[Dopaminergic stimulation in the non-motor symptoms of Parkinson's disease]

INTRODUCTION AND DEVELOPMENT

The non-motor symptoms of Parkinson's disease have a great impact in terms of quality of life. They are frequently underdiagnosed and clinical experience suggests that not only is dopamine therapy ineffective but that in many cases it is also responsible for the appearance of some of these symptoms. Different studies have drawn attention to the involvement of the dopaminergic pathways in the pathogenesis of some non-motor symptoms. It has been observed that they can undergo fluctuations in relation to dopaminergic stimulation, generally in wearing off states, while displaying a significant correlation with motor fluctuations and a clinical response with continuous dopaminergic therapy.

CONCLUSIONS

Although recent reviews offer insufficient evidence for treatment of non-motor symptoms with dopaminergic therapy, involvement of the dopaminergic pathways in the aetiopathogenesis of some of these disorders and the clinical observation that such symptoms undergo fluctuations in relation to pulsatile dopaminergic stimulation may lead us to reconsider the possible role of dopaminergic therapy in the treatment of these symptoms.

[Treatment of obstructive sleep apnea syndromes]

The detection, correction or withdrawal of any cause or associated factor including obesity, drugs or alcohol is essential in the treatment of obstructive sleep apnea syndrome. Treatment is mainly mechanical or surgical, but not medical. Nasal continuous positive airway pressure (NCPAP) has now largely replaced tracheostomy and successful long-term domestic use of this method has been reported on many occasions. Oropharyngeal surgery can solve a large part of social snoring problems. However criteria for procedure selection and evaluation of results are still needed to clarify the indication of this operation in patients with full clinical expression of the syndrome. In this regard, a comprehensive preoperative evaluation and a logical approach to the reconstruction of the upper-airway has recently led to the association of palatopharyngoplasty and maxillo-mandibular surgery, with an excellent long-term success rate.

[Therapy control of theophylline evening dosage in patients with sleep-related respiratory disorders--follow-up study]

We conducted a prospective study to perform classification according to responder types and follow-up during theophyllin treatment (500 mg/d) in a group of (up to now) 65 patients suffering from sleep apnoea. Changes in the apnoea index (AI) and clinical symptoms were taken as response criteria. A significant AI reduction was seen during a follow-up period of 3 months. At the last control measurement after 6 months no significant change has been detected so far. 10 patients were classified as Type I responders (improvement in initial AI 60%, over the total period at least 25%). No patient had a responder type II profile. 13 patients were nonresponders (improvement in initial AI and over the whole period not more than 25%, no improvement in the pattern of clinical symptoms). 13 patients dropped out of the trial due to non-compliance. Side effects typical of theophyllin leading to discontinuation of the treatment course occurred in 5 patients. 22 patients have not yet completed the course at the time of writing. Standardised questioning of patients showed a definite improvement in feeling tone, especially with regard to the tendency to fall asleep during the day and refreshed feeling in the morning. Nocturnal complaints occurred in only a few isolated cases. Hence, administration of theophyllin retard preparations in evening doses of 500 mg/d remains a meaningful therapeutic approach to sleep apnoea.

[Nocturnal hypertension and sleep apnea: effect of the ACE inhibitor cilazapril on apnea-induced blood pressure increases during sleep]

The nocturnal increases in blood pressure in cases of obstructive sleep apnea are discussed as causes in connection with increased cardiovascular mortality in sleep apnea. Previous antihypertension therapy studies revealed the antihypertensive action of the ACE inhibitor cilazapril averaged over NREM (NR) and REM sleep (R). In the present study, the effect of this drug on the blood pressure increase within the stress segment of obstructive apnea in NR and R was investigated in a double-blind randomized study versus placebo. Data were collected in digital form with the help of cardiorespiratory polysomnography and intra-arterial blood pressure measurements; a total of 640 apnea in 16 patients were evaluated. Relevant increases in blood pressure occurred during the apnea which were, as expected, more pronounced in R (150/74 mmHg) than in NR (135/69 mmHg). The antihypertensive action of cilazapril was also stronger in R (systole--11.9/diastole--6.4 mmHg) than in NR (systolic--9.0 mmHg/diastolic--5.7 mmHg). Placebo caused significantly lower decreases in blood pressure (systolic--3.7 mmHg/diastolic--2.4 mmHg in R, systolic--2.8 mmHg/diastolic--1.8 mmHg in NR). Thus, evidence is provided for a clinically relevant blood pressure lowering effect of the drug cilazapril on the stress-induced blood pressure increases accompanying obstructive apnea both in NREM and in REM sleep.

