Multi-level obstruction in obstructive sleep apnoea: prevalence, severity and predictive factors.

OBJECTIVES: To characterise multi-level obstruction in terms of prevalence, obstructive sleep apnoea severity and predictive factors, and to collect epidemiological data on upper airway morphology in obstructive sleep apnoea patients. METHODS: Retrospective review of 250 obstructive sleep apnoea patients. RESULTS: On clinical examination, 171 patients (68.4 per cent) had multi-level obstruction, 49 (19.6 per cent) had single-level obstruction and 30 (12 per cent) showed no obstruction. Within each category of obstructive sleep apnoea severity, multi-level obstruction was more prevalent. Multi-level obstruction was associated with severe obstructive sleep apnoea (more than 30 events per hour) (p = 0.001). Obstructive sleep apnoea severity increased with the number of obstruction sites (correlation coefficient = 0.303, p < 0.001). Multi-level obstruction was more likely in younger (p = 0.042), male (p = 0.045) patients, with high body mass index (more than 30 kg/m2) (p < 0.001). Palatal (p = 0.004), tongue (p = 0.026) and lateral pharyngeal wall obstructions (p = 0.006) were associated with severe obstructive sleep apnoea. CONCLUSION: Multi-level obstruction is more prevalent in obstructive sleep apnoea and is associated with increased severity. Obstruction at certain anatomical levels contributes more towards obstructive sleep apnoea severity.

The separation between music and speech: evidence from the perception of Cantonese tones.

This study investigates the relationship between music and speech, testing whether musical training has any facilitatory effects on native tone language speakers. Some Cantonese tone pairs are merging in recent years. The merging subjects have poorer general lexical tone perception than the control subjects. Previous studies showed that musical training facilitates lexical tone perception of nontone language speakers, but it is unclear if the same is true for tone language speakers. Three groups of listeners (standard Cantonese, merging Cantonese, nontone) with and without musical training participated in AX discrimination tasks of Cantonese monosyllables and pure tones resynthesized from Cantonese lexical tones. Results show that while musical training enhances lexical tone perception of nontone listeners, it has little influence on Cantonese listeners. The findings suggest that the linguistic use of tones is more fundamental and more robust than musical tones. Our results are compatible with the idea that linguistic and musical mechanisms belong to separate but overlapping domains.

Language-specific realizations of syllable structure and vowel-to-vowel coarticulation.

This paper investigates the effects of syllable structure on vowel-to-vowel (V-to-V) coarticulation using Thai and English data. Languages differ in syllable complexity and their realizations of syllable structure. It was hypothesized that languages with complex syllable structure (English) would allow more V-to-V coarticulation than languages with simple syllable structure (Thai). Onset and coda consonants are different acoustically, articulatorily, typologically and perceptually. Onsets are generally 'stronger' and more stable than codas because they are longer, louder, and involve tighter articulatory constrictions. It was hypothesized that closed syllables (that end in a consonant C, i.e., VC#V) would allow more V-to-V coarticulation than open syllables (V#CV). /C(1)V(1)#C(2)V(2)/ and /C(1)V(1)C(2)#V(2)t/ sequences were recorded from six native speakers in Thai and six in English. First and second formant frequencies were measured. Results show that English allows more V-to-V coarticulation than Thai regardless of the intervocalic duration and vowel quality difference, but open and closed syllables only affect V-to-V coarticulation minimally. In addition to syllable structure, other possible factors contributing to the language difference in V-to-V coarticulation are discussed.

Why generic and disease-specific quality-of-life instruments should be used together for the evaluation of patients with persistent allergic rhinitis.

BACKGROUND: The importance of assessing health-related quality of life (HRQL) of patients with allergic rhinitis (AR) has been well established, but the specific roles of rhinitis-specific or general health instruments have not been delineated. OBJECTIVE: We analysed the psychometric properties of a disease-specific instrument, the Rhinoconjunctivitis Quality-of-Life Questionnaire (RQLQ) and the general health instrument, the Medical Outcome Short-Form 36 (SF-36) as they are employed in combination in patients with persistent AR in clinical practice. METHOD: We analysed the data collected from a prospective study of 43 newly diagnosed patients with persistent AR and 44 controls. We interviewed the patients four times, at baseline, weeks 4, 8 and 10. RESULTS: The RQLQ and SF-36 have good discriminative property, internal consistency, and test-retest reliability. The RQLQ is superior to the SF-36 as an evaluative instrument because more of its domains respond to change, the magnitude of change was greater, and the response was faster. The SF-36 is more susceptible to floor and ceiling effects. Both instruments are unsuitable for mildly symptomatic patients based on Rasch model analysis. Each questionnaire assesses a distinct and significant portion of the total HRQL of persistent AR. CONCLUSION: The SF-36 and RQLQ are good for discriminating rhinitis patients from controls, but the former is poor for detecting changes in QOL. Both are inappropriate for mildly symptomatic patients. Each instrument measures non-overlapping halves of the measurable HRQL. For an assessment of the HRQL in persistent AR that is complete and responsive both instruments should be employed together.

Tracheoesophageal puncture outcomes and predictors of success in laryngectomised patients.

INTRODUCTION: Prosthetic voice restoration has been widely used for vocal rehabilitation in laryngectomised patients. The objectives of this study were to examine success rates, predictors of success and complications for our patients who had undergone tracheoesophageal punctures (TEPs) and voice prosthesis placement after laryngectomy. To our knowledge, this is the first analysis of the use and complications of TEPs in Singapore. PATIENTS AND METHODS: Thirty-eight patients seen in our centre were analysed in this retrospective case review. Factors analysed included voice quality with age, timing of insertion, type of closure, use of radiotherapy, regular maintenance and attendance at our clinic. Twenty-eight had undergone primary TEP surgery and 10 had undergone secondary TEP surgery for voice restoration after laryngectomy for cancer. Thirty-five patients had primary closure of the pharynx with 13 vertical, 19 horizontal and 3 T-shaped closures. The other 3 patients required reconstructive surgery. Thirty-five patients had radiotherapy. A numerical assessment of voice production was made of patients immediately and at 6 months post-insertion. A review of the complications was also done. RESULTS: TEPs provided a fair to good voice in 74% of our laryngectomees. Patients who attended the voice restoration clinics and who regularly cleaned their prostheses were found to have statistically better voices (P = 0.044 and P = 0.002, respectively). Patients less than 60 years old had better results, as did patients with horizontal or T-shaped closures; however, these were not statistically significant. Secondary TEPs provided fair/good voices in 90% of cases compared to 68% of primary TEPs. Voice quality during radiotherapy was diminished but recovered at 6 months postradiotherapy. The commonest complications noted included crusting (seen in 40% of cohort), candida infections and leaks which were seen in 16% of our patients. There was no mortality attributable to the use of TEPs in our study.

Quality of life of patients with perennial allergic rhinitis: preliminary validation of the Rhinoconjunctivitis Quality of Life Questionnaire in Singapore.

Though sufferers of perennial allergic rhinitis do not die from their ailment, they endure years of chronic nose disease that Interferes with many important aspects of their lives. A rhinitis-specific instrument to gauge the quality of life of patients with this disease was published in 1991. Here, we validated the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) for use in English-speaking patients with perennial allergic rhinitis. We established that the RQLQ distinguishes between patients and control, demonstrates internal consistency and is sensitive to change. This study suggests that the RQLQ can be used to assess the quality of life of patients with perennial allergic rhinitis in Singapore.