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Biomedical subjects

S L Hamlet

Publications and source records attributed to S L Hamlet.

At least 19 recordsLinked to original sources
PubMed1996

Scintigraphic quantification of aspiration reduction with the Passy-Muir valve.

The Passy-Muir "speaking" tracheostomy valve has been noted to aid in swallowing, based on videofluoroscopy to assess aspiration. In this study scintigraphy was used to quantify the amount of material aspirated. Eleven patients were studied who currently had a tracheostomy in place and were either known to aspirate or were suspected of aspirating. Most were post-treatment head and neck cancer patients who were tumor free at the time of testing. Swallowing was evaluated using videofluoroscopy and scintigraphy. Videofluoroscopy was performed to assess anatomy and determine whether aspiration had occurred. Scintigraphic testing was then performed when the patient had the one-way valve on, and again with it off and tracheostomy open. Following a swallow, the amount (%) of aspirate with the valve in place was found to be significantly less than with the tracheostomy open. A one-way valve can be helpful in reducing aspiration in patients who are at risk for aspiration and who require that their tracheostomy be open.

Humans↗
PubMed1994

Scintigraphic assessment of swallow efficiency postlaryngectomy.

There have been reports of a high incidence of hypopharyngeal stenosis in total laryngectomy patients when the surgery requires a partial pharyngectomy for pyriform sinus involvement. In this study, three groups were compared: total laryngectomy patients without partial pharyngectomy, total laryngectomy patients with partial pharyngectomy, and normal controls. All patients had received radiation therapy following surgery. All were maintaining oral nutrition, and none complained of dysphagia. Patients were tested between 1 and 7 months postradiation therapy, with a mean of 3 months. Measures of swallowing efficiency were based on scintigraphic data for a liquid swallow. Patients with partial pharyngectomy had abnormally long oropharyngeal transit times and low efficiency scores. For a subgroup of patients with partial pharyngectomy, swallowing data were available postsurgery and postradiation therapy. Postsurgery this patient group did not differ significantly from normal patients in swallowing efficiency, and swallowing efficiency deteriorated in postradiation therapy. This scintigraphic methodology is shown to be a sensitive method of assessing swallowing function in this patient population.

Adult↗
PubMed1992

Sounds of swallowing following total laryngectomy.

Accelerometer transduced sounds of swallowing in total laryngectomees did not show acoustical differences for liquid vs paste swallows, as are found in normals. Compared with normal swallows, tongue propulsion of the bolus in laryngectomee swallows occurred closer in time to a distinctive spectral change associated with bolus flow into the esophagus. Interpretation stressed the lack of mechanical traction from laryngeal elevation contributing to pharyngoesophageal sphincter opening, and the increased role of tongue propulsion in laryngectomee swallows.

Adult↗
PubMed1992

Velar activity and timing of eustachian tube function in swallowing.

Velar motion for dry and liquid swallows was investigated. as well as velar activity in speech, based on X-ray microbeam pellet tracking data. Electromyographic recordings for tensor and levator veli palatini were obtained simultaneously. Velar pellet trajectories for swallowing were more complex than for speech, since there was a high-velocity anterior component in swallowing. For some swallows this anterior component was integrated with velar elevation (especially in liquid swallows), but in other cases initial velar elevation occurred considerably earlier (chiefly in dry swallows). The burst of tensor and levator veli palatini activity characteristic of swallowing was associated with the anterior component of velar pellet motion, but not consistently with velar elevation per se. The conventional view on timing of tensor veli palatini contraction in a swallow, which governs Eustachian tube opening, is that this is associated with velar closure. The X-ray microbeam data suggest rather that Eustachian tube ventilation is more closely associated in time to the onset of pharyngeal peristalsis, which may or may not coincide with initial velar elevation.

Adult↗
PubMed1991

Flexible fiberoptic laryngoscopy used to assess swallowing function.