Sleep apnoea occurring only in REM (possible relevance of the case for some cot deaths)

A case of sleep apnoea occurring only within REM sleep in a 57-year-old man is described. It was successfully treated with clomipramine for a period. The patient probably had persistent phrenic nerve damage which accounted for, or contributed to, the phenomenon. It is suggested that this mechanism may operate in some cot deaths.

[Intensive care and respiratory sleep disorders]

The study of respiratory sleep disorders in intensive care is a developing field. Indeed sleep pathology concerns not only pneumologists and neurophysiologists but also numerous specialties including medicosurgical resuscitation. The advent of "portable" appliances should facilitate access to polysomnography (PSG) for diagnosis of sleep respiratory disorders (RDS) in the intensive care unit. This examination can be appropriate in two separate circumstances. RDS in life-threatening situations (generally respiratory and/or cardiac failure) or when RDS is worsened by the specific conditions of intensive care units: "intensive care-induced RDS". In both cases, easy diagnosis of RDS by PSG allows adjustment of the treatment (corrections of iatrogenic factors, continuous positive airway pressure [CPAP], noninvasive ventilation [NIV], oxygen [O2]. A specific treatment of the well documented RDS is most desirable, as the patients are considered to be at high risk for endotracheal intubation. If diagnosis of RDS is not made during the acute phase, the intensive care physician should be informed of the clinical and paraclinical elements leading to prescription of a delayed polysomnography in order to reduce the risk of further vital distress.

Effect of salicylate on upper airway stability and pressure flow: relationship in anesthetized dogs

Previous studies have shown that upper airway muscle activity is augmented in response to increased respiratory drive, thereby improving upper airway patency. In the present study we evaluated the effect of salicylate, a well-known respiratory stimulant, on upper airway stability and pressure-flow relationship. Multiple levels of airflow were used to assess pressure-flow relationship in the isolated airways of anesthetized dogs and to calculate the coefficients of Rohrer's equation P = K1V + K2V2. In addition, we measured the negative intraluminal pressure needed to collapse the upper airway. These measurements were repeated after intravenous administration of sodium salicylate, 250 mg/kg. Salicylate-induced hyperventilation was associated with increased alae nasi electrical activity. Resistance to airflow and K2 decreased significantly (p less than 0.01), suggesting dilation of the upper airway lumen. The intraluminal pressure under which upper airway collapse occurred became more negative in all dogs (from -5.0 +/- 0.8 to -8.5 +/- 1.3 cm H2O, p less than 0.01), indicating improved stability of the upper airway walls. These findings suggest that salicylate, and presumably other pharmacologic agents that stimulate ventilation, can improve both upper airway patency and upper airway stability.

[Theophylline in the treatment of sleep-related breathing disorders]

The methylxanthine derivates are known to have respiratory stimulant properties. Therefore theophylline is used in sleep related disturbances of breathing. Theophylline reduces central apneas and periodic breathing in infants. The efficiency of theophyllin is confirmed in reducing central apneas in patients with neurologic diseases or Cheyne Stokes breathing in patients with congestive heart failure. In patients with obstructive sleep apnoea the effect of theophylline is doubtful. An effect of therapy exists in some mild forms of sleep apnoea (apnoea index < 20/h total sleep time). Further studies are necessary to investigate the precise mechanism of of theophylline in obstructive sleep apnoea.

[Treatment of sleep apnea syndromes]

NECESSARY TREATMENT: Sleep apnea syndrome requires treatment because it affects cardiovascular and cerebrovascular morbidity and mortality and has important neuropsychological consequences with the risk of accidents due to impaired wakefulness. The patientís quality of life is greatly altered. GENERAL MEASURES: Patients should be informed of the risk due to the lack of sleep, advised that alcohol tranquilizers and hypnotic drugs are contraindicated, and counseled about loosing weight, the most difficult problem for obese patients. POSITIVE PRESSURE VENTILATION: Continuous positive pressure ventilation with a facial mask acts like a pneumatic prosthesis holding the airways open during sleep. Sleep can be reconstructed by eliminating the recorded pathological nocturnal events and thus reducing diurnal hypersomnia. Quality of life is improved and accidents related to diminished wakefulness are avoided. Death rate in treated patients is significantly lower than in non-treated patients. In France, the national health care system will reimburse positive pressure ventilation for sleep apnea syndromes recognized to cause more than 30 events per hour of recording or fragmented sleep due to respiratory impairment. OTHER TREATMENTS: Indications for other treatments in case of moderately severe sleep apnea syndrome (or if health care benefits are not recognized for positive pressure ventilation) are currently debated. No medication has been proven to be effective. Mandibular advancement ortheses are in the development stage and require multidisiplinary cooperation to verify their efficacy. Velar surgery has been proposed but is usually disappointing except for young patients actively participating in an integrated surgical treatment strategy.

