Tremor is the involuntary or unintentional rhythmic movement of one or more parts of the body and it may involve the hands, arms, legs, face, head, trunk, or vocal cords. It may be caused by a number of factors such as neurological disorders due to various causes with Parkinson’s disease being one of them as well as certain drugs, alcohol abuse or withdrawal, mercury poisoning, hyperthyroidism, or liver failure. Certain types of tremors may be inherited and are seen to run in families, but for which no known cause can be found, and these are called essential tremors.

Types of Tremor

Tremors may be classified clinically into :

• Rest tremor occurs in a body part that is supported while lying in bed or seated.

• Action tremor which comprises of :

1. Postural tremor occurs when trying to hold up a body part against the force of gravity such as when extending the arms horizontally, sitting up straight without support, pointing with fingers, or sticking out the tongue.
2. Kinetic tremor occurs during a voluntary movement such as in nose-finger-nose testing, heel-knee-shin testing, drinking from a cup, writing, eating and so on.

Characteristics of an Essential Tremor

• An essential tremor is an action tremor, where there is a combination of postural and kinetic tremor in various degrees. The patient may have problems such as difficulty in holding a glass without spilling, shaving, or eating but there is no tremor on rest.
• Genetic factors play an important role in essential tremor and is inherited as an autosomal dominant gene.
• Essential tremor is bilateral and the hands are almost always affected, along with the face, head or trunk. Lower extremities are rarely affected.
• Absence of neurological signs.
• Isolated head tremor without problems in posture.
• Absence of features of Parkinson’s disease associated with bradykinesia (slow movements) and rigidity.
• Cause of essential tremor is not known.
• Medicines responds well to primidone and beta-adrenergic blockers such as propranolol but does not respond to anti-Parkinson medications.

Characteristics of a Parkinson’s Tremor

• A Parkinson’s tremor is observed at rest and there is a typical pill-rolling type of tremor with rolling of thumb over forefinger. The tremor disappears during sleep or may improve during intentional movements.
• No strong genetic factors have been identified in Parkinson’s disease although research in this field is still ongoing.
• In the initial stages, the Parkinson’s tremor is unilateral, starting on one side of the body, but may become generalized in the later stages.
• Other neurological signs related to Parkinson’s disease may be present.
• Absence of a head tremor but postural instability present.
• Parkinson’s tremor is associated with bradykinesia and rigidity, leading to typical features of Parkinson’s disease such as slow shuffling gait, reduced arm swing and shortened stride.
• Parkinson’s disease is a degenerative disease of the brain with symptoms caused by a decreased production of dopamine,  resulting in characteristic features of Parkinsonism such as tremor, rigidity, bradykinesia and postural instability.
• Anti-Parkinson’s medicines assists with reducing the symptoms of Parkinson’s disease which is not evident in essential tremors.

Symptoms for Diagnosing Parkinson’s Disease

• Diagnosis is made more difficult in the early stages of Parkinson’s disease since there may not be any of the typical symptoms initially and only a few non-specific symptoms may be present such as tiredness, depression, or mental slowness, which may be mistaken for normal signs of aging.
• Symptoms of Parkinson’s disease usually start on one side of the body but gradually affect both sides.
• Parkinson’s disease is a disease of old age, rarely starts before the age of 50 and is more common after the age of 65. However, early onset of Parkinson’s disease before the age of 40 years is possible.
• Of the three major signs – tremor, rigidity and bradykinesis – at least two need to be present to confirm the diagnosis of Parkinson’s disease.
• One of the earliest symptoms is tremor present at rest, starting in the upper limb and gradually involving the legs, mouth and tongue. It is a coarse tremor with a “pill rolling” action of thumb over fingers commonly referred to as the Parkinson’s tremor.
• The rigidity, or increased muscular tone, causes an increase in resistance to the passive stretching of muscles, which may be continuous and is called ‘lead pipe’ rigidity or may be interrupted by tremors and is then called ‘cogwheel’ rigidity.
• Bradykinesia, or slowness of initiation or repeating of movements, develops gradually and results in slowness of gait. Difficulty with fine rapid movements, especially of the fingers, results in problem in performing tasks such as shaving, fastening buttons or writing.
• Expressionless face, drooling, soft indistinct speech, and short shuffling steps are all features that may develop in Parkinson’s disease.
• Dementia may be a late feature of the disease, often associated with depression and psychosis.

