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Frequency Differences (frequency + difference)
Kinds of Frequency Differences Selected AbstractsLarge Allele Frequency Differences between Human Continental Groups are more Likely to have Occurred by Drift During range Expansions than by SelectionANNALS OF HUMAN GENETICS, Issue 1 2009T. Hofer Summary Several studies have found strikingly different allele frequencies between continents. This has been mainly interpreted as being due to local adaptation. However, demographic factors can generate similar patterns. Namely, allelic surfing during a population range expansion may increase the frequency of alleles in newly colonised areas. In this study, we examined 772 STRs, 210 diallelic indels, and 2834 SNPs typed in 53 human populations worldwide under the HGDP-CEPH Diversity Panel to determine to which extent allele frequency differs among four regions (Africa, Eurasia, East Asia, and America). We find that large allele frequency differences between continents are surprisingly common, and that Africa and America show the largest number of loci with extreme frequency differences. Moreover, more STR alleles have increased rather than decreased in frequency outside Africa, as expected under allelic surfing. Finally, there is no relationship between the extent of allele frequency differences and proximity to genes, as would be expected under selection. We therefore conclude that most of the observed large allele frequency differences between continents result from demography rather than from positive selection. [source] The experimental study of a polarization orthogonal single-longitudinal-mode distributed Bragg reflector fiber laserMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2008Luo Jian-Hua Abstract In this article, we reported a polarization orthogonal single-longitudinal-mode distributed Bragg reflector (DBR) fiber laser. The laser operated robustly in single longitudinal mode and dual polarizations with frequency difference of 976.93 MHz. This laser has simple structure as well as frequency adjustable. It can be used in a wide range of communication, sensor, and spectroscopic applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1658,1660, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23454 [source] Statistical power when testing for genetic differentiationMOLECULAR ECOLOGY, Issue 10 2001N. Ryman Abstract A variety of statistical procedures are commonly employed when testing for genetic differentiation. In a typical situation two or more samples of individuals have been genotyped at several gene loci by molecular or biochemical means, and in a first step a statistical test for allele frequency homogeneity is performed at each locus separately, using, e.g. the contingency chi-square test, Fisher's exact test, or some modification thereof. In a second step the results from the separate tests are combined for evaluation of the joint null hypothesis that there is no allele frequency difference at any locus, corresponding to the important case where the samples would be regarded as drawn from the same statistical and, hence, biological population. Presently, there are two conceptually different strategies in use for testing the joint null hypothesis of no difference at any locus. One approach is based on the summation of chi-square statistics over loci. Another method is employed by investigators applying the Bonferroni technique (adjusting the P -value required for rejection to account for the elevated alpha errors when performing multiple tests simultaneously) to test if the heterogeneity observed at any particular locus can be regarded significant when considered separately. Under this approach the joint null hypothesis is rejected if one or more of the component single locus tests is considered significant under the Bonferroni criterion. We used computer simulations to evaluate the statistical power and realized alpha errors of these strategies when evaluating the joint hypothesis after scoring multiple loci. We find that the ,extended' Bonferroni approach generally is associated with low statistical power and should not be applied in the current setting. Further, and contrary to what might be expected, we find that ,exact' tests typically behave poorly when combined in existing procedures for joint hypothesis testing. Thus, while exact tests are generally to be preferred over approximate ones when testing each particular locus, approximate tests such as the traditional chi-square seem preferable when addressing the joint hypothesis. [source] UCHL-1 gene in multiple system atrophy: A haplotype tagging approachMOVEMENT DISORDERS, Issue 10 2005Daniel G. Healy MD Abstract To date, the etiology of multiple system atrophy (MSA) has proved impenetrable. We investigated the role of genetic variation in the UCHL-1 gene in MSA and looked for the presence of disease susceptibility alleles. We determined the linkage disequilibrium structure of the gene and employed a haplotype tagging strategy with power to represent 95% of the haplotype diversity. This approach was performed using a set of tagging single nucleotide polymorphisms (SNPs) that can infer the allelic