Onset of nocturnal attacks of chronic cluster headache in relation to sleep stages

The objective assessment of sleep in cluster headache: State of the art and future directions

Several lines of evidence suggest that cluster headache is related to chronobiology and sleep. Nevertheless, the nature of such a relationship is unclear. In this view, the objective evaluation of sleep in cluster headache has strong theoretical and clinical relevance. Here, we provide an in-depth narrative review of the literature on objective sleep assessment in cluster headache. We found that only a small number of studies (N = 12) focused on this topic. The key research aims were directed to assess: (a) the relationship between cluster headache and sleep breathing disorders; (b) the temporal relationship between sleep stages/events and cluster headache attacks; (c) sleep macrostructure in patients with cluster headache. No studies considered sleep microstructure. The reviewed studies are heterogeneous, conducted by a few research groups, and often characterised by relevant methodological flaws. Results are substantially inconclusive considering the main hypothesis. We outline several methodological points that should be considered for future research, and suggest that evaluating sleep microstructure, local sleep electrophysiology and actigraphic measures may strongly increase knowledge on the relationship between sleep and cluster headache.

Headache and Sleep Disturbances in the Pediatric Population

The relationship between sleep disturbances and headaches in the pediatric population is bidirectional. Common underlying molecular mechanisms of sleep and headaches have been speculated to explain the clinical connection. We will summarize various sleep disturbances and their known relationships to headache, focusing on the pediatric population. Careful recognition and assessment of sleep disturbances in patients with headache is critical and may help guide treatment. First line therapies for sleep disturbances consist of behavioral approaches, though surgical and pharmacologic strategies are utilized in particular circumstances.

“To sleep”, “to cough” and “to love’: Uncommon primary headaches

IntroductionThere are some physiological situations in which the individual may experience headache, such as to sleep, to cough and to love. In the first situation, "to sleep", the patient does not have headache when awake, but is awakened by pain during sleep; in the second, the act of "to cough" is a trigger for the onset of pain and finally, "to love," here, meaning sexual intercourse, can be a headache trigger.ObjectiveTo review the epidemiological, pathophysiological aspects and therapeutic management of headaches that arise when sleeping, coughing and having sexual intercourse.MethodA narrative review of literature including case reports and clinical trials were carried out. The articles were systematically obtained and assessed by the authors.ResultsThree primary forms considered rare were identified: hypnic headache, primary cough headache and primary headache associated with sexual activity. Hypnic headache occurs only during sleep, predominantly in women after 50 years of age. It was described in 1988 by Raskin, and has a prevalence ranging from 0.07% to 0.22%. Primary cough headache is triggered by coughing or another Valsalva maneuver and is more common in men over40 years of age. It was first described by Jules Tinel and has a prevalence of 0.4% to 1.2%. Primary headache associated with sexual activity occurs during sexual intercourse. It is more frequent in men after 40 years of age. It was described in the second century of the Christian era, by the Persian physician Avicenna. Its prevalence ranges from 0.9% to 1.6%.ConclusionPrimary headaches in the "to sleep", "to cough", and "to love" group are rare. They predominate in men, after 40 years of age, are of short duration, can be primary or secondary and have a therapeutic response to indomethacin.

Current Understanding of the Chronobiology of Cluster Headache and the Role of Sleep in Its Management

Cluster headache is uniquely rhythmic in its occurrence both diurnally and annually. This has implications for the clinical approach to the patient but also for our understanding of the role of central structures in its pathological basis. Many intrinsic and extrinsic factors seem to influence CH rhythmicity, including genetics. The proclivity for attacks to occur at night and the possible association with particular sleep phenomena, including sleep apnea, have motivated a number of studies which has improved our understanding but many questions remain unanswered. The sleep-headache interaction seems to be bidirectional and possibly both direct and indirect. The latter could involve more disperse networks of homeostatic regulation, which may better encompass recent observations. Treatment of the headache patient with concurrent sleep problems can be particularly challenging, especially considering side-effects and interactions of commonly used medications. While current treatment guidelines do not incorporate chronotherapeutic thinking, some evidence may suggest that application of such principles on an individual level may be beneficial.

