Clinical Features Of Parkinsonism
Tremor. The characteristic tremor of Parkinson's disease is a 3 to 6 hertz (hz) rest tremor with pill-rolling quality, that is, the tremor is more pronounced when the person is at rest and, when looking at the hands, the thumb and index finger move in a circular motion. This too can be seen in patients with other parkinsonian syndromes. For example, up to 80 percent of patients with multiple system atrophy, have tremor. In DLB, tremor occurs in 25 to 76 percent of patients.
Rigidity. Muscle rigidity occurs in 89 to 99 percent of patients with Parkinson's disease, and it is also seen in patients with other parkinsonian syndromes. Patients with rigidity have the sensation of stiffness. Clinicians who examine them find that the muscles feel rigid when they are put through passive movement.
Bradykinesia. Bradykinesia is defined as slowness of movement and an inability to maintain a motor act. It is present in 77 to 98 percent of patients with Parkinson's disease, and can also occur in all other parkonsonian syndromes.
Postural instability. While postural instability is one of the cardinal features of Parkinson's disease, it occurs in many other parkinsonian syndromes. In the aging population, because of multiple sensory deficits, including musculoskeletal problems, postural instability results in a sense of poor balance and tendency to fall.
Asymetric onset. Asymmetric onset: that is, onset of symptoms such as tremor or rigidity, on one side, is found in most patients with Parkinson's disease, and in many other parkinsonian syndromes. For example, up to 42 percent of patients with asymmetric onset of parkinsonism had a diagnosis other than Parkinson's disease.
Speech disturbance. Many patients with Parkinson's disease have low volume of speech (hypophonia). They may also have stuttering or involuntary repetition of phrase with increased rapidity (palilalia). These speech disturbances are also seen in other disorders, such as PSP, in which a pronounced change in voice may be an early feature.
Dementia. While dementia has been estimated to occur in between 25 to 40 percent of patients with Parkinson's disease, the cognitive deficits are not as prominent as in other parkinsonian syndromes. So-called dementia subcortical syndrome (with mental slowing and decreased mood) can occur in other parkinsonian syndromes, such as PSP and MSA. Mood and psychotic disorders do occur in some patients with Parkinson's disease, but can be more common in other parkinsonian syndromes.
Autonomic dysfunction. Autonomic dysfunction, such as blood pressure falling when the patient stands, occurs in some patients with Parkinson's disease and is exacerbated by medications. This, however, is not a prominent feature of Parkinsons' disease, but it can be a significant feature of other parkinsonian syndromes. For example, orthostatic hypotension is one of the hallmarks of MSA.
Eye movements. While patients with Parkinson's disease exhibit mild abnormalities in their eye movements, such abnormalities are a subtle feature and are often not readily evident in clinical examination. They can be a significant feature, however, in other parkinsonian syndromes, such as PSP, in which there is marked difficulty in looking down.
- Parkinsonism - Neuroanatomical Considerations
- Parkinsonism - Clinical Syndromes
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