Effects of abdominal trussing on breathing, vocalization, and speech in persons with cervical spinal cord injury

Abstract

Abdominal trussing has been advocated for a number of years as a method to improve speech in persons with paralyzed or weak muscles of the breathing apparatus. There have been a few studies that have examined the effect of abdominal trussing on speech and voice. However, these studies have had little experimental control. For this study, two experiments were undertaken to examine the effect of abdominal trussing in men with a cervical spinal cord injury on breathing, vowel prolongation and reading. For both experiments, a special trussing device and procedure where developed to have maximum control over inward abdominal placement during the trussing procedure. Respiratory, acoustic and linguistic measures were made for both experiments. For the first experiment, three persons with cervical spinal cord injury were studied using three single-subject-experimental designs. Abdominal trussing had some effect on the inspiratory component of the breathing apparatus. This was demonstrated by some of the subjects by an increase of inspiratory capacity, phonation duration, more syllables per utterance and fewer pauses. There was no evidence that trussing had an effect on the expiratory component of the breathing apparatus. A perceptual component included having judges indicate if they preferred portions of the reading passage when the abdomen was trussed versus when it was untrussed. No differences were detected for the preferential listening task. For the second experiment, one subject from the first experiment was used to examine the effect of three different inward abdominal placements (25%, 50%, and 75%) on breathing and speech. The 50% inward position was found to be the best position for improving the inspiratory component of the breathing apparatus. With the improvement of the inspiratory component, utterance duration and the number of syllables per utterance increased and the number of pauses decreased during reading. In addition, the perceptual component of analysis for the second experiment showed, that for reading, the 50% inward abdominal position was preferred to the other two inward positions. Future clinical applications and research of abdominal trussing in different clinical populations are also discussed.