Nutrition education tools used in phenylketonuria: clinician, parent and patient perspectives from three international surveys.

BACKGROUND: Three international surveys were developed aiming to identify the current nutrition educational tools used in the management of phenylketonuria (PKU) and the perceived effectiveness of these tools by clinicians, parents and patients. METHODS: The first two surveys were distributed through the Metabolic Dietitians ListServe (pno-metabl@listserv.cc.emory.edu), and the third survey was distributed by international clinics and the National PKU Alliance website (www.npkua.org). A total of 888 responses (S1, n = 88; S2, n = 81; S3, n = 719) were collected from all three surveys. The surveys represent participants from 17 countries, in Europe; North America (USA and Canada); Mexico; Argentina; Turkey; Australia; and Africa (Tunisia). RESULTS: A consistent decline in 'parents as role models' as an educational tool was observed starting at age 10 years. Patients responded they feel their families are the most effective form of education, whereas handouts were selected as the least effective educational tool by patients. Parents responded they feel the most effective educational tool is one-on-one counselling. Patients and parents show a desirable trend in wanting to attend group clinic, even in centres where this type of educational tool is not offered. CONCLUSIONS: There was a discrepancy between clinicians and patient views regarding the perceived effectiveness of the nutrition education tools. Future research is needed surrounding the impact nutrition education may have on improved dietary compliance in patients with PKU.

Enhanced speechreading in deaf adults: can short-term training/practice close the gap for hearing adults?

This study investigated effects of short-term training/practice on group and individual differences in deaf and hearing speechreaders. In two experiments, participants speechread sentences with feedback during training and without feedback during testing, alternating 10 times over six sessions spanning up to 5 weeks. Testing used sentence sets balanced for expected mean performance. In each experiment, participants were adults who reported good speechreading and either normal hearing (n = 8) or severe to profound hearing impairments (n = 8). The experiments were replicates, except that in one participants received vibrotactile speech stimuli in addition to visible speech during training, testing whether vibrotactile speech enhances speechreading learning. Results showed that (a) training/practice did not alter the relative performance among individuals or groups; (b) significant learning occurred when training and testing were conducted with speechreading only (although the magnitude of the effect was small); and (c) there was evidence that the vibrotactile training depressed rather than raised speechreading scores over the training period.

Is subjective word familiarity a meter of ambient language? A natural experiment on effects of perceptual experience.

The present study examined the sensitivity of a subjective familiarity measure to differences in word exposure within and between populations that differ dramatically in their perceptual experience. Descriptive measures of language ability and subjective familiarity ratings for 450 words were collected from a group of college-educated adults with normal hearing and a group of college-educated deaf adults. The results demonstrate the sensitivity of subjective familiarity ratings to both between- and within-group differences in word experience. Specifically, the deaf participants consistently rated words as less familiar than did hearing participants. Furthermore, item-level correlations within a participant group were higher than ones between groups. Within groups, mean familiarity ratings were correlated with descriptive measures of language ability. The results are discussed in relation to a simple sampling model of word experience and the language experience of the participant groups.

Speech perception without hearing.

In this study of visual phonetic speech perception without accompanying auditory speech stimuli, adults with normal hearing (NH; n = 96) and with severely to profoundly impaired hearing (IH; n = 72) identified consonant-vowel (CV) nonsense syllables and words in isolation and in sentences. The measures of phonetic perception were the proportion of phonemes correct and the proportion of transmitted feature information for CVs, the proportion of phonemes correct for words, and the proportion of phonemes correct and the amount of phoneme substitution entropy for sentences. The results demonstrated greater sensitivity to phonetic information in the IH group. Transmitted feature information was related to isolated word scores for the IH group, but not for the NH group. Phoneme errors in sentences were more systematic in the IH than in the NH group. Individual differences in phonetic perception for CVs were more highly associated with word and sentence performance for the IH than for the NH group. The results suggest that the necessity to perceive speech without hearing can be associated with enhanced visual phonetic perception in some individuals.

Potential perceptual bases for successful use of a vibrotactile speech perception aid.

This paper examines the possibility that perception of vibrotactile speech stimuli is enhanced in adults with early and life-long use of hearing aids. We present evidence that vibrotactile aid benefit in adults is directly related to the age at which the hearing aid was fitted and the duration of its use. The stimulus mechanism responsible for this effect is hypothesized to be long-term vibrotactile stimulation by high powered hearing aids. We speculate on possible mechanisms for enhanced vibrotactile speech perception as the result of hearing aid use: (1) long-term experience receiving degraded or improverished speech stimuli results in a speech processing system that is more effective for novel stimuli, independent of perceptual modality; and/or (2) long-term sensory/perceptual experience causes neural changes that result in more effective delivery of speech information via somatosensory pathways.

