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Biomedical subjects

J A Fleetham

Publications and source records attributed to J A Fleetham.

At least 19 recordsLinked to original sources
PubMed2001

Cephalometric and physiologic predictors of the efficacy of an adjustable oral appliance for treating obstructive sleep apnea.

The purpose of this study was to investigate whether any physiologic or cephalometric parameters could be used to predict the efficacy of an adjustable mandibular advancement appliance for treating obstructive sleep apnea (OSA). Forty-two male and 5 female patients with OSA were recruited on the basis of baseline polysomnography with a documented Apnea and Hypopnea Index (AHI) greater than 15 per hour. Repeat polysomnography was performed with the appliance in place. Baseline cephalometry was performed for each patient, and follow-up cephalometry was completed for 19 of the subjects. The subjects were divided into 3 groups on the basis of the degree of change in the AHI with oral appliance therapy: good response (> 75% decrease in AHI), moderate response (25% to 75% decrease in AHI), and poor response (< 25% decrease in AHI). Patients with a good response were younger and had smaller upper airways. In a linear regression analysis, the change in AHI (%) was associated with physiologic (age and body mass index), cephalometric (overjet, height of the maxillary molars, vertical height of the hyoid bone), and airway variables. However, changes in either overbite or overjet were not related to changes in any of the polysomnographic variables for the 19 subjects. A stepwise regression analysis revealed a better treatment response with the adjustable mandibular advancement appliance in patients who were younger and had a lower body mass index, a longer maxilla, a smaller oropharynx, a smaller overjet, less erupted maxillary molars, and a larger ratio of vertical airway length to the cross-sectional area of the soft palate.

Adult↗
PubMed2000

Treatment, airway and compliance effects of a titratable oral appliance.

STUDY OBJECTIVES: To measure the effects of a titratable anterior mandibular repositioner on airway size and Obstructive Sleep Apnea (OSA) and to evaluate its compliance. DESIGN: Before and after insertion sleep studies were obtained in a total of 38 OSA patients of varying severity from three different sites. Covert compliance was measured by means of a newly-developed, miniaturized, temperature-sensitive, imbedded monitor. Validity testing was completed in six adult volunteers who wore monitors imbedded into small acrylic appliances. MEASUREMENTS AND RESULTS: The mean RDI before treatment was 32.6 (SEM 2.1) and after the insertion of the appliance, the RDI was reduced to 12.1 (SEM 1.7, p<0.001). RDI was reduced to less than 15/hour in 80% of a group of moderate OSA patients (RDI 15 to 30) and in 61% of a group of severe OSA patients (RDI > 30) with respect to baseline RDI. Fiber optic video endoscopy was performed on 9 OSA patients with and without the appliance. No significant differences in hypopharynx or oropharynx cross sectional areas were found, but at the level of the velopharynx, the airway size was significantly increased (p<0.05). The index of agreement was 0.99 between the monitor clock time and the subject's log sheets. Compliance data from eight OSA subjects instructed to wear the appliance during sleep indicated that it was worn for a mean of 6.8 hours with a range of 5.6 to 7.5 hours per night. CONCLUSION: The titratable adjustable mandibular advancement appliance, made from thermoelastic acrylic, significantly reduces RDI in moderate to severe OSA patients, has a direct effect on airway size and is well worn throughout the night.

Adult↗
PubMed2000

Sleep bruxism in patients with sleep-disordered breathing.

