Early experience of Cued Speech enhances speechreading performance in deaf

It is known that deaf individuals usually outperform normal hearing subjects in speechreading; however, the underlying reasons remain unclear. In the present study, speechreading performance was assessed in normal hearing participants (NH), deaf participants who had been exposed to the Cued Speech (CS) system early and intensively, and deaf participants exposed to oral language without Cued Speech (NCS). Results show a gradation in performance with highest performance in CS, then in NCS, and finally NH participants. Moreover, error analysis suggests that speechreading processing is more accurate in the CS group than in the other groups. Given that early and intensive CS has been shown to promote development of accurate phonological processing, we propose that the higher speechreading results in Cued Speech users are linked to a better capacity in phonological decoding of visual articulators.     

Speechreading and the Bruce-Young model of face recognition: early findings and recent developments

In the context of face processing, the skill of processing speech from faces (speechreading) occupies a unique cognitive and neuropsychological niche. Neuropsychological dissociations in two cases (Campbell et al., 1986) suggested a very clear pattern: speechreading, but not face recognition, can be impaired by left-hemisphere damage, while face-recognition impairment consequent to right-hemisphere damage leaves speechreading unaffected. However, this story soon proved too simple, while neuroimaging techniques started to reveal further more detailed patterns. These patterns, moreover, were readily accommodated within the Bruce and Young (1986) model. Speechreading requires structural encoding of faces as faces, but further analysis of visible speech is supported by a network comprising several lateral temporal regions and inferior frontal regions. Posterior superior temporal regions play a significant role in speechreading natural speech, including audiovisual binding in hearing people. In deaf people, similar regions and circuits are implicated. While these detailed developments were not predicted by Bruce and Young, nevertheless, their model has stood the test of time, affording a structural framework for exploring speechreading in terms of face processing.     

听觉障碍对聋人视觉功能影响的理论之争：缺陷还是补偿？

听觉通道受损,是否会影响聋人的视觉功能？有三种理论对此做出了解释。缺陷理论：聋人视觉功能存在缺陷,包括听觉脚手架假说和劳动分工假说。补偿理论：聋人视觉功能会表现出增强,包括响应增强假说、知觉增强假说、超通道功能假说和背侧通路假说。整合理论：聋人视觉功能既可能表现为缺陷,也可能表现为增强,与实验任务和被试年龄有关。本文评述了听觉障碍对聋人视觉功能影响的三种理论,并对其今后的发展趋势进行了展望。     

Dorsal stream deficits suggest hidden dyslexia among deaf poor readers: correlated evidence from reduced perceptual speed and elevated coherent motion detection thresholds

Prelingual deafness and developmental dyslexia have confounding developmental effects on reading acquisition. Therefore, standard reading assessment methods for diagnosing dyslexia in hearing people are ineffective for use with deaf people. Recently, Samar, Parasnis, and Berent (2002) reported visual evoked potential evidence that deaf poor readers, compared to deaf good readers, have dorsal stream visual system deficits like those previously found for hearing dyslexics. Here, we report new psychometric and psychophysical evidence that deficits in dorsal stream function, likely involving extrastriate area MT, are associated with relatively poor reading comprehension in deaf adults. Poorer reading comprehension within a group of 23 prelingually deaf adults was associated with lower scores on the Symbol Digit Modality Test, a perceptual speed test commonly used to help identify dyslexia in hearing people. Furthermore, coherent dot motion detection thresholds, which reflect the functional status of area MT, correlated negatively with reading scores in each visual quadrant. Elevated motion thresholds for deaf poor readers were not due to general cognitive differences in IQ but were specifically correlated with poor perceptual speed. With IQ controlled, a highly reliable right visual field advantage for coherent motion detection was found. Additional analyses suggested that the functional status of dorsal stream motion detection mechanisms in deaf people is related to reading comprehension, but the direction and strength of lateralization of those mechanisms is independent of reading comprehension. Our results generally imply that dyslexia is a hidden contributor to relatively poor reading skill within the deaf population and that assessment of dorsal stream function may provide a diagnostic biological marker for dyslexia in deaf people.     

Role of speechreading in audiovisual interactions during the recovery of speech comprehension in deaf adults with cochlear implants

Speechreading is an important form of communicative activity that improves social adaptation in deaf adults. Cochlear implantation allows interaction between the visual speechreading abilities developed during deafness and the auditory sensory experiences acquired through use of the cochlear implant. Crude auditory information provided by the implant is analyzed in parallel with conjectural information from speechreading, thus creating new profiles of audiovisual integration with implications for brain plasticity. Understanding the peculiarities of change in speechreading after cochlear implantation may improve our understanding of brain plasticity and provide useful information for functional rehabilitation of implanted patients. In this article, we present a generalized review of our recent studies and indicate perspectives for further research in this domain.     

