Parkinson's Disease

It was first described by James Parkinson in England in 1817. The disease most often develops after age 50. It affects both men and women and is one of the most common neurologic disorders of the elderly.
The disease itself causes degeneration of nerve fibres. The brain consists of cells called 'Neurons' and their fibres called 'Nerves'. Nerves are like cables and in some conditions, thinning of these cables occur; this is known as degeneration.

The patient can [rarely] form any recollection of the precise period of its commencement. The first symptoms perceived are, a slight sense of weakness, with a proneness to trembling in some particular part; sometimes in the head, but most commonly in one of the hands and arms. The propensity to lean forward becomes invincible. As the debility increases and the influence of the will over the muscles fades away, the tremulous agitation becomes more vehement. -James Parkinson, 1817