“Shaking is great. Shaking is one of the oldest practices known to man…connecting the earth and restoring energy through Out…” Jerome Flynn
Is my tremor a sign of PD? This is always the million dollar question on everyone’s mind when they go see a Movement disorder specialist for the first time. Although, this is the one tremor everyone ruminates on it is not the most common of the movement disorders nor the only tremor.
There are many other tremors associated with other neurological and medical conditions w hich can present challenges for daily living for those experiencing tremors independent of etiology.
Therefore, I want to spend a little bit of time talking about some of these and in particular the more common type of tremor also known as “essential tremor” since this seems to be one of the main reasons for which people are referred to a neurologist. Many of these usually have been misdiagnosed as having PD . It is estimated that about 20% of people with ET are labeled as having Parkinson’s according to a study by Henderson et al.(1995)
Essential tremor (ET) unlike Parkinson’s tremor is a postural, action tremor that progress slowly over many years. It is significantly more common than rest tremor of PD. In 60% of those with ET have an autosomal dominant trait. This disease can start early in life but it is much more common in older individuals due to increase in frequency due to age. There is an anticipatory mechanism with every generation making the tremors present sooner or at younger age than parents or grandparents. People with essential tremor can become severely disabled especially socially although diseases progresses very slow. 
Individual’s with ET usually are hard of hearing and have bilateral tremors and can have great difficulty with activities of daily living. They are also at higher risk for developing Parkinson’s disease later in life. Sometimes they also have accompanying head tremors (mostly nodding -yes), voice tremors and at times orthostatic tremors –which I will discuss later.
The test you can do at home is to draw a spiral first with one hand then the other and watch for cauliflower like pattern. also draw a straight line between two other lines in a narrow space and if it looks like the line is an inching worm or squiggly line then you have action tremors. See picture: Also, even though handwriting is affected it is completely different than that of PD. It is shaky and messy.
Furthermore, this type of tremor responds well to alcohol intake sometimes causing patients with severe tremors to become alcoholics. Subsequently, they too are misdiagnosed because physician’s erroneously assume they have tremors due to their drinking and not the other way around. Besides alcohol which is not really recommended is treatment with Mysoline, Neurontin, Klonopin, Topamax, Beta-blockers -which I do not recommend in young people especially men due to tendency to cause severe depression besides lowering blood pressure. Botox works well if focal, but DBS to thalamus is best treatment plan if symptoms are severe.
Parkinson’s (rest) tremor, the second most frequent type of tremor has a much slower amplitude as if sending a ‘Morse’ code. It is often described as -‘pill rolling’ tremor present primarily at rest and starts unilaterally unlike ET. PWP’s often feel like they have to hide their tremors by putting their hands in their pockets when walking or sitting on their hands if at rest as to not draw attention to themselves. Person’s with rest tremor can do normal action specific maneuvers such as shaving or putting on mascara, without much if any interference. Occasionally, PD individuals can experience action tremors but these are different from above tremor in that the frequency is same as rest tremor. When asked to do above diagrams, PWP’s exhibit normal patterns- smooth and even! The handwriting is also affected as you know with PD but instead of messy is small and tight which usually gets smaller and tappers down as we write.
Best treated with Anti-cholinergics – Artane & Amantadine and to a lesser extent dopamine replacement- Best results is DBS.
Another commonly seen tremor is Dystonic tremor. This tremor is said to be a forme fruste of ET. The best example of this is in patients who have cervical dystonia (i.e. spasmodic torticollis) who have a tendency to turn their head involuntarily in a particular direction say to the left and when they try to maintain their head and neck in a neutral position their head will shake involuntarily. One simple way to differentiate this tremor from essential tremors is a clear response and decline in tremor when a person uses antagonistic gestures. This means that the tremor improves through touch of the head or by lifting an arm etc. ET will not respond to antagonistic gestures!!Best treated with Klonopin and Botox.
Orthostatic tremors- Unique tremor syndrome more common in elderly and middle aged. This usually presents as a feeling of unsteadiness or dizziness while standing still. It typically does not interfere with gait unless is severe. the shaking or tremors are concentrated to the trunk and legs occasionally the arms. Best treated with Klonopin.
Cerebellar tremors- Unilateral Intention tremors but unlike essential tremors these patients have trouble with reaching target; not only do they shake as they get closer to target but when asked to do ‘finger to nose’ they overestimate or overshoot distance. Best treatment for this is Isoniazid, Tegretol, Mysoline.
Physiologic tremors. We all have very fine tremors of fingers especially pinky and can be visualized to naked eye. frequency is not as fast as those with ET- much more subtle and fine. yet they can increase under certain conditions such as stress, increased caffeine intake, abnormal metabolic disorders like diabetes and thyroid disease to name a few. Treatment finding root of problem. too much caffeine consumption is usually a big factor but these will present with other non- neurological medical problems.
Although, there are many other less frequent tremors these are the most common type. All tremors should be investigated and evaluated by a neurologist or MDS; so that the correct diagnosis and treatment can be initiated on a timely basis before there is interruption of function.
Sources: http://www.pdf.org
defeatparkinsons 