The aim was to test the hypothesis of a direct association between sleep-disordered breathing and sleep bruxism. The frequency of masseter contraction (MC) episodes and rhythmic jaw movements (RJM) was measured in patients with mild and moderate obstructive sleep apnoea (OSA). The diagnosis of sleep bruxism was made from a combination of questionnaire, clinical observation and all-night polysomnographic recording which included masseter electromyography. A total of 21 patients (19 males/two females, mean age 40.0 years+/-9.2 SD) were randomly selected from a provisional diagnosis of snoring and OSA by a sleep physician. In the patients with mild OSA [n=11, mean apnoea hypopnoea index (AHI)=8.0+/-4.1 SD, body mass index (BMI)=29.1+/-5.0], the diagnosis of sleep bruxism was made in six out of 11 patients (54%); similarly, four out of 10 patients (40%) with moderate OSA (n=10, mean AHI=34.7+/-19.1, BMI=30.6+/-5.0) were identified as bruxists. Although the combination of clinical, subjective estimation and nocturnal electromyographic recording of masseter muscle might provide a more solid base for the diagnosis of sleep bruxism, the result is biased by the variation in the bruxing activity. MC episodes were associated with the termination of apnoea or hypopnoea episodes in only 3.5% of the mild group and 14.4% of the moderate group (p<0.05). It appears that sleep bruxism is rarely directly associated with apnoeic events, but is rather related to the disturbed sleep of OSA patients.

Adult↗
PubMed2000

Cephalometric comparisons between Chinese and Caucasian patients with obstructive sleep apnea.

The purpose of this study was to compare two groups of adult men from different ethnic backgrounds and with obstructive sleep apnea; they were selected by matching age, gender, skeletal pattern, body mass index, and respiratory disturbance index. Pretreatment cephalometric radiographs and overnight polysomnograms of 30 Chinese and 43 Caucasian patients with Class II, Division 1 malocclusions were analyzed to investigate if there were craniofacial and upper airway structural differences between the two ethnic groups. The Chinese group, when compared with the group of Caucasian patients, revealed more severe underlying craniofacial skeletal discrepancies with significantly smaller maxilla and mandibles, more severe mandibular retrognathism, proclined lower incisors, increased total and upper facial heights, and steeper and shorter anterior cranial bases. However, no significant differences were found between the two groups in posterior facial height, ratio of upper to lower anterior facial height, and the position of hyoid bone, maxilla, and upper incisors. With regard to soft tissue and upper airway measurements, there were no significant ethnic differences in tongue and soft palate size, vertical length of oropharynx, and anteroposterior dimensions of the upper airway at most of the levels except for a larger super-posterior airway space, a larger nasopharynx and oropharynx cross-sectional area, and a smaller tongue height in the Chinese group. We conclude that there are a number of craniofacial and upper airway structures that differ between the two ethnic groups that may be relevant to the treatment of obstructive sleep apnea in various ethnic groups.

Asian People↗
PubMed1999

Mandibular posture during sleep in patients with obstructive sleep apnoea.

Vertical mandibular posture is thought to be related to narrowing of the upper airway, because mouth opening is associated with an inferior-posterior movement of the mandible and the tongue which influences pharyngeal airway patency. To test whether the mandibular posture is related to the occurrence and/or termination of obstructive sleep apnoea (OSA), the vertical mandibular position was recorded intraorally using a magnet sensor during a standard sleep study in seven patients with OSA. Measurements were recorded during sleep both in the supine and lateral recumbent positions. The percentage of total sleep time spent with mandibular opening greater than 5 mm was significantly larger (p<0.001) in patients with OSA (69.3+/-23.3%) compared with our previous results obtained from healthy adults without OSA (11.1+/-11.6%). The stage of sleep affected the vertical mandibular posture during sleep in the supine position, but not in the lateral recumbent position in patients with OSA. In non-rapid eye-movement sleep, mandibular opening increased progressively during apnoeic episodes and decreased at the termination of apnoeic episodes. In contrast, no significant change in mandibular posture occurred in apnoeic episodes during rapid eye-movement sleep. It was concluded that the vertical mandibular posture is more open during sleep in patients with OSA than in healthy adults and that mandibular opening increases progressively during apnoeic episodes and decreases at the termination of those episodes.

Analysis of Variance↗
PubMed1999

Shape of the face and tongue in obstructive sleep apnea patients--statistical analysis of coordinate data.

