Changes in voice quality after speech-language therapy intervention in older children with cerebral palsy

We examined whether perceived voice quality is altered in a group of children with cerebral palsy (CP) following an intervention focusing on respiration and phonation, and whether possible improvements might be associated with increased intelligibility levels.

Sixteen individuals with CP and dysarthria (9 girls, mean age 14 years, SD = 2; 9 with spastic type CP, 2 dyskinetic, 4 mixed, 1 Worster-Drought syndrome) completed intelligibility assessments on separate days twice before intervention, at termination of treatment and at 6-week follow-up using 50 words from the Children's Speech Intelligibility Measure lists, and describing cartoon strips. Experienced speech-language pathologists rated voice quality employing GRBAS scales.

There was no clear evidence that change in voice quality pre-post intervention was large compared with change in the pre-intervention or post-intervention periods. Asthenia demonstrated largest improvement (effect size of 0.4). Intelligibility correlated weakly with Grade, Breathiness and Asthenia, but not with Roughness or Strain. A deterioration of 1 unit on the Grade and Asthenia scales was associated with an approximately 11% decrease in intelligibility.

Perceived changes in voice quality were small compared to changes in intelligibility. Further investigations must examine other variables potentially associated with intelligibility gain to better understand the links between the respiratory-phonatory intervention and improved intelligibility.