Parkinson's disease is a progressive condition that attacks the nervous system and affects a sufferer's ability to move. It usually starts gradually, with a barely noticeable tremor in one hand and progresses into symptoms that affect the movement, balance, and speech of those with the disease. Parkinson's disease affects about 1 million people in the U.S., with 50,000-60,000 new cases diagnosed each year.

At the moment, there is no known cure for this puzzling disease. Doctors know that it is caused by the gradual loss of dopamine-producing nerve cells within the brain. Dopamine is critical for regulating muscle movements and controlling dexterity, so when dopamine levels drop, patients begin to feel symptoms. Along with tremors and slurred speech, sufferers may notice muscle rigidity, loss of balance, difficulty writing, and a decreased ability to perform unconscious movements, such as blinking or smiling.

But new research may help doctors unlock the mystery behind Parkinson's disease. Researchers from Lund University in Sweden have found that they can use human embryonic stem cells to produce new dopamine-producing cells in the brain. The lab-made cells brought dopamine levels in the test subjects (lab rats) back to normal within five months.

The researchers explain their findings in the clip below:

The study did look at whether or not these improved dopamine levels correlated to a decrease or reversal of Parkinson's related symptoms or if this method would work as well in humans as it did in lab rats. 

But researchers are hopeful that this new study will be the breakthrough that doctors have been looking for to unlock better treatments and possible even a cure for Parkinson's disease.

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Stem cell work hints at cure for Parkinson's disease
By producing new dopamine-producing cells in the brain, researchers saw brain levels return to normal.