IV. Reading ComprehensionReading 1          Parkinson’s disease, first described in the early 1800s by British physician James Parkinson as “shakingpalsy,” is among the most prevalent neurological disorders. According to the United Nations, at least fourmillion people worldwide have it； in North America, estimates run from 500,000 to one million, with about 50,000 diagnosed every year. These figures are expected to double by 2040 as the world’s elderly populationgrows； indeed, Parkinson’s and other neurodegenerative illnesses common in the elderly (such asAlzheimer’s and amyotrophic lateral sclerosis) are on their way to overtaking cancer as a leading cause ofdeath. But the disease is not entirely one of the aged: 50 percent of patients acquire it after age 60； the otherhalf are affected before then. Furthermore, better diagnosis has made experts increasingly aware that thedisorder can attack those younger than 40.
         So far researchers and clinicians have found no way to slow, stop or prevent Parkinson’s. Althoughtreatments do exist, including drugs and deep-brain stimulation, these therapies alleviate symptoms, notcauses. In recent years, however, several promising developments have occurred. In particular, investigatorswho study the role proteins play have linked miscreant proteins to genetic underpinnings of the disease. Suchfindings are feeding optimism that fresh angles of attack can be identified.
          As its 19th-century name suggests and as many people know from the educational efforts of prominentParkinson’s sufferers such as Janet Reno, Muhammad Ali and Michael J. Fox—the disease is characterizedby movement disorders. Tremor in the hands, arms and elsewhere, limb rigidity, slowness of movement, andimpaired balance and coordination are among the disease’s hallmarks. In addition, some patients have troublewalking, talking, sleeping, urinating and performing sexually.
         These impairments result from neurons dying. Although the victim cells are found throughout the brain,those producing the neurotransmitter dopamine in a region called the substantia nigra are particularly hardhit. These dopaminergic nerve cells are key components of the basal ganglia, a complex circuit deep withinthe brain that fine-tunes and coordinates movement. Initially the brain can function normally as it losesdopaminergic neurons in the substantia nigra, even though it cannot replace the dead cells. But when half ormore of these specialized cells disappear, the brain can no longer cover for them. The deficit then producesthe same effect that losing air traffic control does at a major airport. Delay, false starts, cancellations and,ultimately, chaos pervade as parts of the brain involved in motor control—the thalamus, basal ganglia andcerebral cortex—no longer function as an integrated and orchestrated unit.
【題組】31. Which of the following statements about Parkinson’s disease can be best supported by the article?
(A) Parkinson’s disease will become one of the leading causes of death for the old people.
(B) Parkinson’s disease is not entirely one of the aged, as more than half of the patients are young people.
(C) Parkinson’s disease first appeared in the 19th century.
(D) Parkinson’s disease is both a neurological disorder and a contagious illness.