In spite its rarity, about 6.3 million people worldwide are living with Parkinson's disease. In the United States alone, approximately 60,000 people are diagnosed with this disease every year. It is the second most common neurodegenerative disease after Alzheimer's disease.

Parkinson's disease affects a person's movement. It is caused by the death of nerve cells responsible for the production of dopamine, a chemical that sends signals to the part of the brain that controls movement and coordination.

It's not often easy to diagnose Parkinson's disease. Parkinson's disease often begins with mild symptoms that slowly advance over time. Symptoms in the early stages can be so subtle that doctors sometimes mistake the condition for something else.

Studies indicate that people with Parkinson's disease may lose up to 80% of dopamine in their bodies before symptoms become apparent and may decline as much as 10% every year for people with PD. Early diagnosis and treatment, therefore, is important to help minimize dopamine loss and preserve muscle function.

There are many symptoms associated with Parkinson's disease. The symptoms listed below could be signs of Parkinson's disease. A single symptom may not be enough to establish Parkinson's disease. You should, however, make an appointment with your doctor if you exhibit more than one of these symptoms.

  1. Tremor or shaking

Twitching or shaking of limbs can occur after a lot of exercise or may be caused by a medication that you're taking. However, a constant or erratic shaking in your finger, thumb, hand, chin, lips, tongue, body or leg could indicate Parkinson's disease. The tremor usually occurs when at rest and disappears when you move it.

  1. Changes in handwriting

Our handwriting can change as we get older, when we have stiff hands or whenever we can't see very well. These changes, however, don't happen abruptly and change over time. Watch out for a sudden change in your handwriting, particularly when the letters look smaller or the words appear crowded together. This may be an early sign of Parkinson's disease.

  1. Difficulty moving and walking

Watch out for any tension or stiffness in the body, such as in the wrist, elbow, hip or knee that causes mild to severe pain. If the stiffness does not go away when you move, you might have Parkinson's disease. Other symptoms to watch out for include stiffness when moving, short and shuffling steps, arms that don't swing when walking, difficulty stopping or turning around, stiffness and pain in the shoulders or hips, and inability to lift feet off the floor.

  1. Loss of smell

If you notice a change in your ability to smell like if you can't smell the strong scent of bananas, licorice and pickles, you should ask your doctor about Parkinson's disease. Anosmia or the loss of the sense of smell has been suggested as one of the earliest signs of Parkinson's disease, appearing years even before the cognitive and motor symptoms.

  1. trouble sleeping

Thrashing around in bed during sleep, falling out of bed, and extreme and sudden movements like kicking and punching while in deep sleep could all indicate Parkinson's disease.

  1. Constipation

Not enough water and fiber in your diet or some medications could cause constipation. If you have no reason to have trouble moving your bowels and yet you do, then you should talk to your doctor. Constipation is an early sign of Parkinson's disease that may predate motor symptoms like stiffness and rigidity.

  1. Muffled or soft voice

Watch out for any changes in your voice. You may notice that other people may tell you that you have a soft voice or they ask you to speak up even though you feel that you're speaking in your normal tone. This may be a sign of hypophonia, a weak or soft voice typical of people with Parkinson's disease. People with Parkinson's are usually not aware that they have muffled voice or speak softly.

  1. Dizziness or fainting

If you notice that you feel dizzy or faint when you get up from bed or from a chair, you could be experiencing orthostatic hypotension or a sharp drop in your blood pressure. This sudden drop in blood pressure is a symptom commonly linked to Parkinson's disease. Everyone has had a time when they stood up and felt faint or dizzy, but when this happens often you should talk to your doctor.

  1. Masked face

If people tell you more often than not that you have a serious, depressed or mad look on your face even when you're not in a bad mood, you might be exhibiting a common Parkinson's symptom called facial masking. Masking happens when facial muscles become immobilized, leaving Parkinson's patients with muted expressions or blank stares. Most people with Parkinson's don't realize that they're masking until somebody points it out.

  1. Stooping or hunching over

Watch out for any changes in your posture, such as if you lean, stoop or slouch when you stand. Poor posture is characteristic of people with Parkinson's disease, although other factors such as pain or injury and bone disease could also cause poor posture.

See your doctor if you're concerned that you might have symptoms of Parkinson's disease. Your GP will ask you about your symptoms and medical history and will ask you to do some simple exercises to help them decide whether it's necessary to refer you to a specialist. This may be a neurologist, a specialist in conditions affecting the brain and the nervous system, or a gerontologist, a specialist in problems affecting elderly people.

You should see a specialist within six weeks if your GP suspects you may be in the early stages of Parkinson's disease. If your GP suspects you may be in the later stages, see a specialist within two weeks.