Night-to-night variation in snoring sound severity: one night studies are not reliable.

OBJECTIVES: To quantify the night-to-night variation in snoring severity; to compare this with inter-subject variation in snoring intensity: to compare multinight mean snoring scores with self-reported subjective scores. DESIGN: Prospective observational study. SETTING: Subjects were recorded during sleep at their own homes. PARTICIPANTS: Twenty patients with socially disruptive snoring awaiting surgery. MAIN OUTCOME MEASURES: Over four consecutive nights using a solid-state sound recording device, the mean, standard deviation and intra-class correlation coefficient were calculated for (a) the loudest 1% of sound, (b) snore frequency and (c) total snore duration. Results were correlated with Snoring Symptom Inventory scores assessed immediately prior to these recordings. RESULTS: Overall mean and intrasubject standard deviation for the loudest 1% of sound was 65.0 (+/-4.1) dB, for snore frequency was 245 (+/-104) per hour and for total snore duration was 4.3% (+/-2.1). Intraclass correlation coefficients were 0.78, 0.74 and 0.67, respectively, suggesting only moderate reliability of these outcome measures. No significant correlation was found between objective and subjective scores for either endpoint. CONCLUSION: Natural night-to-night variation in snoring severity represents a significant proportion of overall snoring variance, thus one night studies of snoring are not reliable. The random error associated with one-night studies exceeds the expected effect size of snoring interventions and so multi-night studies of at least four nights are recommended to reduce the error. However, even multi-night objective measurements correlate poorly with subjective scores of snoring.

The added value of fibreoptic endoscopic evaluation of swallowing in tracheostomy weaning.

OBJECTIVE: To determine if fibreoptic endoscopic evaluation of swallowing adds information to the clinical assessment of swallowing in tracheostomised patients. DESIGN: A prospective, observational study. SETTING: Addenbrooke's Hospital, Cambridge, UK. PARTICIPANTS: Twenty-five consecutive, adult, tracheostomised patients were recruited over a 3-month period. They were referred to speech and language therapy for a swallowing assessment and were ready to trial cuff deflation. MAIN OUTCOME MEASURES: In current practice the clinical assessment is invariably a precursor to fibreoptic endoscopic evaluation of swallowing and a test would be considered positive when penetration or aspiration are detected. We considered the value of fibreoptic endoscopic evaluation of swallowing following both positive and negative outcomes of the clinical assessment. RESULTS: The positive predictive value of aspiration or penetration was 91% i.e. when a clinical assessment is failed, there is a very high probability the patient would also be failed on fibreoptic endoscopic evaluation of swallowing. However, the negative predictive value was only 64% i.e. over one-third of patients who pass a clinical assessment would later fail a fibreoptic endoscopic evaluation of swallowing. CONCLUSIONS: Despite a small cohort, our data suggest that the assessment of swallowing to aid weaning in tracheostomised patients is currently performed incorrectly; we estimate that over a third of all tracheostomised patients that 'pass' the clinical assessment of swallowing are, in reality, at risk from penetration, aspiration or failed decannulation. This finding supports the use of fibreoptic endoscopic evaluation of swallowing and a change in clinical practice.

Pharyngeal residue across the lifespan: a first look at what's normal.

OBJECTIVES: Without good evidence, post-swallow pharyngeal residue is considered abnormal. Our aim was to document residue from normal food and fluid boluses in young and elderly healthy populations. DESIGN: Prospective, single-blind assessment of residue severity from Fibreoptic Endoscopic Evaluation of Swallowing. SETTING: Tertiary specialist ENT teaching hospital. PARTICIPANTS: Fifty-one healthy participants; twenty-one aged <40 and thirty aged 65+. Each swallowed six representative boluses. OUTCOMES: Two teams independently rated pharyngeal residue severity at 11 anatomical sites. RESULTS: The mean residue scores were less than 1 when averaged across all boluses and anatomic sites. Differences due to age were slight. CONCLUSIONS: Our preliminary data indicate that substantial pharyngeal residue is not common in young or elderly, and probably indicates disordered swallowing.

Total laryngopharyngoesophagectomy with gastric transposition reconstruction: review of long-term swallowing outcomes.

