Mandibular Distalisation for Tooth Wear in Patients Requiring Mandibular Protrusion for Sleep Apnoea

BACKGROUND

Pathological tooth wear is an increasing concern and may require intervention and occlusal rehabilitation. Often the treatment includes distalisaton of the mandible to restore the dentition in centric relation. Obstructive sleep apnoea (OSA) is another condition treated my mandibular repositioning but in this case by an advancement appliance. The authors have a concern that there could be a group of patients with both conditions where distalisation for their tooth wear management would be contrary to their OSA treatment. This paper aims to look at this potential risk.

METHODS

A literature search was carried out using the following keywords (OSA or sleep apnoea or apnea or snoring or AHI or Epworth score) and for tooth surface loss (TSL or distalisation or centric relation or tooth wear or full mouth rehabilitation).

RESULTS

No studies were identified which considered the effect of mandibular distalisation on OSA.

CONCLUSION

There is a theoretical risk that dental treatment involving distalisation may adversely affect patients at risk of OSA or worsening their condition due to the modification of airway patency. Further study is recommended.

Self-reported sleepiness in the context of fitness-to-drive

Background

Excessive daytime sleepiness (EDS) is a contributing factor to road traffic accidents. It is commonly assessed using self-administered questionnaires. These assessments are important information when discussing with the Driver and Vehicle Licensing Agency (DVLA) about fitness-to-drive. We hypothesised that patients may be confounded in their assessments after being informed about these potential implications.

Patients and methods

This was a prospective single-centre study. Patients attending clinics for sleep-disordered breathing were asked to fill in the Epworth Sleepiness Scale (ESS) and the Stanford Sleepiness Scale (SSS). Following their consultation, patients were informed about EDS in the context of driving and that the DVLA might request information based on their self-assessed sleepiness. They were then asked to complete the same questionnaires again. Parameters recorded included age, gender, body mass index (BMI), driving licence holder, and collar size. An ESS score above 10 points was defined as EDS.

Results

One hundred twenty-two subjects were studied (age 59.4 years (15.2); 72 males; BMI 32.1 kg/m² (8.3), driving licence held for 25.2 years (20.6) (n = 94); collar size 42.7 cm (5.0)). There was no difference in the ESS [8 (8) vs 8 (8) points; p = 0.289] or the SSS [2 (2) vs 2 (2) points; p = 0.320] between the two occasions, although seven patients (5.7%) changed their scores from “sleepy” to “non-sleepy” and four patients (3.3%) from “non-sleepy” to “sleepy”.

Conclusion

Providing patients with information about the risk of driving in the context of sleepiness does not significantly change how they score their symptoms using self-administered questionnaires; only about 9.0% of the patients had inconsistent results.

Leptin acts in the carotid bodies to increase minute ventilation during wakefulness and sleep and augment the hypoxic ventilatory response

KEY POINTS

Leptin is a potent respiratory stimulant. A long functional isoform of leptin receptor, LepR^b , was detected in the carotid body (CB), a key peripheral hypoxia sensor. However, the effect of leptin on minute ventilation (V_E ) and the hypoxic ventilatory response (HVR) has not been sufficiently studied. We report that LepR^b is present in approximately 74% of the CB glomus cells. Leptin increased carotid sinus nerve activity at baseline and in response to hypoxia in vivo. Subcutaneous infusion of leptin increased V_E and HVR in C57BL/6J mice and this effect was abolished by CB denervation. Expression of LepR^b in the carotid bodies of LepR^b deficient obese db/db mice increased V_E during wakefulness and sleep and augmented the HVR. We conclude that leptin acts on LepR^b in the CBs to stimulate breathing and HVR, which may protect against sleep disordered breathing in obesity.