Visual movement perception in deaf and hearing individuals

A number of studies have investigated changes in the perception of visual motion as a result of altered sensory experiences. An animal study has shown that auditory-deprived cats exhibit enhanced performance in a visual movement detection task compared to hearing cats (Lomber, Meredith, & Kral, 2010). In humans, the behavioural evidence regarding the perception of motion is less clear. The present study investigated deaf and hearing adult participants using a movement localization task and a direction of motion task employing coherently-moving and static visual dot patterns. Overall, deaf and hearing participants did not differ in their movement localization performance, although within the deaf group, a left visual field advantage was found. When discriminating the direction of motion, however, deaf participants responded faster and tended to be more accurate when detecting small differences in direction compared with the hearing controls. These results conform to the view that visual abilities are enhanced after auditory deprivation and extend previous findings regarding visual motion processing in deaf individuals.     

Parafoveal attention in congenitally deaf and hearing young adults

This reaction-time study compared the performance of 20 congenitally and profoundly deaf, and 20 hearing college students on a parafoveal stimulus detection task in which centrally presented prior cues varied in their informativeness about stimulus location. In one condition, subjects detected a parafoveally presented circle with no other information being present in the visual field. In another condition, spatially complex and task-irrelevant foveal information was present which the subjects were instructed to ignore. The results showed that although both deaf and hearing people utilized cues to direct attention to specific locations and had difficulty in ignoring foveal information, deaf people were more proficient in redirecting attention from one spatial location to another in the presence of irrelevant foveal information. These results suggest that differences exist in the development of attentional mechanisms in deaf and hearing people. Both groups showed an overall right visual-field advantage in stimulus detection which was attenuated when the irrelevant foveal information was present. These results suggest a left-hemisphere superiority for detection of parafoveally presented stimuli independent of cue informativeness for both groups.     

Intellectual functioning of deaf adults and children: Answers and questions

Intelligence has long been seen as linked to the spoken and written word. Because most deaf people have poor spoken language skills and find reading a significant challenge, there is a history in both psychology and education of considering deaf individuals to be less intelligent or less cognitively flexible than hearing individuals. With progress in understanding natural signed languages and cognitive abilities of individuals who lack spoken language, this perspective has changed. We now recognise, for example, that deaf people have some advantages in visuospatial ability relative to hearing people, and there is a link between the use of natural signed languages and enhanced visuospatial abilities in several domains. Such findings contrast with results found in memory, where the modality of mental representation, experience, and organisation of knowledge lead to differences in performance between deaf and hearing individuals, usually in favour of the latter. Such findings demonstrate that hearing loss and use of a natural sign language can influence intellectual abilities, including many tapped by standardised IQ tests. These findings raise interesting questions about the place of spoken language in our understanding of intelligence and ways in which we can use basic research for applied purposes.     

Phonology acquired through the eyes and spelling in deaf children

Hearing and deaf children, ranging in age from 6 years 8 months to 14 years 4 months, and matched for general spelling level, were required to spell high-frequency and low-frequency words. Of interest was performance in relation to degree of exposure to Cued Speech (CS), which is a system delivering phonetically augmented speechreading through the visual modality. Groups were (a) hearing children, (b) deaf children exposed early and intensively to CS at home (CS-Home), and (c) deaf children exposed to CS later and at school only (CS-School). Most of the spelling productions of hearing children as well as of CS-Home children were phonologically accurate for high-frequency as well as for low-frequency words. CS-School children, who had less specified phonological representations, made a lower proportion of phonologically accurate spellings. These findings indicate that the accuracy of phonological representations, independent of the modality (acoustic versus visual) through which spoken language is perceived, determines the acquisition of phonology-to-orthography mappings. Analyses of the spelling productions indicate that the acquisition of orthographic representations of high precision depends on fully specified phonological representations.     

聋人句子阅读中的视觉功能补偿现象：副中央凹−中央凹效应的证据

聋人阅读过程中的视觉功能补偿现象是由于听觉信息的缺失,聋人的视觉功能会发生补偿性改变,表现为对副中央凹视野内文本信息的加工效率更高。本研究采用边界范式,测量聋人的副中央凹-中央凹重复效应,以探究聋人的副中央凹视觉功能补偿现象能否促进其中央凹的词汇识别过程。结果发现,聋人的副中央凹-中央凹重复效应出现在早期阅读指标凝视时间,而阅读能力匹配组只出现在晚期阅读指标总注视时间。因此,相比阅读能力匹配的健听读者,聋人的副中央凹-中央凹重复效应出现得更早,表现出副中央凹视觉功能补偿现象。     

The rhyming skills of deaf children educated with phonetically augmented speechreading

Two experiments investigated whether profoundly deaf children's rhyming ability was determined by the linguistic input that they were exposed to in their early childhood. Children educated with Cued Speech (CS) were compared to other deaf children, educated orally or with sign language. In CS, speechreading is combined with manual cues that disambiguate it. The central hypothesis is that CS allows deaf children to develop accurate phonological representations, which, in turn, assist in the emergence of accurate rhyming abilities. Experiment 1 showed that the deaf children educated early with CS performed better at rhyme judgement than did other deaf children. The performance of early CS-users was not influenced by word spelling. Experiment 2 confirmed this result in a rhyme generation task. Taken together, results support the hypothesis that rhyming ability depends on early exposure to a linguistic input specifying all phonological contrasts, independently of the modality (visual or auditory) in which this input is perceived.     

