Leri Symptom

LERI SYMPTOM (Leri) was described in 1913 and relates to joint reflexes. L. s. is caused by passive flexion of the fingers and the entire hand of the subject; as a result, slow involuntary flexion of the forearm occurs. The peripheral pathways of the reflex pass through the musculo-cutaneous nerve; the spinal center is located at C6-D1. L. s. is normally present in 90% of healthy adults, but is absent in children. - In lesions of the peripheral (sensory or motor) neuron, as well as in lesions of the cervical part of the spinal cord (the reflex's spinal center) or the central motor pathways (in the latter case while preserving the peripheral reflex arc), L. s. is absent or weakened. The absence of L. s. is an auxiliary diagnostic sign in hemiplegia (see), progressive paralysis. L. s. is often absent during an epileptic seizure. L. s. is valuable for distinguishing between functional and organic paralyses (in the first case there is an increase, in the second - absence) and for differentiating between functional and organic nature of convulsive seizures. - Mayer considers that the brevity of the reflex's duration indicates a subcortical, presumably spinal location of the reflex arc. Foerster considers the question of the unconditional connection of L. s. with the integrity of the pyramidal pathways as not yet sufficiently clarified. Some authors dispute the reflex nature of L. s., considering it a conscious painful reaction. Despite this, L. s. in clinical practice in the above-mentioned diseases sometimes has great diagnostic value.