In my consultation practice of neurology, I see both over-diagnosis and under-diagnosis of Parkinson's disease. The problem usually centers on one of most visible of symptoms, tremor. When tremor of hands is present, doctors often diagnose Parkinson's disease, even when another condition is to blame. When tremor is absent, doctors often fail to consider Parkinson's disease, even when it is present.

One key to accurate diagnosis is to focus on characteristics of tremor itself. The Parkinsonian tremor usually affects one hand first, and at all stages of disease initially affected hand remains more tremulous than other hand. And, as Parkinson himself emphasized, tremor is most evident when hand is at rest or supported, and decreases when hand is in air or put to use. In other conditions that cause hand-tremors, hands are more equally affected, and tremor is more evident when hands are in air or put to use.

What about cases in which no tremor is present? Because symptoms of Parkinson's disease worsen slowly—year by year instead of month by month—patients and their families often mistake these changes as due to normal, healthy aging.

Non-tremor symptoms of Parkinson's disease can include relative immobility of body-parts (hypokinesia), especially of face which can show a mask-like lack of expression. Movements, once initiated, are slow (bradykinesia). Walking, as James Parkinson noted, involves a bent-forward posture with shuffling, short steps and reduced swinging of arms. Sometimes body's center of gravity gets ahead of feet's ability to catch up, resulting in passing "from a walking to a running pace" that Parkinson described and is known as festination.

The physical exam also shows clumsiness in hands and feet. Increased muscle tone, called "rigidity," is encountered in patient's neck and arm muscles, even while they are supposed to be relaxed.

Patients who have Parkinson's disease without tremor are often most gratifying cases to treat. Having developed their problems slowly and having believed all along that their symptoms were due to aging, they are happily astonished by rapid improvement in function produced by appropriate medication.

(C) 2005 by Gary Cordingley