A tremor is a rhythmic shaking or trembling. It is one of the movement disorders that may affect the aging person.
There are areas of the brain that control the way we move. They include the cerebellum and the cluster of nerve cells (basal ganglia) deep within the brain. Damage to these parts or decline in their function as part of the aging process may result in a movement disorder.
The cerebellum coordinates the body’s movement, constantly adjusting muscle tone and posture to maintain balance. Memories of complex movements that have been learned by practice such as a dance step are stored in this part of the brain.
The basal ganglia through their neurotransmitter dopamine coordinate and smooth out movements. Damage to these nerve cells cause involuntary movements or decrease in motion without affecting muscle strength and reflexes.
Kinds of tremors
Tremors are classified by the way they occur.
Resting tremor is a slow, coarse shaking that occurs when the muscles are at rest. An arm or leg shakes even when the victim is completely relaxed. Movements of this kind can be very embarrassing as when drinking a glass of water or spooning soup. Resting tremors can be caused by Parkinson’s disease or by antipsychotic and mood drugs such as lithium.
Action tremor is the type that accompanies movements such as writing or using utensils and some light, hand-held gadgets. It usually stops when the movement ends. Action tremor is a characteristic of tremors that begin in elderly people. It can be intensified by beta agonist drugs that patients with asthma and emphysema take for relief of bronchospasm.
Intentional tremor is a slow, broad shaking that occurs at the end of a precise, purposeful movement like pressing a button or putting a key in a lock. It may be caused by damage to the cerebellum or by excessive alcohol drinking.
Postural tremor is what happens when the body is held in one position such as extending the arms from the side. It usually stops the body is relaxed (putting the arms down). It may be caused by the intake of lithium and thyroid hormones.
Flapping tremor is a unique type occurring when the arms are stretched out. One or both hands quickly drop then return to their original position. Flapping is due to loss of muscle tone and can be encountered in patients with brain damage due to lack of oxygen, liver or kidney failure and hypoglycemia (low blood sugar). Flapping tremor is actually a kind of lightning-like jerky movement called myoclonus.
Essential tremor is a benign shaking that begins in early adulthood slowly becoming more obvious as the person gets older. Its cause is unknown. When this tremor of unknown cause—although a cerebellum disorder is sometimes suspect—occurs in old age, it is called senile tremor. Essential tremors that run in families are called familial tremors.
Essential tremors are usually of the action type usually involving the arms and rarely the legs. They can make handwriting and using utensil difficult and embarrassing. Sometimes, these tremors may involve the head causing it to shake and bob, and also the vocal cords causing the voice to quiver. By and large, essential tremors remain mild and don’t indicate any serious disease. Emotional stress, anxiety, fatigue, caffeine and prescribed stimulants can intensify the tremors. Although moderate alcohol intake (one or two bottles of beer or one to two shots of hard drinks a night) can reduce the tremor in some people, heavy drinking and alcohol withdrawal can worsen the shaking.
Does senile tremor become the much dreaded Parkinson’s disease?
First of all, Parkinson’s disease is due to damage to the basal ganglia with depletion of the nerve chemical dopamine. It may be caused by virus infection (viral encephalitis), head trauma (suspected among boxer victims), street-peddled opiates, environmental neurotoxins and prescription drugs that block dopamine. The disease may begin in patients in their early 40s although most common between the ages of 50 and 79.
It usually begins in one hand while at rest making the fingers move as if rolling pills. The tremor disappears when the hand is moving purposefully and disappears completely during sleep. The tremor progresses gradually and soon may spread to the other hand, the arms and the legs. The jaws may also be involved. In some cases tremor may not be the first sign and may not develop at all.
Early in PD, the patient may not be able to smell probably because they have difficulty sniffing or taking a deep breath. The disease affects muscles including those used in breathing. Indeed early on, the muscles become rigid. For instance, if the forearm is stretched by another person, it may be stiff or move in jerks.
One characteristic of PD patients is that they have difficulty starting movements. Gradually, walking becomes impaired and the patient often shuffles and takes short steps without swinging their arms. Some have difficulty stopping and turning. In the middle of a movement, they may suddenly freeze feeling as if their feet are glued to the ground. Other times they may quicken their pace, breaking into short-stepped stumbling run to avoid falling. They may talk faster, running words in a mumble.
Loss of balance is a prominent sign of PD. Patients become stooped, their head drooping forward and resting on their chest. They may not be able to move quick enough to break a fall. Another remarkable feature of the disease is the lack of facial expression. The face takes on a blank stare with the mouth open and eyes that don’t blink. Because the muscles of the face and throat become rigid, the patient drools (uncontrolled flow of saliva) and may even choke and have difficulty of swallowing, a risk factor for aspiration pneumonia which is often fatal.
Senile tremor which may be the bane of some retirees is nowhere near related to PD. However, although they are usually mild, in some cases senile tremors can be a nuisance and even disabling.
What to do with this essential tremor? Do practical things like holding objects firmly and close to the body or using electrical appliances such as can openers and tooth brushes. Utensils with large handles and putting foam around handles can make them easier to hold. Other helpful aids include using straws, button hooks, Velcro fasteners, zipper pulls and shoe horns.
If the essential tremor interferes with daily activities and work, the beta blocker propranolol or anticonvulsants such as gabapentin may be prescribed. Rare, severe cases may require either surgery directed to that part of the brain called thalamus or electrical stimulation of the same part.
