I. GENERAL PRINCIPLES
Degenerative diseases are characterized by progressive neuronal degeneration
and loss in disease specific regions. The disease arises without any clear
inciting event in a patient without previous associated neurologic deficits.
In most disorders, the etiology is unknown. The most common manifestations
involve at least one of the following: dementia, movement disorders, weakness
or sensory loss due to spinal cord involvement.
A. Clinical Signs
- 1. Signs and Symptoms are predictable and dependent upon the
area of the nervous system involved.
- a. Cerebral Cortex - degeneration leads to dementia with
impairment of intellectual function and judgement; memory loss is common.
- b. Basal Ganglia - lesions lead to a variety of movement
disorders and sometimes to "subcortical dementia"
- c. Spinal Cord - degeneration of corticospinal tract causes
weakness; lesions in posterior columns cause sensory impairment.
- 2. Some of the disorders have an hereditary pattern
and family history can be used for screening.
B. Histopathology
- Each of the degenerative diseases has neuronal loss and a resulting
glial reaction seen in disease-specific regions of the brain. There
may also be disease-specific microscopic changes, such as inclusion bodies,
that are part of the diagnostic criteria. The inclusions seen in several
of the diseases are comprised of cytoskeletal components.