Low Dopamine Levels in Parkinson’s Disease

As explained under Parkinson’s disease brain chemistry,  dopamine is a brain hormone (neurotransmitter) that is deficient in PD patients. This is accompanied by a loss of dopaminergic neurons. When more than 60% of these neurons in the substantia nigra and corpus striatum of the brain are lost then the motor signs of Parkinson’s disease becomes evident. L-dopa may therefore help to counteract these symptoms by restoring dopamine levels. When dopaminergic neurons are stimulated, it is released at the nerve terminal into the gap junction known as the synapse. This dopamine is recycled by dopamine transporters (DaT) which pumps it back into the nerve cells and stored for use at a later stage.

Detection of DaT Activity

A substance developed by GE Healthcare known as DaTscan can help to detect these dopamine transporters. If the transporters are working then it indicates the presence of healthy dopaminergic neurons. Until now there was no significant structural change in the brain that were detectable by conventional imaging techniques. Therefore the loss of these dopaminergic neurons could not be isolated in the living patient although microscopic evaluation of brain tissue post mortem noted pallor of the substantia nigra and the loss of these neurons. With the use of DaTscan, dopaminergic neurons are highlight on a SPECT scan. This is type of nuclear imaging study that stands for single-photon emission computerized tomography (abbreviation~ SPECT). DaTscan is a contrast agent that is visible on a SPECT scan.

DaTscan Results

With DaTscan, the brain function can be evaluated rather than just the structural changes associated with Parkinson’s disease.  Healthy dopaminergic neurons are illuminated on a SPECT scan with the use of the DaTscan contrast agent. Therefore the more illuminated areas, the greater the number of healthy neurons. Conversely, dark areas indicate low dopamine activity.

This test holds much promise for accurately identifying patients with Parkinson’s disease or other parkinsonism syndromes. It removes uncertainty associated with undiagnosed or even misdiagnosed cases. While it may not be necessary for every PD patient to confirm the diagnosis, it is hoped that this scan will be a reliable technique to monitor progression of the disease and therefore any treatment that can slow its progression. Currently (August 2011) clinical trials are underway by some 14 medical centers in the United States to evaluate DaTscan as a means of monitory disease progression. This is part of the biomarkers study by the Michael J. Fox Foundation known as the Parkinson’s Progression Markers Initiative.

Since Parkinson’s disease is brought on due to the lack of Dopamine in the brain much of the treatment for the disease relies on ways of replacing, stimulating and substitution of this chemical. Although some very effective drugs have been developed in the treatment of Parkinson’s they do however have their disadvantages, therefore the treatment of the disease doesn’t just rely on medication but on several measures combined together as a package. Some of which include:.

• Exercise.
• Changes in diet.
• General activity.
• Attitude towards the disease.
• Medication.

As Parkinson’s is a chronic disease which progresses the overall aim of the treatment is to maintain the sufferer’s quality of life for as long as possible and not to cure the disease itself. The type of treatment available for you depends on certain factors such as:

• The severity of your symptoms.
• How much distress the symptoms cause you.
• Assessment of possible drug treatments.
• Your personal circumstances.

In order to determine the best possible treatment for the individual doctor and patient will need to be open and honest; this means that if you don’t understand anything that your doctor tells you, you must ask them to make themselves clear. Also you should voice any concerns, fears or worries that you may have regarding the disease.

Medication treatments

Some people with Parkinson’s may from time to time have to visit the hospital when on medication for the disease, this allows for your progress to be checked and alteration to the dosage or drugs needed to be changed depending on your progress. Studies show that early use of Rasagiline may slow down Parkinson’s. It is important that if medication is prescribed for your condition then you know exactly how much to take and when to take it. The patient should also be aware of any possible side effects from the drugs and what steps they need to take in the case of an adverse reaction to the drug.

Holistic therapy

Holistic therapies are now being used in the treatment of more and more illnesses along with traditional medication, possible holistic treatments include:

• Changes to the diet.
• Occupational therapy.
• Aromatherapy.
• Speech therapy.
• Alternative medicine.
• Physiotherapy.

Parkinson’s disease is a disease which affects the control of muscles and affects the movement, speech and posture. It is a degenerative disease of the body’s central nervous system and one which is often characterised by hand tremor, slow physical movement and rigidity of the muscles.

The excessive muscle contraction that is foremost in Parkinson’s disease is caused by insufficient formation of Dopamine, which is a chemical which is naturally produced in our body. While the majority of Parkinson’s disease has no known cause it can sometimes be caused through head trauma, toxicity, genes and other medical disorders.

The main symptoms of Parkinson’s disease

The number one symptom of Parkinson’s disease is how it affects the movement; other typical symptoms are mood disorders, changes in the behaviour, changes in the ways of thinking and changes in sensation. Symptoms occurring can range from person to person with progression of the disease also being distinctly individual.

The motor skills symptoms

The symptoms which are chiefly present are:

• Tremor – one of the most common symptoms of Parkinson’s disease is tremor of the hands, this is more noticeable when the hands are at complete rest. However it is thought that around 30% of the people who have Parkinson’s disease have very little tremor, these people are generally classed as akinetic-rigid.
• Rigidity – this includes stiffness of the joints and when combined with tremor will produce a ratchety rigidity when the limbs are passively moved.
• Akinesia – this is slowness or absence of movement * Postural instability – this often results in the person falling due to impaired balance down to the loss of postural reflexes.
• Shuffling – the person when walking will very often take short steps with their feet barely leaving the ground, very often the person will trip over small obstacles in their path.
• Problems turning – the person will keep their neck and trunk rigid when turning instead of just turning their head to look, this usually requires the person to take several small steps to make a turn.
• Stooped posture – in severe or progressive forms of Parkinson’s disease the person’s head and upper body may become bent at a right angle to the trunk.
• Speaking softly – the speech of the person may become hoarse, quiet and monotonous.
• Drooling – the person may often drool, this is thought to be down to the inability to swallow properly and the persons gait.
• Dysphagia – the person can lose all ability to swallow and this can lead to aspiration and eventually death.
• Fatigue – the person will easily get tired over 50% of sufferers are thought to be affected by tiredness and fatigue.

Non motor skill symptoms

• Depression – depression is thought to affect between 30 to 80% of all people suffering from Parkinson’s disease.
• Slowed reaction times – the persons voluntary and involuntary responses will show a significant delayed reaction.
• Dementia – dementia will often occur in about 20 to 40% of all people suffering, this will be a later development in the disease.
• Memory loss – memory loss is common particularly procedural memory loss rather than declarative.
• Pain – sufferers can experience pain in their joints, muscles and tendons.

Diagnosis

Currently there are no tests which can accurately determine Parkinson’s disease; it is usually diagnosed by way of medical history and a neurological examination. Parkinson’s disease is one disease that is hard to diagnose as the early onset and symptoms of the disease are often mistaken as the effects of normal ageing.