state of all the common SNPs in UCHL-1 with a high coefficient of determination. This strategy enabled us to scan across the gene and maintain the power to detect signal(s) from any potential functional variant(s). In 257 Gilman-probable or -definite MSA subjects and 1,536 controls, we did not detect a case,control frequency difference for either the tagged haplotypes or for individual tagging SNPs. This search included the S18Y variant of UCHL-1, which has been reported to be protective in Parkinson's disease. © 2005 Movement Disorder Society [source] The pattern of linkage disequilibrium in German Holstein cattleANIMAL GENETICS, Issue 4 2010S. Qanbari Summary This study presents a second generation of linkage disequilibrium (LD) map statistics for the whole genome of the Holstein,Friesian population, which has a four times higher resolution compared with that of the maps available so far. We used DNA samples of 810 German Holstein,Friesian cattle genotyped by the Illumina Bovine SNP50K BeadChip to analyse LD structure. A panel of 40 854 (75.6%) markers was included in the final analysis. The pairwise r2 statistic of SNPs up to 5 Mb apart across the genome was estimated. A mean value of r2 = 0.30 ± 0.32 was observed in pairwise distances of <25 kb and it dropped to 0.20 ± 0.24 at 50,75 kb, which is nearly the average inter-marker space in this study. The proportion of SNPs in useful LD (r2 , 0.25) was 26% for the distance of 50 and 75 kb between SNPs. We found a lower level of LD for SNP pairs at the distance ,100 kb than previously thought. Analysis revealed 712 haplo-blocks spanning 4.7% of the genome and containing 8.0% of all SNPs. Mean and median block length were estimated as 164 ± 117 kb and 144 kb respectively. Allele frequencies of the SNPs have a considerable and systematic impact on the estimate of r2. It is shown that minimizing the allele frequency difference between SNPs reduces the influence of frequency on r2 estimates. Analysis of past effective population size based on the direct estimates of recombination rates from SNP data showed a decline in effective population size to Ne = 103 up to ,4 generations ago. Systematic effects of marker density and effective population size on observed LD and haplotype structure are discussed. [source] Optimal Two-Stage Design for Case-Control Association Analysis Incorporating Genotyping ErrorsANNALS OF HUMAN GENETICS, Issue 3 2008Y. Zuo Summary Two-stage design is a cost effective approach for identifying disease genes in genetic studies and it has received much attention recently. In general, there are two types of two-stage designs that differ on the methods and samples used to measure allele frequencies in the first stage: (1) Individual genotyping is used in the first stage; (2) DNA pooling is used in the first stage. In this paper, we focus on the latter. Zuo et al. (2006) investigated statistical power of such a design, among other things, but the cost of the study was not taken into account. The purpose of this paper is to study the optimal design under the given overall cost. We investigate how to allocate the resources to the two stages. Note that in addition to the measurement errors associated with DNA pooling, genotyping errors are also unavoidable with individual genotyping. Therefore, we discuss the optimal design combining genotyping errors associated with individual genotyping. The joint statistical distributions of test statistics in the first and second stages are derived. For a fixed cost, our results show that the optimal design requires no additional samples in the second stage but only that the samples in the first stage be re-used. When the second stage uses an entirely independent sample, however, the optimal design under a given cost depends on the population allele frequency and allele frequency difference between the case and control groups. For the current genotyping costs, we can roughly allocate 1/3 to 1/2 of the total sample size to the first stage for screening. [source] On the relationship between dynamic visual and auditory processing and literacy skills; results from a large primary-school studyDYSLEXIA, Issue 4 2002Joel B. Talcott Abstract Three hundred and fifty randomly selected primary school children completed a psychometric and psychophysical test battery to ascertain relationships between reading ability and sensitivity to dynamic visual and auditory stimuli. The first analysis examined whether sensitivity to visual coherent motion and auditory frequency resolution differed between groups of children with different literacy and cognitive skills. For both tasks, a main effect of literacy group was found in the absence of a main effect for intelligence or an interaction between these factors. To assess the potential confounding effects of attention, a second analysis of the frequency discrimination data was conducted with performance on catch trials entered as a covariate. Significant effects for both the covariate and literacy skill was found, but again there was no main effect of intelligence, nor was there an interaction between intelligence and literacy skill. Regression analyses were conducted to determine the magnitude of