视觉语言对听觉障碍人群阅读能力的影响及作用机制

听觉障碍人群由于听觉部分或完全受损, 视觉语言——唇读和手语就成为其阅读能力发展的主要途径。唇读有助于听觉障碍人群形成语音表征, 与词汇知识相互影响, 且可以促进字词阅读及阅读理解的水平; 口语或书面语的加工可以激活相应的手语表征, 手语影响着听觉障碍人群各个层次的阅读能力。未来研究应该关注语音意识、词汇知识等技能在视觉语言影响听觉障碍人群阅读能力过程中的作用机制, 并以视觉语言为中心, 发展出适合汉语听觉障碍人群阅读能力习得的理论模型。     

听障学生汉语唇读面部加工方式的差异：来自眼动的证据

为探讨高低唇读理解能力听障学生唇读面部加工方式的差异,研究采用视频—图片匹配范式并结合眼动技术,考察高低唇读能力组语前-语中-语后和整体面部加工方式。结果发现,虽然两组都表现出社会协调模式,但高唇读能力组社会协调分数更高,且眼部维持时间更长。表明高唇读能力者整体加工和眼部、口形并行加工能力强,支持凝视假说和社会协调模式;低唇读能力者整体加工效率低,更依赖口形,未能通过补偿策略获得良好的补偿效果。     

聋人手语视觉表象生成能力的实验研究

通过视觉表象判断实验,对聋手语使用者和听力正常人两类被试视觉表象生成的能力进行了比较。实验发现：与听力正常的人相比,聋手语使用者学习和记忆大写字母的时间短于听力正常的被试,并且两组被试记忆复杂字母的时间都较长;聋被试和听力正常被试采用了相同的字母表征方式。但是,习得手语的年龄对聋手语者生成表象的能力没有明显的影响。     

Predictors of reading development in deaf children: A 3-year longitudinal study

The development of reading ability in a group of deaf children was followed over a 3-year period. A total of 29 deaf children (7-8 years of age at the first assessment) participated in the study, and every 12 months they were given a battery of literacy, cognitive, and language tasks. Earlier vocabulary and speechreading skills predicted longitudinal growth in reading achievement. The relations between reading and the predictor variables showed developmental change. Earlier reading ability was related to later phonological awareness skills, suggesting that deaf children might develop their phonological awareness through reading. Deaf children who had the most age-appropriate reading skills tended to have less severe hearing losses and earlier diagnoses and also preferred to communicate through speech. The theoretical implications of the role for speechreading, vocabulary and phonological awareness in deaf children’s literacy are discussed.     

Skilled deaf readers have an enhanced perceptual span in reading

Recent evidence suggests that, compared with hearing people, deaf people have enhanced visual attention to simple stimuli viewed in the parafovea and periphery. Although a large part of reading involves processing the fixated words in foveal vision, readers also utilize information in parafoveal vision to preprocess upcoming words and decide where to look next. In the study reported here, we investigated whether auditory deprivation affects low-level visual processing during reading by comparing the perceptual span of deaf signers who were skilled and less-skilled readers with the perceptual span of skilled hearing readers. Compared with hearing readers, the two groups of deaf readers had a larger perceptual span than would be expected given their reading ability. These results provide the first evidence that deaf readers' enhanced attentional allocation to the parafovea is used during complex cognitive tasks, such as reading.     

听障人群的工作记忆机制

听障人群听觉通道受损,使用手语交流,提供了独特的切入点来探讨工作记忆的结构和功能。研究表明,听障人群具备在功能上与正常人的语音环路平行的手语复述机制。通过发声训练,听障人群也可采用语音编码,即语音环路可被通达。听障人群具有与正常人相当的语言工作记忆资源,但是这种资源在具体使用时受视觉通道处理特性的限制。越来越多的研究支持互补理论,认为手语的使用增强了听障人群非语言的视空间处理能力。     

听觉障碍人群检测任务基于位置的返回抑制

基于位置的返回抑制（IOR）是指对先前注意过的位置上靶子反应变慢的现象。探讨听觉障碍被试检测任务IOR的时程和量是否受听觉剥夺的影响。实验1中,听觉障碍被试和听力正常组被试具有相同的IOR时程和量;但在取消中央线索化的实验2中,当SOA为350ms时,听力正常被试没有出现IOR,听觉障碍被试出现了IOR,说明听觉障碍被试的注意脱离快于听力正常被试。听觉障碍被试对外周靶子的反应快于听力正常被试,表明听障人群外周注意资源增强。这些结果表明听觉障碍被试的空间注意更具有效性和策略性。     

Reading skills of hearing and congenitally deaf children

The present study examined the nature of reading skills in congenitally deaf and hearing children 7–19 years of age. Deaf children were drawn from oralist and total communication programs. A visual detection task was designed to assess the extent of phonological coding and chunking used in reading a story of various degrees of syntactic, semantic, and orthographic complexity. The results provide evidence that (1) like hearing children, deaf children tend to use orthographic regularities in their reading: (2) there is no relation in the deaf child's performance between sensitivity to orthographic regularities and the type of communication method used in training; and (3) hearing and deaf readers use qualitatively similar psycholinguistic strategies in their processing of a story.