Although most deaf individuals could use sign language or sign/spoken language mix, hearing loss would still affect their language acquisition. Compensatory plasticity holds that the lack of auditory stimulation experienced by deaf individuals, such as congenital deafness, can be met by enhancements in visual cognition. And the studies of hearing individuals have showed that visual form perception is the cognitive mechanism that could explain the association between numerical magnitude processing and arithmetic computation. Therefore, we examined numerical magnitude processing (...) and its contribution to arithmetical ability in deaf adolescents, and explored the differences between the congenital and acquired deafness. 112 deaf adolescents and 58 hearing adolescents performed a series of cognitive and mathematical tests, and it was found there was no significant differences between the congenital group and the hearing group, but congenital group outperformed acquired group in numerical magnitude processing and arithmetic computation. It was also found there was a close association between numerical magnitude processing and arithmetic computation in all deaf adolescents, and after controlling for the demographic variables and general cognitive abilities, numerical magnitude processing could predict arithmetic computation in all deaf adolescents but not in congenital group. The role of numerical magnitude processing in deaf adolescents' mathematical performance should be paid attention in the training of arithmetical ability. (shrink)

While cochlear implantation has benefitted many patients with single-sided deafness (SSD), there is great variability in cochlear implant (CI) outcomes and binaural performance remains poorer than that of normal-hearing (NH) listeners. Differences in sound quality across ears – temporal fine structure (TFS) information with acoustic hearing versus coarse spectro-temporal envelope information with electric hearing – may limit integration of acoustic and electric patterns. Binaural performance may also be limited by inter-aural mismatch between the acoustic input frequency and the place (...) of stimulation in the cochlea. SSD CI patients must learn to accommodate these differences between acoustic and electric stimulation to maximize binaural performance. It is possible that training may increase and/or accelerate accommodation and further improve binaural performance. In this study, we evaluated lateralization training in NH subjects listening to broad simulations of SSD CI signal processing. A 16-channel vocoder was used to simulate the coarse spectro-temporal cues available with electric hearing; the degree of inter-aural mismatch was varied by adjusting the simulated insertion depth (SID) to be 25 mm (SID25), 22 mm (SID22), and 19 mm (SID19) from the base of the cochlea. Lateralization was measured using headphones and head-related transfer functions (HRTFs). Baseline lateralization was measured for unprocessed speech (UN) delivered to the left ear to simulate SSD and for binaural performance with the acoustic ear combined with the 16-channel vocoders (UN+SID25, UN+SID22, and UN+SID19). After completing baseline measurements, subjects completed 6 lateralization training exercises with the UN+SID22 condition, after which performance was re-measured for all baseline conditions. Post-training performance was significantly better than baseline for all conditions (p<0.05 in all cases), with no significant difference in training benefits among conditions. Given that there was no significant difference between the SSD and the SSD CI conditions before or after training, the results suggest that NH listeners were unable to integrate TFS and coarse spectro-temporal cues across ears for lateralization, and that inter-aural mismatch played a secondary role at best. While lateralization training may benefit SSD CI patients, the training may largely improve spectral analysis with the acoustic ear alone, rather than improve integration of acoustic and electric hearing. (shrink)

ABSTRACT The paper examines the little-known experiments in audition performed by the prominent experimental physiologist Jan Purkyně in Prague in the 1850s. Purkyně’s original research on spatial hearing and auditory attention is studied against the backdrop of the nineteenth century research on binaural audition and the nascent field of psychophysics. The article revolves around an acoustic research instrument of Purkyně’s own making, the opistophone, in which hearing became both an object of investigation and an instrument of scientific inquiry. It argues (...) that Purkyně’s understanding of auditory attention, which combined acoustic stimulation, physiological conditions, and sensory training, preceded a similar approach to hearing in psychophysical debates in the second half of the nineteenth century. Purkyně was the first scholar to experimentally investigate intracranial sounds, which he studied in his experiments with the inmates of the Prague Institute of Deaf-Mutes. This research on intracranial hearing was part of Purkyně’s study of so-called organic subjectivity, in which subjective hearing experience was interpreted as the result of the interaction between individual perception and objective acoustic phenomena. (shrink)

This volume brings together the published and the previously unpublished works on language by the seventeenth-century thinker George Dalgarno. His 'Art of Signs' - the earliest seventeenth-century work to attempt a fully elaborated universal language scheme - is presented here for the first time with a full English translation alongside the Latin. Also included is a further book-length tract, broadsheets, and correspondence, all of which provide the modern reader with better access to the ideas of this original and stimulating thinker.

