Final answer:
Patients with Parkinson's disease experience a slowed movement, including a shuffling walk and muscle rigidity. This is due to the loss of dopamine neurons in the substantia nigra part of the brain, which affects muscle control.
Step-by-step explanation:
Patients with Parkinson's disease typically experience slowed movement due to a degenerative disorder of the central nervous system that affects the muscular system and movement. This disease is characterized by four motor signs, namely muscle tremor, muscle rigidity, slowness of movement, and postural instability. A characteristic symptom of Parkinson's disease is a shuffling walk, which is a result of the combination of these symptoms. Additionally, Parkinson's patients may face psychological symptoms, such as dementia and emotional problems, which typically develop as the disease progresses.
The progression involves the loss of dopamine neurons in the substantia nigra, which help control muscle movement. As these neurons degenerate, control over voluntary and spontaneous muscle movement diminishes, leading to the aforementioned symptoms. Despite ongoing research, the exact mechanism behind initial neuronal degeneration remains largely unknown, except for a small percentage of familial cases linked to genetic mutations, whereas most cases are sporadic with no identified cause.