the relationship between sensory and literacy skills in the entire sample. Both visual motion sensitivity and auditory sensitivity to frequency differences were robust predictors of children's literacy skills and their orthographic and phonological skills. Copyright © 2002 John Wiley & Sons, Ltd. [source] THE HISTORICAL BIOGEOGRAPHY OF TWO CARIBBEAN BUTTERFLIES (LEPIDOPTERA: HELICONIIDAE) AS INFERRED FROM GENETIC VARIATION AT MULTIPLE LOCIEVOLUTION, Issue 3 2002Neil Davies Abstract Mitochondrial DNA and allozyme variation was examined in populations of two Neotropical butterflies, Heliconius charithonia and Dryas iulia. On the mainland, both species showed evidence of considerable gene flow over huge distances. The island populations, however, revealed significant genetic divergence across some, but not all, ocean passages. Despite the phylogenetic relatedness and broadly similar ecologies of these two butterflies, their intraspecific biogeography clearly differed. Phylogenetic analyses of mitochondrial DNA sequences revealed that populations of D. iulia north of St. Vincent are monophyletic and were probably derived from South America. By contrast, the Jamaican subspecies of H. charithonia rendered West Indian H. charithonia polyphyletic with respect to the mainland populations; thus, H. charithonia seems to have colonized the Greater Antilles on at least two separate occasions from Central America. Colonization velocity does not correlate with subsequent levels of gene flow in either species. Even where range expansion seems to have been instantaneous on a geological timescale, significant allele frequency differences at allozyme loci demonstrate that gene flow is severely curtailed across narrow ocean passages. Stochastic extinction, rapid (re)colonization, but low gene flow probably explain why, in the same species, some islands support genetically distinct and nonexpanding populations, while nearby a single lineage is distributed across several islands. Despite the differences, some common biogeographic patterns were evident between these butterflies and other West Indian taxa; such congruence suggests that intraspecific evolution in the West Indies has been somewhat constrained by earth history events, such as changes in sea level. [source] Incipient speciation of Catostylus mosaicus (Scyphozoa, Rhizostomeae, Catostylidae), comparative phylogeography and biogeography in south-east AustraliaJOURNAL OF BIOGEOGRAPHY, Issue 3 2005Michael N Dawson Abstract Aim, Phylogeography provides a framework to explain and integrate patterns of marine biodiversity at infra- and supra-specific levels. As originally expounded, the phylogeographic hypotheses are generalities that have limited discriminatory power; the goal of this study is to generate and test specific instances of the hypotheses, thereby better elucidating both local patterns of evolution and the conditions under which the generalities do or do not apply. Location, Coastal south-east Australia (New South Wales, Tasmania and Victoria), and south-west North America (California and Baja California). Methods, Phylogeographic hypotheses specific to coastal south-east Australia were generated a priori, principally from existing detailed distributional analyses of echinoderms and decapods. The hypotheses are tested using mitochondrial cytochrome c oxidase subunit I (COI) and nuclear internal transcribed spacer 1 (ITS1) DNA sequence data describing population variation in the jellyfish Catostylus mosaicus, integrated with comparable data from the literature. Results, Mitochondrial COI distinguished two reciprocally monophyletic clades of C. mosaicus (mean ± SD: 3.61 ± 0.40% pairwise sequence divergence) that were also differentiated by ITS1 haplotype frequency differences; the boundary between the clades was geographically proximate to a provincial zoogeographic boundary in the vicinity of Bass Strait. There was also limited evidence of another genetic inhomogeneity, of considerably smaller magnitude, in close proximity to a second hypothesized zoogeographic discontinuity near Sydney. Other coastal marine species also show genetic divergences in the vicinity of Bass Strait, although they are not closely concordant with each other or with reported biogeographic discontinuities in the region, being up to several hundreds of kilometres apart. None of the species studied to date show a strong phylogeographic discontinuity across the biogeographic transition zone near Sydney. Main conclusions, Patterns of evolution in the Bass Strait and coastal New South Wales regions differ fundamentally because of long-term differences in extrinsic factors. Since the late Pliocene, periods of cold climate and low sea-level segregated warm temperate organisms east or west of an emergent Bassian Isthmus resulting in population divergence and speciation; during subsequent periods of warmer and higher seas, sister taxa expanded into the Bass Strait region leading to weakly correlated phylogeographic and biogeographic patterns. The Sydney region, by contrast, has been more consistently favourable to shifts in species' ranges and long-distance movement, resulting in a lack of intra-specific and