The tremor of Parkinson’s disease
Nitin. K. Sethi, MD
Assistant Professor of Neurology
Weill Cornell Medical Center
New York, NY 10065
Since many of the readers of my blog and website (http://braindiseases.info) have written in asking about tremor, I thought in this post I shall describe the tremor seen in Parkinson’s disease in detail. The classical tremor described in Parkinson’s disease is a resting tremor which has a frequency of about 2-5 Hz. Let me explain in more simple terms what I mean by that.
The tremor in Parkinson’s disease is present at rest and not when the hands/ limbs are in motion (when the patient’s hands are placed on a table and are completely at rest, the tremor comes out. Now if you ask the patient to hold the hands in front of themselves or to perform some action like picking up a glass of water and bring it to their lips, the tremor becomes less prominent and may not be noticable. Hence it is called a RESTING TREMOR). Another way to observe the resting tremor is to see the patient walk. When we walk, our arms are held by the side of the body and are completely at rest, if a person has a resting tremor it is clearly visible.
The tremor in Parkinson’s disease has a frequency of about 2-5Hz ( meaning that the tremor is not very fast). It also has a large amplitude (meaning that it is not fine rather it is a gross tremor and can be well appreciated by the naked eye from a distance).
The tremor of Parkinson’s disease disappears/ stops when the patient falls asleep (most of the tremors abate on sleeping and hence this quality does not aid in differentiating the tremor of Parkinson’s disease from other tremors).
The classical tremor of Parkinson’s disease is a pill-rolling tremor (meaning the tremor consists of flexion and extension of the fingers in connection with adduction and abduction of the thumb. Imagine yourself rolling a pill, that is how the tremor looks like!!!)
Most importantly the tremor in Parkinson’s disease is accompanied by other signs of Parkinson’s disease such as rigidity (the tone of the muscles of the limbs is increased), bradykinesia (slowness in the execution of movement) and a disturbance of gait and posture (the gait is slow, stooped forward-we call this a festinating gait and their posture is off so patients are more prone to falls). That said and done signs of Parkinson’s disease may appear at different times and not all at once. At times the first/ earliest manifestation of Parkinson’s disease is the presence of an asymmetrical resting tremor (meaning the tremor usually appears asymmetrically/ only in one hand).