[Respiratory sleep disorders in patients with congestive heart failure]

AIM

To examine respiration in sleeping patients with congestive heart failure (CHF).

MATERIAL AND METHODS

Night cardiorespiratory monitoring was made in 30 CHF patients with coronary heart disease (CHD), arterial hypertension and dilated cardiomyopathy. The control group consisted of 16 patients with obstructive sleep apnea and hypopnea (OSAH) free of CHF.

RESULTS

Respiratory sleep disorders were registered in all the examinees. Moderate and severe OSAH occurred more often. CHF patients vs controls had shorter inhalation, expiration, overall duration of the respiratory cycle, higher rate of the respiratory movements. With aggravation of the respiratory disorders in sleeping CHF patients, minute ventilation, respiratory volume and mean inspiratory flow arose. In severe OSAH there was low functional residual lung capacity and high intraalveolar volume in end expiration positive pressure. The above changes may cause fatigue and weakness of the respiratory muscles and alter intracardiac hemodynamics.

CONCLUSION

For CHF patients it is recommended to perform CPAP-therapy in sleep.

Drug therapy of sleep-related hypoxaemia

In patients with chronic obstructive pulmonary disease (COPD) exhibiting daytime hypoxaemia, a worsening of the latter occurs during sleep, particularly during REM sleep. The most efficient therapy of this sleep-related hypoxaemia is the nocturnal administration of O2 at a flow rate of 1.5-3 l/min. An alternative therapy, when daytime hypoxaemia is not too severe (PaO2 greater than 55 mmHg), is the use of almitrine (100 mg/day), a drug which improves daytime hypoxaemia in most COPD patients. The improvement of sleep hypoxaemia with almitrine is related to the increased daytime PaO2 and cannot be considered as a specific effect of almitrine on sleep-related respiratory events. It must be emphasized that almitrine is ineffective in about 25% of COPD patients ("nonresponders") and that almitrine can be used with conventional O2 therapy in patients with severe hypoxemia (daytime PaO2 less than 55 mmHg).

[Effect of aminophylline therapy in mature infants with sleep apnea syndrome]

Pneumograms of 33 fullterm infants (age 1-16 weeks) with idiopathic sleep apnea syndrome (SAS), treated with aminophyllin administered orally, were compared with pneumograms of 12 age-matched infants without aminophyllin treatment. In a one hour oxycardiorespirography (OCRG) all infants had pneumogram abnormalities defined as apneas greater than or equal to 15 s, greater than or equal to 3 apneas lasting 10 s, MA-value (mean duration of all apneas during sleep time) greater than or equal to 7 s/min, and greater than or equal to 3 episodes of periodic breathing. The diagnosis of an SAS, discussed as a possible risk factor of SIDS, was made in general in the presence of clinical symptoms such as apneas, cyanosis during sleep, poorly coordinated sucking, swallowing and respiration, and gastro-esophageal reflux (GER) in combination with an abnormal pneumogram. Of the 33 infants 12 with a history of an SIDS sibling were clinically asymptomatic. We found that after one week of aminophyllin treatment in 88% the pneumograms were normal. The mean plasma concentration of aminophyllin at this time was 8.3 micrograms/ml (range 4-19 micrograms/ml). All abnormalities showed a statistically significant reduction. In the infants without aminophyllin the pneumogram was still abnormal and no abnormality was significantly reduced. After at least 6 weeks we discontinued aminophyllin and one week later we monitored the OCRG. In 83% of the infants we found a normal pneumogram and compared to the initial pneumogram there was again a statistically significant difference.(ABSTRACT TRUNCATED AT 250 WORDS)