ABSTRACT

Leptin is a potent respiratory stimulant. The carotid bodies (CB) express the long functional isoform of leptin receptor, LepR^b , but the role of leptin in CB has not been fully elucidated. The objectives of the current study were (1) to examine the effect of subcutaneous leptin infusion on minute ventilation (V_E ) and the hypoxic ventilatory response to 10% O₂ (HVR) in C57BL/6J mice before and after CB denervation; (2) to express LepR^b in CB of LepR^b -deficient obese db/db mice and examine its effects on breathing during sleep and wakefulness and on HVR. We found that leptin enhanced carotid sinus nerve activity at baseline and in response to 10% O₂ in vivo. In C57BL/6J mice, leptin increased V_E from 1.1 to 1.5 mL/min/g during normoxia (P < 0.01) and from 3.6 to 4.7 mL/min/g during hypoxia (P < 0.001), augmenting HVR from 0.23 to 0.31 mL/min/g/Δ F I O 2 (P < 0.001). The effects of leptin on V_E and HVR were abolished by CB denervation. In db/db mice, LepR^b expression in CB increased V_E from 1.1 to 1.3 mL/min/g during normoxia (P < 0.05) and from 2.8 to 3.2 mL/min/g during hypoxia (P < 0.02), increasing HVR. Compared to control db/db mice, LepR^b transfected mice showed significantly higher V_E throughout non-rapid eye movement (20.1 vs. -27.7 mL/min respectively, P < 0.05) and rapid eye movement sleep (16.5 vs 23.4 mL/min, P < 0.05). We conclude that leptin acts in CB to augment V_E and HVR, which may protect against sleep disordered breathing in obesity.

Can postural OSA be usefully identified from its severity alone?

Introduction

When obstructive sleep apnoea (OSA) does not occur throughout sleep, there must be factors influencing its presence or absence. These are most likely to be sleep stage, posture and presleep alcohol, among others. We hypothesised that as OSA severity increases, the likelihood of postural OSA (POSA) would also decrease.

Methods

Laboratory sleep studies of 39 patients with OSA were manually reviewed to calculate supine and non-supine oxygen desaturation indices (ODI). The usual definition for POSA was used, a ratio of supine to non-supine ODI of ≥2.

Results

The mean age was 53.2 (SD 12.4) years, the body mass index was 35.0 (SD 8.9) kg/m² and 74% were male. The median supine ODI was 54.3 (IQR 25.7–73.5) and non-supine ODI was 18.7 (IQR 8.6–38.4). The overall prevalence of POSA was 56%. The prevalence of POSA for ODIs of <40 was 68%, and 35% if ≥40.

Conclusions

An ODI ≥40, compared with <40, halved the likelihood of POSA from 68% to 35%. Although there is clearly a relationship between overall ODI and POSA, it is not strong enough to diagnose an individual with POSA. However the relationship provides a useful way to prescreen trial subjects to enrich for POSA.

Navigating the Island of Reil: how to understand the insular cortex

Insular-onset seizures are rare and easily misdiagnosed. In this article, we aim to highlight the often distinctive semiology of seizures involving the insula with reference to three cases. We suggest three points to aid the recognition of seizures involving the insula: (1) Seizures originating in the insula frequently present with a sensation of laryngeal constriction, dyspnoea or unpleasant somatosensory symptoms; (2) Seizures involving the anterior insula may have a silent onset, but tend to propagate rapidly to motor areas causing motor or hypermotor symptoms; (3) Seizures involving the posterior insula cause somatosensory symptoms, which are normally contralateral to the seizure onset.

Treatment of sleep apnoea syndrome decreases cognitive decline in patients with Alzheimer's disease

BACKGROUND

It is essential to detect and then treat factors that aggravate Alzheimer's disease (AD). Here, we sought to determine whether or not continuous positive airway pressure (CPAP) therapy for sleep apnoea syndrome (SAS) slows the rate of cognitive decline in mild-to-moderate AD patients.

METHODS

Between January 2003 and June 2011, we included consecutive, mild-to-moderate AD patients (a Mini Mental State Examination (MMSE) score at inclusion ≥15) with severe SAS as determined by video-polysomnography (an apnoea-hypopnoea index ≥30). In this single-blind, proof-of-concept trial, we analysed the mean decline in the annual MMSE score (the main outcome measure) according to whether or not the patients had received CPAP therapy. The decline was computed for each patient and for the first 3 years of follow-up.

RESULTS

Of the 23 included patients, 14 underwent CPAP treatment. The CPAP and non-CPAP groups did not differ significantly in terms of their demographic characteristics or MMSE score at baseline. The median annual MMSE decline was significantly slower in the CPAP group (-0.7 (-1.7; +0.8)) than in the non-CPAP group (-2.2 (-3.3; -1.9); p=0.013).

CONCLUSIONS

In this pilot study, CPAP treatment of severe SAS in mild-to-moderate AD patients was associated with significantly slower cognitive decline over a three-year follow-up period. Our results emphasise the importance of detecting and treating SAS in this population.

Effect of CPAP on blood pressure in patients with minimally symptomatic obstructive sleep apnoea: a meta-analysis using individual patient data from four randomised controlled trials

BACKGROUND

CPAP reduces blood pressure (BP) in patients with symptomatic obstructive sleep apnoea (OSA). Whether the same benefit is present in patients with minimally symptomatic OSA is unclear, thus a meta-analysis of existing trial data is required.

