Electrophysiological changes during episodes of the Kleine-Levin syndrome.

Diurnal EEGs of a 17 year old male with the Kleine-Levin syndrome revealed moderate diffuse abnormalities and stage REM at sleep onset during attacks. Overnight, stages 3, 4, and REM of sleep were decreased, but sleep onset REM stage was not seen. These records returned to normal between attacks.     

Sleep apnea in patients with postpolio syndrome

We studied sleep architecture and sleep apnea pattern in patients with postpolio syndrome (PPS). Ten patients with clinical signs of PPS underwent polysomnographic recording for two consecutive nights. Although sleep efficiency and proportions of sleep stages were within the normal range, sleep architecture was disrupted owing to sleep apnea. Patients with bulbar involvement had more frequent sleep apnea (mean sleep apnea index, 11.09) than patients without (apnea index, 5.88). The former also had significantly more central apnea, which occurred more commonly during non-rapid-eye-movement (NREM) than rapid-eye-movement (REM) sleep, than those without bulbar signs. This finding suggests reduction in forebrain control of compromised bulbar respiratory centers during NREM sleep in PPS.     

REM-related bradyarrhythmia syndrome

Cardiac arrhythmias during sleep are relatively common and include a diverse etiology, from benign sinus bradycardia to potentially fatal ventricular arrhythmias. Predisposing factors include obstructive sleep apnea and cardiac disease. Rapid eye movement (REM)-related bradyarrhythmia syndrome (including sinus arrest and complete atrioventricular block with ventricular asystole) in the absence of an underlying cardiac or physiologic sleep disorder was first described in the early 1980s. Although uncertain, the underlying pathophysiology likely reflects abnormal autonomic neural-cardiac inputs during REM sleep. The autonomic nervous system (ANS) is a known key modulator of heart rate fluctuations and rhythm during sleep and nocturnal heart rate reflects a balance between the sympathetic-parasympathetic systems. Whether the primary trigger for REM-related bradyarrhythmias reflects abnormal centrally mediated control of the ANS during REM sleep or anomalous baroreflex parasympathetic influences is unknown. This review focuses on the salient features of the REM-related bradyarrhythmia syndrome and explores potential mechanisms with a particular assessment of the relationship between the ANS and nocturnal heart rate fluctuations.     

A case of lissencephaly (agyria) syndrome with apnea--polygraphic study

A 4-month-old infant with lissencephaly syndrome who was diagnosed on the basis of clinical symptoms and computed tomography experienced four apnea attacks during three polysomnographies. Apnea attacks were of two types. Type I apnea attacks were thought to be sleep apnea. The cause is unknown. Apnea was followed by tonic seizures due to hypoxia. Type II apnea attacks were thought to be epileptic apneic attacks, because they proceeded from the epileptic discharges in the right anterior temporal region (lead of electrooculogram). The origin of Type II apnea attacks was focused in the limbic system.     

Polysomnographic studies of Lesch–Nyhan syndrome

Three cases of Lesch–Nyhan syndrome (LNS) were examined by polysomnography to assess the brainstem function, and to determine the causes of the neurological manifestations and sudden death in this syndrome. In the two older cases, the amount of slow wave and rapid eye movement (REM) sleep, the REM density and the frequency of REM bursts were decreased. In the youngest case, symmetrical phasic movements of all four limbs were observed at all sleep stages other than REM sleep. Although movements other than these symmetrical body movements appeared to be normal in this case, the frequency of twitch movements showed an abnormal pattern in each sleep stage in the two older cases. These findings suggest that in the brainstems of younger cases with LNS the REM-non REM generator as well as multiple neurotransmitter systems influencing body movements during sleep remain relatively normal, but become progressively impaired in adult cases. Severe obstructive apnea was observed in one case with hypothyroidism, but there were no respiratory abnormalities in other two cases.     