species-level diversification. Comparisons between the Sydney and Bass Strait regions and prior studies in North America suggest that vicariance plays a key role in generating coastal biodiversity and that dispersal explains many of the deviations from the phylogeographic hypotheses. [source] Nonreplication in Genetic Studies of Complex Diseases,Lessons Learned From Studies of Osteoporosis and Tentative Remedies,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 3 2005Hui Shen Abstract Inconsistent results have accumulated in genetic studies of complex diseases/traits over the past decade. Using osteoporosis as an example, we address major potential factors for the nonreplication results and propose some potential remedies. Over the past decade, numerous linkage and association studies have been performed to search for genes predisposing to complex human diseases. However, relatively little success has been achieved, and inconsistent results have accumulated. We argue that those nonreplication results are not unexpected, given the complicated nature of complex diseases and a number of confounding factors. In this article, based on our experience in genetic studies of osteoporosis, we discuss major potential factors for the inconsistent results and propose some potential remedies. We believe that one of the main reasons for this lack of reproducibility is overinterpretation of nominally significant results from studies with insufficient statistical power. We indicate that the power of a study is not only influenced by the sample size, but also by genetic heterogeneity, the extent and degree of linkage disequilibrium (LD) between the markers tested and the causal variants, and the allele frequency differences between them. We also discuss the effects of other confounding factors, including population stratification, phenotype difference, genotype and phenotype quality control, multiple testing, and genuine biological differences. In addition, we note that with low statistical power, even a "replicated" finding is still likely to be a false positive. We believe that with rigorous control of study design and interpretation of different outcomes, inconsistency will be largely reduced, and the chances of successfully revealing genetic components of complex diseases will be greatly improved. [source] Population structure of the peridomestic mosquito Ochlerotatus notoscriptus in AustraliaMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2004D. H. Foley Abstract.,Ochlerotatus notoscriptus (Skuse) (Diptera: Culicidae) is the predominant peridomestic mosquito in Australia where it is the primary vector of dog heartworm, Dirofilaria immitis (Leidy), and a potentially important vector of arboviruses (Barmah Forest, Ross River) with geographical variation of vector competence. Although widespread, Oc. notoscriptus has low dispersal ability, so it may have isolated subpopulations. The identification of gene flow barriers may assist in understanding arbovirus epidemiology and disease risk, and for developing control strategies for this species. We investigated the population structure of Oc. notoscriptus from 17 sites around Australia, using up to 31 putative allozyme loci, 11 of which were polymorphic. We investigated the effect of larval environment and adult morphology on genetic variation. At least five subpopulations were found, four in New South Wales (NSW) and one unique to Darwin. Perth samples appear to be a product of recent colonization from the Australian east coast. For NSW sites, a Mantel test revealed an isolation by distance effect and spatial autocorrelation analysis revealed an area of effective gene flow of 67 km, which is high given the limited dispersal ability of this species. No consistent difference was observed between ,urban' and ,sylvan' habitats, which suggests frequent movement between these sites. However, a finer-scaled habitat study at Darwin revealed small but significant allele frequency differences, including for Gpi. No fixed allozyme differences were detected for sex, size, integument colour or the colour of species-diagnostic pale scales on the scutum. The domestic habit of Oc. notoscriptus and assisted dispersal have helped to homogenize this species geographically but population structure is still detectable on several levels associated with geographical variation of vector competence. [source] Natal homing in juvenile loggerhead turtles (Caretta caretta)MOLECULAR ECOLOGY, Issue 12 2004BRIAN W. BOWEN Abstract Juvenile loggerhead turtles (Caretta caretta) from West Atlantic nesting beaches occupy oceanic (pelagic) habitats in the eastern Atlantic and Mediterranean, whereas larger juvenile turtles occupy shallow (neritic) habitats along the continental coastline of North America. Hence the switch from oceanic to neritic stage can involve a trans-oceanic migration. Several researchers have suggested that at the end of the oceanic phase, juveniles are homing to feeding habitats in the vicinity of their natal rookery. To test the hypothesis of juvenile homing behaviour, we surveyed 10 juvenile feeding zones across the eastern USA with mitochondrial DNA control region sequences (N = 1437) and compared