Reliability of sensory threshold measurement using a digital vibrogram.

Loss of vibratory sensation has been suggested as an early symptom in the diagnosis of compression neuropathies. The use of a digital vibrogram has recently been examined as a means of evaluating vibratory sensation thresholds over a range of frequencies from 8 to 500 Hz. Although this instrument does yield useful clinical information, little is known about the test-retest reliabilities of the thresholds obtained. To learn more about this, we assessed a total of 76 hands--32 normal and 44 with suspected carpal tunnel syndrome. The average sensory thresholds for onset and cessation of vibratory sensation were obtained. Pearson product-moment correlation coefficients were computed, and demonstrated improvement if an initial practice trial was administered. Our findings suggest that the vibrogram can be a reliable, clinical assessment when an initial practice trial is included as part of the standard administration.