What is Parkonson's Disease?
Parkinson's disease (also known as Parkinson disease or PD) is a degenerative disorder of the central nervous system that often impairs the individual's motor skills, speech and other functions.
The Clinical Features of Parkinson's Disease
There are four cardinal features of PD: resting tremor, rigidity, bradykinesia and postural instability.
Resting Tremor
Resting tremor is the most common and easily recognised symptom of PD. Tremors are unilateral, occuring at a frequency of 4-6 Hz. They are always prominent in the distal part of the extremities. The tremor also occurs in the hands, lips, chin, jaw and legs. Moreover, these tremors disappear with action and during sleep. With regard to the occurrence of resting tremor, it is variable among patients and during the course of the disease.
In addition to the resting tremor, many patients suffering from PD also have postural tremor that is more prominent and disabling than resting tremor and may be the first manifestation of the disease.
Rigidity
Rigidity is featured by increased resistance, accompanied by the ¡°cogwheel¡± phenomenon, especially when it is related with underlying tremor, present throughout the range of passive movenment of an extremity. Rigidity always occurs promoximally and/or distally, such as wrists and ankles.
Some patients may suffer from pains combining with rigidity. Painful shoulder is the most frequent clinical manifestation of PD, which is always misdiagnosed as arthritis, bursitis or ratator cuff injury due to the lack of definitive test for the diagnosis of PD.
Bradykinesia
Bradykinesia refers to the movement slowness. It is hypothesized that bradykinesia is the result of a disruption in normal motor cortex activity mediated by reduced dopaminergic function. The initial manifestation of bradykinesia is slowness in doing daily activities, such as movement and conduct the other tasks. Other manifestation include loss of spontaneous movements and gesturing, drooling due to impaired swallowing, monotonoc and hypophonic dysarthria, loss of facial expression and dicerased blinking and reduced arm swing while walking.
Post Instability
Post instability is a manifestation of the late stages of PD, usually occuring after the onset of the other clinical features. It is the most common reason of falls and contributes significantly to the risk of hip fractures.
Postural instability could be triggered by several aspects, such as other parkinsonian symptoms, orthostatic hypotension, age related sensory changes and the ability to integreate visual, vestibular and proprioceptive sensory input.
As these symptoms become more serious, patients may have difficulty in walking, talking, or completing other simple tasks. PD usually affects people at the age of 50 or more. As the disease progresses, the tremor, which affects the majority of PD patients may begin to interfere with daily lives. Other symptoms may include depression, other emotional changes, difficulty in swallowing, chewing, speaking, urinary problems or constipation and sleep disruptions.
Neural Stem Cell Transplantation for Parkinson's Disease
Previous report had showed that transplanted neural stem cells could survive, migrate and induce behavioral recovery of Parkinson symptoms, which were directly related to reduced dopamine levels in the nigrostriatal system. After transplantation, neural stem cells could provide neuroprotective, anti-inflammatory, angiogenic and neurogenic factors to the brain, thereby creating a reparative, homeostatic microenvironment in vivo.