Multiple Sleep Latency Test findings in Kleine-Levin syndrome

Multiple Sleep Latency Test (MSLT) findings in a case of Kleine-Levin syndrome are reported for the first time. MSLT data indicate sleepiness as severe as in narcolepsy or obstructive sleep apnea and the occurrence of four sleep onset rapid eye movement (REM) periods, with a greater REM propensity at 2:00 p.m. and 4:00 p.m. than at 10:00 a.m. and 12:00 noon. The replication of such findings might suggest that Kleine-Levin syndrome could be considered a form of periodic REM sleep disinhibition. Therefore, the traditional hypothesis of diencephalic dysfunction may require modification to include the role of more caudal brain stem structures specifically activated during REM sleep.     

Marked episodic elevation of cerebrospinal fluid pressure during nocturnal sleep in patients with sleep apnea hypersomnia syndrome

The CSF pressure was measured continuously at the lumbar level during nocturnal sleep in 3 patients with sleep apnea hypersomnia syndrome. Nocturnal sleep was very unstable with frequent episodes of obstructive sleep apnea. When the patients were awake and relaxed in the supine position, their CSF pressure was stable and within the normal range. Episodic marked elevations of CSF pressure occurred frequently during sleep, and each elevation was preceded and accompanied by an episode of sleep apnea or hypopnea. Significant correlations were found between the duration of apneic episodes and increase of CSF pressure, and between decrease of SaO2 or TcPO2 and increase of CSF pressure. The duration of sleep apnea was longer, increase of CSF pressure was greater, and decreases of SaO2 and TcPO2 were more marked during REM sleep than during NREM sleep. It is suggested that the frequent marked episodic elevations of CSF pressure are caused by an increase in the intracranial vascular volume occurring mainly in response to transient hypercapnia and hypoxia, which are induced by pulmonary hypoventilation during the episodes of sleep apnea.     

Sleep patterns in Kleine-Levin syndrome.

Diurnal and nocturnal sleep records were obtained from a male and a female with Kleine-Levin syndrome, during excessive daytime sleep attacks and while they were asymptomatic. A common pattern of abnormal sleep was seen in both patients even during the asymptomatic period. The female, aflicted with a severe form of periodic hypersomnia, showed nocturnal and diurnal sleep onset REM periods. The different pattern of sleep abnormality in the female could be an expression of the severity of her symptoms or might indicate a variant of sleep abnormality present only in females with Kleine-Levin syndrome.     

Actigraphic assessment of sleep in young adults with Asperger syndrome

A high prevalence of subjective insomnia in adults with Asperger syndrome has been reported. In the present study the sleep quality of these patients was studied using wrist actigraphy. Nineteen adults with Asperger syndrome and frequent feelings of insomnia were compared with 10 controls devoid of neuropsychiatric disorders and subjective sleep problems during six consecutive nights. The patients had similar actigraphic sleep profile to the controls. The subjective low sleep quality in patients was not reflected in actigraphic assessment of sleep. This finding suggests that pervasive anxiety inherent in persons with Asperger syndrome predisposes them to insomnia complaints.     

Assessment of intracranial hemodynamics in sleep apnea syndrome.

BACKGROUND AND PURPOSE: Sleep apnea syndrome may lead to changes in cerebral hemodynamics due to altered alveolar ventilation. We investigated the dynamics of CO2- and blood pressure-regulated alterations of cerebral blood flow velocities during apneic episodes and evaluated CO2 reactivity during different sleep stages. METHODS: A computer-assisted pulsed Doppler system (2 MHz) was used for continuous overnight recordings of middle cerebral artery flow patterns together with simultaneous polysomnography, continuous blood pressure recordings, and measurements of end-expiratory CO2 in six patients with sleep apnea syndrome. RESULTS: Increases in mean flow velocity of 19-219% and in blood pressure of 12.5-83.1% could be observed during the apneic episodes, with maximum increases during rapid eye movement (REM) sleep. CO2 reactivity was in the normal range (4.4 +/- 1.2%) in the waking state and was markedly increased during sleep stages 1 and 2 (p less than 0.005 compared with awake). The greatest increase was found during REM sleep, with a rise of up to three times the waking value (p less than 0.0001 compared with sleep stage 2). CONCLUSIONS: The changes of mean flow velocity could be interpreted as reactive adaptation processes because of CO2 and blood pressure increases corresponding to apnea. The increased CO2 reactivity during sleep may indicate a "hypersensitivity" of intracranial vascular CO2 or pH receptors and a disturbance of central catecholaminergic and cholinergic systems. The pronounced velocity changes during apneic episodes and the concomitant alterations of vessel wall tension might lead to microangiopathies and macroangiopathies due to chronic strain on the brain vessels.     

