The meatgrinder : an efficient current-multiplying inductive energy storage and transfer circuit

The meatgrinder is a high-efficiency inductive energy storage and transfer circuit which may be used to supply high-current pulsed power requirements in applications such as electromagnetic propulsion. It overcomes the inherent 25% efficiency limit when transferring energy between uncoupled inductors and simultaneously provides current multiplication. An unloaded six-step demonstration circuit has been used to multiply current from 7A to 76A at an efficiency of 44%, and a single-step demonstration circuit has been used to multiply the current in an uncoupled load induct or from lOA to 30A, the efficiency of energy transfer being 31%. Both circuits use power MOSFETs for switching. These circuits have been used in conjunction with theoretical analysis and computer simulation to study the design and performance of the meatgrinder. Investigations have been carried out in order to confirm the basic theory, to clarify the details of circuit operation, and to provide the information necessary for future feasibility studies

Speechreading in Deaf Adults with Cochlear Implants: Evidence for Perceptual Compensation

Previous research has provided evidence for a speechreading advantage in congenitally deaf adults compared to hearing adults. A ‘perceptual compensation’ account of this finding proposes that prolonged early onset deafness leads to a greater reliance on visual, as opposed to auditory, information when perceiving speech which in turn results in superior visual speech perception skills in deaf adults. In the current study we tested whether previous demonstrations of a speechreading advantage for profoundly congenitally deaf adults with hearing aids, or no amplificiation, were also apparent in adults with the same deafness profile but who have experienced greater access to the auditory elements of speech via a cochlear implant (CI). We also tested the prediction that, in line with the perceptual compensation account, receiving a CI at a later age is associated with superior speechreading skills due to later implanted individuals having experienced greater dependence on visual speech information. We designed a speechreading task in which participants viewed silent videos of 123 single words spoken by a model and were required to indicate which word they thought had been said via a free text response. We compared congenitally deaf adults who had received CIs in childhood or adolescence (N = 15) with a comparison group of hearing adults (N = 15) matched on age and education level. The adults with CI showed significantly better scores on the speechreading task than the hearing comparison group. Furthermore, within the group of adults with CI, there was a significant positive correlation between age at implantation and speechreading performance; earlier implantation was associated with lower speechreading scores. These results are both consistent with the hypothesis of perceptual compensation in the domain of speech perception, indicating that more prolonged dependence on visual speech information in speech perception may lead to improvements in the perception of visual speech. In addition our study provides metrics of the ‘speechreadability’ of 123 words produced in British English: one derived from hearing adults (N = 61) and one from deaf adults with CI (N = 15). Evidence for the validity of these ‘speechreadability’ metrics come from correlations with visual lexical competition data

The impact of universal newborn hearing screening on long-term literacy outcomes: a prospective cohort study

Objective: To determine whether the benefits of universal newborn hearing screening (UNHS) seen at age 8?years persist through the second decade.Design: Prospective cohort study of a population sample of children with permanent childhood hearing impairment (PCHI) followed up for 17?years since birth in periods with (or without) UNHS.Setting: Birth cohort of 100?000 in southern England.Participants: 114 teenagers aged 13-19?years, 76 with PCHI and 38 with normal hearing. All had previously their reading assessed aged 6-10?years.Interventions: Birth in periods with and without UNHS; confirmation of PCHI before and after age 9?months.Main outcome measure: Reading comprehension ability. Regression modelling took account of severity of hearing loss, non-verbal ability, maternal education and main language.Results: Confirmation of PCHI by age 9?months was associated with significantly higher mean z-scores for reading comprehension (adjusted mean difference 1.17, 95% CI 0.36 to 1.97) although birth during periods with UNHS was not (adjusted mean difference 0.15, 95% CI -0.75 to 1.06). The gap between the reading comprehension z-scores of teenagers with early compared with late confirmed PCHI had widened at an adjusted mean rate of 0.06 per year (95% CI -0.02 to 0.13) during the 9.2-year mean interval since the previous assessment.Conclusions: The benefit to reading comprehension of confirmation of PCHI by age 9?months increases during the teenage years. This strengthens the case for UNHS programmes that lead to early confirmation of permanent hearing loss

Speechreading ability is related to phonological awareness and single-word reading in both deaf and hearing children

Purpose. Speechreading (lipreading) is a correlate of reading ability in both deaf and hearing children. We investigated whether the relationship between speechreading and single-word reading is mediated by phonological awareness in deaf and hearing children. Method. In two separate studies, 66 deaf children and 138 hearing children, aged 5–8 years old, were assessed on measures of speechreading, phonological awareness, and single-word reading. We assessed the concurrent relationships between latent variables measuring speechreading, phonological awareness, and single-word reading. Results. In both deaf and hearing children, there was a strong relationship between speechreading and single-word reading, which was fully mediated by phonological awareness. Conclusions. These results are consistent with ideas from previous studies that visual speech information contributes to the development of phonological representations in both deaf and hearing children, which, in turn, support learning to read. Future longitudinal and training studies are required to establish whether these relationships reflect causal effects