METHODS

The electronic databases Medline, Embase and trial registries were searched. Trials were eligible if they included patients with minimally symptomatic OSA, had randomised them to receive CPAP or either sham-CPAP or no CPAP, and recorded BP at baseline and follow-up. Individual participant data were obtained. Primary outcomes were absolute change in systolic and diastolic BP.

FINDINGS

Five eligible trials were found (1219 patients) from which data from four studies (1206 patients) were obtained. Mean (SD) baseline systolic and diastolic BP across all four studies was 131.2 (15.8) mm Hg and 80.9 (10.4) mm Hg, respectively. There was a slight increase in systolic BP of 1.1 mm Hg (95% CI -0.2 to 2.3, p=0.086) and a slight reduction in diastolic BP of 0.8 mm Hg (95% CI -1.6 to 0.1, p=0.083), although the results were not statistically significant. There was some evidence of an increase in systolic BP in patients using CPAP <4 h/night (1.5 mm Hg, 95% CI -0.0 to 3.1, p=0.052) and reduction in diastolic BP in patients using CPAP >4 h/night (-1.4 mm Hg, 95% CI -2.5 to -0.4, p=0.008). CPAP treatment reduced both subjective sleepiness (p<0.001) and OSA severity (p<0.001).

INTERPRETATION

Although CPAP treatment reduces OSA severity and sleepiness, it seems not to have a beneficial effect on BP in patients with minimally symptomatic OSA, except in patients who used CPAP for >4 h/night.

Risk factors for sleep-disordered breathing in pregnancy

RATIONALE

Symptoms of sleep-disordered breathing (SDB) are common among pregnant women, and several studies link SDB symptoms with gestational hypertension and preeclampsia. However, few prospective studies objectively measuring SDB during pregnancy have been performed.

OBJECTIVES

We performed a prospective cohort study examining risk factors for third trimester SDB in pregnant women.

MEASUREMENTS AND METHODS

105 pregnant women from the Hospital of the University of Pennsylvania obstetrics practices completed first and third trimester overnight polysomnography studies. We examined whether the number of SDB events per hour of sleep increased during pregnancy. We performed unadjusted and multivariable logistic regression analyses to estimate the effects of usual and pregnancy-specific characteristics on development of third trimester obstructive sleep apnoea (OSA). In secondary analyses, we examined the relationship between objectively measured SDB, hypertensive disorders of pregnancy, and other adverse maternal-fetal outcomes.

MAIN RESULTS

Mean Apnoea-Hypopnoea Index increased from 2.07 (SD 3.01) events/h at baseline (first trimester) to 3.74 (SD 5.97) in the third trimester (p=0.009). 10.5% of women had OSA in the first trimester. By the third trimester, 26.7% of women had OSA. In multivariable analyses, first trimester body mass index (BMI) and maternal age were significantly associated with third trimester OSA.

CONCLUSIONS

Third trimester OSA is common. Risk factors for third trimester OSA among women without baseline SDB include higher baseline BMI and maternal age.

Central sleep apnoea syndrome in chronic heart failure: an underestimated and treatable comorbidity

Chronic heart failure is a clinical syndrome with a high mortality and morbidity. Despite optimal therapy, five-year survival is still only 50%. Central sleep apnoea syndrome is seen in approximately 40% of patients with congestive heart failure. Sleep apnoea syndrome can be divided into two forms in these patients: obstructive sleep apnoea syndrome (OSAS) and central sleep apnoea syndrome (CSAS, Cheyne-Stokes respiration), of which CSAS is the most common. CSAS is a form of sleep apnoea in congestive heart failure which is driven by changes in pCO(2). As a consequence of apnoea-hypopnoea an imbalance in myocardial oxygen delivery/consumption ratio will develop, sympathetic and other neurohormonal systems will be activated and right and left ventricular afterload will be increased. Sleep apnoea is associated with an increased mortality in patients with systolic heart failure. Treatment of sleep apnoea increases left ventricular ejection fraction and transplant-free survival. Because of its high prevalence, poor quality of life, poor outcome, and the beneficial effects of treatment, physicians treating patients with heart failure should be aware of central sleep apnoea. There are different treatment options, but the exact effects and indications of each option have not yet been fully determined. Further studies should be done to further investigate its prevalence, and to establish the most adequate therapy for the individual patient. (Neth Heart J 2010;18:260-3.).