The biological clock in cluster headache: A review and hypothesis

Objective

To review and discuss the putative role of light, sleep, and the biological clock in cluster headache.

Discussion

Cluster headache attacks are believed to be modulated in the hypothalamus; moreover, the severe pain and typical autonomic cranial features associated with cluster headache are caused by abnormal activity of the trigeminal-autonomic reflex. The temporal pattern of cluster headache attacks suggests involvement of the biological clock, and the seasonal pattern is influenced by the number of daylight hours. Although sleep is often reported as a trigger for cluster headache attacks, to date no clear correlation has been established between these attacks and sleep stage.

Conclusions

We hypothesize that light, sleep, and the biological clock can change the brain’s state, thereby lowering the threshold for activating the trigeminal-autonomic reflex, resulting in a cluster headache attack. Understanding the mechanisms that contribute to the daily and seasonal fluctuations in cluster headache attacks may provide new therapeutic targets.

Sleep and Orofacial Pain

Sleep and pain share a bidirectional relationship. Therefore, it is important for practitioners managing patients experiencing either sleep and/or pain issues to recognize and understand this complex association from a neurobiological perspective involving neuroanatomic and neurochemical processes. Accounting for the influence of pain on the various aspects of sleep and understanding its impact on various orofacial pain disorders assists in developing a prudent management approach. Screening for sleep disorders benefits practitioners in identifying these individuals. Instituting evidence-based multidisciplinary management strategies using both behavioral and pharmacologic strategies enhances the delivery of appropriate care.

Neurobiology and sleep disorders in cluster headache

Cluster headache is characterized by unilateral attacks of severe pain accompanied by cranial autonomic features. Apart from these there are also sleep-related complaints and strong chronobiological features. The interaction between sleep and headache is complex at any level and evidence suggests that it may be of critical importance in our understanding of primary headache disorders. In cluster headache several interactions between sleep and the severe pain attacks have already been proposed. Supported by endocrinological and radiological findings as well as the chronobiological features, predominant theories revolve around central pathology of the hypothalamus. We aimed to investigate the clinical presentation of chronobiological features, the presence of concurrent sleep disorders and the relationship with particular sleep phases or phenomena, the possible role of hypocretin as well as the possible involvement of cardiac autonomic control. We conducted a questionnaire survey on 275 cluster headache patients and 145 controls as well an in-patient sleep study including 40 CH-patients and 25 healthy controls. The findings include: A distinct circannual connection between cluster occurrence and the amount of daylight, substantially poorer sleep quality in patients compared to controls which was present not only inside the clusters but also outside, affected REM-sleep in patients without a particular temporal connection to nocturnal attacks, equal prevalence of sleep apnea in both patient and control groups, reduced levels of hypocretin-1 in the cerebrospinal fluid of patients and finally a blunted response to the change from supine to tilted position in the head-up tilt table test indicating a weakened sympathoexcitatory or stronger parasympathetic drive. Overall, these findings support a theory of involvement of dysregulation in hypothalamic and brainstem nuclei in cluster headache pathology. Further, it is made plausible that the headache attacks are but one aspect of a more complex syndrome of central dysregulation manifesting as sleep-related complaints, sub-clinical autonomic dysregulation and of course the severe attacks of unilateral headache. Future endeavors should focus on pathological changes which persist in the attack-free periods but also heed the possibility of long-lived, cluster-induced pathology.

