French consensus: Augmentation syndrome in restless legs syndrome.

Augmentation syndrome is one of the most severe complications of RLS. It is characterised by a worsening of treated symptoms; principally an increase in the severity of symptoms and an earlier onset time. Augmentation syndrome occurs primarily with dopaminergic treatments. It is crucial for the patient to be sufficiently well informed to prevent its occurrence and the prescription of too high doses of dopaminergic agonists avoided. In the presence of augmentation syndrome confirmed using the diagnostic criteria, the specialist treating the restless legs syndrome should quickly modify the patient's treatment. In this article, our expert group proposes a practical strategy for the diagnosis, prevention and treatment of augmentation syndrome.

Role of thyroid surgery in the obstructive sleep apnea syndrome.

OBJECTIVES: To study the impact of thyroid surgery on obstructive sleep apnea syndrome (OSAS) evaluated by the apnea/hypopnea index (AHI) was studied. Secondary objectives were to evaluate the impact on the positional component of OSAS and to highlight possible predictors of improvement of OSAS after thyroidectomy. METHODS: Twenty-eight patients with OSAS are included in this monocentric study: they underwent total thyroidectomy (n = 26) or left loboisthmectomy. Postoperative assessment involves a nocturnal control polysomnography as of 60 days after surgery. RESULTS: The mean age at the time of surgery is 61.3 years (standard deviation ±7.3) and average body mass index is 29.6 kg/m2 (±7.3). Continuous positive airway pressure (CPAP) treatment is introduced preoperatively in 82% of patients. The statistical analysis shows a significant decrease of 33% in postoperative AHI for the total population (p = 0.001), 77% in patients under CPAP (p = 0.05), and 27% in patients without CPAP (p = 0.02). CPAP therapy could be released in four patients. Given the limited number of subjects studied, the surgery did not impact on the positional component of the OSAS. Statistical analysis failed to link a predictive factor to AHI reduction. CONCLUSIONS: We propose thyroid surgery as an alternative or as a complement to CPAP treatment for the patients with goitre: it allows a significant decrease in postoperative AHI, allowing adaptation of the CPAP treatment downward, or even a release in some cases. These results need to be confirmed on a larger series of patients in a prospective study with standardized criteria for polysomnography and multivariate analysis.

Experience-dependent changes in cerebral activation during human REM sleep.

The function of rapid-eye-movement (REM) sleep is still unknown. One prevailing hypothesis suggests that REM sleep is important in processing memory traces. Here, using positron emission tomography (PET) and regional cerebral blood flow measurements, we show that waking experience influences regional brain activity during subsequent sleep. Several brain areas activated during the execution of a serial reaction time task during wakefulness were significantly more active during REM sleep in subjects previously trained on the task than in non-trained subjects. These results support the hypothesis that memory traces are processed during REM sleep in humans.

Experience-dependent changes in cerebral functional connectivity during human rapid eye movement sleep.

One function of sleep is hypothesized to be the reprocessing and consolidation of memory traces (Smith, 1995; Gais et al., 2000; McGaugh, 2000; Stickgold et al., 2000). At the cellular level, neuronal reactivations during post-training sleep in animals have been observed in hippocampal (Wilson and McNaughton, 1994) and cortical (Amzica et al., 1997) neuronal populations. At the systems level, using positron emission tomography, we have recently shown that some brain areas reactivated during rapid-eye-movement sleep in human subjects previously trained on an implicit learning task (a serial reaction time task) (Maquet et al., 2000). These cortical reactivations, located in the left premotor area and bilateral cuneus, were thought to reflect the reprocessing--possibly the consolidation--of memory traces during post-training rapid-eye-movement sleep. Here, the experience-dependent functional connectivity of these brain regions is examined. It is shown that the left premotor cortex is functionally more correlated with the left posterior parietal cortex and bilateral pre-supplementary motor area during rapid-eye-movement sleep of subjects previously trained to the reaction time task compared to rapid-eye-movement sleep of untrained subjects. The increase in functional connectivity during post-training rapid-eye-movement sleep suggests that the brain areas reactivated during post-training rapid-eye-movement sleep participate in the optimization of the network that subtends subject's visuo-motor response. The optimization of this visuo-motor network during sleep could explain the gain in performance observed during the following day.

