Interpretation of subjective measures in a clinical trial of hyperbaric oxygen therapy for multiple sclerosis

Inclusion of subjective measures in clinical trials has raised questions concerning the basis on which their results may be compared with medical findings. Central problems relate to the status of such measures as indicators of 'real' change and to appropriate methods of assessing their significance. These issues were explored in a controlled trial of hyperbaric oxygen therapy (HBO) for multiple sclerosis (MS). Subjective measures were incorporated on the basis of an explicit view of their status vis à vis medical assessments. The General Health Questionnaire (GHQ) and Nottingham Health Profile (NHP) were investigated with respect to their usefulness as indicators of the significance of reported benefit. While neither measure appeared sensitive to the kinds of significance involved, the NHP in particular might have a role in identifying orders of effectiveness which remain untapped by more commonly employed measures of perceived improvement.