Neuropsychology

The hyperbaric chamber: hope for CVA patients

About twenty oxygen therapy sessions in a hyperbaric chamber yield a significant recovery of cerebral activity and cognitive capacity in persons who have suffered a cerebral vascular accident (CVA). Neuropsychologist Paule Hardy demonstrated the effect in doctoral research carried out in the Department of Psychology at University of Montréal, under the direction of Maryse Lassonde. The findings are from some of the first scientific research done on the effects of hyperbaric treatments applied to CVAs.

The subject studied by Ms. Hardy, a 54 year-old man injured in a highway accident, suffered paresis and a loss of sensitivity on his right side. The CVA blocked irrigation of his left cerebral hemisphere. He also suffered severe cognitive deficits.

Eleven months after his accident, the subject underwent an initial series of 20 one-hour sessions in a hyperbaric chamber, at five sessions per week. “After the first few sessions, the subject showed a resumption of sensitivity in the left side of his face,” notes Paule Hardy. After the 20 sessions, the cognitive and motor tests showed considerable improvement in the subject’s motor and cognitive skills, such as attention, cognitive flexibility and the language. These improvements proved to be correlated with a significant increase in neuronal activity in the injured hemisphere, as revealed by electroencephalogram data (evoked potential measurements). “The reactivation shows that the observed progress cannot be attributed to a learning effect from the tests the patient had undergone,” Ms. Hardy emphasizes.

According to the researcher, the fact that the patient was in a chronic state and had therefore reached a level of neurological stabilization minimizes the likelihood of spontaneous recovery, which is now less likely than in the acute phase of the first months after the accident.

One year after these oxygen therapy treatments, the casualty had returned to the same cognitive and motor level as before the hyperbaric chamber sessions. The neuropsychologist subjected the same topic to a second set of 60 treatments. “The patient achieved the same progress as in the first treatments,” she says. The subject showed a recovery of sensitivity in the face, better balance and greater information processing, accompanied by a resumption of cerebral activity.

The results were, however, no better after 60 treatments than after the first 20. According to the researcher, if the hyperbaric treatments were done together with traditional therapies (which was not done in this case), the results would probably be more effective and, especially, more lasting. “When he recovered cerebral activity, exercises might have enabled him to keep restored networks active.” Moreover, the results would also be better if the treatments were done soon after the cerebral vascular accident.