Macrophage scavenger receptor 1 mediates lipid-induced inflammation in non-alcoholic fatty liver disease

BACKGROUND & AIMS

Obesity-associated inflammation is a key player in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). However, the role of macrophage scavenger receptor 1 (MSR1, CD204) remains incompletely understood.

METHODS

A total of 170 NAFLD liver biopsies were processed for transcriptomic analysis and correlated with clinicopathological features. Msr1^-/- and wild-type mice were subjected to a 16-week high-fat and high-cholesterol diet. Mice and ex vivo human liver slices were treated with a monoclonal antibody against MSR1. Genetic susceptibility was assessed using genome-wide association study data from 1,483 patients with NAFLD and 430,101 participants of the UK Biobank.

RESULTS

MSR1 expression was associated with the occurrence of hepatic lipid-laden foamy macrophages and correlated with the degree of steatosis and steatohepatitis in patients with NAFLD. Mice lacking Msr1 were protected against diet-induced metabolic disorder, showing fewer hepatic foamy macrophages, less hepatic inflammation, improved dyslipidaemia and glucose tolerance, and altered hepatic lipid metabolism. Upon induction by saturated fatty acids, MSR1 induced a pro-inflammatory response via the JNK signalling pathway. In vitro blockade of the receptor prevented the accumulation of lipids in primary macrophages which inhibited the switch towards a pro-inflammatory phenotype and the release of cytokines such as TNF-ɑ. Targeting MSR1 using monoclonal antibody therapy in an obesity-associated NAFLD mouse model and human liver slices resulted in the prevention of foamy macrophage formation and inflammation. Moreover, we identified that rs41505344, a polymorphism in the upstream transcriptional region of MSR1, was associated with altered serum triglycerides and aspartate aminotransferase levels in a cohort of over 400,000 patients.

CONCLUSIONS

Taken together, our data suggest that MSR1 plays a critical role in lipid-induced inflammation and could thus be a potential therapeutic target for the treatment of NAFLD.

LAY SUMMARY

Non-alcoholic fatty liver disease (NAFLD) is a chronic disease primarily caused by excessive consumption of fat and sugar combined with a lack of exercise or a sedentary lifestyle. Herein, we show that the macrophage scavenger receptor MSR1, an innate immune receptor, mediates lipid uptake and accumulation in Kupffer cells, resulting in liver inflammation and thereby promoting the progression of NAFLD in humans and mice.

Evaluation of Spontaneous Swallow Frequency in Healthy People and Those With, or at Risk of Developing, Dysphagia: A Review

Dysphagia is a common and frequently undetected complication of many neurological disorders and of sarcopoenia in ageing persons. Spontaneous swallowing frequency (SSF) has been mooted as a possible tool to classify dysphagia risk. We conducted a review of the literature to describe SSF in both the healthy population and in disease-specific populations, in order to consider its utility as a screening tool to identify dysphagia. We searched Medline, Embase, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials databases. Metadata were extracted, collated and analysed to give quantitative insight. Three hundred and twelve articles were retrieved, with 19 meeting inclusion and quality criteria. Heterogeneity between studies was high (I² = 99%). Mean SSF in healthy younger sub-groups was 0.98/min [CI: 0.67; 1.42]. In the Parkinson's sub-group, mean SSF was 0.59/min [0.40; 0.87]. Mean SSF in healthy older, higher risk and dysphagic populations were similar (0.21/min [0.09; 0.52], 0.26/min [0.10; 0.72] and 0.30/min [0.16; 0.54], respectively). SSF is a novel, non-invasive clinical variable which warrants further exploration as to its potential to identify persons at risk of dysphagia. Larger, well-conducted studies are needed to develop objective, standardised methods for detecting SSF, and develop normative values in healthy populations.

A Bioreactor Technology for Modeling Fibrosis in Human and Rodent Precision-Cut Liver Slices

Precision cut liver slices (PCLSs) retain the structure and cellular composition of the native liver and represent an improved system to study liver fibrosis compared to two-dimensional mono- or co-cultures. The aim of this study was to develop a bioreactor system to increase the healthy life span of PCLSs and model fibrogenesis. PCLSs were generated from normal rat or human liver, or fibrotic rat liver, and cultured in our bioreactor. PCLS function was quantified by albumin enzyme-linked immunosorbent assay (ELISA). Fibrosis was induced in PCLSs by transforming growth factor beta 1 (TGFβ1) and platelet-derived growth factor (PDGFββ) stimulation ± therapy. Fibrosis was assessed by gene expression, picrosirius red, and α-smooth muscle actin staining, hydroxyproline assay, and soluble ELISAs. Bioreactor-cultured PCLSs are viable, maintaining tissue structure, metabolic activity, and stable albumin secretion for up to 6 days under normoxic culture conditions. Conversely, standard static transwell-cultured PCLSs rapidly deteriorate, and albumin secretion is significantly impaired by 48 hours. TGFβ1/PDGFββ stimulation of rat or human PCLSs induced fibrogenic gene expression, release of extracellular matrix proteins, activation of hepatic myofibroblasts, and histological fibrosis. Fibrogenesis slowly progresses over 6 days in cultured fibrotic rat PCLSs without exogenous challenge. Activin receptor-like kinase 5 (Alk5) inhibitor (Alk5i), nintedanib, and obeticholic acid therapy limited fibrogenesis in TGFβ1/PDGFββ-stimulated PCLSs, and Alk5i blunted progression of fibrosis in fibrotic PCLS. Conclusion: We describe a bioreactor technology that maintains functional PCLS cultures for 6 days. Bioreactor-cultured PCLSs can be successfully used to model fibrogenesis and demonstrate efficacy of antifibrotic therapies.

