Dietary profile of pediatric obstructive sleep apnea patients, effects of routine educational counseling, and predictors for outcomes.

Background: Dietary behavior is a main contributing yet modifiable factor to the body weight status of children and may be involved in the pathophysiology of childhood obstructive sleep apnea (OSA). This study aimed to investigate the dietary profile of pediatric OSA patients, effects of educational counseling after adenotonsillectomy, and predictor for disease resolution. Methods: This observational study included 50 pediatric OSA patients undergoing adenotonsillectomy with routine educational counseling (Group 1), 50 pediatric OSA patients undergoing adenotonsillectomy without formal educational counseling (Group 2), and 303 healthy children without OSA (Control). The three groups were matched by age. The consumption frequency of 25 food items/groups was assessed by the Short Food Frequency Questionnaire. Quality of life was evaluated by the OSA-18 questionnaire. Sleep architecture and OSA severity were measured by standard polysomnography. Between- and within-group comparisons were analyzed by non-parametric approaches and generalized estimating equations. Prediction of disease recovery was performed by multivariable logistic regression models. Results: Group 1 children consumed fruit drinks with sugar, vegetables, sweets, chocolate, rice, and noodles more frequently than Control Group children. At baseline, the distributions of sex, weight status, OSA-18 scores, and polysomnographic variables were comparable between Group 1 and Group 2. After a 12-month follow-up, Group 1 had better improvements in physical suffering, caregiver concerns, sleep architecture, and mean peripheral oxygen saturation compared to Group 2. Furthermore, Group 1 no longer had excessive consumption of fruit drinks with sugar, chocolate, and noodles; however, food consumption frequencies did not change significantly. Notably, younger age and reduced intake of butter/margarine on bread and noodles were independent predictors of cured OSA in Group 1. Conclusion: The present study preliminarily characterized an unhealthy dietary profile among pediatric OSA patients and suggested that routine educational counseling in addition to adenotonsillectomy yielded some clinical benefits. Certain items/groups of food frequencies may be associated with disease recovery and further investigations are warranted.

Adenotonsillectomy-related changes in systemic inflammation among children with obstructive sleep apnea.

BACKGROUND: Adenotonsillar hypertrophy is the most common cause of pediatric obstructive sleep apnea (OSA). Although adenotonsillectomy considerably reduces OSA and systemic inflammation, whether and how systemic inflammation influences the effects of adenotonsillectomy on OSA has yet to be determined. METHODS: This study investigated the associations between changes in anatomical variables, % changes in subjective OSA-18 questionnaire scores, % changes in 11 polysomnographic parameters, and % changes in 27 systemic inflammatory biomarkers in 74 children with OSA. RESULTS: Fifty-six (75.6%) boys and 18 (24.4%) girls with the mean age of 7.4 ± 2.2 years and apnea-hypopnea index (AHI) of 14.2 ± 15.9 events/h were included in the statistical analysis. The mean period between before and after adenotonsillectomy was 5.6 ± 2.6 months. After adenotonsillectomy, the OSA-18 score, eight of 11 polysomnographic parameters, and 20 of 27 inflammatory biomarkers significantly improved (all p < 0.005). Notably, there were significant associations between change in tonsil size and % change in AHI ( r = 0.23), change in tonsil size and % changes in interleukin-8 (IL-8) ( r = 0.34), change in tonsil size and % change in and IL-10 ( r = -0.36), % change in IL-8 and % change in C-C chemokine ligand 5 (CCL5) ( r = 0.30), and % change in CCL5 and % change in AHI ( r = 0.38) (all p < 0.005). Interestingly, % change in IL-8 and % change in CCL5 serially mediated the relationship between change in tonsil size and % change in AHI (total effect: ß = 16.672, standard error = 8.274, p = 0.048). CONCLUSION: These preliminary findings suggest that systemic inflammation is not only a complication of OSA but also that it mediates the surgical effects, which may open avenues for potential interventions to reduce tonsil size and OSA severity through the regulation of IL-8 and CCL5.

Using sleep heart rate variability to investigate the sleep quality in children with obstructive sleep apnea.

