What is Polynenritic Insanity?

Legal Definition
is insanity arising from an inflammation of the nerves, of the kind called "polyneuritis" or "multiple neuritis" because it involves several nerves at the same lime. This is often preceded by tuberculosis and almost always by alcoholism, and is characterized specially by delusions and falsification of the memory. It is otherwise called "KorssakofTs disease." (Kraepeiin.)
-- Black's Law Dictionary