Arousal threshold to respiratory stimuli in OSA patients: evidence for a sleep-dependent temporal rhythm.

It has recently been described that the maximal respiratory effort developed at the end of an apnea (Pesmax)--which is regarded as an index of arousal threshold in patients with obstructive sleep apnea syndrome (OSA)--increases progressively during the night, probably as a consequence of associated sleep fragmentation. In order to find out whether the nocturnal trend of Pesmax may be more influenced by a sleep-dependent circadian rhythm than by sleep fragmentation, we revised the polygraphic recordings of 37 patients in whom obstructive apneas were recorded for at least 7 hours. In 15 of these patients, analysis was made for eight hours of the night. During each hour we analyzed at least 7 obstructive apneas, in which we measured the minimal esophageal pressure at the start of the apnea, the maximum value recorded at the end of the apnea (Pesmax), the difference from the minimum to the maximum (delta Pes), and the rate of increase in esophageal pressure (RPes). As indices of sleep fragmentation, we defined the number of arousals, awakenings and sleep state transitions. In the group of patients as a whole, we found a trend toward a gradual increase for apnea duration (F = 98.8, p < 0.001) and Pesmax F = 31.6, p < 0.001) which was significant from the first to the last hour. The time-dependent evolution of apnea duration and Pesmax showed that the rise in these two variables peaked during the first 3 hours of sleep, followed by a plateau and a decrease in the last hour of the night. This temporal profile was more evident when the analysis was available for 8 hours. No significant changes across the night were found for nocturnal hypoxemia and number of arousals. Considering the slope of Pesmax changes across the night, we saw that neither the apnea+hypopnea index nor the indices of sleep fragmentation affected the nocturnal trend. The present data demonstrate the presence of a nocturnal trend in arousal threshold in OSA patients independent of sleep fragmentation. The biphasic evolution of the arousal threshold may be caused by factors that influence the circadian and homeostatic processes.

Long-term compliance with CPAP therapy in obstructive sleep apnea patients and in snorers.

A prospective study aimed at objectively evaluating compliance with nasal continuous positive airway pressure (CPAP) treatment was conducted in 728 obstructive sleep apnea [OSA; apnea/hypopnea index (AHI) > 15 events/hour] patients and 98 nonapneic snorers (AHI < or = 15 events/hour). Five-hundred seventy-five OSA patients and 33 nonapneic snorers underwent CPAP therapy and were followed-up for an average of 1,176 +/- 38 days (27 to 4,203 days). Compliance to treatment was measured by the mean rate of use of the CPAP device obtained from a built-in time counter. Acceptance of treatment was measured using Kaplan-Meier's model. The acceptance of CPAP was greater than 90% at 3 years and greater than 85% at 7 years in OSA patients. It was greater than 60% at 3 years in nonapneic snorers. The mean rate of CPAP use was 5.7 +/- 1.8 hours/day in OSA patients and 5.6 +/- 1.4 hours/day in snorers who were still on CPAP on October 1, 1995. It was correlated positively with age, body mass index, and AHI, and it was correlated negatively with daytime partial pressure of oxygen (PaO2), forced expiratory volume in 1 second (FEV1), and vital capacity in the group of OSA patients. This study shows that CPAP therapy is reasonably accepted by OSA patients as well as by nonapneic snorers. Both within and between groups, objective disease severity (as measured by the respiratory event index and daytime and nighttime hypoxemia), rather than patients' symptoms or complaints, seemed to play a role in the quality of compliance to treatment.

REM sleep behavior disorder: clinical and physiopathological findings.