Functional Visual Loss in Cambodian Refugees: A Study of Cultural Factors in Ophthalmology

South East (SE) Asians accounted for a disproportionate percentage of the functional visual loss (FVL) seen in our area between 1983 and 1987. Moreover, 94% of the SE Asian FVL patients were Cambodian, although Cambodians only represented 20-30% of the local SE Asian patient population. Cambodian refugees are, at present, generally from lower socio-economic classes than the Vietnamese, and a much larger percentage of them have a history of camp incarceration and previous trauma. The Cambodians presenting with FVL may have conversion hysteria influenced by their wartime experience and cultural background. This study demonstrates that the SE Asian refugees in California are not a homogenous group with respect to visual problems, and that an awareness of cultural or historical factors can be important to the management of ophthalmic symptoms in our multi-cultural societies.

Swallowing performance and tube feeding status in patients treated with parotid-sparing intensity-modulated radiotherapy for head and neck cancer

BACKGROUND

The purpose of this prospective study was to evaluate the swallowing performance of patients with head and neck cancer treated with parotid-sparing intensity-modulated radiotherapy (IMRT).

METHODS

Sixty-two patients were recruited. Data were collected before and up to 12 months after treatment. Measures included the Performance Status Scale for head and neck cancer (PSS-HN Normalcy of Diet and Eating in Public subscales), tube feeding status, and 100 mL water swallow test (WST) volume and capacity scores.

RESULTS

There was a significant reduction in PSS-HN and WST scores from baseline to 3 months (p < .001). Significant improvements were observed up to 12 months on the PSS-HN. Swallowing volume and capacity scores recovered but did not reach statistical significance. Tube feeding was not required in 47% of the patients.

CONCLUSION

IMRT significantly impacts on swallowing performance, although there is a trend for improvement up to 12 months after treatment. Our data support a case-by-case approach to tube feeding. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1436-E1444, 2016.

Patient-reported outcomes following parotid-sparing intensity-modulated radiotherapy for head and neck cancer. How important is dysphagia?

OBJECTIVES

Swallowing can be significantly affected during and following radiotherapy for head and neck cancer (HNC). The purpose of this study was to understand: (1) the trajectory of swallowing recovery following parotid-sparing intensity-modulated radiotherapy (IMRT) and (2) overall physical and social-emotional wellbeing and how patients prioritise swallowing following treatment.

MATERIALS AND METHODS

Sixty-one HNC patients completed questionnaires as part of a prospective study exploring patient-reported swallowing outcomes following parotid-sparing IMRT. Participants were asked to complete the M.D. Anderson Dysphagia Inventory (MDADI) and University of Washington Quality of Life Questionnaire (UW-QoL) v.04 before treatment and 3, 6 and 12months after treatment. Given the rise in human papilloma virus (HPV) and associated oropharyngeal cancers, we completed a sub analysis of the data in those participants.

RESULTS

There was a significant reduction in the MDADI composite scores 3months after completion of treatment. Improvements were observed by 12months, however, scores did not recover to baseline. The recovery in physical function was limited in comparison to social-emotional recovery at 12months. When oropharyngeal cancer scores were analysed, there was not a substantial difference to the whole group results. There was a shift in priorities following treatment. Swallowing was highlighted as a concern by 44% of HNC patients up to 12months after treatment with swallowing-related factors (saliva, taste and chewing) rated highly.

CONCLUSIONS

Patient reported swallowing outcomes were significantly affected from baseline to all follow-up time points and remained a priority concern at 12months following treatment. Overall social-emotional functioning does improve, suggesting that patients have the potential to adapt to their "new normal" following IMRT for HNC.

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.

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.

Voice loudness and gender effects on jitter and shimmer in healthy adults

PURPOSE

The aim of this study was to investigate voice loudness and gender effects on jitter and shimmer in healthy young adults because previous descriptions have been inconsistent.

METHOD

Fifty-seven healthy adults (28 women, 29 men) aged 20-40 years were included in this cross-sectional single-cohort study. Three phonations of /a/ at soft, medium, and loud individual loudness were recorded and analyzed using PRAAT software (P. Boersma & D. Weeninkk, 2006). Voice loudness and gender effects on measured sound pressure level, fundamental frequency, jitter, and shimmer were assessed through the use of descriptive and inferential (analysis of variance) statistics.

RESULTS

Jitter and shimmer significantly increased with decreasing voice loudness, especially in phonations below 75 dB and 80 dB. In soft and medium phonation, men were generally louder and showed significantly less shimmer. However, men had higher jitter measures when phonating softly. Gender differences in jitter and shimmer at medium loudness may be mainly linked to different habitual voice loudness levels.

