In Parkinson’s disease, nerve cells in the midbrain that produce the chemical messenger dopamine are gradually lost. Dopamine is needed for smooth movement. Typical signs are movements that become slower and smaller, stiff muscles and a tremor at rest, often on one side of the body first. Steps and handwriting become smaller, the voice quieter. Years beforehand, a declining sense of smell, constipation or restless sleep in which dreams are acted out may already occur.
Multiple sclerosis is a chronic inflammatory disease of the brain and spinal cord. The immune system attacks the protective sheath around the nerve fibres, and areas of inflammation develop in many places. The symptoms vary accordingly: visual disturbances, tingling and numbness, paralysis, problems with balance and the bladder, or severe fatigue. Initially, it usually progresses in relapses that subside completely or partially; in some people, symptoms later worsen even without relapses. It often begins in young adulthood.
Neurologists diagnose Parkinson’s on the basis of the symptoms and a thorough examination; an MRI scan of the head helps rule out other causes. If MS is suspected, MRI shows typical lesions in the brain and spinal cord. Examination of the spinal fluid and measurement of evoked potentials – the conduction time of nerve pathways such as the optic nerve – support the diagnosis.
So far, neither disease can be cured. Treatment aims to relieve symptoms and preserve independence for as long as possible and, in MS, also to slow the course of the disease. In Parkinson’s, medication compensates for the lack of dopamine; doses and timings are adjusted again and again over the years, and in later stages medication pumps or deep brain stimulation at specialised centres may also be options. In MS, relapses are treated with high-dose anti-inflammatory medication. Long-term therapy that acts on the immune system aims to make relapses less frequent and slow progression.