Deaf Subjects Research Articles

Sign language activated the auditory cortex of a congenitally deaf subject: revealed by positron emission tomography.

Sign language activated the auditory cortex of a congenitally deaf subject: revealed by positron emission tomography.

Cochlear implant in patients with residual hearing

Objective: The postoperative speech perception abilities of severely hearing-impaired patients with multi-channel cochlear implant were compared with preoperative speech perception performance with conventional hearing aids. Methods: Cochlear implantation was performed in six severely to profoundly hearing-impaired patients. They had unaided pure-tone thresholds of 70–100-dB HL and aided thresholds of 35–90-dB HL in the better ear, but were not able to perceive speech sounds well with hearing aids. Results: Postoperatively, all the patients had significantly improved speech perception performance, exceeded the average skills of profoundly deaf cochlear implant users, and were able to communicate without writing. Conclusion: These results imply that cochlear implant may be indicated for severely to profoundly deaf subjects, if they receive little or no benefit from conventional hearing aids.

Do deaf people see better? Texture segmentation and visual search compensate in adult but not in juvenile subjects.

The research concerning the visual perception in deaf subjects has led to contradictory results: Deaf subjects have been reported to show enhanced visual perceptual skills compared to hearing subjects (Neville & Lawson, 1987). On the other hand, there are indications that acoustic deprivation may produce an inferiority in all sensory modalities (Myklebust, 1964). These contradictions may be due to methodological differences: The investigators selected different conditions (e.g. attentive/nonattentive) and various samples of deaf subjects (e.g., different age, language, and aetiology groups). In our study, we tested a large sample of deaf subjects with texture segmentation and visual search conditions, which allowed us to differentiate between visual processing with and without attentional load. All deaf subjects had profound hearing loss within the first year of life. Our results suggest that the visual processing capacity of deaf children and adolescents does not exceed that of age- and gender-matched hearing subjects. Rather, deaf school children show deficits in visual processing in conditions with and without attentional load. Age (6 to 20 years), language used (oral, sign, oral + sign), and aetiology for deafness (genetic, maternal rubella, perinatal, infection in the first year of life, unknown) did not consistently influence the results. The deficits in visual processing were partially compensated for in adult deaf subjects. The performances of deaf and hearing adults in trials that could be solved preattentively did not differ statistically significantly, but in attention-dependent trials the deaf subjects were more efficient than the hearing controls. We conclude that visual compensation for deafness is limited to attention-dependent tasks and does not develop until adulthood.

PET imaging of cochlear-implant and normal-hearing subjects listening to speech and nonspeech

Functional neuroimaging with positron emission tomography (PET) was used to compare the brain activation patterns of normal-hearing (NH) with postlingually deaf, cochlear-implant (CI) subjects listening to speech and nonspeech signals. The speech stimuli were derived from test batteries for assessing speech-perception performance of hearing-impaired subjects with different sensory aids. Subjects were scanned while passively listening to monaural (right ear) stimuli in five conditions: Silent Baseline, Word, Sentence, Time-reversed Sentence, and Multitalker Babble. Both groups showed bilateral activation in superior and middle temporal gyri to speech and backward speech. However, group differences were observed in the Sentence compared to Silence condition. CI subjects showed more activated foci in right temporal regions, where lateralized mechanisms for prosodic (pitch) processing have been well established; NH subjects showed a focus in the left inferior frontal gyrus (Brodmann’s area 47), where semantic processing has been implicated. Multitalker Babble activated auditory temporal regions in the CI group only. Whereas NH listeners probably habituated to this multitalker babble, the CI listeners may be using a perceptual strategy that emphasizes ‘coarse’ coding to perceive this stimulus globally as speechlike. The group differences provide the first neuroimaging evidence suggesting that postlingually deaf CI and NH subjects may engage differing perceptual processing strategies under certain speech conditions.