Background: Obstructive sleep apnea (OSA) is associated with impaired sleep quality and autonomic dysfunction. Adenotonsillectomy significantly improves subjective and objective sleep quality in children with OSA. However, the postoperative changes in heart rate variability (HRV) indices (indicators of cardiac autonomic function) and their importance remain inconclusive in childhood OSA. This retrospective case series aimed to investigate the association of sleep HRV indices, total OSA-18 questionnaire score (a subjective indicator of sleep quality) and polysomnographic parameters (objective indicators of sleep quality), and effects of adenotonsillectomy on HRV indices, total OSA-18 questionnaire score and polysomnographic parameters in children with OSA. Methods: Seventy-six children with OSA were included in baseline analysis, of whom 64 (84%) completed at least 3 months follow-up examinations after adenotonsillectomy and were included in outcome analysis. Associations between baseline variables, and relationships with treatment-related changes were examined. Results: Multivariable linear regression models in the baseline analysis revealed independent relationships between tonsil size and obstructive apnea-hypopnea index (OAHI), adenoidal-nasopharyngeal ratio and very low frequency (VLF) power of HRV (an indicator of sympathetic activity), and normalized low frequency power (an indicator of sympathetic activity) and OAHI. The outcome analysis showed that adenotonsillectomy significantly improved standard deviation of all normal-to-normal intervals, and high frequency power, QoL (in terms of reduced total OSA-18 questionnaire score), OAHI and hypoxemia. Using a conceptual serial multiple mediation model, % change in OSA-18 questionnaire score and % change in VLF power serially mediated the relationships between change in tonsil size and % change in OAHI. Conclusions: The improvement in OAHI after adenotonsillectomy was serially mediated by reductions in total OSA-18 questionnaire score and VLF power. These preliminary findings are novel and provide a direction for future research to investigate the effects of VLF power-guided interventions on childhood OSA.

Obstructive Sleep Apnea and Auditory Dysfunction-Does Snoring Sound Play a Role?

The objective of the study was to investigate the relationship between obstructive sleep apnea (OSA) and auditory dysfunction, and to clarify the role of snoring sounds in contributing to auditory dysfunction. A comprehensive assessment of OSA and the auditory system was performed, including overnight polysomnography, detection of the intra-ear canal snoring sound energy (SSE), pure tone average (PTA), tinnitus pitch matching, the tinnitus handicap inventory (THI), and the Epworth sleepiness scale (ESS). The patients were identified as having tinnitus if their THI score was higher than zero or their tinnitus pitches were matched to specific frequencies. The median age, body mass index, and apnea-hypopnea index score were 41 years, 26.4 kg/m2, and 29.9 events/h, respectively. Among the 50 participants, 46 (92%) had a normal PTA, and only 4 (8%) patients had mild hearing loss. There was no significant difference in PTA among OSA severities (p = 0.52). Among the 50 participants, 33 patients (66%) were identified as having tinnitus. In the tinnitus group (n = 33), the ESS score (p = 0.01) and intra-ear canal SSE of 851-1500 Hz (p = 0.04) were significantly higher than those in the non-tinnitus group (n = 17). OSA patients with a higher ESS score had a higher risk of tinnitus (odds ratio 1.22 [95% CI: 1.01-1.46]). OSA-related auditory dysfunction emerged in tinnitus rather than in hearing impairment. OSA patients with daytime sleepiness had a higher risk of tinnitus. High-frequency SSE can jeopardize cochlea and is a potential mechanism contributing to tinnitus. Detection of snoring sounds through an intra-ear canal device may be more precise in assessing acoustic trauma from snoring sounds to vulnerable auditory system and thus warrants further research.

Long-term Average Spectrum and Nasal Accelerometry in Sentences of Differing Nasality and Forward-Focused Vowel Productions Under Altered Auditory Feedback.

