Parkinson's: What Neil Diamond (and millions) face

Parkinson's disease (PD) belongs to a group of conditions called motor system disorders, which are the result of the loss of dopamine-producing brain cells. The four primary symptoms of PD are tremor, or trembling in hands, arms, legs, jaw, and face; rigidity, or stiffness of the limbs and trunk; bradykinesia, or slowness of movement; and postural instability, or impaired balance and coordination. As these symptoms become more pronounced, patients may have difficulty walking, talking, or completing other simple tasks. PD usually affects people over the age of 60.  Early symptoms of PD are subtle and occur gradually.  In some people the disease progresses more quickly than in others.  As the disease progresses, the shaking, or tremor, which affects the majority of people with PD may begin to interfere with daily activities. 

At present, there is no cure for PD, but a variety of medications provide dramatic relief from the symptoms.  Usually, affected individuals are given levodopa combined with carbidopa.  Carbidopa delays the conversion of levodopa into dopamine until it reaches the brain.  Nerve cells can use levodopa to make dopamine and replenish the brain's dwindling supply.  Although levodopa helps at least three-quarters of parkinsonian cases, not all symptoms respond equally to the drug. Bradykinesia and rigidity respond best, while tremor may be only marginally reduced. Problems with balance and other symptoms may not be alleviated at all.  Anticholinergics may help control tremor and rigidity.  Other drugs, such as bromocriptine, pramipexole, and ropinirole, mimic the role of dopamine in the brain, causing the neurons to react as they would to dopamine. 

PD is both chronic, meaning it persists over a long period of time, and progressive, meaning its symptoms grow worse over time.  Although some people become severely disabled, others experience only minor motor disruptions. Tremor is the major symptom for some individuals, while for others tremor is only a minor complaint and other symptoms are more troublesome.  It is currently not possible to predict which symptoms will affect an individual, and the intensity of the symptoms also varies from person to person.

Source: NINDS/NIH

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