Other diseases with similar symptoms like Parkinson’s disease

• Alzheimer’s disease – this is also a disease of old age and diagnosis may be further complicated since Alzheimer’s and Parkinson’s disease may co-exist.
• Diffuse vascular disease.
• Lewy body disease – here dementia is an early symptom.
• Essential tremor – tremor is more of the head, worsening on motion and less on rest
• Wilson’s disease
• Multiple system atrophy
• Drugs such as certain antipsychotics and antiepileptics.
• Hyperthyroidism

Final Diagnosis of  Parkinson’s Disease

• Diagnosis of Parkinson’s disease is based mainly on the history, symptoms, and neurological examination of the patient.
• Blood tests, EEG, CT scan or MRI of brain show no definite abnormality in patients with Parkinson’s disease but may be done to rule out other diseases.
• Levodopa challenge test – patients with Parkinson’s disease show dramatic and significant improvement on starting treatment with levodopa, thus differentiating them from other neurological diseases.

References

1. Diagnosing Parkinson’s Disease. University of Maryland
2. Parkinson’s Disease. Medline Plus

Initially the Parkinson’s tremor may seem mild and most patients notice it when reading a newspaper or picking up a mug. These early tremors do not prevent functioning in daily tasks but rather interferes with the level of functioning. It initially occurs as episodes lasting from a few minutes to hours and the episodes per week varies in individual cases. An early stage Parkinson’s disease sufferer may try their utmost to hide the tremors from their family, friends or work colleagues but with time, they accept that further medical intervention is needed.

“Pill Rolling” Tremor

The Parkinson’s tremor tends to more often affect the hands and causes a movement sometimes referred to as “pill rolling”. This “pill rolling” ‘tremor’ involves the uncontrolled movement of the thumb and finger(s) in a back and forth motion. This may also appear as the thumb and fingers are rubbing together, hence the term “pill rolling” movement. These tremors are usually rhythmic and may occur between 4 to 5 cycles per second. It may only affect one side of the body, or one hand, but as the disease progresses, the tremor may become more generalized affecting many parts of the body.

Resting Tremor

Parkinson’s tremors are often worse at rest or when a limb is extended, like holding out the hand. It may also aggravate when tired, excited, stressed or emotional. The tremors often ease significantly or totally go away during movement and this is one of the reasons why new techniques such as stress ball or tennis ball exercises are now used to ease Parkinson’s tremors. These tremors usually go away completely while asleep but quickly return upon waking.

Parkinson’s Treatment

One of the biggest concerns of Parkinson’s sufferers is the extent to which the tremors will affect their job, taking care of themselves in basic daily chores or that of their family. Initially, these tremors are mild and manageable but with time, the tremors may become unbearable. It is therefore essential that treatment for Parkinson’s disease is sought as early as possible as the appropriate medication can significantly reduce the severity of tremors. Alternatively, medication may be able to give the sufferer periods of time with minimal tremors thereby allowing the completion of necessary tasks.

With time, Parkinson’s tremors can become quite debilitating and severely hamper daily functioning. Parkinson’s tremors usually do not entirely disable the patient. Depending on the severity and frequency, the tremors may make the most mundane of tasks a difficult and at times embarrassing experience, especially when the tremors affect other parts of the body, particularly the face.

Stage 1 of Parkinson’s Disease (Mild)

• Symptoms are mild and may only affect one side.
• Daily functioning is not impaired although tremors create difficulty.
• Slightly evident changes in balance, posture, movement and facial expression.

Stage 2 of Parkinson’s Disease (Moderate)

• Symptoms are bilateral – affecting both sides.
• Mild difficulty in movement – walking, balance and posture.
• Impairment in completing daily physical activities.

Stage 3 of Parkinson’s Disease (Difficult)

• Difficulty in maintaining balance and posture.
• Impairment of walking or standing although sufferer is usually able to do so independently.
• Physical movements are noticeably slow.

Stage 4 of Parkinson’s Disease (Severe)

• Unable to maintain balance or posture.
• Instability when walking or standing and requires assistance.
• Tremors usually reduce in this stage although independent completion of daily physical tasks is usually not possible.

Stage 5 of Parkinson’s Disease (Advanced)

• Almost complete inability to function independently.
• Walking or standing usually not possible.
• Constant attention and nursing care required.
• Confusion, dementia and other mental disturbances may occur in some cases.

Differentiating stages of Parkinson’s varies among cases, with certain individuals showing signs of two stages simultaneously. Therefore the guideline is intended to outline and identify the progression of the disease in accordance with level of functioning rather than the onset of symptoms of Parkinson’s disease. In certain cases, a Parkinson’s sufferer may skip the first two stages especially if the condition was not being monitored closely. However the slow progression of Parkinson’s disease means that the shift to the latter stages does not occur overnight and may be delayed with effective treatment.