OBJECTIVES AND BACKGROUND: To investigate whether voice focus adjustments can alter the audio-vocal feedback and consequently modulate speech/voice motor control. Speaking with a forward-focused voice was expected to enhance audio-vocal feedback and thus decrease the variability of vocal fundamental frequency (F0). MATERIALS AND METHOD: Twenty-two healthy, untrained adults (10 males and 12 females) were requested to sustain vowel /a/ with their natural focus and a forward focus and to naturally read the nasal, oral, and mixed oral-nasal sentences in normal noise-masked auditory conditions. Meanwhile, a miniature accelerometer was externally attached on the noise to detect the nasal vibrations during vocalization. Audio recordings were made and analyzed using the long-term average spectrum (LTAS) and power spectral analysis of F0. RESULTS: Compared with naturally-focused vowel production and oral sentences, forward-focused vowel productions and nasal sentences both showed significant increases in nasal accelerometric amplitude and the spectral power within the range of 200∼300 Hz, and significantly decreased the F0 variability below 3 Hz, which has been reported to be associated with enhanced auditory feedback in our previous research. The auditory masking not only significantly increased the low-frequency F0 variability, but also significantly decreased the ratio of the spectral power within 200∼300 Hz to the power within 300∼1000 Hz for the vowel and sentence productions. Gender differences were found in the correlations between the degree of nasal coupling and F0 stability as well as in the LTAS characteristics in response to noise. CONCLUSIONS: Variations in nasal-oral acoustic coupling not only change the formant features of speech signals, but involuntarily influence the auditory feedback control of vocal fold vibrations. Speakers tend to show improved F0 stability in response to a forward-focused voice adjustment.

Increased nasality of connected speech in patients underwent modified Lothrop procedure for refractory chronic rhinosinusitis: Cross-sectional and prospective study.

BACKGROUND: The endoscopic modified Lothrop procedure (EMLP) is performed to create a large frontal neostium in patients who had failed previous frontal sinus surgeries. EMLP causes obvious changes in the volume and anatomy of the sinuses, which may cause a more significant change in nasality. This study aimed to evaluate the changes in nasalance in patients who underwent EMLP by comparing their preoperative nasalance to the established normative values and postoperative nasalance. METHODS: This was a prospective study. Twenty-one patients diagnosed with refractory frontal sinusitis who were indicated to undergo EMLP were enrolled. One hundred one healthy participants were enrolled as norm references. The Nasometer II Model 6400 (KayPENTAX) was used to analyze the nasalance scores. Nasalance scores were tested before surgery and 1 and 3 months after the surgery. RESULTS: The normative references of nasalance were (mean ± SD) 14.6% ± 6.7%, 39.4% ± 8.4%, and 55.8% ± 8.3% for the oral passage, oral-nasal passage, and nasal sentences, respectively. The mean nasalance scores pre-EMLP and 1 and 3 months post-EMLP were 23.2% ± 9.6%, 29.0% ± 9.3%, and 29.9% ± 0.4% for the oral passage; 48.7% ± 10.7%, 54.7% ± 7.7%, and 56.4% ± 7.2% for the oral-nasal passage; and 62.7% ± 10.9%, 69.8% ± 6.7%, and 70.7% ± 6.4% for the nasal sentences, respectively. Compared with the normative references, pre-EMLP nasalance was higher for all the three speech stimuli (t-test, p < 0.05). Post-EMLP nasalance also significantly increased for all the three stimuli at the 1- and 3-month follow-up visits (Paired t-test, p < 0.05). CONCLUSION: EMLP has a short-term impact on resonance; however, long-term follow-up is required for further study.

Comparisons of auditory brainstem response elicited by compound click-sawtooths sound and synthetic consonant-vowel /da/.

The auditory brainstem response to complex sounds (cABR) could be evoked using speech sounds such as the 40 ms synthetic consonant-vowel syllable /da/ (CV-da) that was commonly used in basic and clinical research. cABR consists of responses to formant energy as well as the energy of fundamental frequency. The co-existence of the two energy makes cABR a mixed response. We introduced a new stimulus of click-sawtooths (CSW) with similar time-lock patterns but without formant or harmonic energy. Ten young healthy volunteers were recruited and the cABRs of CV-da and CSW of their 20 ears were acquired. The response latencies, amplitudes, and frequency-domain analytic results were compared pairwisely between stimuli. The response amplitudes were significantly greater for CSW and the latencies were significantly shorter for CSW. The latency-intensity functions were also greater for CSW. For CSW, adjustments of energy component can be made without causing biased changes to the other. CSW may be used in future basic research and clinical applications.

Contributions of Forward-Focused Voice to Audio-Vocal Feedback Measured Using Nasal Accelerometry and Power Spectral Analysis of Vocal Fundamental Frequency.

