Tremor is defined as an involuntary regular and repetitive shaking of a body part around a fixed point. Tremors are of various types, which include- Resting tremors, postural or action tremors and intention tremors.
Resting Tremors Symptoms
- A resting tremor occurs with the body part at rest and often subsides with action. It is commonly seen in Parkinson’s disease.
- In the limbs, the tremor is most pronounced distally in the fingers (pill rolling tremor).
- The frequency is characteristically 4-6 Hz.
Postural or Action Tremor
- Postural tremor in the fingers is best seen when the arms are outstretch.
- Tremor of head is seen in the upright posture.
Common types of postural tremor are physiological tremor and essential tremor. Physiological tremor has a frequency of 10-12 Hz and is seen in normal individuals during fatigue and stress.
Symptoms Of Essential Or Familial Tremor
- It has a frequency of 5-8 Hz and mainly affects the fingers.
- It is absent at rest, becoming evident with sustained postures or action.
- Patients frequently complain of difficulty with hand-writing, pouring a drink or holding a cup.
- The head is also tremulous (titubation) in 50% of patients.
- The tremor may be inherited as an autosomal dominant trait (familial variety) but half of those affected do not give any family history.
- It can begin at any age.
- A striking characteristic is its responsiveness to low doses of alcohol.
- Not all patients require treatment.
- For those whose symptoms are disabling propranolol or primidone can be given.
Intention And Rubral Tremor Symptoms
Intention Tremor
- This term refers to coarse tremor of a limb as it moves towards a target.
- The tremor increases in amplitude as the limb nears the target.
- It has a frequency of 3-5 Hz.
- It is most commonly seen with lesions of cerebellum and its connections.
- No drug has been found useful in treatment.
Rubral Tremor
- It is a coarse, slow (2.5-4 Hz) tremor of arms which is present at rest, increases with arms outstretched and is maximum as they move towards a target.
- Proximal arm muscles are affected more than distal.
- The tremor is likely to be due to interruption of fibers of superior cerebellar peduncle.
- It occurs most often as a sequel of multiple sclerosis; head injury and stroke are other common causes.
Levodopa, isoniazid and 5-hydroxy-tryptophan have been reported to have some beneficial effect.