Neurodegenerative disease is a range of medical conditions that primarily affect the neurons in the brain. Because human brain is involved all of the body’s activities, neurodegenerative disease is associated with progressive deterioration of nervous system affecting balance, movement, talking, cognition, memory and organ function. Neurodegenerative diseases are not curable and hereditary. Examples of the neurodegenerative disorders include amyotrophic lateral sclerosis (ALS – Lou Gehrig's disease), Parkinson's disease, and Alzheimer's disease.

Even though the features of the neurodegenerative disorders appear quite different, there are similarities regarding the way in which the different parts of the nervous system degenerate. Many of the neurodegenerative diseases are associated with dementia, a decline in mental ability such as memory or communication and language.

What are the features of neurodegenerative disorders?

Amyotrophic lateral sclerosis (ALS):

  • muscle wasting starting with hands or feet, and progressing to the forearms, shoulders, and lower limbs
  • weakness of face, tongue, chest wall muscles (due to loss of neurons in one part of the brain – the cortex), and spine
  • weight loss, fatigue, difficulty swallowing, and increased salivation
  • vision, bladder, and bowel functions, and thought processes are usually not affected
  • dementia in some ALS patients

50% of patients die within 3 years of disease onset, and 10% live 10 years.

Parkinson's disease:

  • tremor, slowness of movement, and stiffness of muscle
  • difficulty with arm and leg movement and speech, mainly due to loss of neurons in one part of the brain (the basal ganglia)
  • impaired balance
  • sleep disorders
  • thought processes are usually affected
  • non-motor symptoms such as depression or difficulty swallowing may appear

Some studies suggest the life expectancy of people with Parkinson’s disease is comparable to the general population, while others suggest it is slightly shorter.

Alzheimer's disease:

  • impaired memory and thought process
  • decline in language, thinking, and judgment
  • possible eventual difficulty with movement and walking
  • often, behaviour disorders such as agitation

The disease lasts about 8 years, ending in death, but it can range up to 20 years.

The cause of neurodegenerative disorders

The neurodegenerative disorders have genetic predisposition in some cases, although most cases are sporadic. No treatment, as yet, has been shown to significantly postpone the onset of these illnesses. Treatments are available to control the symptoms and to improve quality of life. Many researchers think that there are probably several factors, likely genetic, environmental, and age-related, that trigger the onset of these diseases. Once the origins of these mechanisms are understood, it may become possible to control them through gene therapy.

Andrew Eisen , MD 
with updates by the MediResource Clinical Team