AIM: The aim of this review was to examine long-term swallowing and eating outcomes following laryngopharyngoesophagectomy with gastric pull-up reconstruction. METHODS: Ten patients underwent clinical examination and completed the performance status scale for head and neck questionnaire and also a gastric pull-up swallowing questionnaire designed for this review. Nine of the 10 patients underwent videofluoroscopic examination of swallowing. RESULTS: One patient had a stricture at the orogastric anastomosis, and one patient had bilateral tongue immobility secondary to XIIth nerve palsies. Eight participants reported eating a normal diet, and five reported not limiting their eating environment. Regurgitation, slower eating and reduced capacity were the most common functional limitations. CONCLUSIONS: These results support previous opinions that the gastric pull-up procedure has good swallowing outcomes, and indicate that such outcomes continue in the long term.

Exploring the relationship between severity of dysphonia and voice-related quality of life.

OBJECTIVES: To explore whether severity and/or consistency of dysphonia are linked to voice-related quality of life. DESIGN: Cross-sectional study. SETTING: Specialist voice clinics, University Teaching Hospital. PARTICIPANTS: Sixty adult patients attending with a primary complaint of dysphonia. Exclusion criteria were those below 16 years of age, transexual patients and those with a persistent dysphonia of >2 years. MAIN OUTCOME MEASURES: Voice-related quality of life as assessed by VoiSS. EXPLANATORY FACTORS: Severity of dysphonia as judged by perceptual ratings of voice (GRBAS); a visual analogue scale to judge best, worst and today's voice. RESULTS: There was a highly significant correlation between perceptual dysphonia severity as assessed by GRBAS and the total, impairment and emotional subsets of the VoiSS questionnaire (r from 0.48 to 0.64). There was a similar and highly significant correlation between best, worst and today's self-rated voice and the total, impairment and emotional subsets of the VoiSS questionnaire (r from -0.40 to -0.60). However, none of the self-rated parameters was demonstrably better at explaining the effect on quality of life. CONCLUSIONS: An increasingly negative effect on quality of life appears to be associated with an increase in the severity of dysphonia. Further research on the role of quality of life measures in the assessment and treatment of dysphonia would be of value.

Fibreoptic endoscopic evaluation of swallowing and videofluoroscopy: does examination type influence perception of pharyngeal residue severity?

OBJECTIVES: The aim of the study was to investigate whether the type of instrumental swallowing examination (Fibreoptic Endoscopic Evaluation of Swallowing (FEES) or videofluoroscopy) influences perception of post-swallow pharyngeal residue. DESIGN: Prospective, single-blind assessment of residue from simultaneous videofluoroscopy and FEES recordings. All raters were blind to participant details, to the pairing of the videofluoroscopy and FEES examinations and to the other raters' scores. SETTING: Tertiary specialist ENT teaching hospital. PARTICIPANTS: Fifteen adult participants consecutively recruited; seven women and eight men aged between 22 and 73, mean age 53. All participants underwent one FEES examination and one videofluoroscopy examination performed simultaneously. INCLUSION CRITERIA: referred to speech and language therapy for assessment of dysphagia. EXCLUSION CRITERIA: nil by mouth or judged to be at high risk of aspiration. MAIN OUTCOME MEASURES: The FEES and videofluoroscopy examinations were recorded simultaneously. Fifteen speech and language therapists independently scored pharyngeal residue as none, coating, mild, moderate or severe. All examinations were scored twice by all raters. RESULTS: Intra- and inter-rater agreement were similar for both examinations. There were significant differences between FEES and videofluoroscopy pharyngeal residue severity scores (anova, P < 0.001). FEES residue scores were consistently higher than videofluoroscopy residue scores. CONCLUSIONS: Pharyngeal residue was consistently perceived to be greater from FEES than from videofluoroscopy. These findings have significant clinical implications as FEES and videofluoroscopy findings are used to judge aspiration risk and to make recommendations for oral intake. Further research is required to examine the impact of FEES and videofluoroscopy examinations on treatment decisions.

Variation in invasive and noninvasive measurements of isovolumetric bladder pressure and categorization of obstruction according to bladder volume.