This volume brings together the published and the previously unpublished works on language by the seventeenth-century thinker George Dalgarno. His 'Art of Signs' - the earliest seventeenth-century work to attempt a fully elaborated universal language scheme - is presented here for the first time with a full English translation alongside the Latin. Also included is a further book-length tract, broadsheets, and correspondence, all of which provide the modern reader with better access to the ideas of this original and stimulating thinker.

Cochlear implants electrically stimulate surviving auditory neurons in the cochlea to provide severely or profoundly deaf people with access to hearing. Signal processing strategies derive frequency-specific information from the acoustic signal and code amplitude changes in frequency bands onto amplitude changes of current pulses emitted by the tonotopically arranged intracochlear electrodes. This article first describes how parameters of the electrical stimulation influence the loudness evoked and then summarizes two different phenomenological models developed by McKay and colleagues that have been (...) used to explain psychophysical effects of stimulus parameters on loudness, detection, and modulation detection. The Temporal Model is applied to single-electrode stimuli and integrates cochlear neural excitation using a central temporal integration window analogous to that used in models of normal hearing. Perceptual decisions are made using decision criteria applied to the output of the integrator. By fitting the model parameters to a variety of psychophysical data, inferences can be made about how electrical stimulus parameters influence neural excitation in the cochlea. The Detailed Model is applied to multi-electrode stimuli, and includes effects of electrode interaction at a cochlear level and a transform between integrated excitation and specific loudness. The Practical Method of loudness estimation is a simplification of the Detailed Model and can be used to estimate the relative loudness of any multi-electrode pulsatile stimuli without the need to model excitation at the cochlear level. Clinical applications of these models to novel sound processing strategies are described. (shrink)

“An original, compelling, and provocative exploration of ethical issues in our society, with thoughtful and balanced commentary. I have not seen anything like it.” —Alan Lightman, author of Einstein’s Dreams Drawing upon the author’s two decades teaching medical ethics, as well as his work as a practicing psychiatrist, this profound and addictive little book offers up challenging ethical dilemmas and asks readers, What would you do? A daughter gets tested to see if she’s a match to donate a kidney to (...) her father. The test reveals that she is not the man’s biological daughter. Should the doctor tell the father? Or the daughter? A deaf couple prefers a deaf baby. Should they be allowed to use medical technology to ensure they have a child who can’t hear? Who should get custody of an embryo created through IVF when a couple divorces? Or, when you or a loved one is on life support, Who says you’re dead? In short, engaging scenarios, Dr. Appel takes on hot-button issues that many of us will confront: genetic screening, sexuality, privacy, doctor-patient confidentiality. He unpacks each hypothetical with a brief reflection drawing from science, philosophy, and history, explaining how others have approached these controversies in real-world cases. Who Says You’re Dead? is designed to defy easy answers and to stimulate thought and even debate among professionals and armchair ethicists alike. (shrink)

Three of the articles included in this issue of the Journal of Medicine and Philosophy - Ron Amundson and Shari Tresky's "On a Bioethical Challenge to Disability Rights"; Rachel Cooper's "Can It Be a Good Thing to Be Deaf?"; and Mark T. Brown's "The Potential of the Human Embryo" - interact (in various ways) with the concepts of disability, humanity, and personhood and their normative dimensions. As one peruses these articles, it becomes apparent that terms like "disability," "human being," and (...) "person" carry with them great normative significance. There is, however, much disagreement concerning both the definition and the extension of such terms. This is significant because different terms and definitions are associated with different sets of normative requirements. In what follows we reconstruct the argument of each of the articles, and then offer some brief critical analysis intended to stimulate further thought about and discussion of the issues that each raises. (shrink)

Background Speech understanding may rely not only on auditory, but also on visual information. Non-invasive functional neuroimaging techniques can expose the neural processes underlying the integration of multisensory processes required for speech understanding in humans. Nevertheless, noise (from fMRI) limits the usefulness in auditory experiments, and electromagnetic artefacts caused by electronic implants worn by subjects can severely distort the scans (EEG, fMRI). Therefore, we assessed audio-visual activation of temporal cortex with a silent, optical neuroimaging technique: functional near-infrared spectroscopy (fNIRS). Methods (...) We studied temporal cortical activation as represented by concentration changes of oxy- and deoxy-hemoglobin in four, easy-to-apply fNIRS optical channels of 33 normal-hearing adult subjects and 5 post-lingually deaf cochlear implant (CI) users in response to supra-threshold unisensory auditory and visual, as well as to congruent auditory-visual speech stimuli. Results Activation effects were not visible from single fNIRS channels. However, by discounting physiological noise through reference channel subtraction, auditory, visual and audiovisual speech stimuli evoked concentration changes for all sensory modalities in both cohorts (p<0.001). Auditory stimulation evoked larger concentration changes than visual stimuli (p<0.001). A saturation effect was observed for the audiovisual condition. Conclusions Physiological, systemic noise can be removed from fNIRS signals by reference channel subtraction. The observed multisensory enhancement of an auditory cortical channel can be plausibly described by a simple addition of the auditory and visual signals with saturation. (shrink)

