The connection between the basal ganglia and Parkinson’s involves two pathways in the brain that regulate motor control. The basal ganglia receive complex signals from areas of the brain that excite or inhibit motor activities. A direct pathway permits muscle movement, while an indirect pathway prevents unwanted movement, such as spasms. When one of these direct or indirect pathways becomes damaged, neural signals become skewed and dopamine levels unbalanced, a key factor in Parkinson's.
Disorders of the basal ganglia and Parkinson’s represent one of the most common disorders of the neurological system. Experts believe the disorder is caused by genetic and environmental factors. In rare cases, only one cause is found.
Two findings usually lead to a diagnosis of damaged basal ganglia and Parkinson’s. Doctors might find a loss of dopamine neurons in one part of the basal ganglia. Lewy bodies might also appear. These are abnormal accumulations of a certain protein in nerve cells. They also appear in dementia patients.
Loss of dopamine neurons might occur before physical signs of damage to the basal ganglia and Parkinson’s disease become evident. Researchers found up to 80 percent of these pigmented neurons can be lost before patients show signs of Parkinson’s disease. The first symptom usually involves involuntary tremors.
Lewy bodies also might appear before motor difficulties surface. These collections of protein might also occur in people with other neurological disorders. They have been found in people with Parkinson’s and in people without the disease. The chance of developing Lewy bodies increases as a person ages.
Parkinson’s causes involuntary tremors in the hands and fingers similar to a wringing motion. In some patients, spasms in the limbs and facial muscles might occur, which might appear as violent jerking movements. Problems with posture represent another common sign of the disease, which might distort one part of the body.
Clinical or physical symptoms of problems in the basal ganglia and Parkinson’s might be mild at first. Doctors typically identify four signs in a patient suffering from the disorder. They look for tremors occurring at rest, unstable posture, slow movements, called bradykinsia, and rigidity in parts of the body.
Genetics might determine when symptoms first appear, whether before the age of 50 or after. The average age is 60. Environmental factors increase the risk of Parkinson’s, with people living near industrial plants and quarries facing greater risks of contracting the disorder.
Pesticides and herbicides are also linked to the disease, especially in rural areas where these chemicals might be used more often. Water contaminated with these substances might lead to Parkinson’s. Links are also found between deterioration of the basal ganglia and Parkinson’s in people who smoke cigarettes and consume caffeine. All of these factors are associated with dopamine levels.