these samples to potential source (nesting) populations in the Atlantic Ocean and Mediterranean Sea (N = 465). The results indicated a shallow, but significant, population structure of neritic juveniles (,ST = 0.0088, P = 0.016), and haplotype frequency differences were significantly correlated between coastal feeding populations and adjacent nesting populations (Mantel test R2 = 0.52, P = 0.001). Mixed stock analyses (using a Bayesian algorithm) indicated that juveniles occurred at elevated frequency in the vicinity of their natal rookery. Hence, all lines of evidence supported the hypothesis of juvenile homing in loggerhead turtles. While not as precise as the homing of breeding adults, this behaviour nonetheless places juvenile turtles in the vicinity of their natal nesting colonies. Some of the coastal hazards that affect declining nesting populations may also affect the next generation of turtles feeding in nearby habitats. [source] Population genetics of shortnose sturgeon Acipenser brevirostrum based on mitochondrial DNA control region sequencesMOLECULAR ECOLOGY, Issue 10 2002C. Grunwald Abstract Shortnose sturgeon is an anadromous North American acipenserid that since 1973 has been designated as federally endangered in US waters. Historically, shortnose sturgeon occurred in as many as 19 rivers from the St. John River, NB, to the St. Johns River, FL, and these populations ranged in census size from 101 to 104, but little is known of their population structure or levels of gene flow. We used the polymerase chain reaction (PCR) and direct sequence analysis of a 440 bp portion of the mitochondrial DNA (mtDNA) control region to address these issues and to compare haplotype diversity with population size. Twenty-nine mtDNA nucleotide-substitution haplotypes were revealed among 275 specimens from 11 rivers and estuaries. Additionally, mtDNA length variation (6 haplotypes) and heteroplasmy (2,5 haplotypes for some individuals) were found. Significant genetic differentiation (P < 0.05) of mtDNA nucleotide-substitution haplotypes and length-variant haplotypes was observed among populations from all rivers and estuaries surveyed with the exception of the Delaware River and Chesapeake Bay collections. Significant haplotype differentiation was even observed between samples from two rivers (Kennebec and Androscoggin) within the Kennebec River drainage. The absence of haplotype frequency differences between samples from the Delaware River and Chesapeake Bay reflects a probable current absence of spawning within the Chesapeake Bay system and immigration of fish from the adjoining Delaware River. Haplotypic diversity indices ranged between 0.817 and 0.641; no relationship (P > 0.05) was found between haplotype diversity and census size. Gene flow estimates among populations were often low (< 2.0), but were generally higher at the latitudinal extremes of their distribution. A moderate level of haplotype diversity and a high percentage (37.9%) of haplotypes unique to the northern, once-glaciated region suggests that northern populations survived the Pleistocene in a northern refugium. Analysis of molecular variance best supported a five-region hierarchical grouping of populations, but our results indicate that in almost all cases populations of shortnose sturgeon should be managed as separate units. [source] Evolutionary and statistical properties of three genetic distancesMOLECULAR ECOLOGY, Issue 8 2002Steven T. Kalinowski Abstract Many genetic distances have been developed to summarize allele frequency differences between populations. I review the evolutionary and statistical properties of three popular genetic distances: DS, DA, and ,, using computer simulation of two simple evolutionary histories: an isolation model of population divergence and an equilibrium migration model. The effect of effective population size, mutation rate, and mutation mechanism upon the parametric value between pairs of populations in these models explored, and the unique properties of each distance are described. The effect of these evolutionary parameters on study design is also investigated and similar results are found for each genetic distance in each model of evolution: large sample sizes are warranted when populations are relatively genetically similar; and loci with more alleles produce better estimates of genetic distance. [source] Analysis of RYR1 Haplotype Profile in Patients with Malignant HyperthermiaANNALS OF HUMAN GENETICS, Issue 1 2009D. Carpenter Summary This study represents a new approach to characterising patients at risk of malignant hyperthermia (MH) through the use of a recently published method for identifying high-risk haplotypes in candidate genes. We present analysis based upon the largest standardised and genotyped database of MH patients worldwide. We used unphased RYR1 SNP data directly to (1) assess RYR1 haplotype frequency differences between susceptible cases and control groups and (2) analyse population-based association via clustering of RYR1 haplotypes based on disease risk. Our results show a significant difference in RYR1 haplotype frequency between susceptible cases and UK Caucasian population controls. Furthermore