Case of Broca's Aphasia as an Expression of Cerebral Decompression Sickness with Advanced Non-Invasive Monitoring During HBO2 Treatment

ABSTRACT

We present a case of severe CNS decompression sickness (DCS) that included Broca’s aphasia in a recreational diver, offering insights into the application of advanced non-invasive monitoring during hyperbaric oxygen therapy (HBO2). This 64-year-old male diver, following a rapid ascent after a deep dive, experienced the onset of expressive aphasia, vertigo, and right-sided hemiparesis about 30-120 minutes after surfacing. Initial monitoring with bispectral index (BIS) and density spectral array (DSA) revealed significant 2asymmetry between cerebral hemispheres, particularly in spectral edge frequency (SEF) values, with the left hemisphere showing marked reduction during air breaks at HBO2 pressures. This pattern resolved progressively over three HBO2 sessions, with full clinical recovery after four sessions coinciding with the resolution of this DSA hemispheric asymmetry. The case indirectly supports the theoretical role of microparticles and endothelial dysfunction as contributors to cerebral hypo-perfusion in DCS beyond the conventional focus on gas bubbles, reflected by the clinical findings, representing a clinical gradient. This novel application of BIS-DSA in hyperbaric medicine offers promising potential for real-time monitoring of cerebral involvement. It could enhance patient outcomes by guiding individualized treatment in neurologically compromised DCS cases.

Keywords: bispectral index; brain; cerebral blood flow; decompression sickness; density spectral array; electroencephalography; microparticles