Coactivation Sign
Coactivation Sign
This sign is said to be characteristic of psychogenic tremors, namely increased tremor amplitude with loading (cf. reduced amplitude of organic tremor with loading), perhaps due to muscle coactivation to maintain oscillation.
References
Deuschl G, Koster B, Lucking CH, Scheidt C. Diagnostic and pathophysiological aspects of psychogenic tremors. Movement Disorders1998; 13: 294-302
Cross References