Analysis of oral-nasal balance after intensive speech therapy combined with speech bulb in speakers with cleft palate and hypernasality

Objective: To evaluate the efficacy of the combination of a speech bulb with an intensive speech therapy program in hypernasal participants with cleft palate. Methods: Twenty hypernasal speakers with cleft palate (12 females and 8 males, median age 28.45 years), who were wearing speech bulbs underwent an intensive speech therapy program of 45 sessions over 3 weeks. Three experienced speech-language pathologists rated the participants’ speech recordings before and after intensive speech therapy, with and without the speech bulb. Nasometric recordings and long-term averaged spectra were also analyzed using repeated-measures ANOVAs. Results: The ANOVA of the hypernasality ratings showed significant effects of therapy [F (1,19) = 15.97; p <.001], speech bulb [F(1,190 = 28.54, p <.001] and a therapy –speech bulb interaction effect [F(1.19) = 22.30, p < 0.001]. The most favorable listener ratings of hypernasality were obtained post-therapy when participants were wearing their speech bulbs. Without the speech bulb, intensive speech therapy by itself did not result in a significant improvement. With speech bulb, nasalance scores for high [F (1,19) = 14.07, p <.001] and low pressure [F (1,19) = 14.84, p <.001] sentences were significantly lower post-therapy, providing preliminary evidence that an intensive speech therapy program may enhance the effect of a speech bulb. Before and after comparisons of individual nasalance profiles demonstrated variable improvement in 15 participants, no progress in 2 participants and more severe hypernasality after therapy in 3 participants. Long-term averaged spectra corroborated the findings of the perceptual analysis. Based on a frequency bin from 201 to 300 Hz, there was a significant within-subject effect for with and without speech bulb [F(1, 18) = 4.54, p =.047] as well as for before vs. after session [F (1,18) = 7.14, p =.015]. Conclusion: The speech bulb in combination with intensive speech therapy resulted in improved oral-nasal balance for the majority of participants. More research is needed to investigate long-term outcomes as well as individual factors contributing to therapy success.