It is very significant to understand that not every person suffering from Parkinson's develops all signs or symptoms of the disease. For instance, some people experience tremors as the most tell-tale symptom, but there can be others who do not have tremors but then have sense of balance problems. For some patients the disease progresses rapidly whereas it does not in others. The following are descriptions of the most manifestations of the common crucial indicators of Parkinson's Disease.

Tremor
In the initial onset of the PD, nearly 70 percent of people experience an insignificant tremor and/or twitching in the extremities on one side of the body, or less frequently in the facial area. It becomes manifest as an involuntary throbbing or back and forth movement of the muscles. For the reason that quivering generally occurs when a person is at rest and the muscles are relaxed, it is often called resting tremor. The only instance that the affected body part trembles is when it is not doing work and the trembling normally stops as soon as the person begins to move. The tremor frequently spreads to other parts of the body as PD progresses, but generally remains most perceptible on the side where it originally happened.

Rigidity
This is also referred to as increased muscle tone, meaning hardness of the muscles. Muscles stretch when moved, and relax at rest. In rigidity, the muscle tone of an affected extremity is always stiff and unable to relax, which oftentimes result in a reduction in the range of movement. A person with rigidity may be unable to swing his arms when walking because the muscles are too tight, causing the patient to suffer pain and cramping.

Bradykinesia
Bradykinesia is the incidence of a person experiencing slow movements. Aside from slow movements, a person with bradykinesia will almost certainly also have incomplete movement, inconvenience in initiating movements and abrupt stopping of movements. They may also walk with short, shuffling steps. Bradykinesia and rigidity may also occur in the facial muscles thereby lessening a person's range of facial expressions.

Impaired Motor Coordination
This is also referred to as postural instability or impaired balance and coordination. PD patients often experience a sense of a loss of balance and loss of motor coordination when standing. The lack of motor coordination symptoms when recombinant with other symptoms such as bradykinesia contributes to the increase in the probability of falling. People suffering from balance impairments generally have difficulty in making turns and abrupt movements. Sometimes, they may even experience a sensation of being rooted where they stand and find difficulty in walking. The slowness and incompleteness of movement can also affect speaking and swallowing.

Aside from the above manifestations and common symptoms of PD, there are also secondary symptoms which for some can be as problematic as the primary symptoms. These can include hunched posture, a tendency to lean forward or backward and speech problems caused by lack of muscle control in the vocal chords including non-motor related indicators such as depression and anxiety.