Cervical spine injuries present with dysfunctions of the respiratory system characterized by: a reduction in forced vital capacity, ineffective cough, decreased peak expiratory and speech problems. Speech therapy intervention using an exercise program improves the intensity of the voice and fluency, the objective of this study was to determine the effect of electrotherapy in abdominal muscles on respiratory capacity proportional to speak in cervical injuries. We studied 60 people with chronic traumatic cervical spinal cord injury and restrictive breathing; they were divided in two groups: experimental (n=30) and control (n=30). Control group received speech therapy exercises and the experimental group received speech therapy and electrotherapy in abdominal muscles prior to the workout. Patients were assessed before and after application of the treatment with the following variables: forced vital capacity, peak expiratory flow, maximum phonation time, reading the words of two syllabes, vocal intensity and rate of speech disabilities. Two groups showed significant improvement in speech therapy variables evaluated after treatment (p ≤0.05). However, the use of electrical stimulation significantly increased the recovery of variables: vocal intensity (p =0.0485) and peak expiratory flow (p =0.0000) and both variables showed positive correlation [F (1, 28)=7.5478, p <0.01]. Conclusions: electrotherapy in abdominal muscles is beneficial for the improvement of peak expiratory flow and vocal intensity. Peak expiratory flow demonstrated to be a predictor of vocal in tensity.

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