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Biomedical subjects

W N Williams

Publications and source records attributed to W N Williams.

At least 37 records · Page 2Linked to original sources
PubMed1987

Lateral and anterior-posterior mandibular position discrimination by normal subjects.

This study examined and compared lateral and anterior-posterior (A-P) mandibular position discrimination for a group of twenty normal subjects (mean age = 26 years). A specially designed and constructed sliding scale required subjects to position their mandible precisely in the horizontal plane and to try to discriminate differences in the control of their mandibular position. The results revealed that subjects are more sensitive in detecting changes in the lateral positioning of their mandible than in the A-P positions. Subjects' difference limen (DL) values (threshold of discrimination between two positions) in detecting changes in mandibular position to the right of centre was 1.59 mm, and to left of centre was 1.41 mm. Subjects' DL values obtained with the mandible forward, and back of, the reference position were 1.39 and 2.61 mm respectively.

Adult↗
PubMed1987

The effect of periodontal bone loss on bite force discrimination.

This study compared bite force discrimination between 14 treated periodontal patients with significant bone resorption and 14 control subjects who were free of periodontal disease. Bite force was measured using a strain gauge scale which permitted subjects to visually monitor when their bite force equaled a preset resistance. A bite force of 500 gm was selected as the standard. Subjects were presented with a series of paired resistance settings, one at a time, the first of each pair being the standard and the second being the comparator setting of some predetermined different amount. This procedure was continued until the subject's difference limen (DL) value, the threshold of discrimination between two bite forces, was established. The periodontal patients required an average of 334 additional grams of resistance over the standard before they could detect a difference, whereas the control subjects required only 201 additional grams. These group means were significantly different (P less than 0.01). The results of this study suggest that the periodontal ligament provides sensory feedback relative to bite force discrimination.

Adult↗
PubMed1986

Obstructive sleep apnea following treatment of velopharyngeal incompetence by Teflon injection.

From 1967 to 1974 a clinical trial of Teflon injection into the posterior pharyngeal wall for correction of velopharyngeal incompetence (VPI) was conducted in thirty-six patients. Six years after Teflon injection, one of the patients reported the onset of severe snoring punctuated by silences when he seemed not to be breathing, daytime hypersomnolence, and tiredness severe enough to interfere with work and studies. The diagnosis of obstructive sleep apnea (OSA) was confirmed by polysomnographic sleep monitoring, and the dynamics of the obstruction elucidated by cinefluoroscopy performed with the patient asleep. Resection of the lower 3/4 of the Teflon pad, leaving the upper rim to avoid recurrence of his VPI, has eliminated the symptoms of OSA and produced an improvement in his polysomnographic findings.

Adult↗
PubMed1985

Bite force discrimination by individuals with complete dentures.

The purpose of this study was to determine whether differences existed in interincisor bite force discrimination between a group of subjects wearing complete dentures and a group of dentate individuals. It was hypothesized that biting force is monitored at least in part by the sensory mechanism within the PDL and that the absence of the PDL would result in reduced bite force discrimination. A specially designed strain gauge scale was constructed for the measurement of bite force. Bite force discrimination was assessed at three different standards including 500, 1000, and 3000 gm. Data analysis revealed that, overall, bite force discrimination was not significantly different for the two groups. However, at the lightest standard of 500 gm, the dentate group performed significantly better (p less than .05) than the denture wearers. It is concluded that the sensory system within the PDL plays a role in monitoring bite force discrimination.

Adult↗
PubMed1985

Assessment of lingual function when ankyloglossia (tongue-tie) is suspected.

Dental specialists are frequently confronted with the task of attempting to determine whether a cause and effect relationship exists between a short or restricting lingual frenum (ankyloglossia or tongue-tie) and a specific oral motor dysfunction. Because there is no standardized definition of what constitutes a condition of tongue-tie, the dental practitioner is often unsure as to the appropriate course of action with a patient with suspected ankyloglossia. This paper describes clinical measures that permit quantifying several anatomic and functional aspects of the tongue. Such baseline analysis provides a more definitive appraisal of lingual function as well as a more objective basis for making pre- and posttreatment comparisons.

Child↗
PubMed1984

Comparing the unaided visual exam to lateral cinefluorography in estimating several parameters of velopharyngeal function.

Retrospectively, the medical records of patients with known velopharyngeal insufficiency (VPI) were reviewed for comments based on an unaided visual examination regarding their velopharyngeal function. These comments were compared to objective findings obtained from the cinefluorographic evaluations performed on each of the patients. A total of 68 recorded comments (47 patients) were identified and fell into four broad categories: (1) velar length, (2) depth of the nasopharynx, (3) velopharyngeal closure, and (4) velar mobility. The results revealed an agreement level of 60% between judgements made from visual examinations and cinefluorographic evaluations. This relatively poor agreement suggests that management decisions concerning VPI must include some method of objectively assessing velopharyngeal form and function during connected speech.

