The use of sensory action potentials in the diagnosis of peripheral nerve disease
J. M. Shefner and D. M. Dawson
Division of Neurology, Brigham and Women's Hospital, Boston, MA 02115.
We review the different measurements that can be derived from recordings of
compound sensory action potentials, and describe how less commonly measured
aspects may be of use in clinical situations. In addition to the frequently
obtained maximum conduction velocity and amplitude, minimum conduction
velocity may be measured if near nerve electrodes and response averaging
are used. Minimum conduction velocity is a sensitive measure of both axonal
and demyelinating peripheral nerve pathology. Activity-dependent conduction
is another aspect of sensory conduction that may provide additional
information for the clinician. Refractory period of transmission has been
used to diagnose subtle demyelinating lesions, as well as some axonal
disorders. Supernormal period and the conduction of trains of stimuli may
also be useful, although, at present, they remain predominantly research
tools.