Sleep and chronic daily headache

Sleep and headache have a complex and extensive interrelationship. This review focuses on the relationship between sleep and chronic daily headache, examining recent advances in the epidemiology and insights into possible mechanisms of this relationship as well as reviewing advances in treatment. There is a clear relationship between obstructive sleep apnoea (OSA) and snoring and morning headache, but the relationship between OSA and snoring and other primary headaches requires clarification. OSA and chronic migraine share both obesity and patent foramen ovale (PFO) as possible co-morbidities. Hypoxia does not clearly predispose to morning headache. Continuous positive airway pressure (CPAP) is an established treatment for OSA, and mixed results have been reported with regards to headache improvement with this treatment.

Sleep in cluster headache - beyond a temporal rapid eye movement relationship?

BACKGROUND AND PURPOSE

Cluster headache (CH) is a primary headache disorder characterized by severe attacks of unilateral pain following a chronobiological pattern. There is a close connection with sleep as most attacks occur during sleep. Hypothalamic involvement and a particular association with rapid eye movement (REM) sleep have been suggested. Sleep in a large, well-characterized population of CH patients was investigated.

METHODS

Polysomnography (PSG) was performed on two nights in 40 CH patients during active bout and one night in 25 age, sex and body mass index matched controls in hospital. Macrostructure and other features of sleep were analyzed and related to phenotype. Clinical headache characterization was obtained by semi-structured interview.

RESULTS

Ninety-nine nights of PSG were analyzed. Findings included a reduced percentage of REM sleep (17.3% vs. 23.0%, P = 0.0037), longer REM latency (2.0 vs. 1.2 h, P = 0.0012) and fewer arousals (7.34 vs. 14.1, P = 0.003) in CH patients. There was no difference in prevalence of sleep apnea between patients (38%) and matched controls (32%, P = 0.64) although the apnea index in patients was numerically higher (mean apnea-hypopnea index 10.75 vs. 4.93). No temporal association between nocturnal attacks (n = 45) and particular sleep stages was observed.

CONCLUSIONS

To date, this is the largest study of sleep in CH. It is demonstrated that REM sleep is affected which is in line with our current understanding of CH and hypothalamic involvement in the regulation of this sleep stage. Further, fewer arousals were found in CH patients but no association between apnea events or specific sleep stages. The findings support a central role of the hypothalamus and arousal systems in CH.

Sleep apnea in patients with cluster headache: A case-control study

Objective

Polysomnographic investigations have shown an unspecific association between cluster headache and obstructive sleep apnea syndrome. The aim of this study was to investigate this association in a cluster episode compared with a symptom free interval, and to further characterize this association.

Methods

We investigated 42 patients with episodic ( n = 26) or chronic ( n = 16) cluster headache by means of polygraphic screening for sleep apnea and compared the data to 28 healthy control subjects matched according to age, sex, and BMI. The patients with episodic cluster headache were screened twice, once in a cluster episode and once in a symptom free interval.

Results

Patients with active cluster headache showed a significantly higher respiratory distress index (8.6 ± 16.0) compared with healthy control subjects (3.4 ± 2.1; p = 0.002). More patients fulfilled the criteria for an obstructive sleep apnea syndrome (29%) than control subjects (7%; p = 0.018). Patients only, but not the control subjects, had central apneas. These differences were only significant when measured during an active cluster episode but not during a symptom free interval.

Conclusion

Cluster headache is associated with a sleep apnea syndrome only in the active cluster episode. The increased rate of central apneas might be a result of involvement of the hypothalamus in the pathophysiology of cluster headache. Out of five anecdotal cases treated with nasal continuous positive airway pressure, only one patient showed benefit with respect to cluster headache attack frequency.

Sleep in trigeminal autonomic cephalagias: a review

PURPOSE OF REVIEW

Sleep and cluster headache (CH) are believed to be interconnected but the precise relation to the other trigeminal autonomic cephalalgias (TACs) is uncertain and complex. A better understanding of these relations may eventually lead to a clarification of the underlying mechanisms and eventually to more effective therapeutic regimens. This review aims to evaluate the existing literature on the subject of TACs and sleep. An association between episodic CH and distinct macrostructural sleep phases, especially the relation to rapid eye movement (REM) sleep, has been described in some older studies but could not be confirmed in other, more recent studies. Investigations into the microstructure of sleep in these patients are lacking. Only a few case reports exist on the relation between sleep and other TACs.

