Treatment of cerebral palsy with hyperbaric oxygen stirred a lively debate in 2001 when a Québec study, indicating that it did not produce improvements in the children’s motor functions greater than those seen with slightly pressurized air, was published in The Lancet. New data, published in Developmental Medicine Child Neurology, support this hypothesis.

Paule Hardy, who took part also in the study that appeared in The Lancet, measured the effect of hyperbaric oxygen therapy on cognitive performance in 75 children suffering from cerebral palsy. "In four different stages, we measured attention, working memory, processing speed, and psychosocial functioning," Paule Hardy explains. Approximately 80% of children suffering from cerebral palsy show deficiencies in these functions. “We observed an improvement of these cognitive capacities even three months after the end of the 60 treatment sessions, but we found no significant difference between children who took the treatments and those who received slightly pressurized air.”

Ms. Hardy attributes this improvement mainly to a placebo effect and to a learning effect of the tests themselves. “Despite the use of alternate forms of tests on the four measure intervals, repeated assessments inevitably open to improvement due to learning and practice effect”, she explains. “The subjects become familiar with the operation and improve their performance. Furthermore, the research context created a very stimulating experience for the participants, thus promoting the parent-child interaction in manners different from usual life. Within this motivating research context, children also learned to face uncertainties and deal with complex situations, which may have accelerated cognitive progress.”

The improvement in cognitive capacities may be therefore due to the test environment. The researchers reached this conclusion after they measured the motor capacities of these same children. Paule Hardy also assessed the effect of hyperbaric oxygen therapy on 12 persons who did not have cerebral palsy and whose cognitive functions were normal, because “some parents who accompany children in the hyperbaric chamber have said that they were more alert after the treatment”. However, none of the normal subjects who took the cognitive tests showed any “measurable” change in their functions of attention and working memory. Paule Hardy's research work toward a doctoral degree in psychology was directed by Maryse Lassonde, Professor in the Department of Psychology at Université de Montréal, and Karen Johnston of McGill University.

Researcher: Paule Hardy
Telephone: (514) 343-6959
Funding: Québec Ministry of Health and Social Services