Left-Hemisphere Dominance for Motion Processing in Deaf Signers

Evidence from neurophysiological studies in animals as well as humans has demonstrated robust changes in neural organization and function following early-onset sensory deprivation. Unfortunately, the perceptual consequences of these changes remain largely unexplored. The study of deaf individuals who have been auditorily deprived since birth and who rely on a visual language (i.e., American Sign Language, ASL) for communication affords a unique opportunity to investigate the degree to which perception in the remaining, intact senses (e.g., vision) is modified as a result of altered sensory and language experience. We studied visual motion perception in deaf individuals and compared their performance with that of hearing subjects. Thresholds and reaction times were obtained for a motion discrimination task, in both central and peripheral vision. Although deaf and hearing subjects had comparable absolute scores on this task, a robust and intriguing difference was found regarding relative performance for left-visual-field (LVF) versus right-visual-field (RVF) stimuli: Whereas hearing subjects exhibited a slight LVF advantage, the deaf exhibited a strong RVF advantage. Thus, for deaf subjects, the left hemisphere may be specialized for motion processing. These results suggest that perceptual processes required for the acquisition and comprehension of language (motion processing, in the case of ASL) are recruited (or “captured”) by the left, language-dominant hemisphere.

Gap detection by early-deafened cochlear-implant subjects.

Two studies investigating gap-detection thresholds were conducted with cochlear-implant subjects whose onset of profound hearing loss was very early in life. The Cochlear Limited multiple-electrode prosthesis was used. The first study investigated the effects of pulse rate (200, 500, and 1000 pulses/s) and stimulus duration (500 and 1000 ms) on gap thresholds in 15 subjects. Average gap thresholds were 1.8 to 32.1 ms. There was essentially no effect of pulse rate and for almost all subjects, no effect of stimulus duration. For two subjects, performance was poorer for the 1000-ms stimulus duration. The second study investigated the relationships between gap thresholds, subject variables, and speech-perception scores. Data from the first study were combined with those from previous studies [Busby et al., Audiology 31, 95-111 (1992); Tong et al., J. Acoust. Soc. Am. 84, 951-962 (1988)], providing data from 27 subjects. A significant negative correlation was found between age at onset of deafness and gap thresholds and most variability in gap thresholds was for the congenitally deaf subjects. Significant negative correlations were found between gap thresholds and word scores for open-set Bamford-Kowal-Bench (BKB) sentences in the auditory-visual condition and lipreading enhancement scores for the same test.

Phonological representations in postlingual deaf subjects using a multichannel cochlear implant

Our research is a first attempt to study phonological representations in postlingually deaf subjects using a multichannel cochlear implant. Before deafness, these subjects had developed normal language. The present study investigated how phonological representations are assessed through cochlear implant inputs by comparing priming within the auditory modality, and priming in a visual–auditory, cross-modal, condition. Two postlingually deafened adults participated in two lexical decision experiments where word primes were phonologically paired with a word target (e.g. vedette/dette), or a pseudoword target (e.g. banane/nane). The same word primes were also paired with non phonologically related target words (e.g. vedette/chat) and pseudowords (e.g. banane/repe). In addition, the same targets were used in phonologically-related pairs and in phonologically-unrelated ones. Results showed different priming effects for each patient. In one patient, priming was observed for word targets in the unimodal condition only. In the other patient, priming was observed for word targets and interference was observed for pseudoword targets in the cross-modal condition, whereas no effect was observed in the unimodal condition. In addition, this last patient made more errors for pseudowords than for words in the cross-modal condition. These results were interpreted as suggesting that lexical phonological representations participated to priming effects. Moreover, our results suggest that phonological word forms can be activated by visual primes via cochlear implants.

What's right about the neural organization of sign language? A perspective on recent neuroimaging results

