Final answer:
The chronic demyelinating disease of the CNS characterized by progressive disability is Multiple Sclerosis (MS), which damages the myelin sheath insulating neurons in the brain and spinal cord.
Step-by-step explanation:
The chronic demyelinating disease of the CNS characterized by progressive disability is Multiple Sclerosis (MS). MS specifically involves inflammation and damage to the myelin sheath insulating the neurons in the brain and spinal cord. As the myelin is compromised, communications between neurons are hindered, leading to a wide range of symptoms, including physical, psychiatric, and cognitive deficits. Unlike some other neurodegenerative disorders, such as amyotrophic lateral sclerosis (ALS) or Parkinson's disease, which involve the death of neurons controlling voluntary movements or dopamine neurons respectively, MS is marked by the deterioration of the protective coating around nerve fibers leading to disrupted nerve signal transmission.