Essential tremor is a condition in which an individual develops a rhythmic, involuntary movement of the hands or other part of the body. It may be progressive or non-progressive. While often mild, it may become more severe as age advances. It is not associated with any neurological or other disease which could be the cause of the tremor.
Treating essential tremor is difficult because its cause is unknown. Some research points to the presence of cerebellar damage as the reason for the tremor. A genetic component is also postulated. However, all cases do not show evidence of the marker genes identified so far.
While essential tremor is not a lethal condition, it can cause profound embarrassment, and real difficulty with accomplishing daily routine activities. The typical head-nodding or head-shaking movement may be interpreted as conveying agreement or disagreement during conversational interchanges, for instance, without any basis in fact. This may cause a lot of confusion during the individual’s communications, and cause withdrawal or social shyness.
Modes of treatment
Treatment of essential tremor includes:
The mainstay of medical treatment for benign essential tremor remains beta-blocker drugs and anticonvulsant drugs. Beta-blockers blocks the receptors in the body which respond to the stimulatory neurotransmitters by increased activity. Thus the drug prevents overactivity of skeletal muscle, and reduces the frequency and intensity of the tremor. These drugs are effective in up to 75% of patients with essential tremor.
Sedatives may also be used to help decrease the anxiety levels, which in turn contributes to reducing the intensity of the tremor. However, they may cause dependence, and drowsiness is a common adverse effect.
Botulinum toxin is used under exceptional circumstances to paralyze nerve conduction. It is injected directly around the nerves supplying the hand muscles.
Avoiding tremor triggers
It is often advised to avoid the use of stimulants such as caffeine, amphetamines, and excessive fatigue, by appropriate changes to one’s lifestyle. Adequate and regular sleep should be ensured. It is wise to meet one’s healthcare provider and review all current medications, so that any drug which may cause or exacerbate tremor can be tapered and stopped where possible.
Physical and occupational therapy
A physical therapist can guide individuals with essential tremor to strengthen and increase the coordination of their muscular movements. This will improve their muscle control, in many cases. Thus an initial assessment of the patient will be performed, including:
The type of tremor
The position in which tremor onset occurs
The degree of muscle control
The muscular strength
The level of functional muscle skill
Physical therapy will then be started, focusing on coordination exercises, and exercises to increase the balance of the body. Patients may also learn how to reduce the occurrence of the tremor while using the affected body part. Bracing the limb when a tremor comes on is often useful.
Occupational therapy will help identify which kinds of adaptations are useful to optimize function with a tremor. These may include large-handled cups and utensils, splints, and weights.
Deep brain stimulation is sometimes done to relieve essential tremors. This involves the insertion of an electrode in a specific area of the brain, connecting to a pulse generator under the skin over the chest by thin wires. The generator continuously sends signals to the dysfunctional parts of the brain, muffling the abnormal signals which produce tremor. This mode of treatment reduces the frequency of tremor by approximately 90%.
Adverse effects include:
Surgical site infection
Neurological damage such as numbness or nerve paralysis
Thalamotomy and pallidotomy are stereotactic procedures, in which a tiny area of the thalamus or globus pallidum which produces the tremor is destroyed by targeted electrical current. Side effects include:
Impaired cognitive skills
Problems with maintaining balance
Surgical site infection
Since surgical intervention may produce severe side effects, it is only resorted to in the case of severe and refractory tremors.
Newer treatments, one of which includes the use of octanoic acid, which have a tremor-relieving action analogous to that of alcohol, are under study. Occupational therapy and physiotherapy are helpful in some cases as well.
Reviewed by Afsaneh Khetrapal BSc (Hons) References
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3907068/ Further Reading