Sleep and respiration in the syndrome "apnea during sleep" in the child]

A sleep apnea syndrome has been diagnosed in eight children (age range 5-14). Before undertaking therapeutic trials, sleep and respiration were extensively studied. Sleep and respiration were again analyzed 3 months after tonsillectomy and adenoidectomy (6 cases) or tracheostomy with insertion of valve (2 cases). Sleep induced apneic apisodes in these children who had normal respiration during wakefulness. Three types of apnea (central, upper airway, and mixed) were recorded in each case. The minimum number of apneas recorded during a single night was 75; the maximum was 816. Polygraphic monitoring demonstrated greatly disturbed sleep. Sleep changes were quantitative as well as qualitative. REM sleep percent was decreased, but stages 3 and 4 NREM sleep were also impaired. A relationship between stages 3-4 NREM sleep and respiration was noted: stages 3-4 sleep disappeared when apneic episodes were numerous; no apnea was recorded during stage 4 sleep. Follow-up nocturnal recordings of two tracheostomized children with valve open, then closed, confirmed this "stage 4/no apnea" relationship. Apneas were also noted to induce marked sinus arrhythmia during sleep.     

Cortical cerebellar atrophy presenting with central type sleep apnea syndrome]

The patient was a 55-year-old man who had shown progressive dysarthria and unsteady gait since 48 years of age. Neurologically, pure cerebellar ataxia without either pyramidal or extrapyramidal signs was seen. He had been diagnosed as having cortical cerebellar atrophy (CCA) at age 53. Polysomnography was carried out at June 17th, 2003, because of snoring and sleep apnea had occurred since January 2003. The results showed central dominant sleep apnea with an apnea index (AI) of 16.6. Apnea occurred during shallow sleep, stages I and II, while the length of REM sleep was almost normal, occupying 17.7% of total sleep time. The rhythm of his sleep was well preserved. Brain MRI showed cerebellar atrophy without any brainstem abnormality. Except for the central type sleep apnea, no other autonomic symptoms were found. We considered that the diagnosis of CCA remained applicable to the patient because of the presence of pure cerebellar symptoms over a 7-year-course, and the absence of brainstem atrophy on MRI. Sleep apnea seen in the present patient was distinct from MSA in which central type sleep apnea dominated, and that the sleeping rhythm including REM was preserved.     

Hypnic headache: a case report with polysomnography

We report on a case of nocturnal headache attacks fulfilling the criteria for hypnic headache syndrome. Using an overnight polysomnography, one nocturnal headache attack was captured during the REM phase of sleep. Quality of sleep was poor with desaturation episodes. However, the hypnic headache attack was not associated with oxygen desaturation. This additional case supports the view of a relationship between the hypnic headache syndrome and the REM sleep stage. Lithium therapy decreased the intensity and frequency of headache attacks.     

The immediate effects of nasal continuous positive airway pressure treatment on sleep pattern in patients with obstructive sleep apnea syndrome

We studied the immediate effects of continuous positive airway pressure (CPAP) applied nasally on the pattern of sleep in 12 patients, aged 30-58 years, with obstructive sleep apnea syndrome. All patients demonstrated a moderate to severe syndrome on the control night; apnea index ranged 28-83 apneas/h sleep. Nasal CPAP completely abolished all obstructive apneas and allowed apnea-free breathing in all 12 patients. Nasal CPAP had a marked effect on the sleep pattern. It significantly reduced stage I/II non-rapid eye movement (NREM) sleep and markedly increased stage III/IV NREM and REM sleep on the first treatment night. Stage I/II NREM sleep decreased from a control of 62.7 +/- 2.3% to 29.1 +/- 2.3% on the first treatment night. Stage III/IV NREM sleep increased from a control of 6.7 +/- 1.6% to 31.5 +/- 1.6%. The rebound in this sleep stage was especially marked in 3 patients aged 55-58 years. REM sleep increased from a control of 18.4 +/- 2.0% to 30.6 +/- 2.0% on the first treatment night. There was an increase in REM density. All patients were treated for another 2 nights and their sleep pattern analyzed on the third night. All sleep stages were still significantly different to the control night. The possible mechanisms involved are discussed.     

