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Biomedical subjects

S L Hamlet

Publications and source records attributed to S L Hamlet.

32 records · Page 2Linked to original sources
PubMed1980

Ultrasonic measurement of larynx height and vocal fold vibratory pattern.

This paper describes the modification and extension of an ultrasonic through-transmission technique for examining vocal fold activity. The purpose was to achieve improved lateral resolution in the cranio-caudal dimension. A transducer was specially designed to produce an eliptical beam, so that a measurable signal might be received through the extreme upper and lower edges of the vibrating vocal folds. An interpretation of amplitude variation within the ultrasonic waveform is offered, with illustrative data shown for a single subject.

Humans↗
PubMed1979

Physiological control of sibilant duration: insights afforded by speech compensation to dental prostheses.

Temporal relationships among tongue contact, phonation, and presence of frication were examined for /s/ and /z/. In cases where /s/ and /z/ were produced with a supraglottal articulation of the same duration, the duration of the resulting frication was 17 ms longer for /s/. The difference can be attributed to glottal activity. The presence of a unfamiliar dental prosthesis in the mouth caused the tongue to contact the alveolar ridge sooner and release later. This physiological effect was reflected in lengthening of frication for sibilants, but the acoustical consequences were greater and more reliable for /z/ than for /s/. Reasons for this difference were sought in adaptation of timing of tongue contact, and in aerodynamic conditions expected for voiced versus voiceless sibilants. A rapid adaptation of tongue contact timing was found, with the adaptation being greater for /s/. Timing of vocal fold adduction at the end of unvoiced sibilants, and its aerodynamic consequences, are suggested to consequences, are suggested to contribute to the relative stability of /s/ acoustical durations.

Adaptation, Physiological↗
PubMed1976

Effect of a dental prosthesis on speaker-specific characteristics of voice.

Subjects were fitted with an experimental dental appliance which had the effect of lowering and retracting the alveolar-palatal contour. Recordings of subjects speaking without the prosthesis and with the prosthesis at two stages of speech adaptation were analyzed acoustically and by judgmental evaluation for the effect of the appliance in disguising the voice. Individual differences were found in the type and extent of sibilant anf vowel changes produced by wearing the prosthesis. Listeners made more errors on a speaker authentication task involving recordings obtained immediately after the unfamiliar prosthesis was placed in the mouth than on recordings made after a week of accomodation to the appliance, or recordings made a week apart when no prosthesis was worn.

Acoustics↗
PubMedDate not supplied

Tongue mobility in speech after partial glossectomy.

Recovery of tongue mobility in speech was investigated in 5 partial glossectomy patients. Jaw range of motion used in speech, and tongue contour changes relative to the jaw, were assessed using sequential videofluoroscopic data recorded presurgery, postsurgery, and postradiotherapy. Data from 2 normal controls were included for comparison. Tongue mobility relative to the jaw was found to be restricted postsurgery. Approximately 4 months later, following radiotherapy, tongue mobility increased. Range of jaw motion used in speech was unchanged. Results are interpreted as preliminary evidence that in this small group of cancer patients, radiotherapy following surgery did not prevent continued recovery of tongue function for speech in the early postradiation period.

Adult↗
PubMedDate not supplied

Objective assessment of swallowing function in head and neck cancer patients.

Swallowing function was evaluated with scintigraphy in 37 patients with head and neck cancer. The patients were examined before and during the course of either surgery, chemotherapy, and/or radiotherapy. A total of 118 scintigraphic studies were performed. Scintigraphic results of bolus flow and aspiration were correlated with clinical findings. Both scintigraphic and clinical studies indicated a worsened swallowing function in 12 patients. These same studies indicated improvement of swallowing in another 13 patients. In 11 patients, both studies revealed either no apparent change or mixed changes in swallowing function after the course of therapy. In only 1 patient was there disagreement between the scintigraphic and clinical assessment of swallowing function. It is our opinion that scintigraphy is a useful method for objective assessment of swallowing function during and after the course of treatment of head and neck cancer patients.

Aged↗
PubMedDate not supplied

Swallowing of bolus types by postsurgical head and neck cancer patients.

BACKGROUND: Clinically, head and neck cancer patients with anterior resections have better postoperative outcomes than do patients with posterior resections. METHODS: Videofluoroscopy was used to study the swallowing characteristics in postsurgery head and neck cancer patients and normal controls. Most patients received post-operative radiotherapy and chemotherapy, and no cancer recurrence was noted at the time of study, 4-8 months posttreatment. Bolus types included: 3 mL and 10 mL liquid barium, barium paste, and barium-coated cookie. Temporal measurements and a count of the number of swallows required to ingest each material were made from the videotaped data. Statistical analysis using an unbalanced univariate repeated measures ANOVA was performed. RESULTS: The major differences were found between bolus types, with few differences noted between surgical groups (anterior vs posterior resections) and normal controls. Patients took longer to ingest viscous material, accomplishing this by multiple piecemeal and clearing swallows. Coordination of mastication and swallowing of the cookie was different between normal and patient groups. CONCLUSIONS: Patients who are able to swallow reasonably well postoperatively maintain normal coordination and timing of swallowing activity and do not vary these parameters to compensate for structural inadequacy. Instead, repeated swallows are used.

Adult↗
PubMedDate not supplied

Elicitation of the acoustic reflex with synthetically produced consonant and vowel stimuli.

Acoustic reflexes were elicited from seven normal hearing subjects with synthesized isolated consonant and vowel speech stimuli. Stimulus intensity and duration were controlled so that equivalent amplitudes and durations from 100 to 300 msec were produced. The recorded stimulus items were presented over an earphone to the subject's right ear, while susceptance changes caused by bilateral acoustic reflex activity were monitored in the subject's left ear. Analysis of variance revealed no significant difference between reflex threshold values for isolated synthetic consonant and vowel stimuli. Main effects of stimulus duration and subjects and the two-way interaction of phoneme type by subject were found to be significant.

Acoustic Impedance Tests↗