DALLAS, Dec. 9 – Tick…32,000 brain cells just died. In 59 seconds more, an ischemic stroke will have killed 1.9 million brain cells, according to a study published in Stroke: Journal of the American Heart Association.

In a unique study, a scientist has quantified and timed the brain damage that occurs during a stroke caused by a blood clot cutting off blood flow to a part of the brain (ischemic stroke), the most common type of stroke.

“Stroke is a highly treatable disease but, unfortunately, the time in which physicians can effectively reverse a stroke is short,” said author Jeffrey L. Saver, M.D., professor of neurology at the University of California, Los Angeles. “Precious tissue is lost every second. Patients need to get to the hospital at the first sign a stroke is occurring.”

Saver used data from numerous research studies to quantify the loss of brain cells that occurs during an ischemic stroke in a large blood vessel in the upper part of the brain. Using neuroimaging and quantitative neurostereology – a three dimensional cell counting technique, he calculated the average rate at which ischemic stroke destroys neural circuitry.

Ischemic strokes are caused when a clot blocks the flow of blood through one of the arteries feeding the brain. Deprived of oxygen, nerve cells in the affected area begin to die, and function is lost in the part of the body that area of the brain controls. Survivors can be left with paralysis, inability to speak, visual field deficits, emotional problems and other disabilities.

“When a clot blocks a blood vessel and stroke occurs, blood is cut off completely to a small group of cells and they die almost immediately,” said Saver, who is also director of the UCLA Stroke Center. “Surrounding that is a larger region of cells that suffers moderately reduced blood flow, a situation it can tolerate for a short period. This gives us a brief window of opportunity to intervene and save the threatened brain.” he said.

Saver said his calculations should motivate patients, those who witness stroke symptoms and physicians to act quickly.

For every minute’s delay, the brain loses:

• 1.9 million neurons;
• 14 billion synapses;
• 7.5 miles of myelinated fibers.

If a stroke runs its full course – an estimated 10 hours on average – the brain loses:

• 1.2 billion neurons;
• 8.3 trillion synapses;
• 4,470 miles of myelinated fibers.

In volume, Saver estimates that a pea-sized piece of brain dies for every 12 minutes that treatment is delayed, and brain tissue the size of 1.5 ping-pong balls is irretrievably lost if a typical stroke runs its course without treatment.
During normal aging, a predictable number of brain cells die. The estimated loss of brain cells during stroke can be translated into accelerated brain aging – 8.7 hours for every second’s delay, 3.1 weeks for every minute, 3.6 years for every hour, and 36 years for a stroke that goes untreated, according to the report.
The calculations emphasize the importance of calling 9-1-1 to seek immediate medical help if you have any of these stroke warning signs:

• Sudden numbness or weakness of the face, arm, or leg, especially on one side of the body;
• Sudden confusion, trouble speaking or understanding;
• Sudden trouble seeing in one or both eyes;
• Sudden trouble walking, dizziness or loss of balance or coordination;
• Sudden severe headache with no known cause.

Stroke symptoms may make it impossible for someone to walk to the phone, dial 9-1-1 and talk to an operator, or even realize anything is amiss, Saver emphasizes.

“It is often up to witnesses to recognize what is going on and make the call for them. Knowing just how much is at stake, family members and co-workers should feel empowered to call 9-1-1,” Saver said.

Within three hours of symptom onset, the clot-busting drug tPA (tissue plasminogen activator) can reduce the long-term disability of a stroke. Other treatments may include aspirin or anticoagulants (blood thinners) to keep blood vessels open, surgery, hospital care and rehabilitation.

“Every minute you wait, hoping your symptoms will go away, you lose almost 2 million brain cells. Don’t try to tough it out, and don’t waste time trying to get in touch with your primary physician or neurologist. You need emergency help,” Saver said.

The study was funded in part by the National Institute of Neurological Disorders and Stroke.