Flexible fiberoptic laryngoscopy can be used to evaluate swallowing dysfunction by observing the patient's pharynx with a fiberoptic laryngoscope while the patient's swallowing function is challenged with various food materials. This technique provides much of the same information obtained from the formal videofluoroscopic swallowing examination and has the advantages of being a bedside technique requiring only a fiberoptic laryngoscope that can be performed in 15 minutes by a single otolaryngologist.

Deglutition↗
PubMed1990

Interpreting the sounds of swallowing: fluid flow through the cricopharyngeus.

The sounds of swallowing in normal subjects were recorded by means of a miniature accelerometer on the throat, simultaneously with videofluoroscopy of a modified barium swallow. Consistent correspondence was found between a rapid change in the acoustic spectrum of the accelerometer signal (the appearance of a region of energy prominence above 1,000 Hz) and bolus flow through the cricopharyngeus.

Adult↗
PubMed1989

Pharyngeal transit time: assessment with videofluoroscopic and scintigraphic techniques.

The swallowing function of 31 normal and dysphagic subjects between the ages of 39 and 79 was tested with both videofluoroscopy and scintigraphy. Pharyngeal transit times for the pair of tests were compared. A statistically significant correlation of 0.66 was found. Normal pharyngeal transit time was under 1.2 s with either method, but mean values for scintigraphy were slightly longer than those for videofluoroscopy.

Adult↗
PubMed1989

Dynamic aspects of lingual propulsive activity in swallowing.

This investigation concerned the effect of different bolus volumes on the characteristics of lingual propulsive activity in swallowing. Young normal subjects were asked to perform dry swallows and swallows of 5, 10, and 15 ml of water. Tongue activity was recorded by tracking multiple gold pellets affixed to the tongue, utilizing the specialized research capabilities of the X-ray Microbeam facility at the University of Wisconsin. The major differences were between dry and liquid swallows, with dry swallows showing smaller range of movement, higher tongue position at the initiation of lingual propulsive activity, a slightly different direction of motion, a humped or flat rather than grooved cross-sectional contour of the tongue, lower peak velocity of motion, and slower progression of activity from tongue blade to dorsum. Within the 5-15 ml range of liquid bolus volumes, fewer consistent differences were found as a function of bolus size, and some marked individual differences in swallowing patterns were seen. Data are presented on normal within-subject variability in swallowing, with discussion of the possible contribution of sensory assessment of bolus size to the modification of oral and pharyngeal characteristics of swallowing.

Deglutition↗
PubMed1989

Comparisons of perceptual and acoustic characteristics of tracheoesophageal and excellent esophageal speech.

The results of recent studies have established significant acoustic differences between tracheoesophageal (TE) and conventional esophageal speech. Listener preferences and acoustic differences between TE and excellent esophageal speech were examined in the present investigation. Although, as a group, TE speech was characterized by longer extended phonation, more syllables per breath, and increased intensity, there were no significant differences in listener preference between the groups.

Acoustics↗
PubMed1988

Nasal consonants in esophageal speech.

Nasalization of nasal consonants was measured using the ratio of a nasal accelerometer signal amplitude to air-borne microphone signal amplitude. Utterances produced by 3 esophageal speakers were studied. Word position (and time following air injection) of the nasal consonants was varied. Degree of nasal resonance was dependent on word position, with significantly higher values for word-final than for word-initial position.

Humans↗
PubMed1988

Speech compensation for prosthodontically created palatal asymmetries.

Symmetry of alveolar and palatal contour was altered prosthodontically for five subjects. There was palatographic evidence, for both /s/ and /l/, that the prosthodontic changes were not always compensated for in one week of adaptation. Compensation was more pervasive for /s/ and took the form of preservation of the general orientation of the air channel in spite of the palatal asymmetries present.

Adaptation, Physiological↗
PubMed1987

Coarticulation effects on the nasalization of vowels using nasal/voice amplitude ratio instrumentation.