Overnight polygraphic study of Lennox-Gastaut syndrome

Nine children with Lennox-Gastaut syndrome, aged 2-14 years, were studied by overnight polygraphy for one night. Percentage of sleep period time (SPT) for stage rapid eye movement (REM) and REM density during REM sleep decreased in Lennox-Gastaut syndrome as compared with control. Alpha rhythm was seen in only 3 cases and sleep spindles in only 6 cases. The effect of sleep-wake or REM-non-REM (NREM) sleep rhythm on the rate of generalized epileptiform discharges varied with the individual. Ictal discharges with or without clinical tonic seizures observed in 5 children appeared during NREM sleep and awakening in the morning, and in 2 of these cases they also occurred frequently during the NREM sleep of the first sleep cycle. Subclinical ictal discharges were also seen during REM sleep in the early morning in one case who was 2 years old. The Lennox-Gastaut syndrome is assumed to involved a considerable degree of brain stem dysfunction.     

Decreased sleep quality and increased sleep related movements in patients with Tourette's syndrome

OBJECTIVE: Sleep quality and movement patterns across sleep stages in patients with Tourette's syndrome were examined to determine the influence of syndrome severity on sleep quality and the differential effect of sleep stages on tic and non-tic movements. METHODS: Twenty five patients with Tourette's syndrome (mean age 29 (SD 7) years) and 11 control subjects (29 (5) years) were studied by polysomnography and simultaneous split screen video monitoring to record standard sleep variables as well as to evaluate movements to differentiate between tics and regular movements. Severity of Tourette's syndrome during the day was assessed with the Tourette's syndrome severity scale. RESULTS: Sleep was significantly more disturbed in patients with Tourette's syndrome than in controls, with decreased sleep efficiency and slow wave sleep percentage, increased sleep latency, percentage of stage I, percentage of awakeness, number of awakenings, and sleep stage changes and more overall movements during sleep. Severity of Tourette's syndrome during the day correlated significantly and positive with number of awakenings and sleep stage changes and negatively with sleep efficiency. In addition to an increased number of regular movements patients had tics in all sleep stages. Tic frequency as well as frequency of regular movements was significantly higher in REM than in non-REM sleep which was also the case for regular movements of the controls. No disturbance of either REM sleep percentage or REM latency was found. CONCLUSION: Despite normal total sleep time and unaltered REM sleep variables patients with Tourette's syndrome have markedly disturbed sleep. Severity of the syndrome during the day is an important predictor of sleep alteration in patients. The increased rate of tics during REM sleep parallels the overall increased movement activity of patients during REM as well as non-REM sleep. The increased motor activity may be attributable to a state of hyperarousal rather than a disturbed cholinergic system.     

Headache complaints in relation to nocturnal oxygen saturation among patients with sleep apnea syndrome

BACKGROUND: Morning headaches are often ascribed to patients with sleep apnea syndrome (SAS) but the etiology of headaches in SAS is unclear. Given the relationship between oxygen and other headache syndromes, nocturnal hypoxia might be one factor contributing to headaches in SAS. METHODS: All subjects 18-80 years of age who were determined to have SAS and who underwent a continuous positive airway pressure trial in our sleep laboratory between March 1, 1997 and March 18, 1998 were considered for inclusion. Subjects were grouped according to whether they endorsed that waking with headaches is a problem for them. Polysomnography and standardized questionnaires were used to test the main hypothesis that patients with SAS and headaches would spend more time at lower oxyhemoglobin levels than those SAS patients without headache. RESULTS: Headache and non-headache patients did not differ in the percentage of time spent with an oxygen saturation less than 90%, either in total sleep time or in rapid eye movement sleep (REM). The headache patients were more likely to be female and spend a lower percentage of time in REM sleep. The REM sleep difference was not accounted for by the use of REM suppressing medications or by depression (as measured by the Zung scale). CONCLUSIONS: These data do not support the hypothesis that the duration of nocturnal hypoxemia relates to headache complaints in patients with SAS. The lower REM sleep percentage and higher variability in REM apnea index among the headache patients warrants further investigation.     