OBJECTIVES: To determine the shape difference of the face and tongue of obstructive sleep apnea (OSA) patients, in comparison to those of non-apneic patients. DESIGN: Retrospective analysis of observational data on a cohort of patients. SETTING: A university teaching hospital and sleep referral center. SAMPLE POPULATION AND METHOD: Eighty patients referred for overnight polysomnography and lateral cephalometry and who met the selection criteria were included. Upright and supine cephalograms were obtained and subgrouped based on the severity of clinical symptoms. Shape differences between the groups were assessed by a multiple analysis of variance and a Hotelling's T2. MEASUREMENTS AND RESULTS: A set of anatomical landmarks were selected for outlines of the face and the tongue on cephalograms. X and Y coordinates of each landmark were utilized as variables. As symptoms become severe, the hyoid bone and the submental area positioned inferiorly and the fourth vertebra relocated posteriorly with respect to the lower mandibular border. When subjects changed their body position from the upright to the supine, the posterior part of the tongue appeared to sink down. The hyoid bone position to epiglottis-retrognathion line in the supine position distinguishes OSA patients from non-apneic subjects. CONCLUSION: Despite many limitations, we demonstrate that the supine cepahlometrics during wakefulness can be a useful adjunctive diagnostic tool for OSA, when cephalograms are analyzed in a coordinate data form.

Adult↗
PubMed1999

Mandibular advancement oral appliance therapy for obstructive sleep apnoea: effect on awake calibre of the velopharynx.

BACKGROUND: The mechanisms of action of oral appliance therapy in obstructive sleep apnoea are poorly understood. Videoendoscopy of the upper airway was used during wakefulness to examine whether the changes in pharyngeal dimensions produced by a mandibular advancement oral appliance are related to the improvement in the severity of obstructive sleep apnoea. METHODS: Fifteen patients with mild to moderate obstructive sleep apnoea (median (range) apnoea index (AI) 4(0-38)/h, apnoea-hypopnoea index (AHI) 28(9-45)/h) underwent overnight polysomnography and imaging of the upper airway before and after insertion of the oral appliance. Images were obtained in the hypopharynx, oropharynx, and velopharynx at end tidal expiration during quiet nasal breathing in the supine position. The cross sectional area and diameters of the upper airway were measured using image processing software with an intraluminal catheter as a linear calibration. RESULTS: AI decreased to a median (range) value of 0 (0-6)/h (p<0.01) and AHI to 8 (1-28)/h (p<0.001) following insertion of the oral appliance. The median (95% confidence interval) cross sectional area of the upper airway increased by 18% (3 to 35) (p<0.02) in the hypopharynx and by 25% (11 to 69) (p<0.005) in the velopharynx, but not significantly in the oropharynx. Although in general the shape of the pharynx did not change following insertion of the oral appliance, the lateral diameter of the velopharynx increased to a greater extent than the anteroposterior diameter. Following insertion of the oral appliance the reduction in AHI was related to the increase in cross sectional area of the velopharynx (p = 0.01). CONCLUSIONS: A mandibular advancement oral appliance increases the cross sectional area of the upper airway during wakefulness, particularly in the velopharynx. Assuming this effect on upper airway calibre is not eliminated by sleep, mandibular advancement oral appliances may reduce the severity of obstructive sleep apnoea by maintaining patency of the velopharynx, particularly in its lateral dimension.

Adult↗
PubMed1998

Mandibular posture during sleep in healthy adults.

To test whether the mandible opens more during deep sleep and whether the mandibular position is affected by body position during sleep, the vertical mandibular position was recorded intraorally using a magnet sensor at the same time as a standard sleep study in seven normal healthy male adults. Measurements were recorded during the period before sleep onset (WAKE) and during sleep. Two-way ANOVA showed that vertical mandibular position was significantly affected by sleep stage but not by body position (supine vs lateral recumbent). The proportion of time during which the mandible was in a near-closed position (0-2.5 mm) significantly and progressively decreased, and significantly more time was spent at wider gaps (2.5-5 mm) as non-rapid-eye-movement (NREM) sleep deepened. In REM sleep, the proportion of time during which the mandible was at wider gaps was significantly greater than in WAKE and stage 1 (but not later stages) of NREM sleep. It was concluded that mandibular posture during sleep in healthy adults is significantly influenced by sleep stage but not by body position. Mandibular opening progressively increases with the depth of NREM sleep stage, and the mandible is more open in REM sleep than in light NREM sleep.

