NEW YORK, New York (CBS) — One and a half million Americans are living with Parkinson’s Disease. now scientists say gene therapy could help manage the symptoms and help make life better for patients.

Walter Liskiewicz loves jazz, but it wasn’t his first calling. he was forced to give up his career as a surgeon 16 years ago because of Parkinson’s disease. he says, “I had to retire.”

Medications helped ease Walter’s symptoms like tremors, stiffness and difficulty with movement. but eventually they didn’t work as well. so he volunteered for the first gene therapy experiment for Parkinson’s. he had billions of copies of a specific gene inserted directly into his brain to try and reverse his symptoms.

Dr. Michael Kaplitt with New York-Presbyterian-Weill Cornell Medical Center and study co-author says, “We’re putting in a gene to change the way these cells actually function.”

Parkinson’s disease attacks nerve cells in the brain and typically develops after age 50. Gene therapy is not a cure-but could be a breakthrough in helping patients lead better lives.

Dr. Kaplitt says, “As a group the patients that got treated did much better. and about half of the patients in the treated group did dramatically well, had a moderate to large improvement in their symptoms.”

Walter was one of the treated patients. His wife says despite his continued struggle with symptoms, he’s doing much better. Constance says, “I’m just excited he’s back. We’ve dialed the disease back probably 10 years.”

Scientists say now that they’ve reached this milestone, they can proceed to the final study which could eventually make this treatment available to more people with Parkinson’s.

Researchers are also hopeful this new therapy could lead to treatments for other neurological conditions like Alzheimer’s Disease, depression and epilepsy.