Scandcleft randomized trials of primary surgery for unilateral cleft lip and palate: Speech proficiency at 10 years of age.

BACKGROUND & AIM: To assess consonant proficiency and velopharyngeal function in 10-year-old children born with unilateral cleft lip and palate (UCLP) within the Scandcleft project. METHODS & PROCEDURES: Three parallel group, randomized, clinical trials were undertaken as an international multicentre study by nine cleft teams in five countries. Three different surgical protocols for primary palate repair (Arm B-Lip and soft palate closure at 3-4 months, hard palate closure at 36 months, Arm C-Lip closure at 3-4 months, hard and soft palate closure at 12 months, and Arm D-Lip closure at 3-4 months combined with a single-layer closure of the hard palate using a vomer flap, soft palate closure at 12 months) were tested against a common procedure (Arm A-Lip and soft palate closure at 3-4 months followed by hard palate closure at 12 months) in the total cohort of 431 children born with a non-syndromic UCLP. Speech audio and video recordings of 399 children were available and perceptually analysed. Percentage of consonants correct (PCC) from a naming test, an overall rating of velopharyngeal competence (VPC) (VPC-Rate), and a composite measure (VPC-Sum) were reported. OUTCOMES & RESULTS: The mean levels of consonant proficiency (PCC score) in the trial arms were 86-92% and between 58% and 83% of the children had VPC (VPC-Sum). Only 50-73% of the participants had a consonant proficiency level with their peers. Girls performed better throughout. Long delay of the hard palate repair (Arm B) indicated lower PCC and simultaneous hard and soft palate closure higher (Arm C). However, the proportion of participants with primary VPC (not including velopharyngeal surgeries) was highest in Arm B (68%) and lowest in Arm C (47%). CONCLUSIONS & IMPLICATIONS: The speech outcome in terms of PCC and VPC was low across the trials. The different protocols had their pros and cons and there is no obvious evidence to recommend any of the protocols as superior. Aspects other than primary surgical method, such as time after velopharyngeal surgery, surgical experience, hearing level, language difficulties and speech therapy, need to be thoroughly reviewed for a better understanding of what has affected speech outcome at 10 years. WHAT THIS PAPER ADDS: What is already known on the subject Speech outcomes at 10 years of age in children treated for UCLP are sparse and contradictory. Previous studies have examined speech outcomes and the relationship with surgical intervention in 5-year-olds. What this study adds to the existing knowledge Speech outcomes based on standardized assessment in a large group of 10-year-old children born with UCLP and surgically treated according to different protocols are presented. While speech therapy had been provided, a large proportion of the children across treatment protocols still needed further speech therapy. What are the potential or actual clinical implications of this work? Aspects other than surgery and speech function might add to the understanding of what affects speech outcome. Effective speech therapy should be available for children in addition to primary surgical repair of the cleft and secondary surgeries if needed.

Regulation of a continuous yeast bioreactor near the critical dilution rate using a productostat.

Regulation of a continuous bioreactor with Saccharomyces cerevisiae is investigated. A number of different sensors are evaluated for this purpose and the process dynamics is investigated around the critical dilution rate. A sensor for reducing gas concentration in exhaust gases is selected for regulating the substrate flow rate. Closed loop identification experiments are carried out to enable identification of the process dynamics near the critical diluton rate. Due to the time-varying nature of this process an adaptive regulator seems to be a promising tool for providing good regulatory and setpoint tracking performance. A simple third order model is used for a model based control design with a Linear Quadratic (LQ)-regulator. The LQ-regulator performs well experimentally, both in an adaptive version where the model parameters are updated on-line, and in a non-adaptive version. During the test the process is exposed to a large disturbance in substrate feed concentration and to a small setpoint disturbance. The proposed regulator is a practical realisation of a productostat where the product in this case is an undesired primary metabolite. Thus, this paper demonstrates a more general principle of utilizing metabolic overflow metabolism for directing fluxes through a desired metabolic pathway. This principle is applicable in the presented form, if a (by-)product can be measured on-line.