To summarize the argument so far, our main points are (1) that the vast majority of behavioral, neuropsychological, and functional imaging data support the hypothesis that the left hemisphere is dominant for lexical and grammatical aspects of sign language perception and production, (2) that because of potential design confounds, the Neville et al. study does not present any serious challenge to existing claims concerning the lateralization of sign language, and (3) that there is evidence from both lesion and functional imaging data which suggests that the within-hemisphere organization of signed and spoken language is in many respects the same—but not in all respects.One difference (which has been overlooked thus far) in the brain regions that were activated in the processing of ASL stimuli compared with those that are activated in the processing of auditorily presented spoken language stimuli concerns the supratemporal plane, the dorsal aspect of the temporal lobe, which includes the transverse temporal (or Heschl's) gyrus and the planum temporale. This region is uniformly activated in hearing subjects listening to spoken language[17xFunctional magnetic resonance imaging of human auditory cortex. Binder, J.R. et al. Ann. Neurol. 1994; 35: 662–672CrossRef | PubMed | Scopus (299)See all References, 18xFunctional magnetic resonance imaging of the central auditory pathway following speech and pure-tone stimuli. Millen, S.J., Haughton, V.M., and Yetkin, Z. Laryngoscope. 1995; 105: 1305–1310CrossRef | PubMedSee all References, 24xFunctional MR imaging of auditorily presented words: a single-item presentation paradigm. Hickok, G. et al. Brain Lang. 1997; 58: 197–201CrossRef | PubMed | Scopus (27)See all References] but was not activated in deaf subjects watching ASL sentences in the Neville et al. study, nor was it activated in an fMRI study of single-sign perception in a native deaf signer[25xSensory mapping in a congenitally deaf subject: MEG and fMRI studies of cross-modal non-plasticity. Hickok, G. et al. Hum. Brain Mapp. 1997; 5: 437–444CrossRef | PubMed | Scopus (17)See all References][25].One potential explanation for this is that supratemporal plane structures are involved in processing non-linguistic auditory information[26xFunction of the left planum temporale in auditory and linguistic processing. Binder, J.T. et al. Brain. 1996; 119: 1239–1247CrossRef | PubMedSee all References][26]: because these are not language processing systems, perception of ASL would not be expected to activate these areas; speech stimuli on the other hand, would produce activation in supratemporal plane as a result of some type of acoustic response. Another possibility, however, is that the supratemporal plane contains systems directly and critically involved in the perception of speech (that is, extracting linguistic information from an auditory signal), as some authors have suggested (Ref. [27xLanguage-specific phoneme representations revealed by electric and magnetic brain responses. Naatanen, R. et al. Nature. 1997; 385: 432–434CrossRef | PubMed | Scopus (723)See all References][27] and D. Poeppel, PhD thesis, MIT, 1995). This hypothesis could explain the presence of supratemporal activation in auditory language perception and its absence in sign language perception. It also predicts that there should be some processing system outside of canonical language areas involved in the extraction of sign information from the visual input. On this view, there are both modality dependent and modality independent components to the neural organization of language perception. Modality dependent components are those involved in extracting linguistic information from the sensory input, modality independent components are those involved in operating on higher-level linguistic representations. Based on available data, it's possible that supratemporal plane structures are part of a modality dependent system involved in speech perception, whereas lateral temporal lobe structures are part of a modality independent system involved in higher-level linguistic operations.But all of this discussion hasn't really answered the question posed at the outset; that is, what is driving the neural organization of language? Well, we don't yet know for sure. In fact, the data reviewed above render this problem a bit more puzzling (and thus perhaps more interesting). What we do know is that modality-specific factors aren't the whole story. Save for the possibility of speech perception, the neural organization of language appears to be largely independent of the modalities through which it is perceived and produced. But notice that this conclusion rules out the most intuitive and probably the oldest answer to the above question, namely that language systems are really just dynamically organized subsystems of the particular sensory and motor channels through which language is used. Instead, the answer will have to be couched in terms that can generalize over modality. Whether such an account will ultimately appeal to genetically constrained domain-specific regional specializations or to some complex interaction of domain-general processing biases (or both) remains to be seen. Provocative issues indeed.

