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Script activation in lipreading.

In three experiments the roles of script, basic and low-level contexts in lipreading (Abbott et al., 1985) were studied. Three scripts were used: a restaurant, a railway station, and a clothing store. Presence or absence of script headers constituted a between-subjects factor. Basic and low-level context, as well as test-sentences (referring to basic and low-level of abstraction), were within-subjects factors. Also, different kinds of working memory tests were employed to assess potentially important information-processing skills for lipreading. The results show that (a) lipreaders benefit from a compatibility between context level and sentence type, (b) the directions of inferences were asymmetric such that the basic context prevented inferences at the low-level of abstraction, but not vice versa, (c) low-level context in general was most useful for skilled lipreaders in the script group, (d) skilled lipreaders in the non-script group took most advantage of basic level sentences, and (e) working memory capacity did not prove to be important for lipreading skill. Guessing and pure lipreading control experiments established that each of these potentially confounding factors only accounted for about 5% of the lipreading performance, and thus, can not explain the obtained interactive effects between visual information conveyed by lip movements and context. Theorizing departing from prototypicality vs. script accounts of inference-making was critically evaluated, and a predictive script activation mechanism, relevant to lipreading skill, was suggested.

Adult

The neuropsychology of lipreading.

Lipreading presents a unique glimpse of the intersection of sensory processes with modular, cognitive ones. It presents speech to the eye in an automatic and natural way, whether performed silently or in conjunction with heard speech. It therefore allows us to examine closely claims concerning the relation between input modality and cognitive function. In this paper I consider some of the ways in which the investigation of single neuropsychological cases casts light on this; such cases show us that lipreading can dissociate from other aspects of face perception and recognition, and from auditory speech perception and reading, too. Furthermore, different cognitive components of lipreading itself can be inferred from dissociations on different lipreading tasks. This leads to closer consideration of the boundaries of the necessary cognitive (and possibly anatomical) structures that subserve these functions.

Brain

Peripheral vision lipreading aid.

Lipreading provides a limited amount of information about speech signals to profoundly deaf people. Visual displays using peripheral vision as an alternative sensory modality can provide supplementary speech information. The utility of a cosmetically acceptable peripheral vision display was explored. A pair of eyeglasses with a commercially available two-dimensional red LED array (5 x 7), and its associated electronics was developed. The display is visible only to the wearer, and is located in the temporal field and the horizontal meridian of the right eye. Selected speech features were encoded as visual patterns for presentation to the lipreader. These features of the speech signal (the fundamental frequency of the speech, high-frequency energy, and low-passed speech signal or total energy envelope) were presented with the objective of providing information about voicing and plosion/frication. Experiments demonstrate the capability of the peripheral display in conveying speech information. Presenting vowel-consonant-vowel syllables, the performance was in excess of 76% with aided lipreading as compared to 41% by lipreading only.

Communication Devices for People with Disabilities

Measurement of performance of a peripheral vision lipreading aid.

Lipreading, as the most important tool of speech understanding for profoundly deaf people, carries only a limited amount of information about speech. We explored the usefulness of a peripheral vision display in providing profoundly deaf people with supplementary information to lipreading. A pair of eye-glasses with a commercially available two-dimensional red LED array, and associated electronics was developed. The display is located on the rim of the eyeglasses in the temporal field and the horizontal meridian of the right eye. Selected speech features were encoded as visual patterns for presentation to the lipreader. These features (the fundamental frequency of the speech, high-frequency energy, and low-passed speech signal or total energy envelope) provide information about voicing and plosion/friction in order to supplement lipreading. Experiments with 3 normal and 5 deaf subjects demonstrated the capability of the aid to convey speech information for video taped vowel-consonant-vowel (VCV) nonsense syllables. Average identification of 12 VCV syllables using the aid was about 76%, as compared with 40% without the aid.

Adolescent

Effects of sentence context on recognition of words through lipreading by deaf children.

Twenty monosyllabic nouns (10 animate, 10 inanimate) were presented in isolation and in three different positions in sentences to 15 profoundly deaf children to determine the effect of context on word intelligibility through lipreading. Isolated words were more intelligible (80%) than were words in sentences (46%). Animate nouns were more intelligible (70%) than inanimate nouns (33%) when used in initial position (as subjects) in sentences. Teacher ratings of children's "general lipreading ability" were correlated more highly with their recognition of words in the test sentences (r = 0.93) than with their recognition of words presented in isolation (r = 0.53). The results indicate that teachers of deaf children could enhance the intelligibility of important words by isolating them from sentences. The results also suggest that some speech-perception difficulties of deaf children could be diagnosed through lipreading tests which are scored on the basis of correctness of "key words" in sentences.

Adolescent

Lipreading sentences with vibrotactile vocoders: performance of normal-hearing and hearing-impaired subjects.

Three vibrotactile vocoders were compared in a training study involving several different speech perception tasks. Vocoders were: (1) the Central Institute for the Deaf version of the Queen's University vocoder, with 1/3-oct filter spacing and logarithmic output scaling (CIDLog) [Engebretson and O'Connell, IEEE Trans. Biomed. Eng. BME-33, 712-716 (1986)]; (2) the same vocoder with linear output scaling (CIDLin); and (3) the Gallaudet University vocoder designed with greater resolution in the second formant region, relative to the CID vocoders, and linear output scaling (GULin). Four normal-hearing subjects were assigned to either of two control groups, visual-only control and vocoder control, for which they received the CIDLog vocoder. Five normal-hearing and four hearing-impaired subjects were assigned to the linear vocoders. Results showed that the three vocoders provided equivalent information in word-initial and word-final tactile-only consonant identification. However, GULin was the only vocoder significantly effective in enhancing lipreading of isolated prerecorded sentences. Individual subject analyses showed significantly enhanced lipreading by the three normal-hearing and two hearing-impaired subjects who received the GULin vocoder. Over the entire training period of the experiment, the mean difference between aided and unaided lipreading of sentences by the GULin aided hearing-impaired subjects was approximately 6% words correct. Possible explanations for failure to confirm previous success with the CIDLog vocoder [Weisenberger et al., J. Acoust. Soc. Am. 86, 1764-1775 (1989)] are discussed.