PURPOSE: We developed a noninvasive test that provides an estimate of isovolumetric bladder pressure by measuring the pressure required to interrupt voiding using controlled inflation of a penile cuff. We noted variation in serial measurements obtained during a single void and, therefore, we determined whether this represents variation in detrusor contraction strength, as predicted in previous studies, or measurement error. MATERIALS AND METHODS: A total of 36 symptomatic men underwent simultaneous invasive and noninvasive pressure flow studies. Corresponding values of isovolumetric bladder pressure and cuff interruption pressure were recorded at each flow interruption and grouped according to bladder volume to calculate measurement error and bias at various points during a void. Individual variation in the 2 measurements across a range of normalized bladder volumes was then examined using ANOVA. RESULTS: Cuff interruption pressure showed a consistent level of accuracy as an estimate of isovolumetric bladder pressure across a range of volumes. There were similar, statistically significant differences in isovolumetric bladder pressure and cuff interruption pressure recorded at specific volume increments with the highest values seen in the mid range and the lowest seen at lower bladder volumes (each p <0.01). When plotting, the maximum recorded value of cuff interruption pressure in each individual on our proposed noninvasive pressure flow nomogram provided the best diagnostic accuracy for obstruction. CONCLUSIONS: This study shows that cuff interruption pressure varies in the expected manner with bladder volume and provides a consistent estimate of isovolumetric bladder pressure throughout a void. These data provide important guidance for interpreting noninvasive pressure flow studies and classifying obstruction on the proposed nomogram.

A nomogram to classify men with lower urinary tract symptoms using urine flow and noninvasive measurement of bladder pressure.

PURPOSE: Bladder pressure during voiding can be estimated by a noninvasive technique using controlled inflation of a penile cuff. This test provides a valid and reliable estimate of isovolumetric bladder pressure but to our knowledge the role of the test for the routine clinical treatment of patients with lower urinary tract symptoms (LUTS) has yet to be demonstrated. As a first step, we evaluated a proposed nomogram for the diagnosis of bladder outlet obstruction in men with LUTS using noninvasive measurements of pressure and flow. MATERIALS AND METHODS: Using a combination of theoretical calculation and experimental data the existing International Continence Society pressure flow nomogram was modified to allow noninvasive measurement of isovolumetric bladder pressure in place of detrusor pressure at maximum urine flow. Accuracy of the nomogram for classifying obstruction was then tested in a group of 144 men with LUTS who underwent an invasive and a noninvasive pressure flow study. RESULTS: The modified nomogram identified men with obstruction with 68% positive predictive value and 78% negative predictive value. Predictive accuracy could be improved by adding an additional criterion of obstruction, that is maximum urine flow less than 10 ml second, whereby an identifiable 69% of all cases could be classified as obstructed (88% positive predictive value) or not obstructed (86% negative predictive value). In the remaining 31% of patients invasive pressure flow studies would provide additional information, although some results would remain equivocal. CONCLUSIONS: The proposed nomogram combined with the additional flow rate criterion can classify more than two-thirds of cases without recourse to invasive pressure flow studies. We must now evaluate the usefulness of this classification for the treatment of men with LUTS.

An automated penile compression release maneuver as a noninvasive test for diagnosis of bladder outlet obstruction.

PURPOSE: We tested the hypothesis that the previously described penile urethral compression release (PCR) maneuver provides a valid diagnosis of bladder outlet obstruction (BOO) using automated rather than manual penile compression by controlled inflation of a penile cuff. We also investigated urodynamic events underlying generation of the PCR index. MATERIALS AND METHODS: A total of 150 subjects attending for pressure flow studies were studied using conventional and noninvasive cystometry. Patients were classified into urodynamic diagnostic groups using standard invasive studies. The PCR index was calculated for each individual from noninvasive penile cuff data and the results were summarized for each group. ROC analysis of the PCR index was performed to define an optimum threshold for BOO diagnosis. Simultaneous invasive and noninvasive data were used to define the relationship between the PCR index, bladder contractility and the maximum flow rate. RESULTS: The mean PCR index +/- SD was significantly higher in the BOO group compared to the normal cystometry group (215% +/- 84% vs 93% +/- 39, p <0.01). ROC analysis showed that a PCR index of greater than 160% diagnosed BOO with 78% sensitivity, 84% specificity and a positive predictive value of 69%. There was a strong positive correlation between the PCR index and isovolumetric detrusor pressure, which is a measure of bladder contractility (r = 0.44, p <0.01). CONCLUSIONS: The results of this study suggest that the PCR index combines valid estimates of bladder contractility and the maximum flow rate, and it represents a clinically useful, noninvasive urodynamic parameter for the diagnosis of BOO.

