[Electromyographic characteristics of acute poisonings with chlorine derivatives of phenoxy acids]

In acute poisonings with chlorine derivatives of phenoxy acids, the myotonic period of poisoning is marked electromyographically by the manifestations specific and non-specific for myotonia. The characteristic signs involve multiple electrical responses of muscle fibers stimulated by a single excitation impulse--potential or myotonic discharges. Non-specific alterations are characterized by prolongation of the latent period, decreased amplitude and shortening of the length of evoked action potentials, which indicates the suppression of muscle excitability. Electromyographic changes are a consequence of deranged muscle rather than of synaptic processes.