Abnormalities of REM sleep i.e. absence of atonia and abnormal motor control which are described in patients with REM sleep behavior disorder, have induced clinical and physiopathological interest. Initial hypothesis of a simple dysfunction of REM sleep generators has not been confirmed. The prevalence in older subjects and in patients with parkinsonian syndromes suggest that the appearance of the parasomnia is related to alteration in the neurons of pontine area i.e. nucleus peduncolopontine, in which there is an integration of sleep-wake mechanisms and locomotor systems. Controversy surrounds the specificity of absence of atonia in the diagnosis of the parasomnia. Since this polygraphic finding may be present in subjects without any sleep complaint and in patients with initial neurological impairment, diagnosis of the sleep disorders might be allowed only when the polygraphic characteristic of persistent tonus and complex motor behavior are recorded.

Respiratory effort during obstructive sleep apnea: role of age and sleep state.

OBJECTIVE: To evaluate the patients' individual characteristics predictive of the degree of respiratory effort developed during obstructive sleep apneas (OSAs). DESIGN: Prospective consecutive sample, collection of clinical and polysomnographic data. SETTING: University teaching hospital. PATIENTS: One hundred sixteen consecutive OSA patients with clinical symptoms of OSA and more than 20 apneas per hour of sleep. MEASUREMENTS: Anthropomorphic data, daytime blood gas values, and polysomnographic data. From esophageal pressure measurements during sleep, three indexes of respiratory effort during OSAs were derived: the maximal end-apneic esophageal pressure swing (PesMax), the increase in esophageal pressure swing (deltaPes) during the apnea, and its ratio to apnea duration (RPes). RESULTS: The indexes of respiratory effort were significantly lower in rapid eye movement (REM) than in non-REM sleep (PesMax: 50.9+/-2.5 vs 39.6+/-1.9 cm H2O, p<0.001; deltaPes: 30.9+/-1.7 vs 23.4+/-1.4 cm H2O, p<0.001; RPes: 1.05+/-0.05 vs 0.53+/-0.03 cm H2O/s, p<0.001); therefore, a separate analysis was conducted in non-REM and in REM sleep. Indexes were also significantly lower in subgroups of older as compared to younger patients (PesMax: 55.6+/-3.5 vs 40.0+/-2.2 cm H2O, p<0.001; deltaPes: 34.2+/-2.3 vs 24.1+/-1.6 cm H2O, p=0.001; RPes: 1.21+/-0.08 vs 0.8+/-0.05 cm H2O/s, p<0.001). The three indexes were closely correlated with each other and only PesMax correlation data are reported. In non-REM sleep, age was the most important single independent correlate of PesMax (r=-0.37, p=0.000). In REM sleep, the apnea-related hypoxemia, apnea duration, and age were the main contributors to the variance of PesMax. CONCLUSIONS: Respiratory effort in response to upper airway occlusion in OSA patients is lower in REM than in non-REM sleep and decreases with increasing age.

Respiratory effort. A factor contributing to sleep propensity in patients with obstructive sleep apnea.

To test the hypothesis that respiratory effort during obstructive apneas contributes, together with hypoxemia and sleep fragmentation, to excessive daytime sleepiness, we investigated the relationship between daytime sleepiness and polysomnographic variables in 44 patients with obstructive sleep apnea (OSA). In all patients, daytime sleep propensity was assessed by an 11-item standardized self-questionnaire yielding a sleepiness score and by a modified sleep latency test yielding a mean sleep latency. Respiratory effort during apneas was evaluated by measuring esophageal pressure swings using an esophageal balloon. Within each apneic cycle, we measured the esophageal pressure swings during the first three and the last three occluded efforts during the apnea to define the overall increase, its ratio to apnea duration, and the maximal effort developed during obstruction. In the group of patients as a whole, the sleepiness score was negatively correlated with the mean sleep latency (r=-0.38, p=0.01). The sleepiness score was correlated with the indexes of respiratory effort during apneas (ie, the overall increase, its ratio to apnea duration, and the maximal end-apneic swing in esophageal pressure) and with the apnea+hypopnea index. The mean sleep latency was correlated with all indexes of nocturnal hypoxemia (ie, the mean lowest oxyhemoglobin saturation [SaO2] and the index of apnea associated with a fall in SaO2 below 90% and 80%). We conclude that the degree of respiratory effort during obstructive apneas contributes to self-rated sleep propensity in patients with OSA.

