Characteristic Relationships Between Healthy CPT Measures
This chart plots the mean healthy Neurometer® CPT values for the median, trigeminal and peroneal nerves gathered from clinical studies of 337 healthy subjects. Each site was stimulated with a 5 Hz , 250 Hz to 2000 Hz Neurometer CPT stimulus to independently evaluate the functioning of the unmyelinated, small myelinated and large myelinated sensory nerve fibers respectively. Two significant characteristics of healthy CPTs can be observed in this graph. The first is the consistent increase in mean sensory threshold (CPT) measures as the frequency of the stimulus is raised from 5 Hz to 250 Hz to 2000 Hz (within-site ratios). The second is the consistent relationship between CPT measures recorded from different body sites but evoked with the same frequency stimulus (between-site ratios). Mean Trigeminal (cephalic) nerve threshold measures are the lowest illustrating the nerve's higher sensitivity to the stimulus. Median nerve (finger) threshold measures are consistently higher than the trigeminal measures and mean peroneal (toe) measures higher still - indicating a less sensitive nerve. Abnormalities in these characteristic relationships that should exist between healthy within-site and between sites rations of measures are often the earliest sign of a sensory dysfunction.