These MANOVA analyses were repeated using the following measures as covariates: sex, non-verbal ability (RCPM), severity of hearing loss, presence of multiple disabilities, additional medical conditions, mother's education, English as first language in home, and socioeconomic status.
The effect of early confirmation remained non-significant in the MANCOVA with sex, non-verbal ability (RCPM), severity of hearing loss, presence of multiple disabilities, additional medical conditions, mother's education, English as first language in home, and social economic status as covariates (multivariate F=0.14, Wilk's λ=0.99, df = 4,94, p=0.968).
Different aspects of hearing ability as well as hearing-aid usage were assessed by 11 questions.
For assessment of "visual ability", participants were asked whether they can read the newspaper clearly with or without reading glasses, and for assessment of "hearing ability", participants were asked whether they need voices to be raised for conversation or the volume to be raised for watching television.
To evaluate the effect of hearing aids, and because it provides a more ecologically valid measure of hearing ability than pure tone audiometry, speech-in-noise testing was performed with and without hearing aids, using lists and methods from Magnusson et al. [29].
However, despite being statistically independent phenotypes, all three PCs were derived from the same single measure of hearing ability.
Meta-analysis was performed using 2.3 million single-nucleotide polymorphisms (SNPs) tested against each of the three PCs of hearing ability in 4939 individuals.
6 The test has been used in large-scale trials of approximately 15 000 people 7 and is continually recommended clinically as a simple test of hearing ability.
With respect to physical condition, the effects on SRH of visual ability, hearing ability, chewing ability, chronic disease, and inability to go out have been studied in previous surveys [ 8- 11].
Furthermore, the authors of those studies did not calculate regressions of hearing abilities including all data from each individual study specimen, but instead compared the mean results of different size groups.
