Mark E. Lehman

Factors influencing ratings of speech naturalness in augmentative and alternative communication

The concept of speech naturalness has been used in the field of speech-language pathology as a clinical measure of perceptual quality of “normal” and “not normal” speech. Whereas measures of intelligibility have been commonly used to assess the quality of voice output augmentative and alternative communication (AAC) devices using DECTalk™ speech, measures of speech naturalness have not. Three studies were conducted to determine the effects of manipulation of rate, pitch, and pause on ratings of speech naturalness by naive listeners of DECTalk synthetic speech. The results indicate that DECTalk speech characterized by faster rate and no added pauses was perceived as being more natural than speech with slow rate and added pauses. Manipulation of pitch had no effect on naturalness ratings.

Shooting habits of U.S. waterfowl hunters

Exposure to high-intensity impulse noise from the recreational use of firearms is a common cause of noise-induced hearing loss (NIHL). Although recreational firearm users who shoot firearms without proper hearing protection are at risk for NIHL, a specific subgroup involved in hunting waterfowl may also be at risk due to their particular shooting habits. The goal of the present study was to investigate the shooting habits of this particular group of U.S. recreational firearm users. A 23-item written survey was sent to waterfowl hunting club members regarding their shooting behaviors, use of hearing protective devices (HPDs), and auditory status. Results indicated that waterfowl hunters in this study typically used large bore semiautomatic shotguns, did not consistently utilize HPDs during target practice or hunting and were exposed to multiple, unprotected shots during the past waterfowl season. Most subjects reported hunting in reverberant acoustic environments (hunting blinds). This group of recreational firearm users also reported high incidences of hearing loss and tinnitus. Information provided by this study may help hearing conservationists and hearing healthcare providers understand and better educate these shooters regarding the risk of acquiring NIHL.

Electropalatographic and spectrographic descriptions of allophonic variants of /1/.

Prevocalic and postvocalic /l/ were investigated in three adult subjects utilizing a combination of electropalatographic and acoustic techniques. Results indicated that prevocalic /l/ was characterized by both alveolar and lateral lingua-palatal contact, while postvocalic /l/ was primarily alveolar contact only. Acoustically, prevocalic /l/ had a lower first formant and higher second formant than postvocalic /l/. In addition, the second and third formants were often weak or absent for prevocalic but not postvocalic /l/. Vowel context had a greater effect on the electropalatographic and acoustic characteristics of prevocalic than postvocalic /l/. Models that relate physiological and acoustical aspects of speech were utilized to account for the observed results.

EFFECTS OF PREPARATION TIME FOR TWO QUANTITATIVE MEASURES OF NARRATIVE PRODUCTION

Narratives are important for language assessment at the level of discourse. To investigate the effect of preparation time narratives were collected from 19 third graders, 19 eighth graders, and 19 college students. In one condition, all subjects saw a picture and told a story; in a second one they saw a picture and were instructed to wait for 1 min. before telling a story. Students also generated a story without a picture and with no instructions to wait. Measures of narrative length and mean length of communication unit were analyzed to assess the effects of preparation time. Narratives produced under the Instructions to Wait condition were longer and their mean length of communication unit was longer than narratives produced under the No Instructions to Wait condition, for all 3 age groups. Narratives generated without picture stimuli, however, were longer than those produced under either picture condition. Clinical implications for those who work with children with language and learning disabilities are discussed.

DEVELOPMENTAL DIFFERENCES IN VOWEL DURATION IN OPEN AND CLOSED SYLLABLES

Vowel duration in open and closed syllables was investigated in groups of ten normal 5-, 8-, and 10-year-old children, and adults. Productions of three syllables (bee, bead, beet), analyzed acoustically for vowel duration, indicated that for all age groups, mean vowel durations for “bee” and “bead” were significantly different from “beet” but were not different from each other. Developmental effects were noted in mean and variability of vowel duration. In addition, a context effect was observed, with adult-like values for both mean and variability obtained at an earlier age for “beet” than for “bee” and “bead.” These results suggest that both phonemic and phonetic factors are important in accounting for developmental changes in mean and variability of vowel duration.

Understanding the mechanisms underlying pulsating aerosol delivery to the maxillary sinus: In vitro tests and computational simulations

BACKGROUND Pulsating aerosol delivery has been demonstrated in depositing medications into paranasal sinuses. However, its mechanisms are not fully understood. Influences of the nasal anatomy and sound frequency on intrasinus delivery are not yet clear. OBJECTIVES This study aimed to gain a better understanding of the mechanisms for enhanced intrasinus delivery with pulsating sound. Specifically, effects of the pulsation frequency, ostium size, and sinus shape on the intrasinus dosage and resonance frequency would be examined. METHODS AND MATERIALS Both experiments and computational modeling were conducted to understand the pulsating aerosol delivery in both idealized (two-bottle) and realistic nose-sinus models. A computational model of intrasinus pulsation delivery was developed using COMSOL and was cross-validated with both experimental and theoretical results. RESULTS In contrast to previous studies, seemingly erratic relations between the intrasinus dosage and ostium diameter were observed in experiments, which suggested a more complicated particle transport mechanism. Improved agreement was achieved when grouping the ostium size and sinus volume into the resonance frequency, and therefore, validated the hypothesis that intrasinus deposition strongly depends on the resonance frequency. Extensive computational simulations revealed that the deposition was highest at the resonance frequency and decreased gradually at off-resonance frequencies. The resonance frequency depended on the ostium and sinus morphology, but was independent of the nasal cavity. CONCLUSION Results of this study verified the hypothesis of resonance being the mechanism for enhanced particle deposition in the maxillary sinus. A better knowledge of the relationship between sinus dosages, pulsating frequency, and nasal morphometry is essential for improving the design of intrasinus delivery devices.

Use of TimeSlips to Improve Communication in Persons with Moderate–Late Stage Dementia

There is currently a lack of published research on the effectiveness of a creative expression (CE) program known as TimeSlips (TS), which has the goal of improving quality of life and social connectedness for individuals in the mid to late stages of dementia. This study focused on measuring the impact of TS on the frequency and type of communicative exchanges and the relationship to social connectedness. A quasi-experimental design was conducted in a single long-term care facility with seven participants in the mid to late stages of dementia. A time-series analysis was used to assess change in communicative output and interactions. Positive communication changes in addition to maintained or improved quality of life were observed. Implementing a creative expression program such as TS for those in the middle to late stages of dementia improves social connectedness and communicative interactions.

Metrics for Comparing Three Word-Based Software Programs Used for Augmentative and Alternative Communication

The purpose of this investigation was to conduct an analysis of a set of metrics developed for comparing features of software used in speech generating devices (SGD) for augmentative and alternative communication (AAC). These metrics – measures of speed, efficiency, and accuracy – were employed during a sentence reconstruction task. Twenty two participants without disabilities reconstructed nine sentences using each of three SGD software programs, counterbalanced to remove order effects. Results revealed differences in the metrics across the software programs that were supported by a social validation survey completed by the participants. These results provide benchmark data about relative speed, accuracy, and efficiency of these software programs in structured use, and can inform professionals in matching potential AAC users with specific features of word-based software.