Adult↗
PubMed1998

Natural head posture, upper airway morphology and obstructive sleep apnoea severity in adults.

Enlarged tonsils, adenoids, and chronic respiratory problems have been associated with the compensatory adaptations of natural head posture (NHP) in children. Recently, it has been shown that adult patients with Obstructive Sleep Apnoea (OSA) also tend to exhibit a craniocervical extension (CCE) with a forward head posture (FHP). This study was designed to search for some characteristics of OSA patients that may be related to these adaptive changes in NHP. Overnight polysomnographic, demographic, and cephalometric records of 252 adult male subjects with various types of skeletal patterns and dental conditions were examined. Apnoea Index (AI) and Apnoea + Hypopnoea Index (AHI) variables were assessed to separate the non-apnoeic snorers (n = 35), and mild (n = 101), moderate (n = 63), and severe (n = 53) OSA groups. Results of the Tukey tests revealed that severe OSA patients had a greater tendency to exhibit a CCE with a FHP (P < or = 0.05 to P < or = 0.001). Differences in head extension (NSL.VER) between groups could not be identified. Pearson's 'r' correlation coefficients revealed that the CCE and FHP in OSA patients were associated with a higher disease severity, a longer and larger tongue, a lower hyoid bone position in relation to the mandibular plane, a smaller nasopharyngeal and a larger hypopharyngeal cross-sectional area, and a higher body mass index (P < or = 0.05 to P < or = 0.001). It is concluded that a CCE with a FHP is more likely to be seen in severe and obese OSA patients with certain morphological characteristics of the upper airway and related structures.

Adult↗
PubMed1997

A thin-plate spline analysis of the face and tongue in obstructive sleep apnea patients.

The shape characteristics of the face and tongue in obstructive sleep apnea (OSA) patients were investigated using thin-plate (TP) splines. A relatively new analytic tool, the TP spline method, provides a means of size normalization and image analysis. When shape is one's main concern, various sizes of a biologic structure may be a source of statistical noise. More seriously, the strong size effect could mask underlying, actual attributes of the disease. A set of size normalized data in the form of coordinates was generated from cephalograms of 80 male subjects. The TP spline method envisioned the differences in the shape of the face and tongue between OSA patients and nonapneic subjects and those between the upright and supine body positions. In accordance with OSA severity, the hyoid bone and the submental region positioned inferiorly and the fourth vertebra relocated posteriorly with respect to the mandible. This caused a fanlike configuration of the lower part of the face and neck in the sagittal plane in both upright and supine body positions. TP splines revealed tongue deformations caused by a body position change. Overall, the new morphometric tool adopted here was found to be viable in the analysis of morphologic changes.

Anthropometry↗
PubMed1997

A role of pharyngeal length in obstructive sleep apnea patients.

A narrow pharyngeal pathway may be one of the most significant predisposing factors for obstructive sleep apnea (OSA). Accordingly, the objectives of many treatment modalities are focused on widening the constricted part of the pharynx. Despite the obvious limitations as a two-dimensional imaging technique, cephalometrics has been used more recently as a clinical screening tool for OSA. This study was designed to investigate whether pharyngeal variables more reliable than a single measurement of the most constricted area exist in cephalograms. A total of 80 pairs of upright and supine cephalograms were obtained and subclassified into four groups, in accordance with OSA severity. A medial axis program conveniently provided the variables for the study by transforming digitized outlines of the pharyngeal structure. The results indicate that the pharyngeal length and the pharyngeal width below the most constricted area may be the most important variables. We observed that the pharynx becomes considerably longer in the apneic group after a body position change from upright to supine. Pharyngeal length in the supine position may be more important than a one-dimensional measurement of the most constricted area in the diagnosis and treatment of OSA.

Analysis of Variance↗
PubMed1997

Cephalometric and demographic characteristics of obstructive sleep apnea: an evaluation with partial least squares analysis.

