Algebraic attacks on SOBER-t32 and SOBER-t16 without stuttering

This paper presents algebraic attacks on SOBER-t32 and SOBER-t16 without stuttering. For unstuttered SOBER-t32, two different attacks are implemented. In the first attack, we obtain multivariate equations of degree 10. Then, an algebraic attack is developed using a collection of output bits whose relation to the initial state of the LFSR can be described by low-degree equations. The resulting system of equations contains 2^69 equations and monomials, which can be solved using the Gaussian elimination with the complexity of 2^196.5. For the second attack, we build a multivariate equation of degree 14. We focus on the property of the equation that the monomials which are combined with output bit are linear. By applying the Berlekamp-Massey algorithm, we can obtain a system of linear equations and the initial states of the LFSR can be recovered. The complexity of attack is around O(2^100) with 2^92 keystream observations. The second algebraic attack is applicable to SOBER-t16 without stuttering. The attack takes around O(2^85) CPU clocks with 2^78 keystream observations.

The Effectiveness of the precision fluency shaping program controlling stuttering behaviour in adults

This study was done to test the effectiveness of the Precision Fluency Shaping Program in controlling stuttering behaviour in adults. Two sites were chosen, each using the Precision Fluency Shaping Program to treat stuttering. At each clinic, a Speech Patbologist made a random selection of the subjects' pre- and post-therapy video-taped interviews, totalling 20 in all. During the interviews, the clients were asked questions and re~d a short passage to determine the frequency of stuttering in natural conversation and in reading. Perceptions of Stuttering Inventory questionnaires vvere also filled in before and after therapy. Two judges were trained to identify stuttering behaviour, and were given an inter-rater reliability test at selected intervals throughout the study. Protocols",:m.a;d;6 of each interview tape, were scored for (a) stuttering behaviour and (b) words spoken or read. An Analysis of Variance Repeated Measures Test was used to compare before and after scores of conversations, readings, and Perceptions of Stuttering Inventory to determine whether the Precision Fluency Shaping Program controlled stuttering behaviour significantly. A Pearson R Correlation Test was also administered to determine if a relationship existed bet\veen Perceptions of Stuttering Inventory and (i) conversation and (ii) reading scores.

Sudden onset stuttering in an adult: Neurogenic and psychogenic perspectives

A healthy 33 year old man with no previous history of speech language problems was referred to speech language therapy services following an episode which left him with a pronounced stutter, and which worsened over the next ten days. A range of neurological and psychological assessments failed to find any abnormality, as did MRI testing, and a diagnosis of psychogenic stuttering was made. This client was seen for three sessions of fluency therapy without significant improvement, after which he ceased attending. This paper considers the relationship between psychogenic and neurogenic stuttering generally, then more specifically in regard to this client, and the treatment he received. The paper concludes by considering problems in differentially diagnosing neurogenic from psychogenic stuttering.

Disrupted white matter in language and motor tracts in developmental stuttering

White matter tractsc onnecting areas involved in speech and motor control were examined using diffusion-tensor imagingingin a sample of peoplewhostutter (n=29) who were heterogeneous with respect to age, sex, handedness and stuttering severity. The goals were to replicate previous findings in developmental stuttering and to extend ourknowledge by evaluating the relationship between white matter differences in people who stutter and factors such as age, sex, handedness and stuttering severity. We replicated previous findings that showed reduced integrity in white matter underlying ventral premotorcortex, cerebral peduncles and posteriorcorpus callosum in people who stutter, relative to controls. Tractography analysis additionally revealed significantly reduced white matter integrity in the arcuate fasciculus bilaterally and the left corticospinal tract and significantly reduced connectivity within theleft corticobulbar tract in people who stutter. Region-of-interest analyses revealed reduced white matter integrity in people whostutter in the three pairs ocerebellar peduncles thatcarry the afferent and efferent fibers of the cerebellum. Within thegroup of people who stutter, the higher the stuttering severity index, the lower the white matter integrity in the leftangular gyrus but the greater the white matter connectivity in theleft corticobulbartract. Also,in people who stutter, handedness and age predicted the integrity of the corticospinal tract and peduncles, respectively. Further studies are needed to determine which of these white matter differences relate to the neural basis of stuttering and which reflect experience-dependent plasticity.

A study of familial stuttering

Here we study 13 families with stuttering. of the 13 families, 9 were persistent stutterers and 4 were recovered stutterers. In the 9 families with persistent stuttering, 24 were male and 10 were females. of the 4 families with recovered stutterers, 17 were male and 3 were female. of the 17 males, 12 were persistent stutterers and 5 recovered after adolescence. All females were recovered stutterers. We conclude with a short discussion of recent molecular Studies. (c) 2006 Wiley-Liss, Inc.

Identification of a Microdeletion at the 7q33-q35 Disrupting the CNTNAP2 Gene in a Brazilian Stuttering Case

Speech and language disorders are some of the most common referral reasons to child development centers accounting for approximately 40% of cases. Stuttering is a disorder in which involuntary repetition, prolongation, or cessation of the sound precludes the flow of speech. About 5% of individuals in the general population have a stuttering problem, and about 80% of the affected children recover naturally. The causal factors of stuttering remain uncertain in most cases; studies suggest that genetic factors are responsible for 70% of the variance in liability for stuttering, whereas the remaining 30% is due to environmental effects supporting a complex cause of the disorder. The use of high-resolution genome wide array comparative genomic hybridization has proven to be a powerful strategy to narrow down candidate regions for complex disorders. We report on a case with a complex set of speech and language difficulties including stuttering who presented with a 10Mb deletion of chromosome region 7q33-35 causing the deletion of several genes and the disruption of CNTNAP2 by deleting the first three exons of the gene. CNTNAP2 is known to be involved in the cause of language and speech disorders and autism spectrum disorder and is in the same pathway as FOXP2, another important language gene, which makes it a candidate gene for causal studies speech and language disorders such as stuttering. (C) 2010 Wiley-Liss, Inc.