CONCLUSION

This pragmatic study shows significant voice loudness and gender effects on perturbation. In clinical assessment, requesting phonations above 80 dB at comparable loudness between genders would enhance measurement reliability. However, voice loudness and gender effects in other age groups, in disordered voices, or when a minimal loudness is requested should be further investigated.

Assessing penetration and aspiration: how do videofluoroscopy and fiberoptic endoscopic evaluation of swallowing compare?

OBJECTIVES/HYPOTHESIS

We aimed to investigate whether the type of dysphagia examination (fiberoptic endoscopic evaluation of swallowing [FEES] or videofluoroscopy) influences the scoring of penetration and aspiration.

STUDY DESIGN

Prospective, single-blind study.

METHODS

Fifteen dysphagic participants were recruited and underwent one FEES and one videofluoroscopy examination, performed and recorded simultaneously. Fifteen independent raters from 12 centers scored penetration and aspiration from recordings using the Penetration Aspiration Scale. Raters were blind to participant details, the pairing of the FEES and videofluoroscopy recordings, and the other raters' scores. Interrater and intrarater reliability were analyzed using weighted kappa.

RESULTS

The Penetration Aspiration Scale scores were significantly higher for the FEES recordings than for the videofluoroscopy recordings (ANOVA P < .001). The mean difference between the FEES and videofluoroscopy penetration aspiration scores for the same swallows was 1.15 points. Interrater and intrarater reliability ranged from 0.64 to 0.79 (weighted kappa).

CONCLUSIONS

Penetration aspiration is perceived to be greater (more severe) from FEES than videofluoroscopy images. The clinical implications are discussed.

Nonpharmacologic Effects of Botulinum Toxin on the Life Quality of Patients with Spasmodic Dysphonia

OBJECTIVE

Botulinum toxin (BT) injection improves objective and subjective voice measurements in spasmodic dysphonia; however, it is not clear whether the results are entirely caused by the neuromuscular blocking effects of BT or whether other factors (e.g., psychological or emotional) play a part. The aim of this study is to investigate whether nonpharmacologic factors contribute to the changes observed in the quality of life (QoL) after BT treatment of spasmodic dysphonia.

STUDY DESIGN

Prospective cohort study.

METHODS

Thirty-eight consecutive spasmodic dysphonic patients attending for repeat BT injections were investigated by recording their Voice Handicap Index (VHI) scores at three time points: 1) immediately prior to injection (baseline), 2) 1 day postinjection (when least pharmacologic change is expected), and 3) 2 weeks postinjection (when most pharmacologic change is expected). The changes in the total and domain VHI scores were compared between the two postinjection scores and the baseline value using two-way analysis of variance and the post hoc Bonferroni test.

RESULTS

Most of the change in VHI score occurred between the baseline and first postinjection measurement. For two of the domains (total and emotional), the change was statistically significant. The change between the two postinjection assessments was minimal, and no domain showed statistically significant change.

CONCLUSIONS

Our data indicate that the early improvements in QoL after BT injection can only in small part be attributed to the neurotoxic effects of the agent. We cannot say whether the reported effects in our study are attributable to a strong placebo response or are a real consequence of the patient's changing emotional state.

Oropharyngeal dysphagia: the experience of patients with non-head and neck cancers receiving specialist palliative care

BACKGROUND

Difficulty swallowing is a well-documented symptom in head and neck cancer and oesophageal malignancy. The frequency of oropharyngeal swallowing difficulties in the palliative phase of other malignancies is less reported.

AIM

1) To describe the patient experience of swallowing and associated difficulties while receiving specialist palliative care for malignancies other than those affecting the head and neck and 2) to identify the quality of life issues for the participants with dysphagia and compare with normative and dysphagic data provided by SWAL-QOL.

DESIGN

Four month prospective pilot study - questionnaire design.

SETTING

Acute teaching hospital.

PARTICIPANTS

Eleven patients receiving specialist palliative care.

METHODS

Participants were interviewed using a modified version of the SWAL-QOL, a validated quality of life assessment tool for use specifically with people with oropharyngeal dysphagia. Eight quality of life domains were explored as well as fourteen dysphagic symptoms.

RESULTS

Seven of the 11 participants had dysphagic symptoms detailed in the SWAL-QOL and a further two patients reported transient dysphagic symptoms since diagnosis of their disease. Nine participants reported an impact on their quality of life and three reported a considerable impact in four or more domains. Eight of the 11 participants had self-selected softer textured foods. A notable group were three patients with lung cancer and one with lung metastases with a history of vocal fold motion impairment, all of who had experienced dysphagic symptoms since diagnosis.

CONCLUSIONS

Patients with cancers not affecting the head and neck are at risk of developing symptoms of oropharyngeal dysphagia and subsequently, compromized nutrition, hydration and quality of life. Areas for further research are suggested.