Obstructive sleep apnea (OSA) is caused by repeated obstruction of the upper airway during sleep. The purpose of this study was to test the relative contributions of specific demographic and cephalometric measurements to OSA severity. Demographic, cephalometric, and overnight polysomnographic records of 291 male OSA patients and 49 male nonapneic snorers were evaluated. A partial least squares (PLS) analysis was used for statistical evaluation. The results revealed that the predictive powers of obesity and neck size variables for OSA severity were higher than the cephalometric variables used in this study. Compared with other cephalometric characteristics, an extended and forward natural head posture, lower hyoid bone position, increased soft palate and tongue dimensions, and decreased nasopharyngeal and velopharyngeal airway dimensions had relatively higher associations with OSA severity. The respiratory disturbance index (RDI) was the OSA outcome variable that was best explained by the demographic and cephalometric predictor variables. We conclude that the PLS analysis can successfully summarize the correlations between a large number of variables, and that obesity, neck size, and certain cephalometric measurements may be used together to evaluate OSA severity.

Adolescent↗
PubMed1997

Effect of body position on tongue posture in awake patients with obstructive sleep apnoea.

BACKGROUND: Snoring and obstructive sleep apnoea (OSA) are worse or may only occur in the supine position. The effect of body position on upper airway size has been reported, but the effect on tongue posture has not previously been examined. METHODS: Detailed measurements were made of tongue posture from upright and supine lateral cephalograms on 24 men with OSA and 13 men with non-apnoeic snoring matched for age, body mass index, and craniofacial skeletal pattern. Patients with OSA had apnoea/hypopnoea indices (AHI) of > 50/hour and/or apnoea indices (AI) of > 25/hour while non-apnoeic snorers had AHI of < 10/hour and AI of < 5/hour. RESULTS: In non-apnoeic snorers the tongue depth measurements for the superior-posterior portion of the tongue were larger in the supine than in the upright position (p < 0.05). There was no significant difference in tongue depth measurements between the upright and the supine position in the patients with OSA. CONCLUSIONS: When awake patients with OSA move from the upright to the supine position they maintain their upright tongue posture which may tend to protect against upper airway collapse secondary to the increased gravitational load on the tongue. In contrast, when awake non-apnoeic snorers move from the upright to the supine position a significant dorsal movement in the superior-posterior portion of the tongue is observed.

Awareness↗
PubMed1997

A short-term controlled trial of an adjustable oral appliance for the treatment of mild to moderate obstructive sleep apnoea.

BACKGROUND: Although oral appliances are effective in some patients with obstructive sleep apnoea (OSA), they are not universally effective. A novel anterior mandibular positioner (AMP) has been developed with an adjustable hinge that allows progressive advancement of the mandible. The objective of this prospective crossover study was to compare efficacy, side effects, patient compliance, and preference between AMP and nasal continuous positive airway pressure (nCPAP) in patients with symptomatic mild to moderate OSA. METHODS: Twenty four patients of mean (SD) age 44.0 (10.6) years were recruited with a mean (SD) body mass index of 32.0 (8.2) kg/m2, Epworth sleepiness score 10.7 (3.4), and apnoea/hypopnoea index 26.8 (11.9)/hour. There was a two week wash-in and a two week wash-out period and two treatment periods (AMP and nCPAP) each of four months. Efficacy, side effects, compliance, and preference were evaluated by a questionnaire and home sleep monitoring. RESULTS: One patient dropped out early in the study and three refused to cross over so treatment results are presented on the remaining 20 patients. The apnoea/hypopnoea index (AHI) was lower with nasal CPAP 4.2 (2.2)/hour than with the AMP 13.6 (14.5)/hour (p < 0.01). Eleven of the 20 patients (55%) who used the AMP were treatment successes (reduction of AHI to < 10/hour and relief of symptoms), one (5%) was a compliance failure (unable or unwilling to use the treatment), and eight (40%) were treatment failures (failure to reduce AHI to < 10/hour and/or failure to relieve symptoms). Fourteen of the 20 patients (70%) who used nCPAP were treatment successes, six (30%) were compliance failures, and there were no treatment failures. There was greater patient satisfaction with the AMP (p < 0.01) than with nCPAP but no difference in reported side effects or compliance. CONCLUSIONS: AMP is an effective treatment in some patients with mild to moderate OSA and is associated with greater patient satisfaction than nCPAP.