we identify a high-risk cluster of haplotypes that is associated with the commonest UK MH mutation p.G2434R/c.7300G>A. These results demonstrate the applicability of this new and practical method for population based association analysis. [source] Large Allele Frequency Differences between Human Continental Groups are more Likely to have Occurred by Drift During range Expansions than by SelectionANNALS OF HUMAN GENETICS, Issue 1 2009T. Hofer Summary Several studies have found strikingly different allele frequencies between continents. This has been mainly interpreted as being due to local adaptation. However, demographic factors can generate similar patterns. Namely, allelic surfing during a population range expansion may increase the frequency of alleles in newly colonised areas. In this study, we examined 772 STRs, 210 diallelic indels, and 2834 SNPs typed in 53 human populations worldwide under the HGDP-CEPH Diversity Panel to determine to which extent allele frequency differs among four regions (Africa, Eurasia, East Asia, and America). We find that large allele frequency differences between continents are surprisingly common, and that Africa and America show the largest number of loci with extreme frequency differences. Moreover, more STR alleles have increased rather than decreased in frequency outside Africa, as expected under allelic surfing. Finally, there is no relationship between the extent of allele frequency differences and proximity to genes, as would be expected under selection. We therefore conclude that most of the observed large allele frequency differences between continents result from demography rather than from positive selection. [source] Polymorphic Alu Insertions and their Associations with MHC Class I Alleles and Haplotypes in the Northeastern ThaisANNALS OF HUMAN GENETICS, Issue 4 2005D. S. Dunn Summary Polymorphic Alu insertions (POALINs) are known to contribute to the strong polymorphic nature of the Major Histocompatibility Complex (MHC). Previous population studies on MHC POALINs were limited to only Australian Caucasians and Japanese. Here, we report on the individual insertion frequency of the five POALINs within the MHC class I region, their HLA-A and -B associations, and the three and four locus alpha block POALIN haplotype frequencies in the Northeastern (NE) Thai population. Of the five POALINs, the lowest frequency was 0.018 for AluyHF and the highest frequency was 0.292 for AluyHJ and AluyHG. The strongest positive associations between the POALINs and HLA class I alleles was between AluyMICB and HLA-B*57, AluyHJ and HLA-A*24 and HLA-A*01, and AluyHG and HLA-A*02, supporting previous findings in Caucasians and Japanese. Single POALIN haplotypes were found more frequently than multiple POALIN haplotypes. However, of the seven different POALIN haplotypes within the MHC alpha block, there were only two significant differences between the NE Thais, Caucasians and Japanese. This study confirms that the MHC POALINs are in linkage disequilibrium with HLA-A and ,B alleles and that there are significant frequency differences for some of the POALINs when compared between NE Thai, Caucasians and Japanese. [source] Multidimensional assessment of female tracheoesophageal prosthetic speechCLINICAL OTOLARYNGOLOGY, Issue 6 2006R. Kazi Objective:, The objective of this study was to undertake a multidimensional assessment of female tracheoesophageal prosthetic speech. Study Design:, A cross-sectional cohort study. Setting:, Head and Neck Unit in a tertiary oncology referral centre. Patients:, Ten female and 10 male total laryngectomy patients with no signs of recurrence and using voice prosthesis were compared to 10 normal female speakers. Intervention(s):, Electroglottographic and acoustic analysis of voice parameters for both sustained vowel /i/ and connected speech, perceptual evaluation using GRBAS (with 2 experienced raters) and questionnaire assessment using the University of Washington Quality of Life and the Voice Handicap Index. Statistical analysis was done using the Statistical Package for Social Sciences, (v. 14, SPSS Inc., Chicago III). Results:, Median age of the female larygectomy patiemts was 65 years (range: 41-81), that of male laryngectomees was 66.5 years (range: 40-79) and that of the normal female subjects was 47.5 years (range: 35-72). All electroglottographic, acoustic parameters and GRBAS ratings of the female laryngectomy patients were significantly worse as compared with the normal female subjects. The median fundamental frequency (111.8 Hz) was comparable to male tracheoesophageal speakers (115.8 Hz). Mean composite University of Washington Quality of Life score and overall Voice Handicap Index score was 79.3(12.5) and 47.5(27.6) for the female laryngectomy patients and for the males was 81.2 (9.6) and 39.4(18.7). Conclusions:, Gender frequency differences as seen in normal subjects are lost following a laryngectomy operation as evidenced by electroglottographic and perceptual data. Although the quality of life scores are comparable to the male tracheoesophageal speakers, they exhibit a greater voice handicap as compared to their male counterparts. [source] | |||||||||||||