Compliance with Dysphagia Recommendations by Carers of Adults with Intellectual Impairment

Health risks associated with dysphagia in adults with intellectual impairment are well documented. There is little research into compliance with dysphagia recommendations in environments where care is provided for adults with intellectual impairment. This is a pilot study into carer compliance with Speech-Language Pathology recommendations. We aimed to investigate the level of compliance with dysphagia recommendations in day centers and the factors that might affect compliance using a questionnaire. Twenty-seven clients were observed. Results showed an overall high level of compliance with recommendations (82%), with figures ranging from 64% compliance with appropriate utensils to 100% with direct support recommendations. Areas of noncompliance were evident, with level of dependence of clients and training of carers being key issues. Implications for practitioners are discussed.

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.

Objective Computer-Based Assessment of Valleculae Residue – Is It Useful?

There have been questions about the reliability of subjective rating scales used to assess valleculae residue from fluoroscopic images. The aim of this study was to assess interrater agreement on one such scale, and compare it with agreement using a new objective measurement scale. Five speech and language therapists rated 100 valleculae residue still images from 20 consecutive patients using standard clinical practice (i.e., subjective visual grading of the videofluoroscopy still and rating as none, mild, moderate, or severe). The images were rerated by the same clinicians using Picture Archiving Communication System measurement tools. The valleculae residue ratio relates the residue size to the size of an individual's valleculae. A valleculae residue ratio scale was devised using a linear classifier, which defines the cutoff between grades of valleculae residue (none, mild, moderate, and severe). The new method proved at least as reliable as the traditional method; for interrater reliability, kappa = 0.73 vs. 0.73; for intrarater reliability, kappa = 0.87 vs. 0.85. The valleculae residue ratio is proposed as a new quick reliable method of quantifying residue where the Picture Archiving Communication System is available. We now wish to test the impact of this method where poor inter- and intrarater reliability exists.

Cervical Auscultation Synchronized with Images from Endoscopy Swallow Evaluations

Cervical auscultation is the use of a listening device, typically a stethoscope in clinical practice, to assess swallow sounds and by some definitions airway sounds. Judgments are then made on the normality or degree of impairment of the sounds. Listeners interpret the sounds and suggest what might be happening with the swallow or causing impairment. A major criticism of cervical auscultation is that there is no evidence on what causes the sounds or whether the sounds correspond to physiologically important, health-threatening events. We sought to determine in healthy volunteers (1) if a definitive set of swallow sounds could be identified, (2) the order in which swallow sounds and physiologic events occur, and (3) if swallow sounds could be matched to the observed physiologic events. Swallow sounds were computer recorded via a Littmann stethoscope from 19 healthy volunteers (8 males, 11 females, age range = 18-73 years) during simultaneous fiberoptic laryngoscopy and respiration monitoring. Six sound components could be distinguished but none of these occurred in all swallows. There was a wide spread and a large degree of overlap of the timings of swallow sounds and physiologic events. No individual sound component was consistently associated with a physiologic event, which is a clinically significant finding. Comparisons of groups of sounds and events suggest associations between the preclick and the onset of apnea; the preclick and the start of epiglottic excursion; the click and the epiglottis returning to rest; the click and the end of the swallow apnea. There is no evidence of a causal link. The absence of a swallow sound in itself is not a definite sign of pathologic swallowing, but a repeated abnormal pattern may indicate impairment. At present there is no robust evidence that cervical auscultation of swallow sounds should be adopted in routine clinical practice. There are no data to support the inclusion of the technique into clinical guidelines or management protocols. More evaluation using imaging methods such as videofluoroscopy is required before this subjective technique is validated for clinical use by those assessing swallowing outside of a research context.

Adult Dysphagia Assessment in the UK and Ireland: Are SLTs Assessing the Same Factors?

This is the first study to examine dysphagia assessment practices of UK/Ireland speech and language therapists. The aims were to (1) examine practice patterns across clinicians, (2) determine levels of consistency in practice, and (3) compare practices of clinicians in the UK/Ireland with those previously reported of clinicians in the United States. A questionnaire, developed for earlier U.S. research, was adapted following a pilot study. The resulting email survey was completed by 296 speech and language therapists working with dysphagic adults. Respondents were asked to rate how frequently they use 31 components of a clinical dysphagia examination. Consistency was determined by calculating the percentage of respondents who agreed on frequency of use. Low frequency of use was reported for four components: trials with compensatory techniques, obtain patient's drug history, assessment of speech articulation/intelligibility, and screening/assessment of mental abilities. Variability among clinicians was high, with inconsistency observed for 6/31 components (19%) and high consistency for only 10/31 (32%). Results were compared with data from the earlier U.S. study. Notable differences in practice were observed for five components: cervical auscultation, trials with compensatory techniques, gag reflex, assessment of sensory function, and screening/assessment of mental abilities. Inconsistency among UK/Ireland clinicians was higher than in the comparator U.S. study. The clinical implications of these findings are discussed.

Voice Care Knowledge Among Clinicians and People With Healthy Voices or Dysphonia

An important clinical component in the prevention and treatment of voice disorders is voice care and hygiene. Research in voice care knowledge has mainly focussed on specific groups of professional voice users with limited reporting on the tool and evidence base used. In this study, a questionnaire to measure voice care knowledge was developed based on "best evidence." The questionnaire was validated by measuring specialist voice clinicians' agreement. Preliminary data are then presented using the voice care knowledge questionnaire with 17 subjects with nonorganic dysphonia and 17 with healthy voices. There was high (89%) agreement among the clinicians. There was a highly significant difference between the dysphonic and the healthy group scores (P = 0.00005). Furthermore, the dysphonic subjects (63% agreement) presented with less voice care knowledge than the subjects with healthy voices (72% agreement). The questionnaire provides a useful and valid tool to investigate voice care knowledge. The findings have implications for clinical intervention, voice therapy, and health prevention.