Amplitude and period discrimination of haptic stimuli.

As part of a project to examine the ability of the hand to receive speech information, the present study examined subjects' ability to discriminate finger movements along the dimensions of amplitude and period (movement duration). The movements consisted of single-cycle, sinewave movements and single-cycle, cosine movements presented to the index finger. Difference thresholds were collected using an adaptive, two-interval, temporal forced-choice procedure. Amplitudes from 6 to 19 mm were examined, and the difference thresholds ranged from 10% to 18%. The thresholds were unaffected by the period of the movement. Periods from 3000 to 111 ms (0.33-9 Hz) were examined, and thresholds ranged from 6% to 16%. The thresholds were unaffected by the amplitude of the movement. Further measurements in which period was varied in the amplitude discrimination task and amplitude was varied in the period discrimination task indicated that subjects were not using peak velocity as the basis for discrimination. These measurements were collected using a display specifically designed for the examination of haptic stimulation and capable of presenting controlled patterns of movement and vibration to the fingers.

Temporal and spatio-temporal vibrotactile displays for voice fundamental frequency: an initial evaluation of a new vibrotactile speech perception aid with normal-hearing and hearing-impaired individuals.

Four experiments were performed to evaluate a new wearable vibrotactile speech perception aid that extracts fundamental frequency (F0) and displays the extracted F0 as a single-channel temporal or an eight-channel spatio-temporal stimulus. Specifically, we investigated the perception of intonation (i.e., question versus statement) and emphatic stress (i.e., stress on the first, second, or third word) under Visual-Alone (VA), Visual-Tactile (VT), and Tactile-Alone (TA) conditions and compared performance using the temporal and spatio-temporal vibrotactile display. Subjects were adults with normal hearing in experiments I-III and adults with severe to profound hearing impairments in experiment IV. Both versions of the vibrotactile speech perception aid successfully conveyed intonation. Vibrotactile stress information was successfully conveyed, but vibrotactile stress information did not enhance performance in VT conditions beyond performance in VA conditions. In experiment III, which involved only intonation identification, a reliable advantage for the spatio-temporal display was obtained. Differences between subject groups were obtained for intonation identification, with more accurate VT performance by those with normal hearing. Possible effects of long-term hearing status are discussed.

Relationships between subjective ratings and objective measures of performance in speechreading sentences.

Ninety-six participants with normal hearing and 63 with severe-to-profound hearing impairment viewed 100 CID Sentences (Davis & Silverman, 1970) and 100 B-E Sentences (Bernstein & Eberhardt, 1986b). Objective measures included words correct, phonemes correct, and visual-phonetic distance between the stimulus and response. Subjective ratings were made on a 7-point confidence scale. Magnitude of validity coefficients ranged from .34 to .76 across materials, measures, and groups. Participants with hearing impairment had higher levels of objective performance, higher subjective ratings, and higher validity coefficients, although there were large individual differences. Regression analyses revealed that subjective ratings are predictable from stimulus length, response length, and objective performance. The ability of speechreaders to make valid performance evaluations was interpreted in terms of contemporary word recognition models.

Speechreading and the structure of the lexicon: computationally modeling the effects of reduced phonetic distinctiveness on lexical uniqueness.

A lexical modeling methodology was employed to examine how the distribution of phonemic patterns in the lexicon constrains lexical equivalence under conditions of reduced phonetic distinctiveness experienced by speech-readers. The technique involved (1) selection of a phonemically transcribed machine-readable lexical database, (2) definition of transcription rules based on measures of phonetic similarity, (3) application of the transcription rules to a lexical database and formation of lexical equivalence classes, and (4) computation of three metrics to examine the transcribed lexicon. The metric percent words unique demonstrated that the distribution of words in the language substantially preserves lexical uniqueness across a wide range in the number of potentially available phonemic distinctions. Expected class size demonstrated that if at least 12 phonemic equivalence classes were available, any given word would be highly similar to only a few other words. Percent information extracted (PIE) [D. Carter, Comput. Speech Lang. 2, 1-11 (1987)] provided evidence that high-frequency words tend not to reside in the same lexical equivalence classes as other high-frequency words. The steepness of the functions obtained for each metric shows that small increments in the number of visually perceptible phonemic distinctions can result in substantial changes in lexical uniqueness.

