Читать книгу Neurology - Charles H. Clarke - Страница 101

Foundations of neurology emphasised distinctions between positive and negative or primary and secondary phenomena, though these are not rigid. Many brain, cord, root and nerve lesions are destructive, that is with negative, primary effects such as paralysis. Destructive lesions may also cause positive, secondary phenomena, typically release of neuronal inhibition, such as exaggerated tendon reflexes. Positive also describes irritative phenomena, such as seizures.

Symptoms can thus be of two types:

Primary (direct) abnormalities, often negative: one part fails to work. Primary abnormalities can also be positive (irritative) – focal seizures from a glioma, or pain in the distribution of a trapped median nerve.

Secondary (indirect) abnormalities, usually positive, indicate typically over‐activity from release of inhibition, such as spasticity.