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.

The Effectiveness of a Voice Treatment Approach for Teachers With Self-Reported Voice Problems

SUMMARY

Teachers are considered the professional group most at risk of developing voice-problems, but limited treatment effectiveness evidence exists. We studied prospectively the effectiveness of a 6-week combined treatment approach using vocal function exercises (VFEs) and vocal hygiene (VH) education with 20 teachers with self-reported voice problems. Twenty subjects were randomly assigned to a no-treatment control (n = 11) and a treatment group (n = 9). Fibreoptic endoscopic evaluation was carried out on all subjects before randomization. Two self-report voice outcome measures were used: the Voice-Related Quality of Life (VRQOL) and the Voice Symptom Severity Scale (VoiSS). A Voice Care Knowledge Visual Analogue Scale (VAS), developed specifically for the study, was also used to evaluate change in selected voice knowledge areas. A Student unpaired t test revealed a statistically significant (P < 0.05) improvement in the treatment group as measured by the VoiSS. There was not a significant improvement in the treatment group as measured by the V-RQOL. The difference in voice care knowledge areas was also significant for the treatment group (P < 0.05). This study suggests that a voice treatment approach of VFEs and VH education improved self-reported voice symptoms and voice care knowledge in a group of teachers.

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.

Comparison of manual sleep staging with automated neural network-based analysis in clinical practice

We have compared sleep staging by an automated neural network (ANN) system, BioSleep (Oxford BioSignals) and a human scorer using the Rechtschaffen and Kales scoring system. Sleep study recordings from 114 patients with suspected obstructed sleep apnoea syndrome (OSA) were analysed by ANN and by a blinded human scorer. We also examined human scorer reliability by calculating the agreement between the index scorer and a second independent blinded scorer for 28 of the 114 studies. For each study, we built contingency tables on an epoch-by-epoch (30 s epochs) comparison basis. From these, we derived kappa (kappa) coefficients for different combinations of sleep stages. The overall agreement of automatic and manual scoring for the 114 studies for the classification {wake / light-sleep / deep-sleep / REM} was poor (median kappa = 0.305) and only a little better (kappa = 0.449) for the crude {wake / sleep} distinction. For the subgroup of 28 randomly selected studies, the overall agreement of automatic and manual scoring was again relatively low (kappa = 0.331 for {wake light-sleep / deep-sleep REM} and kappa = 0.505 for {wake / sleep}), whereas inter-scorer reliability was higher (kappa = -0.641 for {wake / light-sleep / deep-sleep / REM} and kappa = 0.737 for {wake / sleep}). We conclude that such an ANN-based analysis system is not sufficiently accurate for sleep study analyses using the R&K classification system.

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.

Swallow Respiratory Patterns and Aging: Presbyphagia or Dysphagia?

BACKGROUND

Assessment referrals are increasing for unexpected dysphagia, particularly for older people. It is unclear if this is due to more impaired swallows or healthy age-related changes. Swallow respiration coordination prevents aspiration, and may deteriorate with age. Nonpathological features of the swallow in healthy aging and the factors that influence an individual's ability to eat and drink safely need greater understanding. Some changes might predispose an older person to dysphagic complications in the event of an insult such as a stroke. We investigated the effects of healthy aging on resting and swallow respiratory patterns.

METHODS

Fifty healthy volunteers (aged 20-78 years) were recruited to have swallow respiration patterns recorded on a computer. Bolus volume and consistency variations were studied: 5 and 20 ml of water and 5 ml of yogurt.

RESULTS

Measurable swallows significantly decreased with age for water boluses. Swallow apnea increased with age (5 ml of water r = 0.433, p = .002; 5 ml of yogurt r = 0.367, p = .023). Independent of age were: breathing out (occurred after 98% of boluses); multiple swallowing (occurred with all bolus types); post-swallow respiration reset pattern (more irregular after yogurt, Wilcoxon signed rank Z = -2.236, p = .025); and resting respiration.

CONCLUSIONS

Subtle changes occur in swallow respiration coordination with age. These changes may be compensatory protective mechanisms rather than the result of decreased muscle mobility or reaction times, and not indicative of impairment. Misattributing healthy age-related changes to impairment affects patient care and the use of healthcare resources.

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 ASSESSMENT OF BLADDER CONTRACTILITY IN MEN

PURPOSE

Preoperative assessment of detrusor function by pressure flow study (PFS) improves outcome from prostatectomy but is invasive and uncomfortable for the patient. We report on a large scale validation of a novel noninvasive assessment of detrusor contractility.

MATERIALS AND METHODS

A flexible cuff placed around the penis was inflated automatically during voiding until flow interruption. Cuff pressure at interruption (pcuff.int) reflects isovolumetric bladder pressure (pves.isv), a measure of detrusor contractility. For comparison 151 symptomatic men performed the cuff test with simultaneous PFS monitoring. Test/retest agreement was assessed in 91 subjects who performed a cuff test without PFS on 2 occasions.

