Figure 3: Comparison of vocal quality in spinal cord injury patients undergoing oral motor respiratory exercise and vocal intonation therapy or respiratory training. Intervention group: oral motor respiratory exercise and vocal intonation therapy; control group: respiratory training. (A–D) Sound pressure level (SPL), sing-loud SPL, speak-loud SPL, and sustained note length. Data are expressed as the mean ± SD (n = 9) and were analyzed by two-way analysis of variance. **P < 0.01. The baseline is indicated by 0.