A General Test for Gene-Environment Interaction in Sib Pair-based Association Analysis of Quantitative Traits

Several association studies support the hypothesis that genetic variants can modify the influence of environmental factors on behavioral outcomes, i.e., G 9 E interaction. The case-control design used in these studies is powerful, but population stratification with respect to allele frequencies can give rise to false positive or false negative associations. Stratification with respect to the environmental factors can lead to false positives or false negatives with respect to environmental main effects and G 9 E interaction effects as well. Here we present a model based on Fulker et al. (1999) and Purcell (2002) for the study of G 9 E interaction in family-based association designs, in which the effects of stratification can be controlled. Simulations illustrate the power to detect genetic and environmental main effects, and G 9 E interaction effects for the sib pair design. The power to detect interaction was studied in eight different situations, both with and without the presence of population stratification, and for categorical and continuous environmental factors. Results show that the power to detect genetic and environmental main effects, and G 9 E interaction effects, depends on the allele frequencies and the distribution of the environmental moderator. Admixture effects of realistic effect size lead only to very small stratification effects in the G 9 E component, so impractically large numbers of sib pairs are required to detect such stratification

TATES: Efficient Multivariate Genotype-Phenotype Analysis for Genome-Wide Association Studies

To date, the genome-wide association study (GWAS) is the primary tool to identify genetic variants that cause phenotypic variation. As GWAS analyses are generally univariate in nature, multivariate phenotypic information is usually reduced to a single composite score. This practice often results in loss of statistical power to detect causal variants. Multivariate genotype-phenotype methods do exist but attain maximal power only in special circumstances. Here, we present a new multivariate method that we refer to as TATES (Trait-based Association Test that uses Extended Simes procedure), inspired by the GATES procedure proposed by Li et al (2011). For each component of a multivariate trait, TATES combines p-values obtained in standard univariate GWAS to acquire one trait-based p-value, while correcting for correlations between components. Extensive simulations, probing a wide variety of genotype-phenotype models, show that TATES's false positive rate is correct, and that TATES's statistical power to detect causal variants explaining 0.5% of the variance can be 2.5-9 times higher than the power of univariate tests based on composite scores and 1.5-2 times higher than the power of the standard MANOVA. Unlike other multivariate methods, TATES detects both genetic variants that are common to multiple phenotypes and genetic variants that are specific to a single phenotype, i.e. TATES provides a more complete view of the genetic architecture of complex traits. As the actual causal genotype-phenotype model is usually unknown and probably phenotypically and genetically complex, TATES, available as an open source program, constitutes a powerful new multivariate strategy that allows researchers to identify novel causal variants, while the complexity of traits is no longer a limiting factor

The acceptance and voice quality of a new voice prosthesis ‘Vega High performance’:a feasibility study

Background: The Provox Vega High Performance (PVHP) is a newly developed voice prosthesis (VP) with an aim to achieve a longer and more predictable lifetime.Objectives: This feasibility study aims to assess patient acceptance of the PVHP VP, evaluate adverse events, voice quality, and device lifetime. Methods: Laryngectomized patients previously using a Provox Vega or ActiValve Light were included. Acceptance and voice outcomes were evaluated at two-time points with a 2-week interval. Baseline measurements were taken with the standard VP, followed by placement of the PVHP for the 2-week assessment. Results: Fifteen participants completed the study, with thirteen being initial Vega-users. PVHP acceptance was 87% 2 weeks after placement. Median device lifetime for all VPs was 64 d (range 14–370). In the subgroup without periprosthetic leakage, the median device lifetime was 101 d (range 31–370). Acceptance dropped to 40% after device failure. Voice quality did not differ between PVHP and baseline VP. The most reported adverse event was PVHP valve stickiness (46%). Conclusion and significance: Acceptance of the PVHP is largely dependent on device lifetime, decreasing from 87% to 40% after leakage or replacement. Voice quality remains consistent across different VPs. Developing a long-lasting VP remains a challenge.</p

The acceptance and voice quality of a new voice prosthesis ‘Vega High performance’:a feasibility study