Adult↗
PubMed1996

Associations among upper airway structure, body position, and obesity in skeletal Class I male patients with obstructive sleep apnea.

Interactions between upper airway structure and posture in relation to obesity were studied in a sample of 61 adult Class I skeletal type male patients with obstructive sleep apnea (OSA) and 10 homologous control subjects. A pair of upright and supine lateral cephalometric films were taken for each subject. A Pearson correlation analysis identified significant r values for several demographic variables in patients with OSA such as apnea and hypopnea index, percentage of predicted neck circumference, minimum arterial oxygen saturation, and body mass index (BMI). The difference between cephalometric variables identified in upright and supine subjects was calculated. When patients with OSA changed their posture from upright to supine, significant correlations were observed between the cranial base to upper cervical column angle and the hypopharynx cross-sectional area and BMI. Moreover, the mandibular plane angle and the sella-nasion plane was significantly correlated with BMI. This occurred along with a significant positive correlation between the sella-nasion plane angle and BMI and a significant inverse correlation between the mandibular plane angle in reference to the absolute vertical and horizontal planes, with BMI after the positional change. Such correlations were not observed in control subjects. No correlations were observed between the variables related to the position of the hyoid bone with BMI in either patients with OSA or control subjects after the change in posture. On the basis of these findings, we propose that when patients with OSA change their body position from upright to supine (1) the patient's neck is more extended, and (2) the hyoid bone moves more anterosuperiorly in conjunction with an upward and forward rotation of the mandible. This change in craniofacial structure may be a compensatory geometrical change in the upper airway to secure its patency.

Adult↗
PubMed1996

The effect of the tongue retaining device on awake genioglossus muscle activity in patients with obstructive sleep apnea.

Knowledge of how dental appliances alter upper airway muscle activity when they are used for the treatment of snoring and/or obstructive sleep apnea (OSA) is very limited. The purpose of this study was to define the effect of a tongue retaining device (TRD) on awake genioglossus (GG) muscle activity in 10 adult subjects with OSA and in 6 age and body mass index (BMI) matched symptom-free control subjects. The TRD is a custom-made appliance designed to allow the tongue to remain in a forward position between the anterior teeth by holding the tongue in an anterior bulb with negative pressure, during sleep. This pulls the tongue forward to enlarge the volume of the upper airway and to reduce upper airway resistance. In this study, two customized TRDs were used for each subject. The TRD-A did not have an anterior bulb but incorporated lingual surface electrodes to record the GG electromyographic (EMG) activity. The TRD-B contained an anterior bulb and two similar electrodes. The GG EMG activity was also recorded while patients used the TRD-B but were instructed to keep their tongue at rest outside the anterior bulb; this condition is hereafter referred to as TRD-X. The GG EMG activity and nasal airflow were simultaneously recorded while subjects used these customized TRDs during spontaneous awake breathing in both the upright and supine position. The following results were obtained and were consistent whether subjects were in the upright or the supine position. The GG EMG activity was greater with the TRD-B than with the TRD-A in control subjects (p < 0.05), whereas the GG EMG activity was less with the TRD-B than with the TRD-A in subjects with OSA (p < 0.01). Furthermore, there was no significant difference between the GG EMG activity of the TRD-A and the TRD-X in control subjects, whereas there was less activity with the TRD-X than with the TRD-A in subjects with OSA (p < 0.05). On the basis of these findings, it was concluded that the TRD has different effects on the awake GG muscle activity in control subjects and patients with OSA. The resultant change in the anatomic configuration of the upper airway caused by the TRD may be important in the treatment of OSA because such a change may alleviate the impaired upper airway function.

Adult↗