SUMMARY

Recent studies do not find an association between CH and REM sleep. One older study suggests chronic paroxysmal hemicranias may be locked to REM sleep but otherwise the relation is unknown. Reports indicate that CH and obstructive sleep apnoea are associated in some individuals but results are diverging. Single cases show improvement of CH upon treatment of sleep apnoea, but the causal relationship remains in question. Other TACs are probably not connected to sleep and strictly nocturnal attacks should prompt investigations for secondary causes. The relation between CH and sleep is, however, fascinating and detailed sleep studies in carefully diagnosed patients are warranted.

Headache and sleep in children

Several scientific studies report a close relationship between sleep and headache: sleep changes may reflect the onset and increase of both duration and frequency of headache attacks. Variations in sleep architecture, together with a poor sleep hygiene in children, may indeed be responsible for the onset of headache and its development into a chronic disease. For a correct clinical management of children with headache, it is therefore fundamental to investigate their sleep habits, architecture and potential disturbances, in order to develop adequate therapeutic plans for both sleep and headache.

Primary headache disorders

Primary headache disorders include migraine, tension-type headaches, and the trigeminal autonomic cephalgias (TACs). "Primary" refers to a lack of clear underlying causative pathology, trauma, or systemic disease. The TACs include cluster headache, paroxysmal hemicrania, and short-lasting neuralgiform headache attacks with conjunctival injection and tearing; hemicrania continua, although classified separately by the International Headache Society, shares many features of both migraine and the TACs. This article describes the features and treatment of these disorders.

Trigeminal autonomic cephalgias

1. Trigeminal autonomic cephalgias (TACs) are headaches/facial pains classified together based on:a suspected common pathophysiology involving the trigeminovascular system, the trigeminoparasympathetic reflex and centres controlling circadian rhythms;a similar clinical presentation of trigeminal pain, and autonomic activation. 2. There is much overlap in the diagnostic features of individual TACs. 3. In contrast, treatment response is relatively specific and aids in establishing a definitive diagnosis. 4. TACs are often presentations of underlying pathology; all patients should be imaged. 5. The aim of the article is to provide the reader with a broad introduction to, and an overview of, TACs. The reading list is extensive for the interested reader.

Cluster headache and sleep, is there a connection? A review

PURPOSE OF REVIEW

Sleep and the chronobiological disease cluster headache are believed to be interconnected. Despite efforts, the precise nature of the relationship remains obscured. A better understanding of this relation may lead to more effective therapeutic regimes for patients suffering from this debilitating disease. This review aims to evaluate the existing literature on the subject of cluster headache and sleep.

LATEST FINDINGS

Several previous studies describe an association between episodic cluster headache and distinct macrostructural sleep phases. This association was not confirmed in a recent study of seven episodic cluster headache patients, but it was suggested that further studies into the correlation between cluster headache attacks and the microstructure of sleep are relevant. The connection between cluster headache and the hypocretins is currently under investigation.

SUMMARY

There is evidence in favour of an association between episodic cluster headache and REM sleep whereas no such relation to chronic cluster headache has been reported. Particular features in the microstructure of sleep and arousal mechanisms could play a role in the pathogenesis of cluster headache. Reports indicate that cluster headache and obstructive sleep apnoea are associated. Single cases show improvement upon treatment of sleep apnoea, but the causal relationship remains in question.

Treatment of miscellaneous idiopathic headache disorders (Group 4 of the IHS classification)--report of an EFNS task force

BACKGROUND AND PURPOSE

Certain miscellaneous idiopathic headache disorders, which are regarded as entities, are grouped in Chapter 4 of the International Classification of Headache Disorders. Recent epidemiological research suggests that these headache disorders are underdiagnosed.