PURPOSE: The spectral powers of the modulations of vocal fundamental frequency (f o) less than 3 Hz (low-frequency power, LFP) and between 3 and 8 Hz (middle-frequency power, MFP) had been established to indicate the audio-vocal feedback status and vocal efficiency of a speaker, and a resonant voice may enhance the auditory-vocal feedback. This study aims to determine whether the auditory feedback can be augmented by a forward and resonant voice and therefore contribute to the modulations of f o variability. METHOD: Vocal signals and accelerometric signals of lateral nasal cartilage were obtained from 27 healthy adults who, respectively, sustained vowels /a/ and /i/ with their habitual speaking voice and with a forward-focused voice under three auditory conditions: natural hearing (N0), high-level noise exposure (N90), and low-level noise exposure (N60). Nasal skin vibrations were measured using a nasal accelerometry to reflect voice resonance status. Vocal intensity and f o variability were also analyzed to show the auditory-vocal interactions under varied conditions of auditory feedback and voice resonance. RESULTS: In both N0 and N90 conditions, forward-focused voice showed a significantly lower LFP than the speakers' habitual voice. In addition, LFP of f o would significantly increase during natural voice production as the voice feedback was greatly masked by high-intensity noise; however, with a forward-focused voice, the noise-induced variation in LFP was significantly decreased. Under N90, MFP significantly decreased during forward-focused voice production compared with that measured during natural voice production. The stability of f o modulations was not adversely affected by N60. CONCLUSION: The results support the idea that vocalizing with a forward-focused voice enhance the auditory feedback of the speaker's own voice and, thus, reduce the variability of f o during sustained phonation, especially when vocalizing in the high noise condition.

Snoring Sound Characteristics are Associated with Common Carotid Artery Profiles in Patients with Obstructive Sleep Apnea.

BACKGROUND: Obstructive sleep apnea (OSA) and snoring have been reported to be modifiable risk factors for thick carotid intima-media thickness (CIMT) and carotid atherosclerosis, which are closely linked to cardiovascular disease. METHODS: This cross-sectional study prospectively recruited 70 participants with OSA and without a history of carotid artery disorder, who primarily sought surgical Intervention. OSA and snoring were assessed with the Epworth Sleepiness Scale, Snore Outcomes Survey, polysomnography, and snoring sound recording. The carotid arteries were evaluated with ultrasonography and divided into three types of carotid artery profiles (normal carotid artery, thick CIMT, or significant carotid atherosclerosis). Multivariate linear/logistic/categorical regressions were performed with the forward selection approaches/logistic least absolute shrinkage and selection operator, as appropriate. RESULTS: Normalized snoring sound energy (301-850 Hz) was independently associated with the carotid intima-media thickness (regression coefficient [ß] = 0.01, standard error [SE] = 0.004, P = 0.03; R 2 = 0.067) and type of carotid profile (ß = 0.40, SE = 0.09, P < 0.001; R 2 = 0.156). Normalized snoring sound energy (4-300 Hz) (ß = -0.10, SE = 0.04, P = 0.01) and female sex (ß = 1.90, SE = 0.94, P = 0.04) were independently related to the presence of carotid stenosis (R 2 = 0.159). The optimal regression model of the type of carotid artery profile included normalized snoring sound energy (301-850 Hz) (ß = 0.33, SE = 0.14, P = 0.03), snoring time (ß = 0.26, SE = 0.13, P = 0.047), female sex (ß = 0.26, SE = 0.13, P = 0.047), and increased age (ß = 0.20, SE = 0.10, P = 0.04) under the control of the Snore Outcomes Survey score, 3% oxygen desaturation index, snoring sound energy (4-1500 Hz), normalized snoring sound energy (851-1500 Hz), cigarette smoking, and hyperlipidemia (R 2 = 0.427). CONCLUSION: Our findings suggested that snoring sound characteristics are associated with carotid artery profiles among early OSA patients who cannot be noticed by ultrasound because organic changes of the carotid artery have not yet started. Future studies are warranted to verify the clinical significance of the results.

Screening Severe Obstructive Sleep Apnea in Children with Snoring.

Efficient screening for severe obstructive sleep apnea (OSA) is important for children with snoring before time-consuming standard polysomnography. This retrospective cross-sectional study aimed to compare clinical variables, home snoring sound analysis, and home sleep pulse oximetry on their predictive performance in screening severe OSA among children who habitually snored. Study 1 included 9 (23%) girls and 30 (77%) boys (median age of 9 years). Using univariate logistic regression models, 3% oxygen desaturation index (ODI3) ≥ 6.0 events/h, adenoidal-nasopharyngeal ratio (ANR) ≥ 0.78, tonsil size = 4, and snoring sound energy of 801-1000 Hz ≥ 22.0 dB significantly predicted severe OSA in descending order of odds ratio. Multivariate analysis showed that ODI3 ≥ 6.0 events/h independently predicted severe pediatric OSA. Among several predictive models, the combination of ODI3, tonsil size, and ANR more optimally screened for severe OSA with a sensitivity of 91% and a specificity of 94%. In Study 2 (27 (27%) girls and 73 (73%) boys; median age, 7 years), this model was externally validated to predict severe OSA with an accuracy of 76%. Our results suggested that home sleep pulse oximetry, combined with ANR, can screen for severe OSA more optimally than ANR and tonsil size among children with snoring.

