Mahlon DeLong, Neurology


Neurologist Mahlon DeLong’s efforts to understand the causes of Parkinson’s disease have taken him from the research lab to the bedside of patients. Along the way, he has made unique, award-winning contributions to knowing the origins of the disease, as well as alleviating the suffering of those afflicted with it.

In the early 1990s, researchers understood that Parkinson’s was caused by the brain’s loss of cells that manufacture the neurotransmitter dopamine. Researchers also believed that the tremor and other movements associated with the disease resulted from underactive cellular activity in the brain.

Then DeLong and his colleagues made a groundbreaking discovery. They found that the brain’s loss of dopamine-producing cells actually led to other brain cells being overstimulated (for reasons still not understood). This new insight paved the way for pallidotomy, a treatment that uses radio frequency waves to destroy small groups of cells in the brain as a way of controlling the symptoms of Parkinson's. Pallidotomy had been around for thirty years, but it was abandoned because of the lack of precise surgical techniques.

A few years later, DeLong and his colleagues developed an innovative approach that made pallidotomy much more effective. Their microelectrode brain mapping system allowed surgeons more control over targeting specific brain cells.

The mapping procedure is so sensitive that the electrode advances cell by cell, while the electrical discharge of single nerve cells guides clinicians in pinpointing and eliminating those few overactive and troublesome cells.

Sometimes, within minutes of silencing cells in this tiny region, patients feel relief from the agonizing tremor, rigidity and slowness of movement.

DeLong describes the arc of his 30-year professional life from a basic researcher into a clinical researcher as an “interesting journey.” Clinical research poses its own set of challenges—whereas he was once a lab scientist controlling mice, now he is responsible for treating human patients. In addition, he finds himself dealing with far more regulations and restraints, while receiving less support from funding agencies.

At Emory, DeLong heads one of the nation's largest and most distinguished groups of investigators studying Parkinson's and related neurological diseases. Emory's Parkinson's Disease Research Center of Excellence – one of three in the nation – was awarded a grant of $7.5 from the National Institutes of Health (NIH) in 1999. He also directs the Center for Research on Complementary and Alternative Medicine (CAM) in Neurodegenerative Diseases.

As far as the public is concerned, DeLong is occasionally in the news for another reason, as personal physician to Muhammad Ali, who suffers from Parkinson’s. Interestingly, his famous patient has opted out of trying pallidotomy for himself. As DeLong says, Ali “copes with this [Parkinson’s Disease] as something he’s been given to deal with in life.”

DeLong says that Emory has unique strengths in the neurosciences from both basic and clinical research sides.

“We have one of the strongest neuroscience programs in the country – neurology and psychiatry and basic neuroscience. We have the Yerkes Primate Center, the number one center in the country. We have an affiliation with a genetics corporation in Iceland, DeCode, that is absolutely unique.

“The richness of programs here is quite striking. The volume of patients, the complexity, breadth of patient population is one of largest in country. Together with basic research, that puts us in a strong position.”

He mentions another exciting development at Emory, the Center for Neurodegenerative Disease, which focuses on research related to age-related disorders that cause cell damage or death such as Parkinson’s Disease, Alzheimer’s Disease, Huntington’s Disease, and strokes. The center brings in faculty from all disciplines, from pharmacology to biochemistry to neurology, and provides the communication and proximity that is fundamental to connecting basic and clinical research to find new treatments for diseases.

In April 2002, the Institute for Scientific Information identified DeLong as one of the most highly cited scientific researchers worldwide. Along with his three Emory colleagues in neuroscience, he was one of 110 highly cited scientists in 185 countries.