NIH - Medical Encyclopedia Parkinson's disease

"Parkinson's disease is a disorder of the brain characterized by shaking (tremor) and difficulty with walking, movement, and coordination. The disease is associated with damage to a part of the brain that is involved with movement. … Some people with Parkinson's disease become severely depressed. This may be due to loss of dopamine in certain brain areas involved with pleasure and mood. Lack of dopamine can also affect motivation and the ability to make voluntary movements. Early loss of mental capacities is uncommon. However, persons with severe Parkinson's may have overall mental deterioration (including dementia and hallucinations). Dementia can also be a side effect of some of the medications used to treat the disorder. ...

Symptoms:

• Muscle rigidity • Unstable, stooped, or slumped-over posture • Loss of balance • Gait (walking pattern) changes • Shuffling walk • Slow movements • Difficulty initiating any voluntary movement • Small steps followed by the need to run to maintain balance • Freezing of movement when the movement is stopped, inability to resume movement • Muscle aches and pains (myalgia) • Shaking, tremors (varying degrees, may not be present) • Changes in facial expression • Reduced ability to show facial expressions • Voice or speech changes • Loss of fine motor skills • Frequent falls • Decline in intellectual function (may occur, can be severe) • A variety of gastrointestinal symptoms, mainly constipation.

… symptoms may be difficult to assess, particularly in the elderly. For example, the tremor may not appear when the person is sitting quietly with arms in the lap. The posture changes may be similar to osteoporosis or other changes associated with aging. Lack of facial expression may be a sign of depression. An examination may show "cogwheel" rigidity (jerky, stiff movements), tremors of the Parkinson's type, and difficulty initiating or completing voluntary movements. Reflexes are essentially normal. Tests are not usually specific for Parkinson's, but they may be required to rule out other disorders that cause similar symptoms. See also essential tremor."

Highlighted Article

[Clinical criteria of Parkinson's disease.] (Ther Umsch. 2007)

"The clinical criteria of Parkinson's disease are akinesia in combination with at least one of the following three symptoms: tremor (asymmetrical resting tremor), rigidity, impairment of posture, gait and balance. Symptomatic and atypical parkinsonian syndromes are ruled out by history, clinical examination, cranial CT, MRI, SPECT or PET. Patients with Parkinson's disease respond to levodopa or dopaminagonists throughout the course of the disease."