Ultra-low-field magnetic resonance imaging in upper airways obstruction in sleep apnea syndrome

Abstract The hypothesis that the sites of upper airways obstruction (U AO) are varied in a patient with obstructive sleep apnea syndrome (OSAS) among different sleep stages is studied. Four patients with OSAS underwent ultra-low-field magnetic resonance imaging (MRI) with a field strength of 0.064 Tesla provided real-time images and generated less noise and necessitated less strict magnetic isolation compared with conventional high-field MRI. After the fixed end-apneic sleep stage was determined, the polysomnogram was switched off and ultra-low-field MRI was commenced. The effects of continuous positive airway pressure (CPAP) on the upper airway patency in the deepest sleep stage obtained for each patient was assessed. Upper airway obstruction was found at the level of the palatopharynx (PP) at sleep onset extended to the glossopharynx (GP) during rapid eye movement (REM) sleep in two cases and during NREM sleep in one case. This combined PP and GP obstruction was observed from sleep onset and remained unchanged in one case. The patent upper airways were observed during treatment with CPAP during REM sleep in two patients and during stage two of NREM sleep in the other two patients. It can be concluded that the sites of UAO vary in a patient with OSAS in different sleep stages. The results also suggest the use of the ultra-low-field MRI in order to visualize the dynamic and real-time behaviors of the upper airways during sleep in patients with OSAS.     

Influence of nocturnal hypoxemia on the function of the visual tract in the course of the obstructive sleep apnea syndrome

BACKGROUND AND PURPOSE: In patients with obstructive sleep apnea (OSA) syndrome the episodes of upper airway obstruction lead to hypoxemia during sleep. The aim of the study was to establish the influence of sleep hypoxemia on the function of the visual tract in OSA patients. MATERIAL AND METHODS: The latency and amplitude of wave P100 of visual evoked potentials have been studied in 35 patients with OSA syndrome (mean apnea index 48+/-19). The diagnosis of OSA was established on the basis of continuous recordings of the respiratory function during sleep with additional full polysomnography in 17 patients. RESULTS: Mean absolute latency of P100 was longer in OSA patients than in healthy controls (117.0+/-8.8 ms vs. 104.3+/-4.6 ms, p<0.001). The differences in the amplitude of P100 were not significant (5.9+/-2.6 mV in OSA patients and 7.62+/-3.04 mV in healthy persons). In 60% of patients the latency of P100 exceeded 118 ms; in this group of patients the mean SaO2 during sleep apneas was lower than in patients with normal P100 latency (46+/-15% vs. 69+/-10%, p<0.05). Full polysomnographic studies revealed that in patients with prolonged latencies as compared with patients with normal P100 latencies there were lower: minimal SaO2 during NREM sleep (63+/-12% vs. 78+/-8%, p<0.05), as well as mean and minimal SaO2 during REM sleep (53+/-15% vs. 80+/-5% and 46+/-15% vs. 69+/-10%, p<0.05), without differences in apnea index or apnea duration. CONCLUSIONS: In patients with OSA syndrome the electrophysiological abnormalities suggesting damage of the optical tract may develop probably as a consequence of profound sleep hypoxemia.     

Therapy of obstructive sleep apnea syndrome

Symptomatology and sequelae, as well as diagnosis and therapy of the obstructive sleep apnea syndrome are discussed. The Esmarch prosthesis, which we developed for the prosthetic treatment of obstructive sleep apnea syndrome, was tested in 7 patients. Patients were polysomnographically recorded during two sequential nights with and without Esmarch prosthesis. All apnea parameters improved significantly (apnea time by 78%, apnea index by 67% of baseline values). The mean duration of the remaining apnea phases diminished by 31%. Improvement of O2 saturation of haemoglobin and O2 partial pressure in the tissue paralleled that of the apnea parameters. The severely disturbed sleep profile of the patients showed a clear tendency towards normalization. The Esmarch prosthesis is an efficient method for the treatment of the obstructive sleep apnea syndrome.