[Sleepiness and sleep apnea syndrome. Analysis of 188 questionnaires (102 patients and 86 controls)]. / Somnolence et syndrome d'apnées du sommeil. Analyse de 188 questionnaires (102 malades et 86 témoins).

A questionnaire was given to 102 obstructive sleep apnea patients and 86 controls. A somnolence index was defined by averaging the scores of the answers to eleven questions concerning sleepiness. This index separated patients and controls (P < 0.0001). It was correlated with the apnea + hypopnea index (r = 0.32, P < 0.001), the body mass index (r = 0.45, P < 0.001) and with an objective measurement of sleepiness obtained from a modified multiple sleep latency test (r = -0.54, P < 0.001). Depending upon the current occupation, the tendency to fall asleep decreased in the following order: watching TV, passenger in a means of transport, reading, attending a show, attending a meeting, driving a car, and eating. This order is the same in patients and controls, irrespective of their "overall sleepiness". Thus, the circumstances of falling asleep are indicative of the severity of sleepiness.

[Propensity for sleep and diurnal somnolence in the course of sleep apnea syndrome]. / Propension au sommeil et somnolence diurne au cours du syndrome d'apnées du sommeil.

Daytime sleepiness is one of the major symptoms of obstructive sleep apnea. However, its definition raises problems, since it may be based on either subjective feeling (evaluated by means of questionnaires or analog visual scales), physiological drive or need (inferred by a sleep latency) or on the concept of sleep propensity defined as the probability of falling asleep (measured by the occurrence of sleep in various circumstances of daily life). Data from the literature suggest that sleep fragmentation and hypoxemia, both related to sleep apneas, cause daytime sleepiness. Our own data show that sleep propensity in a group of 44 patients with obstructive sleep apnea was correlated with the increase in esophageal pressure swings during obstructive apneas. This result suggests that the increased respiratory effort against occluded upper airways also contributes to daytime sleepiness in patients with obstructive sleep apnea.

[Starling resister and stability of sleep ventilation]. / Résisteur de starling et stabilité du couple sommeil-ventilation.

The upper airway can be described as a collapsible segment (the pharynx) interposed between two rigid bony (the cavum) or cartilaginous (the trachea) segments. Due to this structure, the pharynx behaves as a collapsible tube, in which airflow does not depend on the downstream pressure, but is limited to a maximum value which depends only on the upstream pressure and on the pressure surrounding the collapsible segment; this behavior, known as a Starling resistor can be modeled by the waterfall effect. Thus, the upper airways can be in three different conditions: an occluded condition, in which no flow is possible, a patent condition, in which flow depends on the difference between upstream and downstream pressures (according to Poiseuille's law), and a situation in which flow is limited. The behavior of the upper airway is largely dependent on its anatomic structure, but functional factors play a critical role. Among these sleep state is both a determinant of the collapsibility of the pharynx, and determined by the simulation of upper airway mechanoreceptors whose activity depends on the activity of respiratory muscles. Thus the interplay of three factors: ventilatory drive, upper airway collapsibility, and arousal threshold can predict most of the situations of stable and unstable ventilatory behavior during sleep. The level of the arousal threshold governs the stability of the ventilatory pattern, as it determines whether a combination of slow, respiratory effort, and blood gases can be maintained or is interrupted by an arousal.

[Post-radiotherapy multifocal meningioma]. / Méningiome multifocal post-radiothérapique.

We report one case of radio-induced meningiomas revealed by an intracranial hypertension in an 46 year-old woman. A history of cephalic irradiation during infancy for a vascular nevus, not spontaneously reported by the patient, had been discovered because of the association with a radio-induced cataract. Meningiomas are a rare, severe and late complication of cephalic radiotherapy. The history of irradiation is not always spontaneously reported by the patient.