Response from Paulesu and Mehler

As discussed by ourselves[1xRight on in sign language. Paulesu, E. and Mehler, J. Nature. 1998; 392: 233–234Crossref | PubMed | Scopus (17)See all References][1]and also by Hickok and colleagues in the preceding comment[2xWhat's right about the neural organization of sign language? A perspective on recent neuroimaging results. Hickok, G., Bellugi, U., and Klima, E. Trends Cognit. Sci. 1998; 2: 465–468Abstract | Full Text | Full Text PDF | PubMed | Scopus (33)See all References][2]and elsewhere[3xLanguage, modality and the brain. Bellugi, U., Poizner, H., and Klima, E. Trends Neurosci. 1989; 12: 380–388Abstract | Full Text PDF | PubMed | Scopus (79)See all References][3], we believe that the available evidence from fMRI and other studies points to a left hemispheric dominance for language, even in the case of sign language[4xThe neurobiology of sign language and its implications for the neural basis of language. Hickok, G., Bellugi, U., and Klima, E. Nature. 1996; 381: 699–702Crossref | PubMed | Scopus (97)See all References, 5xNeural correlates of thinking in sign language. McGuire, P. et al. NeuroReport. 1997; 8: 695–698Crossref | PubMedSee all References, 6xSign language aphasia during left-hemisphere Amytal injection. Damasio, A. et al. Nature. 1986; 322: 363–365Crossref | PubMed | Scopus (35)See all References]. However, while the left hemispheric activations seen in recent imaging data for sign language could be largely predicted from lesion data, we are still inclined to believe, in contrast to Hickok et al.[2xWhat's right about the neural organization of sign language? A perspective on recent neuroimaging results. Hickok, G., Bellugi, U., and Klima, E. Trends Cognit. Sci. 1998; 2: 465–468Abstract | Full Text | Full Text PDF | PubMed | Scopus (33)See all References][2], that the right hemispheric activations described by Neville et al.[7xCerebral organization for language in deaf and hearing subjects: biological constraints and effects of experience. Neville, H. et al. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 922–929Crossref | PubMed | Scopus (302)See all References][7]are not artefactual—even though a real surprise, given the expectation from patient data. The baseline for the sign-language comprehension task used by Neville et al. (observation of non-linguistic gestures made by a signer) was closely matched to the experimental task. Auditory-language comprehension tasks using a similarly close baseline, such as backwards speech, do not show such prominent activations in the right hemisphere[8xThe bilingual brain: proficiency and age of acquisition of the second language. Perani, D. et al. Brain. 1998; 121: 1841–1852Crossref | PubMed | Scopus (370)See all References][8].As we proposed in our commentary[1xRight on in sign language. Paulesu, E. and Mehler, J. Nature. 1998; 392: 233–234Crossref | PubMed | Scopus (17)See all References][1], reconciliation of the mismatch between functional imaging and lesion data will require further investigations on both sides. Even if our suggestion[1xRight on in sign language. Paulesu, E. and Mehler, J. Nature. 1998; 392: 233–234Crossref | PubMed | Scopus (17)See all References][1]turned out to be true—that the right hemispheric activations seen for sign language by Neville et al. could have been due to prosodic processing[9xDominant language functions of the right hemisphere? Prosody and emotional gesturing. Ross, E. and Mesulam, M. Arch. Neurol. 1979; 36: 144–148Crossref | PubMed | Scopus (381)See all References][9]—this would still be a challenge for our understanding of the biological causes of the regional brain distribution of linguistic competences in both hearing and congenitally deaf subjects. Left-sided `dominance', together with right-sided linguistic competence of the kind seen in hearing subjects[9xDominant language functions of the right hemisphere? Prosody and emotional gesturing. Ross, E. and Mesulam, M. Arch. Neurol. 1979; 36: 144–148Crossref | PubMed | Scopus (381)See all References, 10xThe role of the right hemisphere in the interpretation of figurative aspects of language: a positron emission tomography activation study. Bottini, G. et al. Brain. 1994; 117: 1231–1253Crossref | PubMed | Scopus (407)See all References], is a complex scenario that is not evaluated by the hypotheses usually discussed in neuro-linguistics and neither is it discussed by Hickok et al. in their present comment.

Hemispheric Organization of Local- and Global-Level Visuospatial Processes in Deaf Signers and Its Relation to Sign Language Aphasia

Previous work has shown that deficits in the production and perception of signed language are linked to left hemisphere damage but not right hemisphere damage in deaf lifelong signers, whereas severe deficits in nonlinguistic visuospatial abilities are more frequent following right hemisphere damage than left hemisphere damage in this population. In the present study we investigated the extent to which sign language deficits in deaf individuals can be dissociated from more subtle visuospatial deficits commonly associated with left hemisphere damage in the hearing/speaking population. A group of left- or right-lesioned deaf signers were asked to reproduce (1) two line drawings (a house and an elephant) and (2) four hierarchical figures. Drawings were scored separately for the presence of local vs global features. Consistent with data from hearing patients, left hemisphere-damaged deaf subjects were significantly better at reproducing global-level features, whereas right hemisphere-damaged deaf subjects were significantly better at reproducing local-level features. This effect held for both types of stimuli. Local-level performance in the LHD group did not correlate with performance on sign language tasks, suggesting that language deficits in LHD deaf signers are in fact linguistic specific.

Written Language Abilities in Deaf Italians

Written texts produced by 10 Italian deaf native signers in four different writing tasks were analyzed. Data analysis focused on linguistic and orthographic nonstandard forms. The written production of deaf subjects with deaf parents (DD) was compared to the written production in two control groups: a group of 10 hearing subjects with deaf parents (HD) and a group of 10 subjects who have had no contact with deaf people or sign language (HH). The results duplicate findings from previous studies. Deaf subjects display a pattern of selective difficulty with Italian grammatical morphology, especially with free-standing function words. The four different writing tasks used in the present study yield results indicating that text type does influence our assessment of deaf writing abilities. A comparison of the texts written by deaf native signers with those of two hearing groups confirms the view that difficulties in the acquisition of written Italian are best explained by deafness itself, not by the influence of a previously acquired Sign Language, and that the specific difficulties with grammatical morphology displayed by our deaf subjects cannot be attributed solely to their limited experience with written Italian.

