Since the discovery that MPTP causes parkinsonian symptoms in humans, scientists have found that by injecting MPTP and certain other toxins into laboratory animals, they can reproduce the brain lesions that cause these symptoms. This allows them to study the mechanisms of the disease and helps in the development of new treatments for Parkinson's disease.
They also have developed animal models with alterations of the alpha-synuclein and parkin genes. Other researchers have used genetic engineering to develop mice with disrupted mitochondrial function in dopamine neurons. These animals have many of the characteristics associated with Parkinson's disease.
Biomarkers for PD – measurable characteristics that can reveal whether the disease is developing or progressing – are another focus of research. Such biomarkers could help doctors detect the disease before symptoms appear and improve diagnosis of the disease. They also would show if medications and other types of therapy have a positive or negative effect on the course of the disease. Some of the most promising biomarkers for PD are brain imaging techniques.
For example, some researchers are using positron emission tomography (PET) brain scans to try to identify metabolic changes in the brains of people with Parkinson's and to determine how these changes relate to disease symptoms. Other potential biomarkers for PD include alterations in gene expression.
Research on Treatments for Parkinson's
Researchers also are conducting many studies of new or improved therapies for Parkinson's. While deep brain stimulation (DBS) is now FDA-approved and has been used in thousands of people with PD, researchers continue to try to improve the technology and surgical techniques in this therapy. For example, some studies are comparing DBS to the best medical therapy and trying to determine which part of the brain is the best location for stimulation. Another clinical trial is studying how DBS affects depression and quality of life.
Other clinical studies are testing whether transcranial electrical polarization (TEP) or transcranial magnetic stimulation (TMS) can reduce the symptoms of PD. In TEP, electrodes placed on the scalp are used to generate an electrical current that modifies signals in the brain's cortex. In TMS, an insulated coil of wire on the scalp is used to generate a brief electrical current.