Prediction of treatment response in pain patients: the illness self-concept repertory grid and EMG feedback.

Eighteen patients with chronic musculoskeletal pain completed a trial of EMG feedback where each subject was exposed to biofeedback, a control condition and a waiting list. Pain scores were determined pre- and posttrial, and the percentage change calculated for each subject. EMG activity and present pain measured during the trial gave an EMG/pain correlation for each patient. A repertory grid was completed by each patient at the pretrial evaluation. Repertory grid technique is a highly flexible way of measuring subjective data such as attitudes. The specific test used involved the patient in rating a series of 6 self-concepts across 8 'constructs' or concepts concerning illness and emotional distress. The resulting matrix of 48 ratings was analysed to produce a measurement of 'distance' between the self and ideal-self concepts. The major finding was that the self-ideal-self distance was significantly positively correlated with pain score changes by rank correlation. The self-ideal-self distance is essentially a measure of self-satisfaction or dissatisfaction and the results imply that patients who show a relatively greater degree of self-dissatisfaction are more likely to respond well to EMG feedback. In addition, patients with high EMG/pain correlations had a better outcome and this measure also correlated with pain scores. The relationship between self-concepts and EMG/pain correlations is discussed. The Illness Self-Concept Repertory Grid appears capable of predicting treatment outcome and shows promise as a prognostic tool.