Robert E. Hillman

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Measurements on the inverse filtered airflow waveform (the "glottal waveform") and of estimated average transglottal pressure and glottal airflow were made from noninvasive recordings of productions of syllable sequences in soft, normal, and loud voice for 25 male and 20 female speakers. Statistical analyses showed that with change from normal to loud(More)
This report describes the experimental design and initial results of an ongoing clinical investigation of voice disorders. Its major focus is the development and use of quantitative measures to provide objective descriptions of conditions referred to as "vocal hyperfunction." The experimental design for this project is based on a descriptive theoretical(More)
The quantity, harmonic-to-noise ratio (HNR), has been used to estimate the level of noise in human voice signals. HNR estimation can be accomplished in two ways: (1) on a time-domain basis, in which HNR is computed directly from the acoustic waveform; and (2) on a frequency-domain basis, in which HNR is computed from a transformed representation of the(More)
High-speed videoendoscopy (HSV) captures the true intracycle vibratory behavior of the vocal folds, which allows for overcoming the limitations of videostroboscopy for more accurate objective quantification methods. However, the commercial HSV systems have not gained widespread clinical adoption because of remaining technical and methodological limitations(More)
This two-part investigation assessed functional outcomes related to communication (including amount of speech therapy), swallowing and eating, and employment status for patients who received one of the two treatment modalities for advanced laryngeal cancer (stage III or IV laryngeal squamous cell carcinoma) in Veterans Administration Cooperative Study #268.(More)
We report four patients with methylmalonic acidemia who developed acute extrapyramidal disease after metabolic decompensation. The neurologic findings resulted from bilateral destruction of the globus pallidus with variable involvement of the internal capsules. This complication was unrelated to a specific gene defect responsible for methylmalonic acidemia(More)
Children with phenylketonuria (PKU) obtain a great deal of their protein and mineral intakes from synthetic elemental formulae devoid of phenylalanine. To assess the effect of such diets and/or the disease on bone mineralization, children with PKU were compared to normal children for many parameters of mineral homeostasis and bone mineralization. A total of(More)
This study examines measures of the glottal airflow waveform, the electroglottographic signal (EGG), amplitude differences between peaks in the acoustic spectrum, and observations of the spectral energy content of the third formant (F3), in terms of how they relate to one another. Twenty females with normal voices served as subjects. Both group and(More)
The electrolarynx (EL) voice prosthesis is widely used, but suffers from the inconvenience of requiring manual control. Therefore, a hands-free EL triggered by neck muscle electromyographic (EMG) activity was developed (EMG-EL). Signal processing circuitry in a belt-mounted control unit transforms EMG activity into control signals for initiation and(More)
OBJECTIVES Recently developed systems for ambulatory monitoring of voice use employ miniature accelerometers placed at the base of the anterior neck to sense phonation. As it is hoped that such systems will help improve the clinical assessment and management of voice disorders, this study was undertaken to determine the impact of dysphonia severity on the(More)