[Jendrassik's maneuver for determination of efferent conduction in spinal cord injuries]

The effect of Jendrassik's manoeuvre on test H-responses of the gastrocnemius muscle was studied in 40 patients with trauma of the spinal cord and in 6 healthy individuals. In healthy individuals Jendrassik's manoeuvre led to a decrease of the amplitude of H-responses by 1.6-2.5 times (2.1 times on the average). The H-responses were also inhibited (by 1.3-2.0 times, 1.7 times on the average) in 7 patients in whom movements of the lower limbs were partly maintained. In 15 of 33 patients with lower limb paraplegia the H-responses were inhibited (by 1.2-2.4 times, 1.5 times on the average); Jendrassik's manoeuvre produced no effect in the other 18 patients of this group. It is concluded that the quantitative index of the effect of Jendrassik's manoeuvre on test monosynaptic reflexes of the lower limb muscles can be used for evaluating the maintenance of conductivity along the efferent conduction pathways of the spinal cord.