Background: Somatosensory evoked potentials are the electrical
potentials generated in sensory pathways at peripheral, spinal,
subcortical and cortical levels of the nervous system. Such
electrical potential is frequently used to evaluate myelopathy. This
study aims to determine the utility of initial posterior tibial
somatosensory evoked potential (PTSEP) as a prognostic factor
associated with the development of severe diving-related spinal cord
decompression sickness (DCS).

Methods: In order to conduct the study, 68 injured divers presenting
the symptoms of spinal cord DCS from Seoul Medical Center were
included in the study. The patients were divided into two groups
normal PTSEP group (n=34) and abnormal PTSEP group (n=34). Diving
information, time interval between symptom onset and hyperbaric
treatment were studied and analyzed accordingly. The initial
severity of spinal cord DCS were then rated using the Boussuges
severity score and muscle power examination. The presence of
sequelae was evaluated at 2 weeks. Initial recompression treatment
at2.8-4 ATA (atmospheres absolute) with 100% oxygen breathing or
deeper recompression.

Results: Analysis of the results showed that there were no
significant differences between each group in age, diving
experience, depth of dive, bottom time of dive, onset to treatment,
Boussuges’s score and the grade of motor power before the
treatment. Marked motor power improvements were noticed in initial
normal PTSEP group (70.6%) than abnormal group (29.4%). There were
significant differences in degrees of motor power improvement
between two groups (p=0.003).

Conclusions: Initial PTSEP can be a useful prognostic factor in
spinal type DCS.

KEYWORDS : Decompression sickness, Evoked potentials, somatosensory, Hyperbaric oxygenation