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Biomedical subjects

K D Hall

Publications and source records attributed to K D Hall.

18 recordsLinked to original sources

A longitudinal investigation of speaking rate in preschool children who stutter.

Both clinical and theoretical interest in stuttering as a disorder of speech motor control has led to numerous investigations of speaking rate in people who stutter. The majority of these studies, however, has been conducted with adult and school-age groups. Most studies of preschoolers have included older children. Despite the ongoing theoretical and clinical focus on speaking rate in young children who stutter and their parents, no longitudinal or cross-sectional studies have been conducted to answer questions about the possible developmental link between stuttering and the rate of speech, or about differences in rate development between preschool children who stutter and normally fluent children. This investigation compared changes in articulatory rate over a period of 2 years in subgroups of preschool-age children who stutter and normally fluent children. Within the group of stuttering children, comparisons also were made between those who exhibited persistent stuttering and those who eventually recovered without intervention. Furthermore, the study compared two metrics of articulatory rate. Spontaneous speech samples, collected longitudinally over a 2-year period, were analyzed acoustically to determine speaking rate measured in number of syllables and phones per second. Results indicated no differences among the 3 groups when articulation rate was measured in syllables per second. Using the phones per second measure, however, significant group differences were found when comparing the control group to the recovered and persistent groups.

Adult↗

Reversion to a previously learned foreign accent after stroke.

Foreign accent syndrome occurs rarely after stroke. Most patients with this syndrome develop an aphasia characterized by a new accent. This report presents a 48-year-old man who sustained a left parietal hemorrhagic stroke resulting in right hemiparesis and the inability to speak. As spontaneous speech emerged several weeks later, he was noted to have a Broca's aphasia and a Dutch accent. Analysis of his speech demonstrated final consonant deletion, substitution of "d" for "th" sounds, vowel distortions, additional "uh" syllables added at the end of words, and errors in voicing. This speech pattern has persisted for more than 5 years after the stroke. Elicitation of additional history found that the patient was born in Holland and lived there until the age of 5 years, when he moved to the United States with his family. Before his stroke, he had no foreign accent. This report illustrates the importance of considering foreign accent syndrome during aphasia recovery and suggests several pathogenetic mechanisms that may contribute to the development of this syndrome.

Brain↗

Comparison of fundamental frequency and perturbation measurements among three analysis systems.

The need for standardization of procedures in approaches to voice measurement has been recently emphasized. The purpose of this study was to determine the extent to which the acoustic perturbation measurements from three different analysis systems agree when standardized recording and analysis procedures are used. High-quality acoustic voice recordings from 20 patients were analyzed. The results showed that, although fundamental frequency measurements were in strong agreement among the three systems tested, frequency and amplitude perturbation measurements were not in agreement. The underlying approaches to perturbation measurement appeared to be sufficiently different to produce different results. An argument is made for a standardized set of acoustic signals representing normal, dysphonic, and synthesized voices with known characteristics to facilitate testing of new acoustic analysis systems and confirm measurement accuracy and sensitivity.

Adolescent↗

Variations across time in acoustic and electroglottographic measures of phonatory function in women with and without vocal nodules.

The purpose of this investigation was to identify variations over time in phonatory function of women with and without vocal nodules using acoustic and electroglottographic measures. Subjects were 10 women with vocal nodules (mean age = 22.1, range = 19-25) and 10 women with healthy larynges (mean age = 25.0, range = 18-32). Electroglottographic and audio recordings of speech were obtained for each subject over 3 consecutive days at three target times: morning, afternoon, and evening. Estimates of fundamental frequency (Hz), jitter (msec), shimmer (dB), and signal-to-noise ratio (dB) were made from a 1000 msec midportion of the vowel /a/ produced in a carrier phrase. In addition, a closed-to-open ratio was derived from the EGG duty cycle of the same 1000 msec segment and used to estimate timing characteristics of vocal fold vibration. The results showed no significant differences between the groups regarding a pattern of change in the acoustic or the EGG measures across times throughout the day. Furthermore, the experimental group demonstrated significantly lower closed-to-open ratios than the control group. With this exception, no other statistically significant differences between the groups were found.

Adolescent↗

Differential strength decline in patients with osteoarthritis of the knee: revision of a hypothesis.

