What is the difference between Parkinson's Disease and Parkinsonism, and how a multidisciplinary therapeutic approach can treat the symptoms.
Parkinson’s disease is one of the most common neurodegenerative disorders that affects people of all races. Approximately 1% of individuals world-wide older than 60 years suffer from this progressively debilitating condition that can only be slowed by treatment.
Parkinsonism is a clinical syndrome that is characterized by rigidity, bradykinesia, tremor and postural instability. Parkinsonism shares symptoms with Parkinson’s disease, after which it was named, however it is not exclusive to this disease.
This complex syndrome can manifest itself in several neurodegenerative disorders, metabolic disorders and toxins, yet Parkinson’s disease remains the most common cause of parkinsonism.
Clinical Sings and Symptoms
Parkinson’s disease presents four cardinal motor manifestations:
Tremor at rest
Often times, patients initially present only one or two of the classic signs of the disorder. Usually, the first complaint is one of motor stiffness or weakness, shortly followed by tremor and postural deficits.
One of the characteristics of this disease is the presence of a tremor at rest, occurring in 70% of patients (1). A prolonged absence of this symptom is cause for careful consideration of other neurologic conditions that can present with signs of parkinsonism such as progressive supranuclear palsy , multiple system atrophies, corticobasal ganglionic degeneration etc.(2).
Rigidity is a resistance to passive movement of the limbs which is more often discovered by the examining physician than the patient. This motor sign is more often than not uniform in the directions of extension and flexion, known as lead pipe rigidity.
Bradykinesia describes a paucity and slowness of movement. Patients can present loss of facial expression and associated movements such as arm swinging when walking. Bradykinesia can lead to potentially life-threatening complications when it affects the oropharynx; leading to swallowing difficulties and in turn aspiration pneumonia.
However, of all the cardinal motor manifestations, postural instability is the most dangerous to a patient. Postural instability could lead to falls that result in life-threatening traumatism. It is also one of the manifestations that respond poorly to levodopa therapy (3).
Another particularly troublesome motor manifestation of Parkinson’s disease is the “motor block”, essentially a freezing phenomenon. Typically, patients are suddenly unable to step forward when walking, or complete their intended action. The freeze is transient and can last from seconds to minutes, after which is suddenly abates.
Cognitive and Psychiatric Manifestations
Patients with Parkinson’s disease have an increased risk of developing a variety of cognitive and psychiatric dysfunctions. The most common manifestations are dementia and depression. Although, patients with delusions, hallucinations, irritability, anxiety and apathy have also been reported (4).
One of the cardinal non-motor manifestations of Parkinson’s disease is dementia. The prevalence of dementia in Parkinson’s patients depends on age. In a study by Aarsland and co-workers (5) 28% of Parkinson’s disease patients were identified with, while Mayeux et al. (6) identified that 65% patients over the age of 85 had dementia. While it is a major cause of disability, there is currently is no effective symptomatic treatment.
In addition to these neurologic symptoms and signs, Parkinson’s disease patients often have disturbing sensory symptoms and pain in affected limbs. Many also present signs of autonomic failure such as constipation ,orthostatic hypertension, urinary hesitancy, and impotence in men (7).
The two hallmark pathologic findings in Parkinson disease are
Loss of pigmented dopaminergic neurons in the substantia nigra pars compacta
Presense of Lewy bodies
Loss of dopaminergic neurons of the substantia nigra pars compacta is essential for the pathologic diagnosis of Parkinson’s disease. Even mildly affected Parkinson’s disease patients have presented at death an approx. 60% loss in dopaminergic neurons(8).
The loss of dopaminergic neurons in the pars compacta leads to an increase in overall excitatory drive in the basal ganglia. This translates as a disruption in voluntary motor control and leading to the characteristic manifestations of Parkinson’s disease.
As the disease progresses, further depletion of dopamine lead to an alteration of basal ganglia neurotransmitters including GABA, glutamate and serotonin.
Lewy bodies are an eosinophilic inclusion identified within neurons that appear in Parkinson’s disease. They are usually round, with an eosinophilic core, surrounded by a pale halo and are observed within the cell soma, but also can be seen in neurites or in the extracellular space.
These inclusions consist of an insoluble fibrillary aggregate that contains misfolded proteins, of which alpha-synuclein represents the main component.
Usually they can be observed in the regions of the brain that have the most neuron loss including substantia nigra, locus coeruleus, the dorsal motor nucleus of the vagus, and the nucleus basalis of Meynert, but they are also observed in neocortex, spinal cord, diencephalon and peripheral autonomic ganglia (9).