Dexterity and coordination are the primary factors for daily functioning in the life of a Parkinson’s sufferer. Changes in either factor may affect individual Parkinson’s sufferers to varying degrees with some coping better than others. However with time, the level of dexterity and coordination is sufficiently impaired to render Parkinson’s disease sufferers incapable of taking care of themselves.

There are no specific tests used to aid in the diagnosis of Parkinson’s disease, a correct diagnosis relies on two out of three major signs being met. The three major signs of Parkinson’s are, tremor of limbs while resting, rigidity in the muscles and bradykinesia.

Other factors will also be taken into account such as the absence of secondary causes such as multiple small strokes and antipsychotic medication. Of the three conditions those suffering from Parkinson’s are usually more generally aware of tremor and bradykinesia.

In order to make a correct diagnosis the doctor will perform a neurological examination which is of a set standard. This examination will involve a variety of simple tests based on reactions, reflexes and movement.

The simple tests involve

• Testing for bradykinesia is determined by how quickly the person can tap their finger and thumb together or stamp their foot on the ground.
• Tremor is diagnosed by simple inspection of the hands at rest.
• Rigidity is testing by turning the patients neck, upper limbs and lower limbs while the patient is in a relaxed position.

Postural instability is tested by performing a pull test on the patient, during this test the patient will stand in front of the doctor and they will then ask the patient to try and maintain their balance while being pulled backwards towards the doctor. The pull will be made briskly in order to access the patient’s ability to recover, while of course making sure that the patient is actually prevented from falling.

The examination will take into account of course the full medical history of the patient, with care being taken for exposure to medications that could block the dopamine function of the brain. There are several other drugs which can have the same properties and your doctor will always ask for a full history of any medications you are not only currently taking but also those which the patient has taken in past years.

It is worthwhile mentioning that there are several other conditions which give very similar symptoms to Parkinson’s disease and which can sometimes be mistakenly diagnosed as Parkinson’s.

These include

• Essential tremor – the only symptom present in this disease is tremor.
• Progressive supraneuclear palsy – this disease is often characterized by the inability to look downward .
• Multiple system atrophy – this disease is characterized by prominent autonomic symptoms.
• Vascular parkinsonism – this is caused by the person having multiple small strokes.
• Carbon monoxide poisoning.
• Manganese poisoning.
• Certain pesticides.

Parkinson’s disease is a debilitating, progressive illness which affects a person’s movement; various parts of the body can be affected and symptoms are stiffness in the muscles, difficulty when starting to move and slowness and tremor in the hands when they are at rest. The disease was named after Dr James Parkinson who first diagnosed the disease around the 1800`s.

Why does Parkinson’s disease happen?

The basal ganglia, a part of the brain is affected by the disease, it is a part which plays a vital role in how we control our movement. Cells in the substantia nigra, which is a part of the ganglia produce what is know as dopamine, when someone is affected by Parkinson’s the dopamine producing cells are lost and this then causes a shortage of dopamine in the brain. As for the reason these cells are lost not much is known on exactly why this happens.

The basal ganglia in our brain stores and helps to adjust voluntary movement, it works alongside another chemical messenger which is called acetylcholine, with dopamine playing a crucial role in the steering mechanism which helps the ganglia to put programs of movement together.

The level of dopamine in someone who has Parkinson’s will fall to about 80% and when this happens this steering mechanism in the brain will fail. The body’s internal communication system will then go awry and messages delivered from the brain to parts of the body are interrupted or slowed down and symptoms of Parkinson’s disease then begin to show.

Exactly which parts of the body and how greatly they are affected will differ from person to person although the symptoms of the disease will always get progressively worse as the disease develops over a period of time; this however will usually happen very slowly. Great strides have been made in the treatment of the disease and there is a lot that can be done to alleviate and ward off the symptoms.

How common is Parkinson’s disease?

Parkinson’s disease occurs anywhere in the world though as the disease chiefly affects older people it is more prevalent in developed countries. It is thought that over 700,000 people worldwide do suffer from the disease with over 50,000 new cases being reported every year. Statistics show that roughly 1 in every 100 people who are over the age of 65 will go on to develop Parkinson’s disease.

What are the common signs of the disease?

There are four major diagnostic symptoms of the disease, these are:

• Tremor or shaking particularly when the limbs are at rest.
• Rigidity or stiffness of the joints which can sometimes be very painful.
• Bradykinesia or slowness of movement.
• Postural instability.