Background: The Provox Vega High Performance (PVHP) is a newly developed voice prosthesis (VP) with an aim to achieve a longer and more predictable lifetime.Objectives: This feasibility study aims to assess patient acceptance of the PVHP VP, evaluate adverse events, voice quality, and device lifetime. Methods: Laryngectomized patients previously using a Provox Vega or ActiValve Light were included. Acceptance and voice outcomes were evaluated at two-time points with a 2-week interval. Baseline measurements were taken with the standard VP, followed by placement of the PVHP for the 2-week assessment. Results: Fifteen participants completed the study, with thirteen being initial Vega-users. PVHP acceptance was 87% 2 weeks after placement. Median device lifetime for all VPs was 64 d (range 14–370). In the subgroup without periprosthetic leakage, the median device lifetime was 101 d (range 31–370). Acceptance dropped to 40% after device failure. Voice quality did not differ between PVHP and baseline VP. The most reported adverse event was PVHP valve stickiness (46%). Conclusion and significance: Acceptance of the PVHP is largely dependent on device lifetime, decreasing from 87% to 40% after leakage or replacement. Voice quality remains consistent across different VPs. Developing a long-lasting VP remains a challenge.</p

The acceptance and voice quality of a new voice prosthesis ‘Vega High performance’:a feasibility study

Background: The Provox Vega High Performance (PVHP) is a newly developed voice prosthesis (VP) with an aim to achieve a longer and more predictable lifetime.Objectives: This feasibility study aims to assess patient acceptance of the PVHP VP, evaluate adverse events, voice quality, and device lifetime. Methods: Laryngectomized patients previously using a Provox Vega or ActiValve Light were included. Acceptance and voice outcomes were evaluated at two-time points with a 2-week interval. Baseline measurements were taken with the standard VP, followed by placement of the PVHP for the 2-week assessment. Results: Fifteen participants completed the study, with thirteen being initial Vega-users. PVHP acceptance was 87% 2 weeks after placement. Median device lifetime for all VPs was 64 d (range 14–370). In the subgroup without periprosthetic leakage, the median device lifetime was 101 d (range 31–370). Acceptance dropped to 40% after device failure. Voice quality did not differ between PVHP and baseline VP. The most reported adverse event was PVHP valve stickiness (46%). Conclusion and significance: Acceptance of the PVHP is largely dependent on device lifetime, decreasing from 87% to 40% after leakage or replacement. Voice quality remains consistent across different VPs. Developing a long-lasting VP remains a challenge.</p

The acceptance and voice quality of a new voice prosthesis ‘Vega High performance’:a feasibility study

Background: The Provox Vega High Performance (PVHP) is a newly developed voice prosthesis (VP) with an aim to achieve a longer and more predictable lifetime.Objectives: This feasibility study aims to assess patient acceptance of the PVHP VP, evaluate adverse events, voice quality, and device lifetime. Methods: Laryngectomized patients previously using a Provox Vega or ActiValve Light were included. Acceptance and voice outcomes were evaluated at two-time points with a 2-week interval. Baseline measurements were taken with the standard VP, followed by placement of the PVHP for the 2-week assessment. Results: Fifteen participants completed the study, with thirteen being initial Vega-users. PVHP acceptance was 87% 2 weeks after placement. Median device lifetime for all VPs was 64 d (range 14–370). In the subgroup without periprosthetic leakage, the median device lifetime was 101 d (range 31–370). Acceptance dropped to 40% after device failure. Voice quality did not differ between PVHP and baseline VP. The most reported adverse event was PVHP valve stickiness (46%). Conclusion and significance: Acceptance of the PVHP is largely dependent on device lifetime, decreasing from 87% to 40% after leakage or replacement. Voice quality remains consistent across different VPs. Developing a long-lasting VP remains a challenge.</p

The acceptance and voice quality of a new voice prosthesis ‘Vega High performance’:a feasibility study

Background: The Provox Vega High Performance (PVHP) is a newly developed voice prosthesis (VP) with an aim to achieve a longer and more predictable lifetime.Objectives: This feasibility study aims to assess patient acceptance of the PVHP VP, evaluate adverse events, voice quality, and device lifetime. Methods: Laryngectomized patients previously using a Provox Vega or ActiValve Light were included. Acceptance and voice outcomes were evaluated at two-time points with a 2-week interval. Baseline measurements were taken with the standard VP, followed by placement of the PVHP for the 2-week assessment. Results: Fifteen participants completed the study, with thirteen being initial Vega-users. PVHP acceptance was 87% 2 weeks after placement. Median device lifetime for all VPs was 64 d (range 14–370). In the subgroup without periprosthetic leakage, the median device lifetime was 101 d (range 31–370). Acceptance dropped to 40% after device failure. Voice quality did not differ between PVHP and baseline VP. The most reported adverse event was PVHP valve stickiness (46%). Conclusion and significance: Acceptance of the PVHP is largely dependent on device lifetime, decreasing from 87% to 40% after leakage or replacement. Voice quality remains consistent across different VPs. Developing a long-lasting VP remains a challenge.</p