OBJECTIVES

To give expert recommendations for the different drug and non-drug treatment procedures of these different headache disorders based on a literature search and on consensus of an expert panel.

METHODS

All available medical reference systems were screened for all kinds of clinical studies on these headache disorders. The findings in these studies were evaluated according to the recommendations of the EFNS resulting in level A, B or C recommendations and good practice points.

RECOMMENDATIONS

For all headache disorders, acute and prophylactic drug treatment is recommended based on case series and on expert consensus. Furthermore, recommendations for the differential diagnoses are given because these headache disorders can also present with a symptomatic form. The most effective drug for the majority of these headache disorders is indomethacin, mostly applied as long-term or short-term prophylaxis.

Sleep and headache

There is a strong interaction between sleep and headache. Sleep and headache disorders overlap epidemiologically, and share elements of anatomy and physiology. Perhaps as a result, their treatment is often mutually interdependent. Despite this, headache and sleep disorders tend to be treated separately, by different subspecialties of neurology. The headache disorders and their relationship to sleep, the commonalities of headache and sleep pathophysiology, and headache disorders that are particularly susceptible to sleep modulation (and vice versa) are reviewed. Practical management advice for sleep-modulated headaches is provided.

Polysomnographic findings in children with headaches

Although previous studies suggested a relationship between headache and sleep disturbances, polysomnographic findings in children with headache are rarely described. We investigated polysomnographic findings in children with headaches, and correlated them with headache type and severity, body mass index, and medical treatment. Analysis of polysomnographic findings of 90 children with migraine (60), chronic migraine (11), tension headache (6), and nonspecific headache (13) indicated that sleep-disordered breathing was more frequent among children with migraine (56.6%) and nonspecific headache (54%) vs chronic migraine (27%). Tension headache was not associated with sleep-disordered breathing. In the nonspecific headache group, children with sleep-disordered breathing had higher body mass indexes (P = 0.008). Severe migraine and chronic migraine were associated with shorter sleep time, longer sleep latency, and shorter rapid eye movement and slow-wave sleep. Fifty percent of children with tension headache manifested bruxism vs 2.4% of children with nontension headache (odds ratio, 1.95; 95% confidence interval, 1.2-4.34). Our results support an association between migraine and sleep-disordered breathing, and between tension headache and bruxism, in children. Moreover, disrupted sleep architecture with reduced rapid eye movement and slow-wave sleep in severe and chronic migraine headaches may support an intrinsic relationship between sleep and headache disorders.

Primary headache and sleep disturbances in adolescents

OBJECTIVE

The aim of the present study was to assess sleep patterns and the prevalence of sleep problems in adolescents with primary headaches using a validated sleep screening instrument, as well as to test the association between headache and pain features and adolescent sleep behaviors.

BACKGROUND

Sleep disturbance is a common complaint that has long been associated with primary headaches, but there exists limited evidence of the headache-sleep relationship among teens.

METHODS

Sixty-nine adolescents aged 13 to 17 years (M= 14.7; SD= 1.4) were evaluated for headaches at 2 pediatric neurology departments (90% migraine; 10% tension-type headache diagnoses). Participants completed the School Sleep Habits Questionnaire and a standardized questionnaire regarding headache characteristics.

RESULTS

Sleep complaints were prevalent among adolescents with headaches including insufficient total sleep (65.7%), daytime sleepiness (23.3%), difficulty falling asleep (40.6%), and night wakings (38%). Statistically significant relationships between headache characteristics (eg, frequency, pain intensity) and teen sleep behaviors also emerged.

CONCLUSIONS

Our findings provide further support for an association between headache and sleep disturbances among adolescents with primary headaches. This information may provide further understanding of the nature and course of the patient's headache experience, as well as facilitate treatment planning to include recommendations for promoting good sleep hygiene.