Prevalence of risk factors for stuttering among boys: analytical cross-sectional study

CONTEXTO E OBJETIVO:Há poucos estudos sobre os fatores de risco para os subgrupos de gagueira. O objetivo deste estudo foi caracterizar os fatores de risco para a gagueira desenvolvimental familial em meninos que gaguejam e que não gaguejam como tipologia das disfluências, fatores qualitativos e comunicativos associados, estresse físico e emocional, atitude familiar e reação pessoal.TIPO DE ESTUDO E LOCAL:Estudo transversal analítico com um grupo controle, realizado no Laboratório de Estudo da Fluência, que faz parte do Departamento de Fonoaudiologia de uma universidade pública.MÉTODOS:Pais de 40 meninos com e sem gagueira pareados por idade fizeram parte do estudo. Os participantes foram divididos em dois grupos: crianças com gagueira e crianças sem gagueira, com idades entre 6 anos 0 meses e 11 anos 11 meses Inicialmente todos os participantes foram submetidos a uma avaliação de fluência e depois os dados foram coletados por meio do Protocolo de Risco para a Gagueira do Desenvolvimento.RESULTADOS:Não foi observada diferença nos fatores de estresse físicos e reações pessoais entre os grupos. As atitudes inadequadas familiares foram apresentadas por 95% das crianças com gagueira e 30% das crianças sem gagueira. Quatro fatores de risco analisados não ocorreram nas crianças sem gagueira, a saber, disfluências gagas, fatores qualitativos, estresse físico e emocional.CONCLUSÕES:Os achados sugerem que a presença de disfluências gagas, fatores qualitativos e comunicativos associados, estresse emocional e atitude familiar inadequada são fatores de risco importantes para a gagueira desenvolvimental familial em meninos.

A genetic linkage study in Brazil identifies a new locus for persistent developmental stuttering on chromosome 10

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A study of the role of the FOXP2 and CNTNAP2 genes in persistent developmental stuttering

A number of speech disorders including stuttering have been shown to have important genetic contributions, as indicated by high heritability estimates from twin and other studies. We studied the potential contribution to stuttering from variants in the FOXP2 gene, which have previously been associated with developmental verbal dyspraxia, and from variants in the CNTNAP2 gene, which have been associated with specific language impairment (SLI). DNA sequence analysis of these two genes in a group of 602 unrelated cases, all with familial persistent developmental stuttering, revealed no excess of potentially deleterious coding sequence variants in the cases compared to a matched group of 487 well characterized neurologically normal controls. This was compared to the distribution of variants in the GNPTAB, GNPTG, and NAGPA genes which have previously been associated with persistent stuttering. Using an expanded subject data set, we again found that NAGPA showed significantly different mutation frequencies in North Americans of European descent (p = 0.0091) and a significant difference existed in the mutation frequency of GNPTAB in Brazilians (p = 0.00050). No significant differences in mutation frequency in the FOXP2 and CNTNAP2 genes were observed between cases and controls. To examine the pattern of expression of these five genes in the human brain, real time quantitative reverse transcription PCR was performed on RNA purified from 27 different human brain regions. The expression patterns of FOXP2 and CNTNAP2 were generally different from those of GNPTAB, GNPTG and NAPGA in terms of relatively lower expression in the cerebellum. This study provides an improved estimate of the contribution of mutations in GNPTAB, GNPTG and NAGPA to persistent stuttering, and suggests that variants in FOXP2 and CNTNAP2 are not involved in the genesis of familial persistent stuttering. This, together with the different brain expression patterns of GNPTAB, GNPTG, and NAGPA compared to that of FOXP2 and CNTNAP2, suggests that the genetic neuropathological origins of stuttering differ from those of verbal dyspraxia and SLI. Published by Elsevier Inc.

Acoustic analyses of diadochokinesis in fluent and stuttering children

OBJECTIVES: The purpose of the study was to acoustically compare the performance of children who do and do not stutter on diadochokinesis tasks in terms of syllable duration, syllable periods, and peak intensity. METHODS: In this case-control study, acoustical analyses were performed on 26 children who stutter and 20 aged-matched normally fluent children (both groups stratified into preschoolers and school-aged children) during a diadochokinesis task: the repetition of articulatory segments through a task testing the ability to alternate movements. Speech fluency was assessed using the Fluency Profile and the Stuttering Severity Instrument. RESULTS: The children who stutter and those who do not did not significantly differ in terms of the acoustic patterns they produced in the diadochokinesis tasks. Significant differences were demonstrated between age groups independent of speech fluency. Overall, the preschoolers performed poorer. These results indicate that the observed differences are related to speech-motor age development and not to stuttering itself. CONCLUSIONS: Acoustic studies demonstrate that speech segment durations are most variable, both within and between subjects, during childhood and then gradually decrease to adult levels by the age of eleven to thirteen years. One possible explanation for the results of the present study is that children who stutter presented higher coefficients of variation to exploit the motor equivalence to achieve accurate sound production (i.e., the absence of speech disruptions).