Patients fit with cochlear implants commonly indicate at the time of device fitting and for some time after, that the speech signal sounds abnormal. A high pitch or timbre is one component of the abnormal percept. In this project, our aim was to determine whether a number of years of CI use reduced perceived upshifts in frequency spectrum and/or voice fundamental frequency. The participants were five individuals who were deaf in one ear and who had normal hearing in the other (...) ear. The deafened ears had been implanted with a 18.5 mm electrode array which resulted in signal input frequencies being directed to locations in the spiral ganglion that were between one and two octaves higher than the input frequencies. The patients judged the similarity of a clean signal presented to their implanted ear and candidate, implant-like, signals presented to their normal-hearing ear. Matches to implant sound quality were obtained, on average, at 8 months after device activation and at 35 months after activation. At Time 1, the matches to CI sound quality were characterized, most generally, by upshifts in the frequency spectrum and in voice pitch. At Time 2, for four of the five patients, frequency spectrum values remained elevated. For all five patients F0 values remained elevated. Overall, the data offer little support for the proposition that, for patients fit with shorter electrode arrays, cortical plasticity nudges the cortical representation of the CI voice toward more normal, or less upshifted, frequency values between 8 and 35 months after device activation. Cortical plasticity may be limited when there are large differences between frequencies in the input signal and the locations in the SG stimulated by those frequencies. (shrink)

It has been argued by some authors that our reaction to deaf parents who choose deafness for their children ought to be compassion, not condemnation. Although I agree with the reasoning proposed I suggest that this practice could be regarded as unethical. In this article, I shall use the term “dysgenic” as a culturally imposed genetic selection not to achieve any improvement of the human person but to select genetic traits that are commonly accepted as a disabling condition by (...) the majority of the social matrix; in short as a handicap. As in eugenics, dysgenics can be achieved in a positive and a negative way. Positive dysgenics intends to increase the overall number of people with a particular genetic trait. Marriage between deaf people or conceiving deaf children through reproductive technology are examples of positive dysgenics. Negative dysgenics can be obtained through careful prenatal or pre-implantation selection and abortion (or discarding) of normal embryos and foetuses. Only deaf children would be allowed to live. If dysgenics is seen as a programmed genetic intervention that undesirably shapes the human condition – like deliberately creating deaf or dwarf people – the professionals involved in reproductive technologies should answer the question if this should be an accepted ethical practice because the basic human right to an open future is violated. (shrink)

We should react to deaf parents who choose to have a deaf child with compassion not condemnationThere has been a great deal of discussion during the past few years of the potential biotechnology offers to us to choose to have only perfect babies, and of the implications that might have, for instance for the disabled. What few people foresaw is that these same technologies could be deliberately used to ensure that children would be born with disabilities. That this is a (...) real possibility, and not merely the thought experiment of a philosopher, is brought home to us by the decision of an American lesbian couple to select a deaf sperm donor in order to maximise the chances that their children, Jehanne and Gauvin, would be deaf like them.1 Their choice has sparked controversy, not only among medical ethicists, but in the opinion pages of newspapers across the world. Ought parents be permitted to make such choices?If the parents of Jehanne and Gauvin have done anything wrong, it must consist in violating their child’s right to an open future—limiting its future potential for choice.2 But what does it mean to respect this right?From the moment a child is born, her parents are making choices for her, which will powerfully shape her future. They will decide what kind of education she will have, what religious experiences, from among what group she can select friends. Thereby, they profoundly mould the person she will be and the life she will have.When this activity is carried out within certain, ill-defined, limits, it is in no way objectionable. It is not merely a …. (shrink)

The cochlear implant controversy involves questions about the nature of disability and the definition of “normal” bodies; it also raises arguments about the nature and significance of culture and the rights of minority cultures. I defend the claim that there might be such a thing as “Deaf culture” and then examine how two different understandings of the role of culture in the lives of individuals can lead to different conclusions about the rights of Deaf parents in relation to their children, (...) and about the ethics of public funding for research on cochlear implants. An argument asserting the rights of minority cultures to equal respect and consideration within a multicultural society, informed by communitarian political philosophy, offers the best prospect for the defence of the unique culture(s) of the Deaf. (shrink)