Noninvasive measurement of bladder pressure. Does mechanical interruption of the urinary stream inhibit detrusor contraction?

PURPOSE: As part of developing a noninvasive method to measure bladder pressure using an inflatable penile cuff, we tested the hypothesis that detrusor contraction is maintained without inhibition during the test. MATERIALS AND METHODS: Five healthy volunteers and 26 male patients with lower urinary tract symptoms underwent interruption of established urine flow by controlled inflation of a cuff placed around the penis with simultaneous invasive bladder pressure monitoring. After interruption of flow the cuff was rapidly deflated and voiding was allowed to resume. The bladder pressure was recorded before, during and after interruption of flow by cuff inflation. RESULTS: During flow interruption an isovolumetric increase in detrusor pressure was observed. When the cuff was deflated the detrusor pressure quickly returned to preinflation values and urine flow immediately resumed. Intra-abdominal pressure did not change during the cuff inflation cycle. CONCLUSIONS: Mechanical interruption of urine flow by controlled inflation of a penile cuff during voiding does not inhibit detrusor contraction. This finding further validates our noninvasive technique of bladder pressure measurement and supports ongoing studies into its clinical usefulness.

Noninvasive measurement of bladder pressure by controlled inflation of a penile cuff.

PURPOSE: A noninvasive test providing reliable objective quantification of bladder pressure during the voiding cycle would make an important contribution to the management of lower urinary tract symptoms. We developed a new noninvasive test to measure bladder pressure in males based on controlled inflation of a penile cuff during voiding. We compared the new technique with simultaneous invasive bladder pressure measurement. MATERIALS AND METHODS: We evaluated 7 volunteers and 32 patients. A conventional pressure flow study was performed first. The bladder was refilled, a penile cuff was fitted and after voiding commenced the cuff was inflated in steps of 10 cm. water every 0.75 seconds until urine flow was interrupted. The cuff was rapidly deflated, allowing flow to resume, and the cycle was repeated until the end of voiding. The flow rate was graphed against cuff pressure for each interruption cycle to determine the pressure at which flow was interrupted. This pressure was compared with simultaneous invasive isovolumetric bladder pressure. RESULTS: Invasive and noninvasive pressure measurements agreed well. Average cuff pressure at interruption of flow exceeded mean simultaneous isovolumetric bladder pressure plus or minus standard deviation by 14.5 +/- 14.0 cm. water. CONCLUSIONS: The new method provides noninvasive quantitative information on voiding bladder pressure in males. Further study is required to assess whether the technique can contribute to the management of lower urinary tract symptoms.

Transmission of penile cuff pressure to the penile urethra.

PURPOSE: We developed a noninvasive method to measure voiding bladder pressure by inflating a penile cuff to interrupt flow. We tested the underlying assumption that cuff pressure is transmitted to the penile urethra. MATERIALS AND METHODS: In 35 men we simultaneously recorded penile cuff and urethral pressure during 2 experimental protocols for 6 cuffs of various widths and manufactures. Initially a urethral pressure transducer was placed at the mid point of the cuff and urethral pressure was continuously recorded during cuff inflation. In experiment 2 cuff pressure was set at 120 cm. water and the urethral pressure profile was measured by withdrawing the urethral transducer through the cuff width. RESULTS: There was excellent agreement of cuff with urethral pressure over the range of 0 to 200 cm. water for cuffs 37 to 54 mm. wide. Narrower cuffs showed wider variation with less efficient transmission of cuff pressure to the urethral lumen. Similarly maximum pressure in the urethral pressure profile showed best agreement for cuffs 38 and 46 mm. wide. Wider cuffs produced higher and narrower cuffs produced lower transmitted pressure within the urethra. Cuff performance was also related to penile size. Results had good within-subject repeatability. CONCLUSIONS: We demonstrated that pressure transmission from cuff to urethra is optimal at a cuff width of 40 to 50 mm. and recommended this width for other investigations of noninvasive bladder pressure measurement.