Vocal fold nodules: A disorder of phonation organs or auditory feedback?

OBJECTIVE: Increasing evidence supports that auditory feedback of one's own voice closely relates to real-time adjustments of vocal control. Previous studies highlighted that the low-frequency modulations of below 3 Hz (LFM) embedded in vocal fundamental frequency (F0) showed a reflex-like response to altered auditory inputs. However, the auditory feedback control of different vocal disorders remains unclear. DESIGN: A cross-sectional, case-controlled study. SETTING: A tertiary medical centre. PARTICIPANTS: Sustained vocalisations of vowel/a/ from adult healthy controls and patients with vocal fold nodules, vocal fold polyps and vocal fold cysts, respectively. The vocalisations were made at a comfortable pitch and at the intensity of 70 ~ 80 dBC under the following four auditory conditions: natural hearing, 90-dBC speech noise, 10-dBC enhanced feedback of self-produced voice and both the noise and voice feedback. MAIN OUTCOME MEASURES: Power spectral analysis of F0 contour of sustained vowel. RESULTS: Patients with vocal fold nodules presented with different audio-vocal feedback behaviour and audio-vocal response to speech noise from the other two vocal pathologies of vocal fold polyp and vocal fold cyst as well as the healthy controls (P < .001, one-way ANOVA). CONCLUSION: The vocal fold nodules may be not only a vocal fold disease but also a disease caused by abnormal audio-vocal feedback. Moreover, the distinct audio-vocal feedback of vocal fold nodules could be revealed by power spectral analysis of vocal fundamental frequencies. Although further investigations are necessary, adjustments of audio-vocal feedback behaviour may provide a new insight and benefit to the treatment of vocal fold nodules in the future.

Snoring sound energy as a potential biomarker for disease severity and surgical response in childhood obstructive sleep apnoea: A pilot study.

OBJECTIVE: To investigate the relationship between baseline snoring sound energy (SSE) and disease severity, changes in SSE after adenotonsillectomy, and the predictors of surgical success in children with obstructive sleep apnoea (OSA). DESIGN: Prospective cohort study. SETTING: Tertiary referral medical centre. PARTICIPANTS: Thirty-two children with OSA whose apnoea-hypopnoea index ≥5 or apnoea-hypopnoea index ≥1.5 with OSA comorbidities were recruited. Patients with complicated OSA were excluded. All participants underwent snoring sound analysis, polysomnography, and adenotonsillectomy. MAIN OUTCOME MEASURES: Snoring sound energy and apnoea-hypopnoea index were assessed at baseline and 6 months after adenotonsillectomy. Surgical success was defined as a postoperative apnoea-hypopnoea index <1.5. RESULTS: The median age, body mass index, and apnoea-hypopnoea index was 9 years, 19.0 kg/m2 , and 13.2 events/h, respectively. Multivariate logistic regression showed that a baseline tonsil size of IV (odds ratio 15.7 [95% CI: 1.5-166.3]) and SSE of 801-1000 Hz > 21.9 dB (odds ratio 32.3 [95% CI: 2.6-396.6]) were significantly related to severe OSA. Following adenotonsillectomy, apnoea-hypopnoea index decreased significantly (P < 0.001). SSE of 41-200 Hz, 201-400 Hz and 801-1000 Hz also decreased significantly (P = 0.04, 0.01 and 0.006, respectively). Baseline SSE of 801-1000 Hz < 8.5 dB significantly predicted surgical success (odds ratio 11.0 [95% CI: 1.4-85.2]). CONCLUSIONS: Our findings suggest the potential utility of SSE of 801-1000 Hz to screen for severe OSA, predict surgical success and assess therapeutic outcomes. Specific baseline SSE may represent a potential biomarker for childhood OSA.