Generalizability of speechreading performance on nonsense syllables, words, and sentences: subjects with normal hearing.

Ninety-six adults with normal hearing viewed three types of recorded speechreading materials (consonant-vowel nonsense syllables, isolated words, and sentences) on 2 days. Responses to nonsense syllables were scored for syllables correct and syllable groups correct; responses to words and sentences were scored in terms of words correct, phonemes correct, and an estimate of visual distance between the stimulus and the response. Generalizability analysis was used to quantify sources of variability in performance. Subjects and test items were important sources of variability for all three types of materials; effects of talker and day of testing varied but were comparatively small. For each type of material, alternative models of test construction and test-score interpretation were evaluated through estimation of generalizability coefficients as a function of test length. Performance on nonsense syllables correlated about .50 with both word and sentence measures, whereas correlations between words and sentences typically exceeded .80.

Immune status of children with phenylketonuria.

OBJECTIVE: To determine the effect of differences in plasma phenylalanine (Phe) concentrations (< 363 umol/L, 363 to 605 umol/L, and > 605 umol/L) on hematological and immunological parameters in 22 children with phenylketonuria (PKU). METHODS: Children with PKU were divided into one of three groups based on fasting plasma Phe levels. Hematologic and immunologic parameters of the children with PKU were compared between the groups and also compared with published values from age-matched children without PKU. RESULTS: Hematologic and immunologic parameters did not differ among children with different plasma Phe concentrations. Specifically, no significant differences between groups of PKU children with differing plasma Phe levels were found for plasma levels of albumin, hemoglobin, amino acids, IgM, complement C3, interleukins 1 and 2, erythrocyte, leukocyte and differential cell counts, hematocrit, percentages and numbers of CD4+, CD8+, CD3+ and total lymphocytes, or CD4 to CD8 ratio. Mean plasma IgG and IgA concentrations of the PKU children were, however, significantly lower than values from similar aged children. Moreover, positive correlations were obtained between plasma albumin and percentages and numbers of CD3+ and CD4+, between plasma IgG and interleukins 1 and 2, and between intakes of energy, protein, iron and plasma IgG levels. No correlations were found between plasma Phe and immunological parameters. CONCLUSION: While differences in plasma Phe concentrations up to concentrations of 866 umol/L do not appear to affect selected immune system parameters, further studies are needed to investigate the relationship between dietary nutrient intake, nutritional status, antibody biosynthesis and cytokine production. Assessment of plasma and cell membrane lipids and trace mineral status of PKU children would be helpful to determine if relationships exist between these nutrients and antibody production.

A computational approach to analyzing sentential speech perception: phoneme-to-phoneme stimulus-response alignment.

A solution to the following problem is presented: Obtain a principled approach to studying error patterns in sentence-length responses obtained from subjects who were instructed to simply report what a talker had said. The solution is a sequence comparator that performs phoneme-to-phoneme alignment on transcribed stimulus and response sentences. Data for developing and testing the sequence comparator were obtained from 139 normal-hearing subjects who lipread (speechread) 100 sentences and from 15 different subjects who identified nonsense syllables by lipreading. Development of the sequence comparator involved testing two different costs metrics (visemes versus Euclidean distances) and two related comparison algorithms. After alignments with face validity were achieved, a validation experiment was conducted for which measures from random versus true stimulus-response sentence pairs were compared. Measures of phonemes correct and substitution uncertainty were found to be sensitive to the nature of the sentence pairs. In particular, correct phoneme matches were extremely rare in random pairings in comparison with true pairs. Also, an information-theoretic measure of uncertainty for substitutions in true versus random pairings showed that uncertainty was always higher for random than for true pairs.

Vocal communication in the first 18 months of life.

Fifty-one normally developing infants aged birth to 18 months, 10 or 11 in each of five age groups, were videorecorded in their homes before and after an expected change in the form of their vocalizations and under a set of conditions that reflected common daily occurrences. The vocalizations produced were coded according to their communicative contexts, defined in nonvocal behavioral terms. Communicative codes were assigned to seven major categories. The distribution of codes across categories was found to be different for different age groups. It varied between the first and second observations; however, the pattern of change differed across age groups. Data from individuals were transformed to proportions, to control for individual differences in productivity. They were then found to reflect differences in level of development of vocal communication. It was concluded that vocal communication follows an orderly developmental sequence in normally developing infants in the first 18 months of life.

Sources of variability in speechreading sentences: a generalizability analysis.

