Update on the diagnostic clinical neurophysiology for rheumatology.

The current concepts on the clinical neurophysiology examinations for the differential diagnosis of rheumatic diseases are presented. The review aims to provide experience and practical guidelines, especially regarding electromyography. More needle than surface electromyography examinations at muscle rest or during its maximal contraction may reveal the characteristic effects of the myogenic injury caused by particular rheumatic diseases. The diagnosis of myopathic disorders, often found in rheumatic diseases is difficult because of the frequent vasculitis coexistence in the patients evoking subsequent changes in nerve fibres leading to degenerative neurogenic changes that may overlap the diagnostic picture of the primary myogenic changes caused by rheumatic diseases. In these cases, the neurophysiological studies of efferent and afferent neural transmission often reveal peripheral neuropathies just at the subclinical level. [ABSTRACT FROM AUTHOR]