Neurological Disorders: Tremors

Tremors, when used in the medical context, are nothing but shaking in the lay terminology. However the term shaking may be used for varieties of conditions other than tremors including: seizures (convulsive type), choreiform movements etc.

This term is used for a certain distinct clinical manifestation characterized by somewhat rhythmic movements of limbs, head or other areas of the body, either isolate or in combination. Hand shakings are frequently encountered.

They are generally considered as neurological condition however there are non neurological conditions too and they develop when agonist and antagonist muscles contract either simultaneously or alternatively. A Neurologist is frequently involved in the care of these patients.

These types of abnormal movements generally originate when there is dysfunction of an area in the brain called as basal ganglia. However they may also result due to dysfunction of structures including cerebellum, peripheral nerves, red nucleus etc.

Physiological type Enhanced physiologic type Non physiological (pathological) type

• Action or postural (e.g. essential tremor)
• Resting type
• Cerebellar (intention) type
• Toxin/chemical induced type
• Hyperactive thyroid gland related type etc

Psychogenic type etc.

Physiological types of shakings:

These are very subtle normal tremors that are usually difficult to see however they may when somebody is anxious or strongly emotional.

Enhanced physiological type of shakings:

As the name implies they are physiological type that become more prominent and visible. They may be precipitated by intense emotional changes as noted above however there are varieties of other pathological & non pathological conditions that can produce this condition.

• Medications (e.g. stimulants like caffeine, amphetamine)
• Toxins
• Hyperactive thyroid
• Fever
• Alcohol withdrawal etc

They appear during an activity or action for example using the arm for feeding, writing etc. Postural type appear in the hands when hands are maintained in the same position for some time for example holding the arms in front in an extended (straight) position will bring out these shakings or make them worse.

Essential tremors:

Essential type is one of the most frequent types of shakings and generally its incidence is high in middle age and older people.

The typical essential shakings are either absent or very mild in a resting state of the limbs and become prominent during activities, accordingly it is a type of action shaking. It is also generally prominently seen during maintaining a sustained posture of the limbs so an example for postural type of shaking too. In advanced stages these shaking may be seen in a resting position of the limbs also although generally such resting type are characteristically seen in patients with parkinsonian conditions like parkinson disease.

Head shaking are considered similar to essential type shakings (or may be part of the same condition) and they may occur with the hand shaking or isolated.

There may be a positive family history for essential type and in that case it is preferably called as familial. If essential type shakings begin in an older individual then they are preferably called as senile shaking. Stress, caffeine etc can exaggerate and alcohol drinks may reduce the intensity of these tremors.

Although essential type can be mild in many patients they can affect their daily activities. These shakings maximally bother the patient when they are doing some activities like writing, feeding with hand or spoon, holding a cup and drinking etc. For some people it is socially embarrassing issue too.

Resting type of shakings:

As the name implies they characteristically occur in the resting state of the limbs. As the patient starts moving the limbs they either disappear or reduce.

If a patient has a concomitant activity related shakings like (essential type) then it is difficult to demonstrate the resting nature of these shakings as during the movement of the limb the essential type will start manifesting.

These shakings are mostly associated with extra pyramidal disorders like Parkinson disease and other similar conditions like drug induced parkinsonism.

A pill rolling type of resting shaking involving the thumb of the patient is very typical for idiopathic Parkinson disease (although not diagnostic).

Intention tremors:

These are typically seen in patients having cerebellar lesions. They are minimal or absent at a resting state however manifest as the hand or finger reaches a target.

The diagnosis is mostly done on clinical basis by its characteristic appearance. Clinical history and examination will provide additional clues as to whether it is Parkinson disease related, essential type etc.

Sometimes still investigations may be necessary and following tests may be ordered on case to case basis;

• Thyroid test especially TSH levels
• CT or MRI of brain
• Very rarely an EMG (electromyography)

Treatment will vary according to the type of shaking and the underlying pathology. In general, depending upon the type and cause of tremors the following treatments may be required (on case to case basis);

• Anti parkinsonian medications
• Medications for essential type of shakings (primidone, beta blockers, topiramae etc)
• Anti hyperthyroid treatment along with beta blockers etc