Using Silent Motion Pictures to Teach Complex Syntax to Adult Deaf Readers

This research tested whether silent motion pictures could be a source of contexts that fostered comprehension of relative clause and passive voice sentences during reading. These two syntactic structures are chronically difficult for some deaf readers. According to the instructional strategy, while subjects watched silent comedy stories, the video display intermittently focused attention on short segments of action and then called for a decision regarding which of two sentences printed in a workbook described the action segment. After this, a display on the video screen provided feedback on the accuracy of the decision. If successful here, this approach might be applied to other areas of competence in order to elevate the generally low level of reading performance by many deaf students. The study applied a single subject design in order to measure sentence comprehension accuracy before and following use of the materials. The computerized testing procedure also measured sentence reading time, an index of attention use. Thus, these data allowed an examination of whether any increases in comprehension were associated with slower, more laborious rates of reading. The instructional approach was an indirect one sharing multiple aspects of whole language methodology, and the sample included deaf subjects at a variety of reading ability levels. This permitted examination of whether an indirect instructional approach could be successful with readers demonstrating relatively low reading ability. The central research question of the study was the following 'Can this instructional method be effective with deaf readers?'.

Use of non-linear EEG analysis to study abnormal brain dynamics in deaf human subjects

We compared the cortical dynamics of deaf subjects to those of control subjects at rest with eyes closed and during reading with the help of a non-linear prediction statistic. This method is suitable for short-term noisy time series such as electroencephalographic signals. Furthermore, we used surrogate data to test for non-linear dynamics underlying the electroencephalographic time series recorded. Our results indicate that significant non-linearity accompanies cortical activation during reading. This is more diffuse in deaf subjects and could be due to the widespread reorganization of their cerebral cortex. Predictability was lower in deaf subjects at rest, which indicates their increased `readiness' in the resting condition. Finally, our results indicate that normal and deaf subjects differ significantly in terms of cortical dynamics.

Cerebral organization of language

It is well known that areas in the left hemisphere of the brain are specialized for the processing of language. An interesting question is to what extent this specialization is innate or influenced by experience. To address this issue, Neville et al.[ 1 Neville H.J. et al. Cerebral organization for language in deaf and hearing subjects: biological constraints and effects of experience. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 922-929 Crossref PubMed Scopus (373) Google Scholar ]conducted a functional magnetic resonance imaging study in which subjects read sentences of English in one condition, and saw sentences signed in American Sign Language (ASL) in another. Three subject groups were tested: (1) (monolingual) native speakers of English; (2) hearing bilinguals who had both English and ASL as their native languages; and (3) deaf, native ASL signers who had learned (written) English at a later age, and scored only moderately on tests of English grammar.

Novel Mitochondrial DNA Mutation in tRNALys(8296A → G) Associated with Diabetes

Mutation in the mitochondrial gene at position 3243 was recently identified in a large pedigree of diabetes mellitus and deafness. As the mitochondria play an important role in glucose-stimulated insulin secretion in pancreatic beta-cells, we therefore searched for such mutations to detect a candidate gene for diabetes. We screened 10 diabetic subjects with clinical features suggesting mitochondrial DNA mutations. An adenine to guanine point mutation in tRNALysin at position 8296 (the 8296 mutation) was newly identified. Subsequently, we screened 1216 diabetic subjects, 44 patients with sensorineural deafness subjects and 300 non-diabetic control subjects for this mutation. We identified the mutation in 11 (0.90%) unrelated diabetic subjects, one (2.3%) patient with deafness and no non-diabetic control subject. Seven of these 12 subjects showed maternal inheritance. Deafness was seen in 7 of 12 probands. Four family pedigrees showed maternal inheritance of diabetes over two or three generations. Subjects carrying the 8296 mutation may develop diabetes and the mutation can explain as high as ca. 1% of the causes of diabetes.

Abraham Farrar (1861-1944): donor of the Farrar Collection of books on the education of the deaf and cognate subjects in the John Rylands University Library of Manchester, Deansgate

La collection Farrar longtemps ignoree par les chercheurs comportent des ouvrages dont les etudes reposent sur l'education des sourds, les traitements mediacux de la surdite, la philosophie du langage et l'etude du langage des signes. Les auteurs en proposent une etude bibliographique critique.