[Paroxysmal neurological manifestations disclosing panic attacks]. / Manifestations neurologiques paroxystiques révélatrices d'attaques de panique.

Thirty-seven patients presented with paroxysmal neurological manifestations attributed to anxiety attacks. The manifestations included loss of consciousness, focal sensorimotor deficits, diffuse dysesthaesiae, visual disorders and tremor. They lasted 10 to 45 minutes and occurred once per day to once per week. Organic pathology was dismissed on the basis of normal examinations and atypical course. In all patients questioning revealed symptoms that were those of acute anxiety. The fact that these attacks took place in suggestive (circumstances e.g. in crowds and car driving), and that they could be induced by challenge tests hyperpnoea, infusion of lactate) suggested that these disorders were consecutive to panic attacks.

[Excessive daytime sleepiness]. / Somnolence diurne pathologique.

When it is not due to an extrinsic origin, somnolence may be the main symptom of various diseases. Among these causes of excessive daytime sleepiness, obstructive sleep apnea syndrome is noteworthy for its very important prevalence, estimated at 4% in adult males. Due to repeated upper airway obstructions during sleep, this disease is efficiently treated by continuous positive airway pressure applied through a nasal masks during sleep. Another syndrome, periodic limb movements during sleep may also lead to a sleep fragmentation at the origin of daytime sleepiness. Its treatment is principally based on dopaminergic agonists. Narcolepsy-cataplexy and idiopathic hypersomnia are two causes of excessive daytime sleepiness in young people. The first is as frequent as multiple sclerosis and the second is ten times less frequent. The treatment of these two diseases is now based on a new French drug: modafinil(Modiodal). Sleep pathology still has only a small place in medical training. Excessive daytime sleepiness is therefore often misdiagnosed. In addition to their major risk of work or road accidents, numerous untreated patients continue to suffer from this very unpleasant symptom, at the origin of a major social handicap.

[Hypersomnia. Investigational strategy for evaluating hypersomnia]. / Les hypersomnies. Stratégie des investigations pour l'exploration d'une hypersomnie.

CLINIC AND HISTORY: Expression of hypersomnia can take on several forms: long period of nocturnal sleep, excessive diurnal somnolence or both. History taking is essential. Useful tools include standardized questionnaires and a diary of sleeping habits. Not only do they provide evidence of the hypersomnia, but also information on possible eccentric origin(s). A pathological hypothesis can then be put forward: sleep apnea syndrome, narcolepsy, idiopathic hypersomnia, or periodic movements during sleep. POLYGRAPHY: Different recording protocols have been designed to determine sleep patterns, often depending on the clinical setting. The goal is to obtain an objective confirmation of hypersomnia and demonstrate a cause. The type of recording (hour and duration of the recording, parameters monitored) depends on the information desired. Because captors themselves sometimes perturb sleep, polygraphic explorations must be adapted to each individual situation.

Restless legs syndrome and low brain iron levels in patients with haemochromatosis.

Regional brain iron levels of two patients with haemochromatosis and severe restless legs syndrome (RLS) were assessed using R2' magnetic resonance imaging (MRI) sequences in both patients and in nine healthy controls. R2' relaxation rates in the patients were decreased in the substantia nigra, red nucleus, and pallidum when compared with the controls. These results indicate that local brain iron deficiency may occur in patients with haemochromatosis and suggest a role for brain iron metabolism in the pathophysiology of RLS.

Nocturnal evolution of respiratory effort in obstructive sleep apnoea syndrome: influence on arousal threshold.

