excellence.

-AFP/pn



Taken from ChannelNewsAsia.com; source article is below:
Autistic brains are heavier, with more neurons: study

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Thursday, January 20, 2011

Watch grandpa's gait for longevity clues

Posted: 05 January 2011

WASHINGTON - If you want to know how long grandpa is going to live, check his pace of walking.

A report appearing in Wednesday's Journal of the American Medical Association found a strong correlation between walking speed and expected survival rates for persons over 65.

The analysis from nine studies between 1986 and 2000 showed faster walking speed among older adults was associated with increased length of survival.

The average gait speed of the 34,485 participants was 0.92 meters (three feet) per second. But analyzing results over periods from six to 21 years, the University of Pittsburgh researchers found the faster ones lived longer.

"Walking requires energy, movement control, and support and places demands on multiple organ systems, including the heart, lungs, circulatory, nervous, and musculoskeletal systems," the researchers wrote. "Slowing gait may reflect both damaged systems and a high energy cost of walking."

All studies had participants walk at their usual pace and from a standing start. The walk distance varied from eight feet (2.4 meters) to six meters (19 feet).

"Predicted years of remaining life for each sex and age increased as gait speed increased," the researchers said.

"Gait speeds of 1.0 meter (3.3 feet) per second or higher consistently demonstrated survival that was longer than expected by age and sex alone. In this older adult population the relationship of gait speed with remaining years of life was consistent across age groups."

The researchers found that gait speed was associated with differences in the probability of survival at all ages in both sexes, but was especially notable after age 75.

"The data provided herein are intended to aid clinicians, investigators, and health system planners who seek simple indicators of health and survival in older adults," said researchers headed by Pittsburgh's Stephanie Studenski.

"Gait speed has potential to be implemented in practice, using a stop watch and a four-meter (13 feet) course.... Gait speed may be a simple and accessible indicator of the health of the older person."

In an editorial accompanying the report, Matteo Cesari of the Universita Campus Bio-Medico, Rome, said that because no evidence definitively supports the hypothesis that gait speed improvements are associated with better health-related outcomes, gait speed should not be considered as a primary target for interventions at present.

"It represents a global marker of health status, and an optimal secondary and complementary outcome to support research findings, clinical decisions, or both aimed at modifying more pragmatic end points," he wrote.

"Future research will be needed to determine whether gait speed has the potential to change the way in which a patient is defined as geriatric."

- AFP/rl


Taken from ChannelNewsAsia.com; source article is below:
Watch grandpa's gait for longevity clues



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