Cognitive and outcome measures seem suboptimal in children with cochlear implants - a cross-sectional study.

OBJECTIVE: This study investigates whether cognition as a single variable significantly influences the hearing and speech outcomes of children with cochlear implants (CIs). More specifically, it identifies various types of cognitive disorders among children with CI, comparing these children's cognitive abilities to the outcomes of CI in terms of hearing and speech performance. STUDY DESIGN: Cross-sectional cognitive testing of children with CIs. SETTING: West Danish CI Centre, Aarhus University Hospital, Denmark. MATERIALS AND METHODS: Fifty-eight CI children underwent postoperative cognitive evaluation. Cognitive tests included Bayley Scales of Infant Development (Bayley-III), Snijders-Oomen Nonverbal Intelligence Test Revised (SON-R) and Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV), depending on the age of the child. Outcome measures of hearing and speech capacity after CI consisted of Categories of Auditory Performance (CAP), Speech Intelligibility Rating (SIR) and Peabody Picture Vocabulary Test-4 (PPVT-4). RESULTS: Only PPVT-4 correlated significantly with cognition scores. Over time, the value of CAP and SIR seems limited by a pronounced ceiling effect. CONCLUSION: The most widely used outcome tests after CI, that is CAP and SIR, may not reflect cognitive disabilities sufficiently due to pronounced ceiling effects. International guidelines suggesting a panel of robust age-matched tests are warranted to optimise rehabilitation programmes as well as the counselling of parents.

Determination of bile acids by hollow fibre liquid-phase microextraction coupled with gas chromatography.

A method based on hollow-fibre liquid phase microextraction combined with gas chromatography was developed for determination of specific bile acids in caecal materials of rats. Nine unconjugated bile acids, including the primary bile acids (cholic acid, chenodeoxycholic acid and α-muricholic acid) and the secondary bile acids (lithocholic acid, deoxycholic acid, ursodeoxycholic acid, hyodeoxycholic acid, ß-muricholic acid and ω-muricholic acid) were quantified. Extraction conditions were evaluated, including: sample pH, type of organic solvent and amount of caecal material to be extracted. To compensate for sample matrix effects during extraction the method of standard addition was applied. The satisfactory linearity (r(2)>0.9840), high recovery (84.2-108.7%) and good intra-assay (6.3-10.6%) and inter-assay (6.9-11.1%) precision illustrated the good performance of the present method. The method is rapid, simple and capable of detecting and determining bile acids with limit of detection (LOD) ranged from 0.002 to 0.067µg/mL and limits of quantification (LOQ) varied from 0.006 to 0.224µg/mL. The results indicated that the concentration of some secondary bile acids, which usually are associated with health problems, were lower in rats fed with fermentable dietary fibre compared with a fibre free control diet, while the concentration of primary bile acids, usually connected with positive health effects, were higher in rats fed with diets containing dietary fibre. Of the dietary fibres, guar gum and to some extent the mixture of pectin+guar gum had the most positive effects. Thus, it was concluded that the composition of bile acids can be affected by the type of diet.