Auditory cortical responses in hearing subjects and unilateral deaf patients as detected by functional magnetic resonance imaging.

Functional magnetic resonance imaging is a non-invasive method for the detection of focal brain activity at high spatial resolution. Acoustic stimulation leads to a blood oxygenation level dependent signal change in the plane of the superior temporal gyrus. The dependence of this response in the auditory cortex on binaural, monaural left and monaural right acoustic stimulation for 10 healthy subjects and five monaural deaf patients is described. Acoustic stimulation consists of 1000 Hz pulsed sine tones at a pulse rate of 6 Hz and a sound pressure level of 95 dB. For monaural stimulation, normal-hearing subjects revealed a strong lateralization of cortical response towards the contralateral hemisphere. The lateralization ratios between left and right hemispheric response areas were 3.4-5.2 for monaural stimulation and nearly balanced for binaural stimulation. Additionally, the sum of cortical activation volumes induced by monaural left and right stimulation was approximately 30% smaller than for binaural stimulation, indicating either inhibitory mechanisms or neuronal facilitation within the auditory pathways. For monaural deaf subjects the lateralization ratio between left to right response was just 1.3 towards the contralateral hemisphere of the healthy ear, which is comparable to binaural responses of normal-hearing subjects. This observation seems to indicate a plasticity or a reorganization of auditory pathways of monaural deaf patients.

Differences in visual search tasks between congenitally deaf and normally hearing adults

In order to study the processes of central vision in deaf subjects, 12 congenitally deaf adults and 12 normally hearing adults performed a visual search task. The task consisted of detecting a “Q” target among “O” distractors in variable numbers and the reverse. The method used a paradigm based on the stimulus onset asynchrony (SOA) specifically designed to measure the visual processing time between the visual array and a mask. A different visual search pattern was observed in each group. The hearing subjects showed an asymmetrical visual search pattern (parallel versus serial processing respectively for “Q” and “O” targets). In contrast, the deaf subjects showed a symmetrical search pattern (parallel processing in both experimental conditions). In a visual task selectively supported by central vision, visual processes of the congenitally deaf are more efficient when the task involves the contribution of serial processes.

Spelling without Phonology: A Study of Deaf and Hearing Children.

To what extent does phonology play a role in spelling English words? The written responses of deaf students and groups of hearing children to five tasks were subjected to quantitative and qualitative analyses. The first three tasks were used to see if deaf students utilized phonology when they generated their own words and to compare their spelling performance with that of hearing subjects. The fourth and fifth tasks were designed to compare the spelling performance of deaf and hearing subjects when they were required to reproduce visually presented common words. Results showed that deaf students, who were chronologically much older, were not better spellers than hearing children from the fifth grade. Analysis of data revealed little evidence that the deaf students involved in the present study utilize phonology in spelling. Nor did word-specific visual memory for entire words appears to play a role in spelling by deaf students. Rote visual memory for letter patterns and sequences of letters within words, however, appears to play a role in the spelling by deaf students. It is concluded that sensitivity to the stochastic-dependent probabilities of letter sequences may aid spelling up to certain point but phonology is essential for spelling words whose structure is morphophonemically complex.

Learning Disability, Neuropsychology, and Deaf Youth: Theory, Research, and Practice

Historically, there have been a variety of perspectives regarding the impact of deafness on the development of intellect, learning, and brain organization in prelingually deaf children. In 1960, for example, Myklebust proposed that auditory or any odier sensory deprivation leads to limitations on deaf people's experience and thus deprives them of information critical for normal psychological functioning. In his view, the absence of sensation alters the integration of information and the functioning of other abilities, thus leading to a differently constituted experience. Such alterations' were seen as occurring naturally and unknowingly, affecting deaf people's perception, conception, imagination, and thought. Myklebust's perspective unfortunately was linked to a broader view of deaf people as not only different but also cognitively deficient relative to hearing people. In a large number of studies, deaf and hearing subjects were compared on measures designed for and normed on hearing populations without consideration of communication needs or the possible effects of early language deprivation in hearing households. While deaf people as a group often did score lower on such measures, there were multiple confounding factors that could have explained the differences without having to assume any inherent deficiencies in the deaf populations' intellectual or cognitive functioning (Greenberg & Kusche, 1989). Deaf people, in fact, have been