Theophylline therapy in sleep apnoea syndrome

There is evidence that theophylline improves obstructive sleep apnoea, although the existing studies are not comparable because of different patient groups, methods and treatment regimes and therefore may give partly conflicting results. In our opinion, patients with mild or moderate sleep apnoea syndrome, who do not need nasal ventilation therapy urgently, or who are not at a high cardiovascular risk, are the favourite group for theophylline therapy and an attempt in oral treatment in this group of patients is recommendable, since all other drugs have failed. Serum theophylline level should be lower than in anti-obstructive therapy, because of its otherwise deleterious effect in sleep structure. The improvement in apnoea index, when responding is not only a short-term effect, but lasts over a long-term treatment period, although patients should still be monitored, because of the possibility of worsening in some cases. The reason for responding and not responding in different patients remains unclear, and further studies are needed to investigate the precise mechanisms of action of theophylline in sleep apnoea, which include central and peripheral effects, to establish predictors for treatment in different groups of sleep apnoea patients.

Diagnosis and therapy of sleep apnea

The presenting symptom complex, diagnostic features, and therapeutic alternatives for obstructive and central sleep apnea are discussed in relation to two illustrative patients. Heavy snoring and restlessness during sleep in an obese individual, usually a male, may indicate obstructive apnea. Daytime hypersomnolence, intellectual deterioration, mental depression, impotence, cardiac arrhythmias, cor pulmonale, systemic hypertension, and erythrocytosis are the most common complications. Tracheostomy, the classic form of therapy, can be replaced by pharmacologic intervention in most patients. The clinical presentation of central apnea is less dramatic, but neurological and cardiac complications can occur. Therapy is less well established for this entity. Knowledge of the increased incidence of these disorders and awareness of more subtle complications indicate that sleep apnea should be placed in the differential diagnosis of pulmonary and systemic hypertension, hypersomnolence states, mental deterioration, psychiatric illness, and even insomnia.

Treatment of apnea and excessive periodic breathing in the full-term infant

Twenty-two full-term infants, aged 0 to 6 weeks, with a history of unexplained apnea and respiratory abnormalities on pneumogram recordings, were treated with theophylline (average dose 7.5 mg/kg/day and average serum level 11 micrograms/ml). Subsequent recordings showed a significant decrease in the amount of periodic breathing (14.3% vs 0.7%) and apnea 10 to 14.9 seconds (12.8 vs 1.0/100 min) when compared to the initial pneumogram. It is concluded that theophylline therapy in this group of infants will result in a reduction of apnea and periodic breathing.

[Treatment of nocturnal periodic hypoxemia with safrazine hydrochloride in a patient with Duchenne muscular dystrophy under nasal intermittent positive pressure ventilation]

Nocturnal periodic hypoxemia occurring in a 25-year-old Duchenne muscular dystrophy patient under NIPPV control was successfully treated with monoamine oxydase inhibitor (MAOI), safrazine hydrochloride. Five mg of safrazine hydrochloride was administered before sleep, and the periodic hypoxemia disappeared within 14 days. The effect lasted almost seven months without notable side effect. MAOI may be effective for nocturnal hypoventilation through suppression of REM sleep as in the case of tricyclic antidepressants. The effect of tricyclic antidepressants appears immediately. However, it usually fades away within forty days. Safrazine hydrochloride was effective obviously longer than tricyclic antidepressants. Consequently MAOI may be a hopeful candidate of medication for a treatment of nocturnal periodic hypoxemia in Duchenne muscular dystrophy.

Effect of serotonin uptake inhibition on breathing during sleep and daytime symptoms in obstructive sleep apnea

Pharmacologic enhancement of serotonergic transmission by serotonin uptake inhibition has been suggested as one approach to improve upper-airway patency and thus nocturnal breathing in patients with obstructive sleep apnea (OSA). To test this hypothesis, we performed a double-blind, randomized, placebo-controlled crossover study testing the effect of paroxetine (20 mg od) on polysomnographic and psychopathologic outcomes in 20 male OSA patients (mean age 52.1 years, mean BMI 28.7 kg/m2, mean oxygen desaturation index on a previous screening 25.4/hour). The two treatment periods of 6 weeks and the separating washout period of 4 weeks were completed by 17 patients. Paroxetine reduced the apnea index during NREM sleep (-35%, p = 0.003), but not during REM sleep. No significant effect on hypopnea indices was found. With the exception of a previously described REM-postponing effect (p = 0.05), sleep architecture was not significantly influenced by paroxetine. Similarly, the effect of paroxetine on apnea was not associated with a significant overall alleviation of psychopathologic symptoms as rated on the Comprehensive Psychopathological Rating Scale or OSA-related daytime complaints assessed by visual analog scales. We conclude that enhanced serotonergic transmission improves breathing during NREM sleep in OSA. This effect is poorly related to effects on sleep architecture or daytime symptoms.