Nasal coarticulation in phonetically controlled nonsense syllables was investigated in four normal adult speakers. Nasalization was determined using the ratio of a nasal accelerometer signal amplitude to airborn microphone signal amplitude. Measurements of nasalization were made at the midpoint of vowels and at a constant time from the nasal consonant. Nasal acoustical coupling was greater for high vowels than for low vowels in all consonant contexts. Nasalization was also greater for vowels between two nasal consonants than for vowels between a nasal consonant and a fricative or stop. Results for progressive versus regressive assimilation depended on the measurement strategy. For within-vowel measurements made a constant time from the nasal consonant, prenasal vowels showed greater nasalization than postnasal vowels. This nasal accelerometric technique shows promise for clinical assessment of articulatory details of velar function.

Adult↗
PubMed1986

Articulatory asymmetries.

Tongue contact patterns for /s/ and /l/ were investigated using dynamic palatography. Both spatial and temporal asymmetries were commonly found extending into the vocalic transitions for these consonants. Implications for the adequacy of tongue motion data taken in a single midsagittal plane are discussed, as well as for articulatory interpretation of speech signals and speaker recognition applications.

Adult↗
PubMed1985

Speech adaptation: an aerodynamic study of adults with a childhood history of articulation defects.

Three groups of subjects were studied; former lispers, persons with a history of /l/ or /r/ distortion, and normal subjects with no history of speech defects. All were normal-sounding adult speakers of English at the time of participation. Subjects were asked to wear an experimental removable dental prosthesis that provided 4 mm of thickness in the alveolar region. Measurements of oral air flow and intraoral pressure during the reading of sentence material were made, with the focus on the consonants /s/ and /t/. The sibilant /s/ was experienced as the greatest problem for speech adaptation, regardless of the type of former articulation defect. Both groups of subjects with a history of articulation defects showed evidence of slower adaptation and use of compensatory strategies for /s/. They tended as a group to have the same minimum airflow values for /s/ after 2 weeks of practice speaking with the prosthesis as after 1 day of practice. Aerodynamic calculation of the size of the constriction for /s/ also showed little or no change for most of the former speech-defective subjects. Evidence based on intraoral pressure indicated that particular effort was expended for /s/ even after 2 weeks of practice in speaking with the prosthesis.

Adaptation, Physiological↗
PubMed1985

Acoustic and physiologic correlates of the voicing distinction in esophageal speech.

This study was designed to compare high- and low-intelligibility productions of /t/ and /d/ in esophageal speakers by using a combination of acoustic, perceptual, and physiologic measurements. Observations from these comparisons were incorporated into clinical strategies for modifying a single subject's low-intelligibility utterances. Acoustic comparison indicated that esophageal speakers used voice onset and phonation off-times but not vowel durations to differentiate /t/ and /d/ in high-intelligibility productions. Intraoral pressure measures during /t/ and /d/ production demonstrated excessively high intraoral pressures in both consonants for a low-intelligibility speaker and did not suggest systematic differences in intraoral pressure between /t/ versus /d/. Two weeks of biofeedback treatment with a low-intelligibility speaker were associated with a reduction in intraoral pressures for /t/ and /d/ productions, improved intelligibility, and changes in acoustic characteristics for /t/.

Acoustics↗
PubMed1982

Speech adaptation to dental prostheses: the former lisper.

Six of 13 former lispers studied reported unusual difficulty in speech adaptation to a dental prosthesis. Palatographic data showed that former lispers tended to make more frequent use of A-P shifts in tongue-palate placement as a compensatory strategy than did normal subjects. Tongue advancement was a common pattern. The nonadaptors showed the highest incidence of A-P tongue contact shifts as a compensatory strategy. Their use of this strategy was the most consistent, and they were more likely to retain the same articulatory speech patterns that were tried initially. Tongue groove width data for sibilants of nonadaptors in the familiar conditions showed a substantial incidence of further groove narrowing, a pattern normally seen only when a prosthesis is unfamiliar to the subject. In data on jaw position, nonadapting subjects had either not changed jaw position or adopted a closer jaw position by the end of 2 weeks. In both palatographic and jaw position data, it was possible to distinguish the adapting and nonadapting groups.

Adaptation, Physiological↗