Cineradiography↗
PubMed1984

Human discrimination of different bite forces.

Twenty young adult subjects were selected to determine normal baseline data of dynamic interdental bite force discrimination by use of a specially designed strain gauge instrument. The data may aid in defining the role of the periodontal ligament, temporomandibular joint and muscles of mastication in the regulation of interincisor bite force.

Adult↗
PubMed1982

Comparison of sign versus verbal symbol training in retarded adults.

Sign language as an alternative or as an augmentive system to verbal language training in the mentally retarded is in widespread use. This study began an exploration of the relationship between sign and verbal learning in 10 institutionalized severely mentally retarded adults. Three experimental groups were taught color labels. Three persons received sign training only, 4 more received verbal training only, and last 3 received combined verbal and sign training. Sign labels tended to be learned more efficiently than verbal labels by this small group. Combined sign and verbal training improved verbal learning whereas sign learning was not improved through the combined approach. Replication and extension of this preliminary work with a larger and more representative sample is needed.

Adult↗
PubMed1982

A long term study on treating velopharyngeal insufficiency by teflon injection.

Thirty-five individuals with velopharyngeal insufficiency, including eight with failed pharyngeal flaps, were treated with injectable Teflon and followed postoperatively for an average of three years. The patients' speech and voice quality were evaluated pre- and postoperatively, and an outcome was judged successful only if there was total elimination of the preoperative symptoms of hypernasality and inappropriate nasal air emission. All patients were evaluated preoperatively with cinefluorography, and an attempt was made to obtain serial postoperative films in order to determine the stability of the Teflon pad with time. An overall success rate of 74% was achieved. Success for patients with VPI, excluding those patients with pharyngeal flaps was 78%. In treating the failed pharyngeal flap cases we achieved a 62% success rate. The stability of the implanted Teflon was assessed over time as determined from measurements made on patients who received two or more postoperative cine films. Statistical analysis revealed no significant change in thickness of the pad over a period of time. Our conclusions are that with careful case selection, the injectable Teflon procedure is safe, effective and that the implant remains stable with time.

Adolescent↗
PubMed1981

Assessing VP function: the lateral still technique vs. cinefluorography.

Thirty consecutive patients with clinical manifestations of velopharyngeal insufficiency were evaluated by the radiographic techniques of 70 mm lateral stills and lateral cinefluorography. The purpose of this study was to make retrospective comparisons between the actual decisions on velopharyngeal competency or incompetency which were originally made on the basis of cinefluorographic findings with those which we believe would have been made from that information obtained from lateral stills alone had the lateral stills been the only radiographic information available. The results of the comparison between the two techniques suggests that one is apt to misdiagnose the presence or absence of velopharyngeal insufficiency on the order of 30% of th time when relying on the lateral still X-ray technique alone. We attribute this potential error rate to the very limited speech sample that can be employed with the lateral still technique. With the increasing number of secondary procedures available for treating VP dysfunction it is our opinion that cine- or videofluoroscopy allows the clinician to examine additional aspects of the patient's palatal function that are as important in the final management decision as simply the identification of closure or the lack of closure of the velopharyngeal sphincter.

Adolescent↗
PubMed1976

Intra-oral shape recognition by 138 mentally retarded subjects.

Among Ss with normal intelligence, oral shape-recognition tests have shown a relationship between articulatory ability and oral sensory integrity. This investigation explored oral sensory impairment as a possible contributory cause of the articulatory difficulties exhibited by the mentally retarded. The Florida Oral-form Recognition Measure (FORM), a task requiring the intra-oral identification of 10 geometric shapes, was administered to 138 mentally retarded Ss. Twenty Ss were retested to establish reliability. Ss were placed in groups according to etiological categories (AAMD classification) and were assigned speech ratings by a speech pathologist. Of the total sample, 86% had varying degrees of defective speech or language. Mean FORM score was 3.5, and preliminary analysis yielded significant correlations between FORM score and IQ and between speech and language rating. Further multivariate analysis with IQ held as a co-variant indicated no significant relationship between FORM score and communicative ability. This suggests caution in inferring that intra-oral shape-recognition scores reflect degree of oral sensory integrity. Perhaps a battery of oral perceptual tasks might more validly assess oral sensation-perception and aid in clarifying its relationship to speech.

Adolescent↗