Effects of 5-hydroxytryptamine and 5-hydroxytryptamine 2A/2C agonist on the genioglossus activity and sleep apnea in rats

BACKGROUND

5-Hydroxytryptamine (5-HT) is a common neurotransmitter in the brain which plays an important role in the pathogenesis of sleep apnea. Dysfunction of 5-HT and 5-HT(2) receptors may lead to the collapse of the upper airway and the instability of respiratory control, which in turn produce apnea. Genioglossus (GG) is one of the most important oropharyngeal muscles maintaining the upper airway open. The present study aimed to investigate the effects of 5-HT and 5-HT(2) receptor on GG activity and the sleep apnea in Sprague-Dawley (SD) rats.

METHODS

Microinjection probes were placed within the fourth ventricle of sixteen SD rats. After recovery for a week, the electromyogram (EMG) of GG was recorded in the anesthetized and vagotomized rats. The changes of GG activity before and after the microinjection of 5-HT or 5-HT(2A/2C) agonist -2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI) were observed. Probes were also laid in another eight SD rats. Electroencephalogram (EEG), EMG of neck muscle and respiration were recorded at the same time a week later. The effects of DOI on the occurrence of sleep apnea were explored.

RESULTS

Both 5-HT and DOI significantly enhanced the activity of GG just 3 minutes after the completion of injection. The effect of 5-HT disappeared quickly and the effect of DOI lasted for more than 27 minutes. DOI also significantly decreased the post-sigh apnea index in non-rapid-eye-movement (NREM) and rapid-eye-movement (REM) sleep and decreased the spontaneous apnea index only in NREM sleep (P < 0.05, respectively).

CONCLUSION

5-HT and 5-HT(2A/2C) system correlated closely with the pathogenesis of the sleep apnea syndrome and 5-HT receptors may become the target of the drug treatment.

[Effects of 5-HT2 agonist/antagonist on sleep apnea in Sprague-Dawley rats]

OBJECTIVE

To evaluate the effects of 5-HT2 agonist/antagonist Ketanserin on sleep apnea in Sprague-Dawley (SD) rats.

METHODS

Twenty adult male SD rats were operated for implantation of EEG and EMG electrodes and a microinjection probe was placed within the fourth ventricle. After recovery for a week, rats were monitored for sleep and respiration in three continuous days. There is no intervention on the first day. Before monitoring, 40 microl ACSF were microinjected into the IV ventricle of the rats on the second day. On the third day before monitoring, 40 microl DOI were microinjected into the IV ventricle of ten rats and 40 microl Ketanserin into another ten ones.

RESULTS

Compared with blank control and microinjection of ACSF, DOI significantly reduced the total apnea index (AI) from 18.3 (11.1, 20.3) times/h and 15.2 (11.4, 18.0) times/h to 10.8 (3.1, 14.1) times/h (P=0.005 and 0.005, respectively). Post sign apnea index (PSAI) during non-rapid eye movement (NREM) and rapid eye movement (REM) sleep as well as spontaneous apnea index (SPAI) during NREM sleep were all significantly decreased; (P<0.05, respectively); while it had no effect on SPAI during REM sleep (P>0.05). Neither sleep efficiency (the percent of total sleep time in total monitoring time) nor the time ratio of NREM sleep and REM sleep was significantly changed. In contrast to blank control and microinjection of ACSF, Ketanserin significantly reduced the total apnea index (AI) from 19.2 (13.7, 20.9) times/h and 19.0 (12.9, 21.6) times/h to 13.1 (9.5, 14.9) times/h (P=0.005 and 0.005, respectively). PSAI during NREM and REM sleep were significantly decreased (P<0.05, respectively). SPAI during NREM and REM sleep were changed without statistically significant (P>0.05, respectively). It also had no effects on sleep efficiency and the time ratio of NREM sleep and REM sleep.

CONCLUSION

Both 5-HT2 agonist and antagonist decreased the sleep apnea index and had no effects on sleep structure. It shows that the role of 5-HT2 receptor in the respiratory regulation during sleep is complex. The mechanisms involved remain to be studied in future.