Relation between heart rate and pulse transit time during paced respiration.

Pulse transit time (PTT) is a simple, non-invasive measurement, defined as the time taken from a reference time for the pulse pressure wave to travel to the periphery. PTT is influenced by heart rate, blood pressure changes and the compliance of the arteries, but few quantitative data are available describing the factors which influence PTT. The aim of this study was to investigate the relationship between the cardiac beat-to-beat interval (RR) and PTT, using paced respiration to generate changes in both variables. We analysed PTT and RR interval from 15 normal healthy subjects during paced breathing, and the cross-correlation function between PTT and RR was used to quantify their relationship. Over the 15 subjects, the maximum change in PTT ranged from 7 to 23 ms with a mean +/- standard deviation of 14 +/- 5 ms, and that in RR interval from 86 to 443 ms (241 +/- 102 ms). Examining changes over time, the best correlation (r = +0.69, p < 0.01) was obtained when PTT was advanced relative to RR, with a change in RR followed by a corresponding change in PTT 3.17 +/- 0.76 beats later. We conclude that there is a strong relationship between PTT changes and RR interval changes, but these changes are not in phase.

Objective benefit of laser palatoplasty for non-apnoeic snoring.

Laser palatoplasty (LPP) is widely used for the treatment of non-apnoeic snoring, despite the lack of objective data supporting its use. We report measurements of snoring in a prospective study of LPP, and we compare the results with a previous study of uvulopalatopharyngoplasty (UPPP). Twenty patients with an apnoea/hypopnoea index < 20 h-1 underwent LPP for habitual snoring. Overnight sound recordings were compared before and 6 months after operation using three objective indices; L, (the level exceeded by the loudest 1% of sound), L5 (the level exceeded by the loudest 5% of sound) and P50 (% total sleep time above 50 dBA). The subjective impression of snoring severity (Wilcoxon test, P < 0.001), and objective indices L1 and P50 (t-test, P < 0.001) showed significant reductions after LPP. The mean change in L1 was 4.2 dBA, comparable to that we previously reported for UPPP, while P50 was reduced to less than one-third its preoperative value. No other sleep variables changed significantly following LPP. We conclude that LPP results in reduced snoring volume comparable to that following UPPP.

Psychometric performance before and after laser palatoplasty for non-apnoeic snoring.

Psychometric tests are an objective way of examining cognitive functioning, and have shown impairment in patients with obstructive sleep apnoea. Non-apnoeic snoring may cause reduced concentration, but psychometric tests have been used rarely in this population. We investigate whether their use can demonstrate an improvement in cognitive performance in 20 non-apnoeic snorers following Laser Palatoplasty (LPP). The subjects completed psychometric tests, Beck Anxiety and Depression Inventories and an Epworth Sleepiness Scale on two occasions before LPP and once postoperatively. The only index to show any significant change with LPP was the Beck Depression Inventory (P < 0.005), which was reduced by a mean of 1.6 units following surgery. There was also a highly significant improvement in information processing between the preoperative tests, for which no explanation could be found. Our results suggest that commonly applied psychometric tests are unable to demonstrate significant improvements following surgery for non-apnoeic snoring. However, we have demonstrated for the first time a significant reduction in depression following surgery, which is evidence that snoring is more than a social nuisance.

Interobserver variability in recognizing arousal in respiratory sleep disorders.