Speechreading Ability Is Related to Phonological Awareness and Single-Word Reading in Both Deaf and Hearing Children

PURPOSE: Speechreading (lipreading) is a correlate of reading ability in both deaf and hearing children. We investigated whether the relationship between speechreading and single-word reading is mediated by phonological awareness in deaf and hearing children. METHOD: In two separate studies, 66 deaf children and 138 hearing children, aged 5–8 years old, were assessed on measures of speechreading, phonological awareness, and single-word reading. We assessed the concurrent relationships between latent variables measuring speechreading, phonological awareness, and single-word reading. RESULTS: In both deaf and hearing children, there was a strong relationship between speechreading and single-word reading, which was fully mediated by phonological awareness. CONCLUSIONS: hese results are consistent with ideas from previous studies that visual speech information contributes to the development of phonological representations in both deaf and hearing children, which, in turn, support learning to read. Future longitudinal and training studies are required to establish whether these relationships reflect causal effects

The impact of universal newborn hearing screening on long-term literacy outcomes: a prospective cohort study

Objective: To determine whether the benefits of universal newborn hearing screening (UNHS) seen at age 8 years persist through the second decade. Design: Prospective cohort study of a population sample of children with permanent childhood hearing impairment (PCHI) followed up for 17 years since birth in periods with (or without) UNHS. Setting: Birth cohort of 100 000 in southern England. Participants: 114 teenagers aged 13–19 years, 76 with PCHI and 38 with normal hearing. All had previously their reading assessed aged 6–10 years. Interventions: Birth in periods with and without UNHS; confirmation of PCHI before and after age 9 months. Main outcome measure: Reading comprehension ability. Regression modelling took account of severity of hearing loss, non-verbal ability, maternal education and main language. Results: Confirmation of PCHI by age 9 months was associated with significantly higher mean z-scores for reading comprehension (adjusted mean difference 1.17, 95% CI 0.36 to 1.97) although birth during periods with UNHS was not (adjusted mean difference 0.15, 95% CI−0.75 to 1.06). The gap between the reading comprehension z-scores of teenagers with early compared with late confirmed PCHI had widened at an adjusted mean rate of 0.06 per year (95% CI−0.02 to 0.13) during the 9.2-year mean interval since the previous assessment. Conclusions: The benefit to reading comprehension of confirmation of PCHI by age 9 months increases during the teenage years. This strengthens the case for UNHS programmes that lead to early confirmation of permanent hearing loss

Computerised speechreading training for deaf children: A randomised controlled trial

Purpose: We developed and evaluated in a randomised controlled triala computerised speechreading training programme to determine a) whether it is possible to train speechreading in deaf children and b) whether speechreading training results in improvements in phonological and reading skills.Previous studies indicate a relationship between speechreading and reading skill and further suggest this relationshipmay be mediated by improved phonological representations. This is important since many deaf children find learning to read to be very challenging. Method: Sixty-six deaf 5-7 year olds were randomised into speechreading and maths training arms. Each training programme was comprised of10 minutesessionsa day, 4 days a week for 12 weeks. Children were assessed on a battery of language and literacy measures before training, immediately after training, 3 months and 10 months after training. Results: We found no significant benefits for participants who completed the speechreading training, compared to those who completed the maths training, on the speechreading primary outcome measure. However, significantly greater gains were observed in the speechreading training group on one of the secondary measures of speechreading. There was also some evidence of beneficial effects of the speechreading training on phonological representations, however these effects were weaker. No benefits were seen toword reading. Conclusions: Speechreading skill is trainable in deaf children. However, to support early reading, training may need to be longer or embedded in a broader literacy programme. Nevertheless, a training tool that can improve speechreading is likely to be of great interest to professionals working with deaf children

Predicting reading ability in teenagers who are deaf or hard of hearing: A longitudinal analysis of language and reading

BACKGROUND: Deaf and hard of hearing (D/HH) children and young people are known to show group-level deficits in spoken language and reading abilities relative to their hearing peers. However, there is little evidence on the longitudinal predictive relationships between language and reading in this population. AIMS: To determine the extent to which differences in spoken language ability in childhood predict reading ability in D/HH adolescents. METHODS AND PROCEDURES: Participants were drawn from a population-based cohort study and comprised 53 D/HH teenagers, who used spoken language, and a comparison group of 38 normally hearing teenagers. All had completed standardised measures of spoken language (expression and comprehension) and reading (accuracy and comprehension) at 6–10 and 13–19 years of age. OUTCOMES AND RESULTS: Forced entry stepwise regression showed that, after taking reading ability at age 8 years into account, language scores at age 8 years did not add significantly to the prediction of Reading Accuracy z-scores at age 17 years (change in R2 = 0.01, p = .459) but did make a significant contribution to the prediction of Reading Comprehension z-scores at age 17 years (change in R2  = 0.17, p < .001). CONCLUSIONS AND IMPLICATIONS: In D/HH individuals who are spoken language users, expressive and receptive language skills in middle childhood predict reading comprehension ability in adolescence. Continued intervention to support language development beyond primary school has the potential to benefit reading comprehension and hence educational access for D/HH adolescents