Responses of Middle-Frequency Modulations in Vocal Fundamental Frequency to Different Vocal Intensities and Auditory Feedback.

OBJECTIVES AND BACKGROUND: Auditory feedback can make reflexive responses on sustained vocalizations. Among them, the middle-frequency power of F0 (MFP) may provide a sensitive index to access the subtle changes in different auditory feedback conditions. MATERIALS AND METHODS: Phonatory airflow temperature was obtained from 20 healthy adults at two vocal intensity ranges under four auditory feedback conditions: (1) natural auditory feedback (NO); (2) binaural speech noise masking (SN); (3) bone-conducted feedback of self-generated voice (BAF); and (4) SN and BAF simultaneously. The modulations of F0 in low-frequency (0.2 Hz-3 Hz), middle-frequency (3 Hz-8 Hz), and high-frequency (8 Hz-25 Hz) bands were acquired using power spectral analysis of F0. Acoustic and aerodynamic analyses were used to acquire vocal intensity, maximum phonation time (MPT), phonatory airflow, and MFP-based vocal efficiency (MBVE). RESULTS: SN and high vocal intensity decreased MFP and raised MBVE and MPT significantly. BAF showed no effect on MFP but significantly lowered MBVE. Moreover, BAF significantly increased the perception of voice feedback and the sensation of vocal effort. CONCLUSIONS: Altered auditory feedback significantly changed the middle-frequency modulations of F0. MFP and MBVE could well detect these subtle responses of audio-vocal feedback.

Saccadic entropy of head impulses in acute unilateral vestibular loss.

BACKGROUND/PURPOSE: To evaluate the complexity of vestibular-ocular reflex (VOR) in patients with acute unilateral vestibular loss (AUVL) via entropy analysis of head impulses. METHODS: Horizontal head impulse test (HIT) with high-velocity alternating directions was used to evaluate 12 participants with AUVL and 16 healthy volunteers. Wireless electro-oculography and electronic gyrometry were used to acquire eye positional signals and head velocity signals. The eye velocity signals were then obtained through differentiation, band-pass filtering. The approximate entropy of eye velocity to head velocity (RApEn) was used to evaluate chaos property. VOR gain, gain asymmetry ratio, and RApEn asymmetry ratio were also used to compare the groups. RESULTS: For the lesion-side HIT of the patient group, the mean VOR gain was significantly lower and the mean RApEn was significantly greater compared with both nonlesion-side HIT and healthy controls (p < 0.01, one-way analysis of variance). Both the RApEn asymmetry ratio and gain asymmetry ratio of the AUVL group were significantly greater compared with those of the control group (p < 0.05, independent sample t test). CONCLUSION: Entropy and gain analysis of HIT using wireless electro-oculography system could be used to detect the VOR dysfunctions of AUVL and may become effective methods for evaluating vestibular disorders.

The Frequency and Energy of Snoring Sounds Are Associated with Common Carotid Artery Intima-Media Thickness in Obstructive Sleep Apnea Patients.

Obstructive sleep apnea (OSA) is a known risk factor for atherosclerosis. We investigated the association of common carotid artery intima-media thickness (CCA-IMT) with snoring sounds in OSA patients. A total of 30 newly diagnosed OSA patients with no history of cardiovascular diseases were prospectively enrolled for measuring mean CCA-IMT with B-mode ultrasonography, body mass index, metabolic syndrome, 10-year cardiovascular disease risk score, high-sensitivity C-reactive protein, and homocysteine. Good-quality signals of full-night snoring sounds in an ordinary sleep condition obtained from 15 participants were further acoustically analyzed (Included group). All variables of interest were not significantly different (all p > 0.05) between the included and non-included groups except for diastolic blood pressure (p = 0.037). In the included group, CCA-IMT was significantly correlated with snoring sound energies of 0-20 Hz (r = 0.608, p = 0.036) and 652-1500 Hz (r = 0.632, p = 0.027) and was not significantly associated with that of 20-652 Hz (r = 0.366, p = 0.242) after adjustment for age and sex. Our findings suggest that underlying snoring sounds may cause carotid wall thickening and support the large-scale evaluation of snoring sound characters as markers of surveillance and for risk stratification at diagnosis.

Relationships Between Formant Frequencies of Sustained Vowels and Tongue Contours Measured by Ultrasonography.