RESULTS

For the 117 (77%) subjects with an acceptable cuff pressure flow trace, Bland Altman analysis showed that pcuff.int overestimated pves.isv by a mean (s.d.) of 16.4 (27.5) cm H2O, predominantly due to the cuff being positioned below the bladder. For test/retest analysis 52 (57%) of the men who were able to attend twice provided acceptable cuff data on both occasions with a mean (s.d.) difference in pcuff.int of -3.3 (32.0) cm H2O, improving to 0.0 (20.3) cm H2O in a subgroup of 39 subjects who voided more than 150 ml. On questionnaire assessment 121 (80%) subjects preferred the cuff test to PFS.

CONCLUSIONS

The cuff test gives a valid and reproducible estimate of isovolumetric bladder pressure in a manner acceptable to patients, although test failure and variability of agreement require improvement. The test may be of value in the assessment of urinary symptoms and may aid in patient selection for prostatectomy.

Reliability and validity of cervical auscultation: a controlled comparison using videofluoroscopy

Cervical auscultation is experiencing a renaissance as an adjunct to the clinical swallowing assessment. It is a controversial technique with a small evidence base. We have aimed to establish whether cervical auscultation interpretation is based on the actual sounds heard or, in practice, influenced by information gleaned from other aspects of the clinical assessment, medical notes, or previous knowledge. We sought to determine (a) rater reliability and its impact on the clinical value of cervical auscultation and (b) how judgments compare with the "gold standard": videofluoroscopy. Swallow sounds were computer recorded via a Littmann stethoscope. Sounds were sampled from 10 healthy control swallows with no aspiration/penetration and 10 patient swallows with aspiration/penetration, all recorded during simultaneous videofluoroscopy. The system generated sound quality similar to "live" bedside listening, a feature rarely seen in cervical auscultation studies. The 20 sound clips were classified as "normal" or "abnormal" by 19 volunteer speech-language pathologists with experience in cervical auscultation. After at least four weeks, 11 of these judges rated the sounds rerandomized on a new CD. Intrarater reliability kappa ranged from -0.12 to 0.71. Individual reliability did not correlate with years of experience, practice pattern, or frequency of use. Interrater reliability kappa = 0.17. Comparison with radiologically defined aspiration/penetration yielded 66% specificity, 62% sensitivity, and majority consensus gave 90% specificity, 80% sensitivity. There was a significant relationship between individual reliability and true positive rate (r(s) = 0.623, p = 0.040). The reliability of individual judges varied widely and thus, inevitably, agreement between judges was poor. Validity is dependent upon reliability: Improving the poor raters would improve the overall accuracy of this technique in predicting abnormality in swallowing. The group consensus correctly identified 17 of the 20 clips so we may speculate that the swallow sound contains audible cues that should in principle permit reliable classification.

Inter-observer agreement in the estimation of bladder pressure using a penile cuff

AIMS

Objective data are useful in quantifying a patient's lower urinary tract symptoms (LUTS). We are investigating the use of an inflatable penile cuff to obstruct flow progressively during voiding, and thereby determine the pressure p(cuff,int) at which flow is interrupted. The aim of this study was to determine the agreement between experienced observers in their estimates of p(cuff,int).

METHODS

We recorded 486 cuff inflation cycles during 142 voids from 42 subjects recruited from urology out-patient's and prostate assessment clinics. Each inflation cycle was assessed independently by three experienced observers, a total of 1,458 ratings. According to our standard assessment procedure, the observers (i) indicated whether the inflation should be analyzed, (ii) estimated p(cuff,int) for those inflation cycles judged suitable for analysis, and (iii) discarded measurements that were clearly inconsistent with others from the same voiding cycle.

RESULTS

Overall, 689 of the 1,458 ratings (45%) were excluded, with just 4% of all ratings discarded for inconsistency. For 385 of the 486 inflation cycles (79%) there was complete agreement that the cycle should or should not be analyzed. Thereafter, for the 262 inflation cycles analyzed by two or three observers, the overall SD error in measurements of p(cuff,int) was 4.6 cm H(2)O.

CONCLUSIONS

We conclude that there is good agreement between experienced observers in their interpretation of data from the cuff test. For practical purposes, there is no need for multiple observers in the clinical application of the cuff method.

Assessment of prostatic obstruction: A cuff may be enough

AIMS

To investigate the use of an inflatable perile cuff to obstruct flow progressively during voiding in order to provide a noninvasive measure of bladder pressure.

METHODS

In this study, we explain the observed relationship of flow rate with applied cuff pressure by analogy with a simple physical model. The model comprised a fixed-pressure reservoir (simulating the bladder), a collapsible tube around which a fixed pressure could be applied (simulating the prostatic urethra), connected by rigid conduit to a further collapsible tube around which pressure could be applied (simulating the penile urethra and cuff). Flow was progressively obstructed by incremental increase of pressure applied to the "penile urethra," with the experiment being repeated for a range of fixed pressures applied to the "prostatic urethra."

