Wouldn't it be wonderful to be able to slow the progression of Parkinson's disease (PD) or even prevent it?
Researchers worldwide are developing new treatments that may make this dream a reality.

In order for these treatments to fulfill their promise, however, physicians will need a way to diagnose PD "pre-clinically," that is, before symptoms such as tremor, stiffness and slowness become evident. The characteristic signs and symptoms of Parkinson's disease do not appear until approximately 80% of the dopamine-producing neurons in the brain have died off, a process which takes many years. If treatments to slow the progression of the illness could be initiated before 80% of these neurons were lost, it might be possible to delay or even prevent disability. Unfortunately, most Parkinson patients are not diagnosed until the symptoms are well established. Diagnosing PD early, when the signs and symptoms are subtle, can be very difficult, even for experts. Unlike many other illnesses which may be confirmed with laboratory tests, there is no widely-accepted test to help the physician confirm PD as the cause of the patient's symptoms. Epidemiological studies suggest that up to 40% of individuals with the disease are unidentified and untreated. In a survey of 93 Parkinson patients in Southern Arizona, 22% reported it took more than a year from the time they first complained of symptoms to a physician to the time they received a diagnosis, and not infrequently, the initial diagnosis was incorrect.

Approximately 8% reported waiting two years for an accurate diagnosis. When you add this one to two year period to the year or so most patients spend wondering what's wrong before seeking a doctor's opinion, it becomes clear that getting a diagnosis takes far too long, particularly if the goal is early treatment designed to keep disability at bay. Currently under study at the University of Arizona are three tests which, when used together, may provide the first reliable way to diagnose PD early and to distinguish it from similar disorders and from normal aging. The test battery includes a test of olfaction (sense of smell), a test of mood, and a test for speed and accuracy of movement. Loss of sense of smell and abnormalities of mood such as depression are commonly observed in Parkinson patients. In many cases, these conditions predate the diagnosis by several years. The movement test uses a video game to assess the speed and accuracy of a specific type of wrist movement. Earlier studies were conducted with non-human primates who were trained to perform a wrist task and then tested before and after being made Parkinsonian with the neurotoxin MPTP. Recording of neuronal activity in these animals while they were performing the wrist movements showed that many nerve cells in the brain are important in achieving the specific type of movement required in the wrist task. This finding pointed the way to the development of special tests of motor function that are highly sensitive to Parkinson's disease. The diagnostic value of the three tests used together is much better than that of one of the tests used alone. We have tested more than 50 normal older individuals and 50 Parkinson patients who were either newly diagnosed or very early in their disease. Our test battery was over 90% specific and 90% sensitive in differentiating the Parkinson patient with mild symptoms from the normal older individual. It has proven especially useful for distinguishing between Parkinson patients and patients with essential tremor, a distinction many experienced clinicians find diffficult to make.

Just how early can we identify a person who might be at risk for Parkinson's disease? This is the next step in our research. We hope to study a large number of older individuals whose symptoms suggest PD but are not sufficient to make a firm diagnosis. We will test these individuals with the three-part battery and follow them for two years. Then we will be able to determine just how accurately the battery detects the disease in its early, most subtle form. Another potential use for the test battery is to help us understand the genetic basis for Parkinson's disease. Current research suggests there may be a gene that plays a role in the development of PD but that not everyone who inherits this gene will actually develop the illness. Most likely, heredity is only part of the picture and environmental factors are also important. Because the disease is usually diagnosed in mid-life or later, it is usually the case that the son or daughter of a Parkinsonian, if he or she is to develop the illness, will do so only after the affected parent has died. This situation makes it difficult to do the studies that would establish the genetic link. Testing the adult children of Parkinsons with the three-part battery increases the likelihood that families with both an affected parent and an affected son or daughter can be identified while both parties are still alive and able to participate in genetic research. When a genetic test becomes available, the three-part battery will assist first degree relatives of Parkinsonians in getting the earliest diagnosis possible. If they are developing PD. With advances in treatments to slow the progression of PD, all patients will benefit from early detection. Actress Lynn Redgrave participated in Dr. Erwin Montomery's research study on pre-clinical detection of PD. Her father, Sir Michael Redgrave had Parkinson's disease and died in 1986. Lynn was in Tucson performing her one-woman show Shakespeare For My Father, a play which addresses the subject of Parkinson's head-on. The play presents a poignant picture of how the illness affected her father and her family.

In a television interview at the APDA reception which followed her final performance in Tucson, Lynn said, "Because my father was a man of extraordinar,v facial mobility who was able to play characters with such extraordinary emotion across his face, it was a particularly cruel blow, that he should be stricken with a disease that robs the face of expression. I think that was the hardest thing for us as a family." Of her experience being tested by Dr. Montgomery she had this to say: "It was a really simple process that took less than an hour, and it gave me a certain peace of mind. While Dr. Montgomary explained that there is no definite way to say "Lynn you will never get Parkinson's disease", at least there was no sign of it during my test. The test was extremely simple and didn't involve anything painful or hard. In fact, it was really quite fun, I think his work is very exciting and I can't wait to tell my brother and sister."