neurodegenerative diseases

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Neurodegenerative disease is a blanket term encompassing a wide variety of disorders, typically slowly progressive, with variable gradual neurologic dysfunction.

Over the years numerous classifications schemas have been described, each adding a layer of confusion for students. The main distinction to be aware of is classifications according to clinical presentation and those relying on underlying pathological processes. As expected, earlier descriptions were primarily of the former, whereas as more and more neurodegenerative diseases are understood at a biochemical level, classifications have shifted towards focusing on these changes.

As such a useful approach is to divide them according to the underlying pathological process, although even so there is much overlap and confusion with many clinical patterns being caused by different pathological processes and each pathology possibly manifesting in a number of clinical patterns . What is worse is that as definitive diagnosis currently necessitates histological diagnosis of brain tissue (either antemortem biopsy or postmortem assessment) the actual diagnosis in most cases is never established, further polluting the published data.

Dividing neurodegenerative disease by the main pathological process involved results in the classification below (under "Related Radiopaedia Articles").

It should be noted that any such classification is, by the very nature of the heterogeneity of the included conditions, not always felt to be complete. For the purpose of this section, diseases that are primarily metabolic in origin are excluded. See primary metabolic encephalopathies.