Chronic decompression illness cognitive dysfunction improved with hyperbaric oxygen: a case report.

INTRODUCTION: Altitude chamber exposures are used for training to allow aircrew to experience their hypoxia and pressure effect symptoms. Decompression illness (DCI) can occur subsequent to altitude chamber training or in operational aircraft when the cabin altitude is at least 18,000 feet. Definitive emergent treatment is hyperbaric oxygen (HBO2) to decrease bubble size, dissipate excess nitrogen, hyperoxygenate tissue and reduce inflammation. CASE REPORT: A 27-year-old female underwent altitude chamber training to 25,000 feet. She developed tingling in both legs and left arm, headache, dizziness, malaise, then difficulty talking. She underwent two HBO2 treatments. Over the next 12 months, she had paresthesia, decreased memory and cognitive function similar to symptoms seen following traumatic brain injury. She was referred 14 months after the event for evaluation. Using pre-deployment Automated Neuropsychological Assessment Metrics (ANAM) and serial tests over 58 HBO2 treatments, the patient demonstrated near-return to her pre-deployment test scores.. DISCUSSION: The reason for HBO2 treatment was based on previous experience with chronic traumatic brain injury subjects where HBO2 improved outcome. The patient's chronic neurological symptoms mimicked chronic TBI. The patient was unique in that baseline cognitive tests existed that could be used to monitor her changes during the treatment series.