Daytime sleepiness is a common consequence of repeated arousal in obstructive sleep apnea (OSA). Arousal indices are sometimes used to make decisions on treatment, but there is no evidence that arousals are detected similarly even by experienced observers. Using the American Sleep Disorders Association (ASDA) definition of arousal in terms of the accompanying electroencephalogram (EEG) changes, we have quantified interobserver agreement for arousal scoring and identified factors affecting it. Ten patients with suspected OSA were studied; three representative EEG events during each of light, slow-wave, and rapid-eye-movement (REM) sleep were extracted from each record (90 events total) and evaluated by experts in 14 sleep laboratories. Observers differed (ANOVA, p < 0.001) in the number of events scored as arousal (totals ranged from 23 to 53 of the 90 events). Overall agreement was moderate (kappa = 0.47), but it was best for events during slow-wave sleep, moderate for REM, and poor for light sleep (kappa = 0.60, 0.52, and 0.28, respectively). Agreement was unrelated to arousal duration. We conclude that the ASDA definition of arousal is only moderately repeatable. Account should be taken of this variability when results from different centers are compared.

Evaluation of activity-based techniques to identify transient arousal in respiratory sleep disorders.

Daytime sleepiness and impaired cognitive function can be a consequence of recurrent transient arousal from sleep. Arousal is often associated with abrupt changes in the electroencephalogram (EEG), and such changes can be used as an index of sleep disturbance, but EEG analysis is laborious and requires trained observers. Possible alternative indices of arousal not reliant on EEG analysis were investigated. Recordings were made from 36 sleeping subjects who were being investigated for sleep-related breathing disorders. In each study awakenings and transient arousals according to EEG criteria were compared with activity in five potential indirect indicators of arousal: wrist movement, ankle movement, left and right tibial electromyogram, and phase change in ribcage-abdominal movement. The mean values of sensitivity to arousal ranged from only 25 to 45%. However, their high positive predictive accuracies (PPAs, 68 to 92%) indicated that activity, when present, was usually associated with arousal. Sensitivity to awakenings was higher (71-87%), though PPAs were lower (42 to 63%). For the indicator based on ribcage-abdominal phase, the number of periods of activity showed a significant relation to the number of arousals (r = 0.70, P < 0.001). It can be concluded that phase changes in chest/abdomen movement are a useful indicator of arousal associated with obstructive apnoea and related conditions. Limb activity has much lower sensitivity for transient arousal, but may be of value in indicating periods of wakefulness.

Automated recognition of EEG changes accompanying arousal in respiratory sleep disorders.

Daytime sleepiness and impaired cognitive function can be a consequence of recurrent transient arousal from sleep, associated with abrupt changes in the electroencephalogram (EEG). EEG is normally assessed by trained observers from paper records, but automation offers the advantages of speed and objectivity. We assessed 10 automated indices of EEG activity as potential indicators of arousal. Arousals from light, slow wave and rapid eye movement sleep were studied in 30 subjects. Segments of EEG recorded immediately before and after each arousal were analyzed by automated measurement of 10 EEG indices using a personal computer. We investigated the ability of each index to recognize arousal while rejecting change due to variability during sleep. Nine of the 10 indices showed significant changes with arousal (p < 0.001); the better indices were related to EEG frequency, and 3 were chosen for further study. In these indices, the mean changes with arousal were 3.8 Hz (ZeroCross), 1.7 Hz (Hjorth's Mobility) and 1.2 Hz (FrqMean, an index of central EEG frequency). With none of these three indices were significant differences in performance due to base sleep stage or subject group found. We conclude that detection of arousal is feasible using automated methods that measure simple indices related to the frequency of the EEG waveform.

Objective measurement of the results of uvulopalatopharyngoplasty.

Thirty-two patients undergoing uvulopalatopharyngoplasty (UPPP) for snoring have been studied prospectively using objective measurement of snoring levels. A significant reduction was found, especially in the supine posture. The quantitative reduction was small and correlations between subjective and objective changes in snoring volume were weak.

Comparison of methods for assessing snoring.

Objective measurements of several sound level indices were made on 32 subjects referred because of snoring and who subsequently underwent uvulopalatopharyngoplasty (UPPP). The measurements were repeated approximately 6 months post-UPPP. The indices were compared with the subjective assessment of snoring by both the subject and his/her bed partner. Correlations between objective and subjective assessments were generally weak and were strongest when the supine posture only was considered. The index which correlated best with subjective assessment was the level which 1% of the sound level samples exceeded.