Adult

Acquisition of lipreading in a deaf multihandicapped child.

Operant techniques were used to develop lipreading in a nine-year-old deaf boy who had failed to respond appropriately to previous speechreading training. Remediation was initiated with two experiments: the first entailed a reversal and the second a multiple baseline. A component analysis revealed that both tokens and social reinforcers presented simultaneously or separately were effective in shaping lipreading. In addition, the child learned to lip-read either voiced or nonvoiced names of objects.

Affective Symptoms

Visual intelligibility of consonants: a lipreading screening test with implications for aural rehabilitation.

A lipreading screening test consisting of 100 consonant-vowel (CV) syllables was prepared on videotape and presented to subjected with normal hearing and vision. The results of visual consonant confusions revealed nine homophenous categories with high test-retest reliability. Based upon these categories, obtained under ideal viewing conditions, criterion levels of performance were specified in an attempt to determine the need for place of articulation instruction during lipreading training. Examples of confusion patterns from hearing-impaired observers are shown and implications for visual training are presented.

Deafness

Lipreading in patients with schizophrenia.

This study was designed to explore whether schizophrenic patients who are able to maintain their gaze with adequate persistence could competently lip-read. Four lipreading tests, designed to assess recognition of syllables, words, and overlearned sentences, were administered to 15 schizophrenic and 15 normal subjects matched for age, sex, and educational level. The patients proved to be competent lip-readers susceptible to the blend illusion and were inferior only in lipreading of overlearned sentences. The latter difficulty may tentatively be attributed to the inadequacy of the patient's premorbid social network for establishing contextual cues that aid in the recognition of overlearned sentences.

Adult

Lipreading and audio-visual speech perception.

This paper reviews progress in understanding the psychology of lipreading and audio-visual speech perception. It considers four questions. What distinguishes better from poorer lipreaders? What are the effects of introducing a delay between the acoustical and optical speech signals? What have attempts to produce computer animations of talking faces contributed to our understanding of the visual cues that distinguish consonants and vowels? Finally, how should the process of audio-visual integration in speech perception be described; that is, how are the sights and sounds of talking faces represented at their conflux?

Auditory Perception

Revised Craig Lipreading Inventory.

The two purposes of this study were to shorten the Craig Lipreading Inventory without affecting its reliability and validity and to establish normative data on the revised version. The full inventory was administered to 75 children. By item analysis, half of the items were selected to comprise the brief version; both versions were administered to another group of 75 children. Scores on the two versions correlated (.91 and .92, respectively, for Word Forms A and B and .97 and .95, respectively, for Sentence Forms A and B), thereby substantiating the construct validity of the briefer version. There was significantly high intertest reliability for the Word Forms (.80) and Sentence Forms (.82) of the briefer inventory. Normative data were computed for each age group. This briefer version is a temporally efficient tool for evaluating lipreading ability of children.

Aptitude

Similarity ratings and confusability of lipread consonants compared with similarity ratings of auditory and orthographic stimuli.

Similarity ratings of pairs of lipread consonants were obtained using a 5-point scale. Matrices were constructed showing mean similarity ratings and confusions among stimuli. Both the similarity and the confusion data provide normative data useful for researchers in many areas. Lipread data collected here are compared with similarity ratings of orthographically and auditorily presented consonants collected by Manning (1977). These comparisons provide information about how stimulus similarity both within and between presentation formats may affect information processing of the three types of stimuli. These data are of special interest to researchers studying the visual processing of speech and the effect of format of presentation on recall.

Adult

Investigating the MESA (multipoint electrotactile speech aid): the transmission of connected discourse.

Three normal-hearing young adults were tested in their reception of connected discourse materials under two receiving conditions; visual-reception alone (lipreading) and visual reception in conjunction with an electrotactile speech aid (MESA). Subjects were artificially deafened with earplugs and white noise; all stimuli were delivered live-voice using a special tracking procedure. Analysis of the data suggests that after an initial period of learning, combined visual and electrotactile receptive performance exceeds lipreading-alone performance. After extensive learning however, performance in lipreading alone or MESA plus lipreading is practically equivalent.

Adult

Audiovisual integration in perception of real words.

Three experiments follow up on Easton and Basala's (1982) report that the "McGurk effect" (an influence of a visibly mouthed utterance on a dubbed acoustic one) does not occur when utterances are real words rather than nonsense syllables. In contrast, with real-word stimuli, Easton and Basala report a strong reverse effect whereby a dubbed soundtrack strongly affects identification of lipread words. In Experiment 1, we showed that a strong McGurk effect does obtain when dubbed real words are discrepant with observed words in consonantal place of articulation. A second experiment obtained only a weak reverse effect of dubbed words on judgments of lipread words. A final experiment was designed to provide a sensitive test of effects of lipread words on judgments of heard words and of heard words on judgments of lipread words. The findings reinforced those of the first two experiments that both effects occur, but, with place-of-articulation information discrepant across the modalities, the McGurk effect is strong and the reverse effect weak.

Attention