Generalizability theory (Cronbach, Gleser, Nanda, & Rajaratnam, 1972) was used to estimate the percentage of variance explained by three sources of variability in speechreading sentences: the subject, the talker, and the sentence materials. Videodisc recordings of the 100 CID Everyday Sentences (Davis & Silverman, 1970), spoken by a male and a female talker, were presented to 104 subjects with normal hearing. For performance on individual sentences (total number of words correct), the most important systematic sources of variability were the sentence (26.3%), the speechreader (10.5%), the talker (4.9%), and the interaction of talker and sentence (5.1%). Residual error accounted for 51.2% of the variance. Generalizability functions are presented, as a function of test length, for five models of test administration and interpretation. For 10-, 50-, and 100-item lists, generalizability is predicted to be .70, .92, and .96, respectively, for a single talker. Psychometric characteristics of these recordings of the CID sentences are also presented.

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.

Speechreading sentences with single-channel vibrotactile presentation of voice fundamental frequency.

The main goal of this study was to investigate the efficacy of four vibrotactile speechreading supplements. Three supplements provided single-channel encodings of fundamental frequency (F0). Two encodings involved scaling and shifting glottal pulses to pulse rate ranges suited to tactual sensing capabilities; the third transformed F0 to differential amplitude of two fixed-frequency sinewaves. The fourth supplement added to one of the F0 encodings a second vibrator indicating high-frequency speech energy. A second goal was to develop improved methods for experimental control. Therefore, a sentence corpus was recorded on videodisc using two talkers whose speech was captured by video, microphone, and electroglottograph. Other experimental control issues included use of visual-alone control subjects, a multiple-baseline, single-subject design replicated for each of 15 normal-hearing subjects, sentence and syllable pre- and post-tests balanced for difficulty, and a speechreading screening test for subject selection. Across 17 h of treatment and 5 h of visual-alone baseline testing, each subject performed open-set sentence identification. Covariance analyses showed that the single-channel supplements provided a small but significant benefit, whereas the two-channel supplement was not effective. All subjects improved in visual-alone speechreading and maintained individual differences across the experiment. Vibrotactile benefit did not depend on speechreading ability.

Characterization of a dermal derived malignant mesenchymal tumor arising in ultraviolet irradiated mice.

Skh/hr-1 hairless albino mice were irradiated with photocarcinogenic dosages of ultraviolet light for periods of 30 weeks or longer. A high proportion of mice developed pleomorphic spindle cell tumors and epidermal neoplasms of various types. These spindle cell tumors were studied by immunofluorescence and immunoperoxidase techniques and by electron microscopy. Freshly isolated tumor cells were grown in tissue culture. Immunocytochemical analysis showed varying expression of markers of mesenchymal differentiation: vimentin, procollagens I and III, type I collagen, and lysozyme. Electron microscopy showed spindled and cuboidal cells with abundant endoplasmic reticulum, filopodia, and lysosomes, but no intercellular connections. The cells grown in vitro were cuboidal and stellate and also showed mesenchymal differentiation by electron microscopy. These results are perhaps similar to those described for a human actinically produced fibrohistiocytic neoplasm, atypical fibroxanthoma, and this system may provide a useful model of ultraviolet-induced dermal neoplasia.

Single-channel vibrotactile supplements to visual perception of intonation and stress.

Two experiments were conducted to explore the effectiveness of a single vibrotactile stimulator to convey intonation (question versus statement) and contrastive stress (on one of the first three words of four 4- or 5-word sentences). In experiment I, artificially deafened normal-hearing subjects judged stress and intonation in counterbalanced visual-alone and visual-tactile conditions. Six voice fundamental frequency-to-tactile transformations were tested. Two sentence types were voiced throughout, and two contained unvoiced consonants. Benefits to speechreading were significant, but small. No differences among transformations were observed. In experiment II, only the tactile stimuli were presented. Significant differences emerged among the transformations, with larger differences for intonation than for stress judgments. Surprisingly, tactile-alone intonation identification was more accurate than visual-tactile for several transformations.

Speech training aids for hearing-impaired individuals: I. Overview and aims.

Prelingual profound deafness typically results in aberrant or unintelligible speech production. For approximately 70 years, researchers and engineers have attempted, with little success, to provide electronic aids for speech training. Recent computer and signal processing technology has provided the impetus for several groups to implement new speech training aids. Following a review of deaf speech characteristics, several current computer-based aids are described. Included among those reviewed are two interrelated speech training aids which resulted from collaboration among the authors.