A quadriceps-to-hamstring isometric peak torque ratio (Q/H ratio) of approximately 2.0 is considered necessary for appropriate knee biomechanics. Lower ratios may affect the function of persons with osteoarthritis (OA) and the progression of the disease. This study examined the isometric Q/H ratio in subjects with and without OA of the knee and explored the effect of age, pain, and joint enlargement on the ratio. Twenty-one pairs of subjects (OA, control) were matched on age (mean = 62.6 years; SD = 13.9), gender (F = 17, M = 4), and leg dominance (Dominant = 10, Nondominant = 11). Isometric quadriceps and hamstring peak torque, knee pain, and joint enlargement were measured. Paired t-tests demonstrated that the OA group had significantly lower quadriceps peak torque than the control group but did not have significantly lower hamstring peak torque or gravity-corrected isometric Q/H ratio. Age correlated with the ratio in subjects without OA (rho = -0.46; P = 0.03) but not in subjects with OA. Pain was not significantly correlated with the ratio in either group. Joint enlargement correlated with the ratio in the OA group (rho = -0.45; P = 0.03). The gravity-corrected isometric Q/H ratio appears to decrease with age in subjects without OA. In subjects with OA, the Q/H ratio appears not to change with disease, pain, or age. Joint enlargement may decrease the ratio and merits further study.

Age Factors↗

Temporal relations within repetitions of preschool children near the onset of stuttering: a preliminary report.

The purpose of this study was to compare duration characteristics of single repetitions of single-syllable words in the speech of preschool children who stutter (N = 15) recorded near the onset of their stuttering to those of control nonstuttering children (N = 18). Disfluent episodes were identified in audio tape recordings of the subjects' conversational speech. The digitized signals were analyzed by means of the CSpeech computer software (Milenkovic, 1987). Using visual displays of the sound-pressure waveforms, as well as spectrography, the durations of the first production of the word (1st Unit), the second production (2nd Unit), the silent interval, and the total disfluency were measured. There were no statistically significant differences between the two groups on any of these segments although there was a tendency for the stutters to exhibit shorter silent intervals between repeated units. Relative measures, however, indicated that the ratio of the 2nd Unit to the total disfluency was significantly larger for the stutterers than the controls. For both groups, the ratio of the 1st to the 2nd Unit was positive, that is, the first production of the word was longer than the second. There was also a tendency for the ratio of the silent interval to total disfluency to be smaller for the stutterers. Overall, there appears to be a tendency for repetitions of very early stutterers to be faster than repetitions of nonstuttering children.

Child, Preschool↗

Fundamental frequency, jitter, and shimmer in preschoolers who stutter.

This investigation examined acoustic correlates of phonatory control in the speech of 10 preschool-aged boys who were stutterers (mean age = 45 months) recorded relatively close to the time of stuttering onset and in the speech of 10 boys who were nonstutterers (mean age = 46 months). For each subject, acoustic measurements of fundamental frequency, jitter, and shimmer were extracted from the 100 msec midportion of 30 vowels selected from fluent utterances in spontaneous speech. Significant differences between the two groups for shimmer measures are among the few positive findings in recent publications concerning the fluent speech of children who stutter.

Child Language↗

Persistence of weight gain and hibernation onset in juvenile thirteen-lined ground squirrels (Spermophilus tridecemlineatus) in spite of long-term administration of naloxone.

Sexual differences in body weight of juvenile thirteen-lined ground squirrels (Spermophilus tridecemlineatus) were significant (P less than 0.05) at all weeks of age except weeks 0-4, 6, 7, 9, 20 and 24. Hibernation onset between sexes did not differ significantly. Naloxone administration did not alter weight gain nor onset of hibernation when compared to saline controls.

Animals↗

[Brain function and level of consciousness in fentanyl anesthesia in heart surgery].

The level of consciousness and the supply/demand ratio of oxygen in the brain was studied in anaesthetized patients undergoing open heart surgery. Anaesthesia was accomplished with intravenous fentanyl; 26 patients received 25 micrograms/kg and 24 patients received 50 micrograms/kg fentanyl. In addition only pancuronium bromide was administered for muscular relaxation; all patients were ventilated with 100% oxygen. The following measurements were made during induction and prior to cardiopulmonary bypass and in the first ten minutes of bypass: 1. EEG with the Klein EEG Analyzer. This instrument permits simultaneous analysis of frequency and amplitude while eliminating muscular artifacts. 2. Cerebral oxygen with the Niroscope. This instrument uses an infrared light beam through the brain to evaluate cerebral oxygen sufficiency. 3. Oxygen supply/demand ratio in the whole body, estimated from mixed venous oxygen saturation measured with a fiberoptic pulmonary artery catheter. Clinical unconsciousness occurred in all patients within about 30 s after the administration of fentanyl. Simultaneously the EEG showed a significant decrease in frequency and an increase in amplitude. With the Niroscope no change in oxygen supply and demand was seen in any patients. This is in contrast to previous studies with thiopental, where changes were seen. A slight increase in mixed venous oxygen saturation was observed. This indicates an increase in the total oxygen supply/demand ratio, probably due to decreased muscle metabolism induced by pancuronium bromide paralysis. From the end of induction until cardiopulmonary bypass a slight increase in cerebral electrical activity was observed; an additional increase occurred in the first ten minutes of bypass.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