PURPOSE: The purpose of this study was to explore the formant-articulation relationships in corner vowels by acoustic analysis of speech signals and measuring tongue contour using ultrasonography. METHOD: Eighteen healthy adults (8 men, 10 women), aged between 20 and 40 years, were enrolled. Speech signals of sustained vowels /ɑ/, /i/, and /u/ were recorded to obtain the first 2 formant frequencies. Tongue height, tongue advancement, and lengths of posterior tongue surface (LPTS) and anterior oral cavity (LAOC) were obtained using ultrasound image processing technique in order to examine the resonance mechanism of the oral vocal tract. RESULTS: LPTS and LAOC, as well as mean frequencies of the first and second formants, showed significant differences between sexes and among vowels. The first formant significantly and better correlated with LPTS than with tongue height (r = -.78, p < .001, Pearson's correlation). The correlation of the second formant with LAOC (r = -.85, p < .001) was also significant and better than the correlation with tongue advancement. Sex, however, did not show significant correlation with the formant frequencies. CONCLUSIONS: Ultrasonographic measurements of tongue contour correlated well to the formant frequencies. The results stressed the importance of tongue shaping in articulation. Although more studies are necessary in clinical implications, disorders associated with abnormal tongue shaping may be the target applications in the future.

Influences of monocular and binocular vision on postural stability.

To compare the influences of monocular vision versus binocular vision on postural control, twenty-seven otherwise healthy adults, aged from 19 to 38 years, with corrected visual acuity of better than or equal to 20/20, were recruited. Body sway for standing 30 seconds on a force platform in 3 conditions was recorded for each participant: one with both eyes open (BEO), one with left eye open (LEO) and the other with both eyes closed (BEC). Postural stability was subsequently evaluated by measuring the total track length (TL) and surface area (SA) of center of pressure of body sway. The results show that the values of TL and SA of BEC were significantly greater than those of LEO and BEO. Moreover, the values of TL and SA of BEO were significantly smaller than those of LEO (p < 0.05, one-way repeated measures ANOVA and post hoc of Fisher's LSD procedure). The Romberg coefficient of LEO was also significantly greater than that of BEO (p < 0.05, paired sample t-test). We concluded that optimal binocular vision provides more information for keeping balance than monocular vision according to the results revealed in our study. Assessment of visual acuity is recommended before doing a posturographic test in the clinical setting. However, the long-term impact of blindness on controlling posture is uncertain and needs further investigation.

Audio-vocal responses of vocal fundamental frequency and formant during sustained vowel vocalizations in different noises.

Sustained vocalizations of vowels [a], [i], and syllable [mə] were collected in twenty normal-hearing individuals. On vocalizations, five conditions of different audio-vocal feedback were introduced separately to the speakers including no masking, wearing supra-aural headphones only, speech-noise masking, high-pass noise masking, and broad-band-noise masking. Power spectral analysis of vocal fundamental frequency (F0) was used to evaluate the modulations of F0 and linear-predictive-coding was used to acquire first two formants. The results showed that while the formant frequencies were not significantly shifted, low-frequency modulations (<3 Hz) of F0 significantly increased with reduced audio-vocal feedback across speech sounds and were significantly correlated with auditory awareness of speakers' own voices. For sustained speech production, the motor speech controls on F0 may depend on a feedback mechanism while articulation should rely more on a feedforward mechanism. Power spectral analysis of F0 might be applied to evaluate audio-vocal control for various hearing and neurological disorders in the future.

Efficacy of paced breathing for insomnia: enhances vagal activity and improves sleep quality.

Fourteen self-reported insomniacs (SRI) and 14 good sleepers (GS) had their cardiac neuronal activity assessed by heart rate variability (HRV) under controlled respiration at a slow frequency rate of 0.1 Hz, and a forced rate of 0.2 Hz during daytime rest. Nighttime sleep was measured by polysomnography. The SRI showed depressed high frequency power of HRV compared to the GS. An increased total power of HRV was observed among the SRI during slow, paced breathing compared with spontaneous breathing and 0.2 Hz. Sleep onset latency, number of awakenings, and awakening time during sleep were decreased and sleep efficiency was increased if SRI practiced slow, paced breathing exercises for 20 min before going to sleep. Our results indicate that there is autonomic dysfunction among insomniacs, especially in relation to vagal activity; however, this decreased vagal activity can be facilitated by practicing slow, paced breathing, thereby improving sleep quality.