We designed an automated
electrophysiologic neurodiagnostic device
(AEND) yielding a distal motor latency
(DML) using automated stimulation
and analysis, volume-conducted waveforms,
and physiologic adjustments.
AEND screening was studied in 75 symptomatic
patients, who also had conventional
electrodiagnostic studies, and 22
asymptomatic subjects. The AEND
yielded a DML in 92% of hands with a
conventional motor response. The correlation
between AEND and conventional
DML was .90 (P < .001). The neurologists
diagnosed 62 of 129 symptomatic hands
with median neuropathy at the wrist
(MNW). At 90% specificity, AEND DML
had a sensitivity of 82% for MNW diagnosed
by the neurologist and 87% for
MNW defined by symptoms plus conventional
electrophysiology. DML adjustment
for age, height, and temperature was associated
with an odds ratio for correct diagnostic
classification of 1.80 in receiver
operating characteristic curve analysis. A
volume-conducted latency determined by
an automated technique, designed for
screening for MNW in an occupational
medicine or primary care setting, is
highly correlated with conventional techniques.
Physiologic adjustments nearly
double the odds of correct diagnostic
classification.