Lewy bodies are hypothesized to represent the pre-symptomatic phase of Parkinson disease. Their prevalence increases with age and they are not specific to Parkinson disease. Lewy bodies have been found in atypical parkinsonism, Hallervorden-Spatz disease and other neurological disorders. Yet, they are a characteristic pathological finding and are required for diagnosis of Parkinson’s disease under current definitions.
The etiology of Parkinson disease remains unclear. However, in most cases it is hypothesized to be due to a combination of environmental and genetic factors.
Environmental risk factors commonly associated with the development of Parkinson disease include use of pesticides, living in a rural environment, consumption of well water, exposure to herbicides, and proximity to industrial plants and quarries.
Currently, know genetic causes of Parkinson’s disease are extremely important when the disease debuts before the age of 50 and accounts for approximately 10% of cases.
The best documented and most widely investigated genetic causes for Parkinson’s disease are the alpha-synuclein gene and the Parkin gene(10).
The medical treatment of Parkinson’s disease aims to control the symptoms and signs and symptoms of this conditions for as long as possible while keeping adverse effects to a minimum.
The gold standard
Levodopa coupled with carbidopa is currently the gold standard symptomatic treatment for Parkinson’s disease.
Carbidopa prevents the decarboxylation of levodopa to dopamine resulting in a greater distribution of levodopa into the central nervous system.
Levodopa provides the greatest control of motor symptoms and signs, and presents the fewest adverse effects in the short term usage. However, long term use of levodopa leads to the development of dyskinesias and motor fluctuations which are difficult to resolve.
When dyskinesias and motor fluctuations can no longer be managed with medication, deep brain stimulation is considered.
In Parkinson’s disease, non-motor symptoms can occur earlier and be just as debilitating as the motor symptoms. Recognizing and adequately treating the non-motor symptoms is essential for the appropriate management of this disease and maintaining the quality of life of patients.
Aside from standard medical treatments, many patients turn to alternative treatment methods in order to manage the symptoms of Parkinson’s disease. The most potent documented aids to traditional treatments are acupuncture, dance therapy, speech therapy, exercise and physical therapy.
Acupuncture, Scalp Acupuncture and Yamamoto new scalp Acupuncture (YNSA) has become a popular aid to conventional treatment for patients with Parkinson's disease. Both manual and electro acupuncture has been found to some motor symptoms in patients with Parkinson's, as well as significantly improve many non-motor symptoms such as sleep disorders, psychiatric disorders and gastrointestinal symptoms.
When used as an adjuvant for levodopa, YNSA and acupuncture. improved the therapeutic efficacy of the drug, reduced dosage requirements and the occurrence of side effects (11).
Reviews of Chinese clinical trials, with meta-analysis on selected trials show that acupuncture is safe and well tolerated(12). It significantly improves sleep and rest in Parkinson’s disease patients and the majority reported subjective improvement in tremor, handwriting, depression and slowness.
Animal studies using Parkinson’s disease models confirmed that electro-acupuncture, Yamamoto new scalp acupuncture and chines scalp acupuncture, at various points (BG-34, LIV-3) or a combination of acupressure points improves motor performance and provides neuro-protection of dopaminergic neurons of the substantia nigra. The effect has been attributed to a significant increase in the dopaminergic projection terminal in the striatum and TH positive neurons(13).
Results are promising, however they vary across studies. Larger, well controlled trials are needed to confirm the efficacy of acupuncture
Tai Chi and Qigong
Tai Chi and Qigong are low impact, moderate intensity aerobic exercises that intertwine with meditation and breathing exercises. They have been used successfully to improve functional ability, postural stability and alleviate the bradykinetic movements associated with Parkinson's disease.
Tai chi protocols imply weight shifting and ankle swaying in order to move a person’s center of gravity to the limit of stability. Exercises alternate between wide and narrow stances in order to continuously change the base of support, thus increasing trailing-leg swing time and support-leg standing time. Other exercises involve performing toe-to-heel and heel-to-toe stepping movements which help fortify plantar flexion and dorsiflexion.
These training features help reduce dyskinesia by increasing the patient’s ability to develop effective swaying strategies and engage in controlled movements. Clinically, Tai chi and Qigong have showed a potential in aiding Parkinson’s disease patients perform daily functions such as walking, taking objects from a cabinet and thus lowering the probability of a fall.
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