RESULTS

The model reproduced the typical pressure/flow curves recorded during voiding by using penile cuff inflation in normal and obstructed men.

CONCLUSIONS

Our data led us to hypothesise that the relationship between cuff pressure and flow rate can be used to deduce bladder pressure during voiding, prostatic opening pressure, and urethral diameter at the flow-controlling zone, three indicators of lower urinary tract function. These measurements may add to the accuracy of diagnosis and quality of care for a large number of men with lower urinary tract symptoms.

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.

Resting respiration in dysphagic patients following acute stroke

The aim of this study was to examine respiration characteristics at rest in healthy volunteers and patients with poststroke dysphagia, using a simple notebook computer-based system. Eighteen patients (age range=51-82 years) with dysphagia poststroke and 50 healthy volunteers (age range=20-78 years) were recruited. The patient group had a wide range of stroke severity as assessed using the Scandinavian Stroke Score (SSS 6-51) and Barthel Index (BI 2-20). Length of breathing cycle, rate, and a measure of the variability of the cycle length were examined. The patient group had a shorter mean cycle length (2.93 s compared with 3.91 s, p < 0.01) and hence faster respiration rate (0.35 Hz compared with 0.26 Hz, p < 0.01). The control group showed greater variability in the cycle length (10.78% compared with 6.56%, p = 0.01). There was no correlation between the SSS and BI and resting respiration variables. This suggests that it is not stroke severity alone that affects breathing. The differences observed in resting respiratory rate suggest that respiratory monitoring as a useful adjunct to the clinical bedside assessment warrants further investigation.

Swallow respiration patterns in dysphagic patients following acute stroke

The aim of this study was to examine swallow respiratory characteristics using a notebook computer system. A relatively simple system assessing easily identifiable features is more likely to be incorporated into everyday clinical practice. Eighteen patients (age range = 51-82 years) with dysphagia poststroke and 50 healthy volunteers (age range = 20-78 years) were recruited. The patient group was less likely to always breathe out postswallow on water (9/15 cf 46/49), and some did not breathe out immediately postswallow at all (3/15 cf 0/49, p < 0.01). The pattern was similar with yogurt. Multiple swallowing was identified in the patient group and surprisingly with a large number of the volunteers for all bolus types but was more common in the patient group (p < 0.01). This trait is usually attributed to impaired swallows; that it is prevalent in the normal population has implications for using it as a dysphagia marker in clinical assessments. Yogurt has intrinsic features that increase multiple swallowing and caution should be used when identifying an impairment based on multiple swallowing with such a test substance. In the control group there was a high correlation of swallow apnea on 5 mL of water compared with 20 mL of water (r = 0.759, p < 0.01) and 5 mL of yogurt (r = 0.871, p < 0.01), indicating a possible individual swallow respiration pattern. This was also evident in the patient group. No significant difference in length of swallow apnea was found between the two groups. No evidence was found to link swallow respiration characteristics with aspiration as identified on simultaneous videofluoroscopy. The patient group had a wide range of impairments which suggests that stroke severity is not the sole determinant of swallow respiratory changes.

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.

Respiratory muscle activity and oxygenation during sleep in patients with muscle weakness

Patients with respiratory muscle weakness show nocturnal hypoventilation, with oxygen desaturation particularly during rapid eye movement (REM) sleep, but evidence in individuals with isolated bilateral diaphragmatic paresis (BDP) is conflicting. The effect of sleep on relative activity of the different respiratory muscles of such patients and, consequently, the precise mechanisms causing desaturation have not been clarified. We have studied eight patients, four with generalized muscle weakness and four with isolated BDP during nocturnal sleep with measurements including oxygen saturation and surface electromyographic (EMG) activity of various respiratory muscle groups. Nocturnal oxygenation correlated inversely with postural fall in vital capacity, an index of diaphragmatic strength. During REM sleep, hypopnoea and desaturation occurred particularly during periods of rapid eye movements (phasic REM sleep). In most subjects, such events were "central" in type and associated with marked suppression of intercostal muscle activity, but two subjects had recurrent desaturation due to "obstructive" hypopnoea and/or apnoea. Expiratory activity of the external oblique muscle was present whilst awake and during non-rapid eye movement (NREM) sleep in seven of the eight subjects in the semirecumbent posture. This probably represents an "accessory inspiratory" effect, which aids passive caudal diaphragmatic motion as the abdominal muscles relax at the onset of inspiration. Expiratory abdominal muscle activity was suppressed in phasic REM sleep, suggesting that loss of this "accessory inspiratory" effect may contribute to "central" hypopnoea. We conclude that, in patients with muscle weakness, nocturnal oxygenation correlates with diaphragmatic strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory muscle activity and oxygenation during sleep in patients with muscle weakness