It has been recently described that the overnight increase in maximal end-apnoeic oesophageal pressure (P(oes,max)), considered as an index of the arousal threshold to occlusion, mostly contributes to apnoea lengthening during the night. However, the rise in apnoea duration could also be caused by changes in hypoxaemia, chemosensitivity and upper airway resistance. To better define the relative contributions of each of these factors, we examined the recordings of nine patients. Before apnoea, the mean pulmonary resistance at peak inspiratory flow (RPIF) was computed. During apnoea, all swings in oesophageal pressure (P(oes)) were measured to define the P(oes,max), the increase from the minimum to the maximum (deltaP(oes)), the rate of increase in P(oes) (RP(oes)) and the P(oes) at the first occluded breath (P(oes,1)). A gradual and significant increase in apnoea duration (p=0.02), P(oes,max) (p=0.02) and deltaP(oes) (p=0.006) was present across the night without any changes in oxygen saturation, RPIF, and P(oes,1). The slope of increase in P(oes,max), apnoea duration and deltaP(oes) was correlated with the apnoea/hypopnoea index. We conclude that in obstructive sleep apnoea, the nocturnal rise in apnoea duration is attributable more to an increase in the arousal threshold related to apnoea recurrence than to changes in chemosensitivity and upper airway resistance.

Decrease in haematocrit with continuous positive airway pressure treatment in obstructive sleep apnoea patients.

Previous preliminary results have shown an overnight decrease in haematocrit and red cell count after the first night of treatment with nasal continuous positive airway pressure (CPAP) in obstructive sleep apnoea (OSA) patients. The present study was designed to confirm these preliminary data, and to analyse the long-term effects of CPAP. The haematocrit and red cell count (RCC) were measured in 80 OSA patients on two consecutive mornings, after an untreated night and after a CPAP treatment night. The haematocrit and RCC significantly decreased with CPAP (from 44.0 +/- 0.5 to 42.4 +/- 0.4%, p less than 0.0001 and from 4.769 +/- 0.051 to 4.597 +/- 0.052 x 10(12) red cells.l-1, p less than 0.0001, respectively). Neither the decrease in haematocrit nor the decrease in RCC were correlated with the decrease in urine volume or flow which occurred with CPAP. Thirty five of these patients remained untreated for 45 +/- 4 days, before home treatment with CPAP was initiated. The haematocrit and RCC had returned to values close to those before initial treatment and decreased again after the first treatment night. Twenty one of the patients were re-evaluated after at least one year of home treatment with CPAP, again on two consecutive nights either with CPAP or untreated. The follow-up, post-CPAP haematocrit and RCC were slightly and nonsignificantly higher than after the baseline CPAP night, but still lower than after the baseline untreated night (p less than 0.02). After the untreated follow-up night, no significant change in haematocrit was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Simplified diagnostic procedure for obstructive sleep apnoea syndrome: lower subsequent compliance with CPAP.

The aim of this study was to investigate whether a simplified diagnostic procedure based on ambulatory monitoring with MESAM IV altered subsequent compliance with continuous positive airway pressure (CPAP) in obstructive sleep apnoea (OSA) patients. During a period of 16 months, 60 patients with symptoms evocative of OSA and positive MESAM recording were prescribed CPAP after titration with standard polysomnography. Compliance was followed during 2 yrs based on built-in time counters and was compared with the compliance in two comparison groups: an equal number of equally severely affected patients diagnosed with standard polysomnography during the 18 months (8 months before and 8 months after) preceding and following the study period and a group of 48 patients with an estimated similar apnoea/hypopnoea index but less typical clinical and/or MESAM features, diagnosed as having OSA based on polysomnography during the study period. The three groups were not different by age, body mass index, or sleepiness score. Patients diagnosed with the ambulatory procedure had higher drop-out rates (21.7% versus 10% and 6.25%; p<0.05) and lower rates of use of their CPAP (43+/-0.3 h x night(-1)) than any of the control groups (53+/-0.2 and 5.6+/-0.2 h x night(-1), p<0.05). In conclusion, there is a risk that ambulatory diagnostic procedures alter the relationship of patients to their disease and/or the medical staff so that subsequent compliance with treatment may be decreased. The greatest care concerning compliance should be taken before an ambulatory-based diagnostic procedure is implemented.