Clinical Features of Parkinson's Disease
The main clinical symptoms of Parkinson's disease can be summarized with the acronym TRAP.
Tremor-rest tremor typically in the upper extremity, which is classically described as pill-rolling.
Rigidity-muscle stiffness, which is evaluated on physical examination. Froment's maneuver (repetitive movements of the other side of the body) is used to elicit mild rigidity.
Akinesia-slow movements, which are exhibited as the typical masked facies (expressionless face), slowness of repetitive movements (bradykinesia) of the fingers or legs, decreased arm swing when walking. Patients may report feeling that they "run of out gas" when performing a movement. For example, someone may stir a large pot with progressively less energy and need to stop. Akinesia is more severe than bradykinesia and means inability to move.
Postural Instability-tested by the pull test. Patients may also experience shuffling gait with small steps and difficulty turning. They may have difficulty initating walking and then rush forward as if an unknown force propelled them. This is called festination or festinating gait from the Latin verb festinare meaning to hurry.
Classic Parkinson's disease starts on one side of the body and later spreads to the other side.
There are other associated features that many Parkinson's disease patients report, such as prior history of constipation and REM Behavior Disorder (RBD). During REM (rapid eye movement) sleep, our bodies are paralyzed, but in individuals with RBD, this does not occur and people act out their dreams for example by talking during sleep. Some patients report seborrhea which manifests as scaly, dry skin on the face. Sialorrhea, or drooling, occurs especially at night-time. Depression may occur in Parkinson's disease.
Early signs of Parkinson's disease
Early Parkinson's disease may manifest with a mild tremor of one hand, mild slowness and stiffness of fingers on one hand or one shoulder, and postural instability. The latter case may be misinterpreted as a frozen shoulder. Family members may report seeing decreased arm swing of one hand and decreased facial expressivity as well as softer voice.
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It is important to differentiate Parkinson's disease from potential mimickers such as Progressive Supranuclear Palsy (PSP), Multiple System Atrophy (MSA), and Corticobasal Degeneration (CBD).
PSP is a disorder that affects both sides of the body equally. Vertical eye movements are impaired, which leads to profound difficulty with walking on stairs and the "sloppy eater" phenotype since the patient is not able to to look down on their plate of food when eating.
MSA has a primarily parkinsonian (MSA-P) and primarily cerebellar (MSA-C) variant. The disorder combines parkinsonism with significant autonomic nervous system damage (such as lightheadedness from profoundly low blood pressure when standing up - orthostatic hypotension). The cerebellar variant also has incoordination, manifested for example by wide-based unstable gait.
Corticobasal Degeneration starts exclusively on one side of the body. The disorder involves parkinsonism together with apraxia-which is akin to forgetting how to perform tasks with the affected arm.