1. Common Types of Movement Disorders
Parkinson's disease is a progressive and degenerative neurological disorder that causes loss of control over body movements.
No-one knows what causes Parkinson's disease and there is currently no cure. What we do know is that the symptoms arise when a small region of the brain called the Substantia Nigra degenerates. As brain cells (or neurons) in the Substantia Nigra die, the brain is deprived of the chemical neurotransmitter dopamine.
Dopamine enables communication between the brain cells that manage motor control, so reduced levels lead to the reduced motor control that is symptomatic of Parkinson's.
Patients can experience extreme swings in movement control - from periods of virtually normal motor function to episodes of complete immobility. Most frustratingly, these can occur in the span of just a few hours.
As Parkinson's progresses, it becomes increasingly disabling, eventually making routine daily activities like bathing, dressing and eating virtually impossible without assistance from a care giver.
Spasticity is an umbrella term for conditions where certain nerve signals are unable to reach the muscles because of damage to the central nervous system (the brain or spinal cord). This damage causes a change in the balance of signals between the nervous system and the muscles, leading to increased activity or 'excitability' of the muscle tissue.
Common specific conditions include cerebral palsy, brain injury, stroke, multiple sclerosis, or spinal cord injury.
Spasticity is characterised by tight stiff muscles that make movement, especially of the arms or legs, difficult or uncontrollable. Spastic muscles resist the normal stretching that occurs during use, and affected muscles will remain abnormally contracted for long periods.
By definition, spasticity is involuntary and velocity-dependent. So the resistance to stretching is partly determined by the speed at which a spastic muscle is stretched. The stretch reflex is an important associated factor. This reflex is essential for coordinating the contracting and relaxing of muscles, and normally keeps the muscles from stretching too far.
Essential Tremor (ET) is not a life-threatening disease, but can be a life-altering condition. People often report changes to their lives as a direct result of their ET.
ET is an uncontrolled rhythmic shaking of a body part. Most commonly, it affects the hands, arms, or head. The condition is caused by abnormal communications between certain areas of the brain, and can often be misdiagnosed as Parkinson's disease.
Perhaps the most common of all neurologic movement disorders, ET is thought to affect as many as 14,000 people across Australia and New Zealand. For most, it is a slowly progressive disorder; while others may experience no progress, just a mild tremor for the rest of their lives.
Unlike the resting tremor associated with Parkinson's disease that is present even when muscles are not voluntarily activated, the symptoms of Essential Tremor are either absent or minimal during periods of rest. The tremors usually disappear completely during sleep.
Nevertheless, ET can be embarrassing and debilitating. Some people may experience the tremors in conjunction with other neurological symptoms, such as an unsteady or uncoordinated manner of walking.
Dystonia is a neurological movement disorder characterised by sustained muscle contractions, usually producing twisting and repetitive movements, or abnormal postures and positions.
Dystonia may occur as a primary condition, or it may be the result of environmental factors that affect the brain (designated secondary or symptomatic dystonia). The condition can sometimes be associated with certain nondegenerative, neurochemical disorders that are characterised by neurological features, such as Parkinsonism. Dystonia may also be a primary feature of certain, usually hereditary, neurodegenerative disorders.