Diagnostic function of the microhuman prototype of the expert system--MUNIN.

This paper describes the diagnostic function of a prototype expert system for electromyography (EMG). The prototype was restricted to a limited "Microhuman" anatomy with only 6 muscles and 8 nerves, and a corresponding limitation on the number of local nerve lesions. It attempted to give a detailed description of the most important groups of generalized nerve and muscle disorders, and the commonly used parameters from needle EMG and nerve conduction studies were included. The system can be used both for "diagnostic" and for "causal" reasoning. In diagnostic reasoning, the system's probabilistic inference engine is used to reason from test results through 14 different aspects of neuromuscular pathophysiology to disorders. In causal reasoning, the system reasons in the opposite direction from disorders through pathophysiology to expected test results. The diagnostic function of the system was illustrated by 3 cases: a normal subject, a patient with a bilateral carpal tunnel syndrome and a patient with both a diabetic polyneuropathy and a bilateral carpal tunnel syndrome.