What are the different forms and stages of Parkinson’s disease?
Speaker: Joseph Jankovic, MD
We know that Parkinson’s disease is not just a single entity.
There are many different subtypes of Parkinson’s disease.
At least 30 years ago we described two major subtypes of Parkinson’s disease.
One is referred to as the tremor dominant for of Parkinson’s disease, which represents
about 75% of all patients with Parkinson’s disease.
And the second subtype would be referred to as PIGD, partial instability gait difficulty
form of Parkinson’s.
The first subtype, the tremor dominant form of Parkinson’s disease, often starts at
a relatively younger age, somewhere between the ages of 45 and 55.
The onset usually is tremor.
The rest tremor usually in the hand and then it spreads to the opposite side and may involve
other parts of the body such as the lips, chin, jaw, legs.
But it never involves the head.
So if one sees an individual with oscillation of the head like “no, no, no” or “yes,
yes, yes” that individual almost certainly does not have Parkinson’s disease, but has
another condition namely essential tremor which is frequently confused with Parkinson’s
disease.
Now for a long time it was thought that essential tremor and Parkinson’s disease are totally
distant disorders.
And this is probably true still for majority of patients with Parkinson’s disease and
essential tremor.
But we have accumulated some evidence over the last the last 2-3 decades to indicate
that there’s a subtype of patients with essential tremor that may evolve into this
tremor dominant form of Parkinson’s disease that some patients with essential tremor are
at an increased risk of developing Parkinson’s disease.
So this is the tremor dominant form of Parkinson’s disease, the most common form of Parkinson’s
disease.
Usually has a much more favorable prognosis than the second subtype of Parkinson’s disease,
the PIGD form of Parkinson’s disease.
In this form of Parkinson’s disease, the partial instability gait difficulty form of
Parkinson’s patients often start with a shuffling gait, some difficulty with their
balance, with tendency to fall forward of backwards.
And they develop falls early in the course of the disease.
The natural cause of progression in the PIDG form of Parkinson’s disease is much more
rapid than in the tremor dominant so the prognosis is less favorable.
And they do not respond as well to anti Parkinson’s medications such levodopa.
So when I see patients with Parkinson’s disease, if they have the tremor dominant
form of Parkinson’s disease, I may tell them that the bad news is that you have Parkinson’s
disease, but the good news is that you have the best kind of Parkinson’s disease.
The kind of Parki nson’s that generally has a good prognosis.
Now in addition to the tremor form of Parkinson’s disease and the PIDG form of Parkinson’s
disease, we often subdivide the Parkinson’s disease according to the age of onset.
So there could be juvenile form of Parkinson’s disease starting in childhood which is extremely
rare, but it does occur.
And then there’s a young onset form of Parkinson’s’ disease that may start in the 20s or 30s.
These patients often respond very well to levodopa but are much more vulnerable to the
side effects of levodopa such as dystonia, which is the twisted, jerky type of involuntary
movements and that is a characteristic feature of young onset Parkinson’s disease.
And then there’s a late onset of Parkinson’s disease which tends to be more of the PIGD
form of Parkinson’s.
These patients tend to develop the gait difficulty, balance problem early on and they may often
develop cognitive decline early on and dementia becomes the dominant feature in the more advance
stages of the disease.
Speaking of stages of the disease, we divide by the natural course of progression of Parkinson’s
disease into the 5 stages, the so called the Hoehn and Yahr stages.
Where stage one represent chiefly unilateral, one-sided symptoms such as tremor, stage 2
means that the symptoms occur bilaterally, on both sides.
Stage 3 means the patient has begun to experience some difficulty with their balance and still
able to operate without assistance.
Stage 4 means they require assistance with operation.
And stage 5 usually means that the patients are wheel chair bound and bed ridden.
So these are the 5 stage of Parkinson’s disease.
And our goal of course is to maintain the patients in the earlier stages of the disease
as possible for the appropriate treatment.