Patients with respiratory muscle weakness show nocturnal hypoventilation, with oxygen desaturation particularly during rapid eye movement (REM) sleep, but evidence in individuals with isolated bilateral diaphragmatic paresis (BDP) is conflicting. The effect of sleep on relative activity of the different respiratory muscles of such patients and, consequently, the precise mechanisms causing desaturation have not been clarified. We have studied eight patients, four with generalized muscle weakness and four with isolated BDP during nocturnal sleep with measurements including oxygen saturation and surface electromyographic (EMG) activity of various respiratory muscle groups. Nocturnal oxygenation correlated inversely with postural fall in vital capacity, an index of diaphragmatic strength. During REM sleep, hypopnoea and desaturation occurred particularly during periods of rapid eye movements (phasic REM sleep). In most subjects, such events were "central" in type and associated with marked suppression of intercostal muscle activity, but two subjects had recurrent desaturation due to "obstructive" hypopnoea and/or apnoea. Expiratory activity of the external oblique muscle was present whilst awake and during non-rapid eye movement (NREM) sleep in seven of the eight subjects in the semirecumbent posture. This probably represents an "accessory inspiratory" effect, which aids passive caudal diaphragmatic motion as the abdominal muscles relax at the onset of inspiration. Expiratory abdominal muscle activity was suppressed in phasic REM sleep, suggesting that loss of this "accessory inspiratory" effect may contribute to "central" hypopnoea. We conclude that, in patients with muscle weakness, nocturnal oxygenation correlates with diaphragmatic strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Respiratory muscle activity during rapid eye movement (REM) sleep in patients with chronic obstructive pulmonary disease

BACKGROUND

In patients with chronic obstructive pulmonary disease (COPD) periods of hypopnoea occur during rapid eye movement (REM) sleep, but the mechanisms involved are not clear.

METHODS

Ten patients with stable COPD were studied during nocturnal sleep. Detailed measurements were made of surface electromyographic (EMG) activity of several respiratory muscle groups and the accompanying chest wall motion using magnetometers.

RESULTS

Hypopnoea occurred in association with eye movements during phasic rapid eye movement (pREM) sleep. During pREM sleep there were reductions in EMG activity of the intercostal, diaphragm, and upper airway muscles compared with non-REM sleep. Episodic hypopnoea due to partial upper airway occlusion ("obstructive" hypopnoea) was seen consistently in four subjects while the others showed the pattern of "central" hypopnoea accompanied by an overall reduction in inspiratory muscle activity. Although activity of the intercostal muscles was reduced relatively more than that of the diaphragm, lateral rib cage paradox (Hoover's sign) was less obvious during pREM-related hypopnoea than during wakefulness or non-REM sleep.

CONCLUSIONS

Hypopnoea during REM sleep in patients with COPD is associated with reduced inspiratory muscle activity. The pattern of hypopnoea may be either "obstructive" or "central" and is generally consistent within an individual. Relatively unopposed action of the diaphragm on the rib cage during REM sleep is not accompanied by greater lateral inspiratory paradox.

Automated measurement of the cyclic activity of respiratory muscles

A microcomputer-based system developed for the automated analysis of the electromyogram (EMG) recorded from respiratory muscles in a variety of situations is described. In addition, an assessment of the performance of the system is presented, along with data relating intercostal EMG activity to ribcage movement in seated subjects. Studies were performed on sixteen normal subjects--non smokers, mean (+/- SD) age 31 (+/- 6) years, mean (+/- SD) mass 78 (+/- 8) kg--of which fifteen studies proved suitable for analysis. Each study lasted for a period of five minutes, during which time recordings of intercostal EMG, ribcage postero-anterior displacement (RCPA) and airflow were made. For every breath taken by each of the subjects, the peak integrated EMG activity (iEMGpeak) was measured both by hand and by the automated system. The automated and manual measurements of iEMGpeak, which ranged from 0.0 to 91.3 microV, differed by only -0.82 +/- 3.34 microV (mean +/- SD). The index iEMGpeak and two additional indices of iEMG activity (iEMGmean, iEMGarea) were evaluated with respect to RCPA, a measure of overall respiratory activity. The indices of iEMG were observed to show an exponential dependence on RCPAamp, the amplitude of ribcage motion. Following a log transformation to linearise the relationship, the correlation of each index with RCPAamp was evaluated; iEMGpeak and iEMGarea correlated similarly with RCPAamp (no significant difference at 5% level), but iEMGmean was found to be a significantly different (p < 0.001) and poorer correlate. We conclude that the automated analysis of respiratory iEMG as described in this paper can provide results showing consistency with manual measurement.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of sound recording and oxygen saturation in screening snorers for obstructive sleep apnoea

It is desirable to screen snoring patients for obstructive sleep apnoea (OSA) prior to surgical treatment. We postulated that the addition of a sound profile would increase the value of overnight oxygen saturation (SaO2) as a screening method. Thirty-nine polysomnographic studies including sound level measured by calibrated meter were performed on snorers being considered for uvulopalato-pharyngoplasty (UPPP). Polysomnography showed an apnoea/hypopnoea index (AHI) > or = 15 per hour of sleep in seven subjects. Two experienced observers independently, without knowledge of other data, classified paper records of SaO2 alone and SaO2 plus sound level obtained during polysomnography as OSA 'unlikely', 'equivocal' or 'definite'. The addition of sound to SaO2 reduced the number of equivocal results from 14 to six and increased the number classified as 'definite' or 'unlikely'. The sensitivity of oximetry +/- sound increased as the threshold AHI used in the definition of OSA increased; addition of sound improved recognition of mild OSA without impairing specificity.