Relationships between headache and sleep in a non-clinical population of children and adolescents

BACKGROUND

Headache and sleep are related in different ways and alterations of chronobiological mechanisms are involved in headache. We investigated the relationships between headache and sleep quality in a large non-clinical population of children and adolescents and evaluated the relationship between headache and circadian typologies.

METHODS

A total of 1073 children and adolescents (50.9% males; mean age=10.56; range=8-15 years) were recruited from four schools in Rome. They filled out the questionnaires individually in classrooms, after brief group instruction about answer formats. The questionnaires included (a) a self-report headache questionnaire to collect information on different aspects of headache attacks based on the International Classification of Headache Disorders-2nd edition (ICHD-2); (b) the School Sleep Habits Survey that incorporated questions about sleep habits, the Sleep-Wake Problems Behaviour Scale (SWPBS), the Sleepiness Scale (SLS) and the Morningness/Eveningness Questionnaire (MEQ).

RESULTS

According to ICHD-2 criteria, we classified 70 (6.5%) children as Migraine Group (MG), 135 (12.7%) as Non-Migraine Headache Group (NMG), and the remaining 868 (80.8%) were classified as Headache-Free Group (HFG). No clear differences have been found between MG and NMG regarding the frequency of the attacks, although MG showed a significantly increased frequency of long-lasting attacks. The modality of onset of pain and the location of pain was similar in both groups. The most frequent triggering factor for headache in MG and NMG was "a bad sleep" (32.2%) followed by emotional distress (27.8%). No differences have been found between MG, NMG and HFG in sleep schedule or sleep duration. MG and NMG showed significantly higher scores on the SWPBS vs. HFG, while MG presented higher scores on the SLS compared to NMG and HFG. MG presented lower MEQ scores, indicating a more pronounced eveningness.

CONCLUSIONS

The relationships between headache and sleep problems are evident even in a non-clinical population of children and adolescents, with MG showing poorer sleep quality, sleepiness and a tendency toward eveningness.

Trigeminal Autonomic Cephalalgias: Current and Future Treatments

The trigeminal autonomic cephalgias include cluster headache, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT). The evidence for the current treatment options for each of these syndromes is considered, including oxygen, sumatriptan, and verapamil in cluster headache, indomethacin in paroxysmal hemicrania, and intravenous lidocaine and lamotrigine in SUNCT. Some treatments such as topiramate have an effect in all of these, as well as in migraine and other pain syndromes. The involvement of the hypothalamus in functional imaging studies implies that this may be a substrate for targeting treatment options in the future.

Headache and sleep

Headache and sleep have long been recognised as being interdependent due to specific causative factors. Yet, the precise understanding of the roles played by these factors in this interdependency remains elusive. Many observations have suggested a reciprocal relationship between headache and sleep; however, these hypotheses have only been partially substantiated by robust findings. Being so, additional well-designed clinical and laboratory studies are required to confirm these relationships. Nonetheless, sleep and headache are known to be related in several ways: primary headache such as migraine, cluster headache (CH) and hypnic headache (HH) can be triggered by sleep, while chronic morning headaches can be caused by sleep disorders such as sleep apnoea and insomnia. Furthermore, headache and sleep disorders can also be symptoms of other underlying pathologies. Migraine, CH and HH seems to be related to sleep stages suggesting that they may in fact be a chronobiological disorder. Patients suffering from chronic morning or nocturnal headache should be considered for the presence of possible sleep disturbances.

Non-rapid eye movement sleep parasomnias

Parasomnias are unpleasant or undesirable behavioral or experiential phenomena that occur during sleep. Once believed unitary phenomena related to psychiatric disorders, it is now clear that parasomnias result from several different phenomena and usually are not related to psychiatric conditions. Parasomnias are categorized as primary (disorders of the sleep states) and secondary (disorders of other organ systems that manifest themselves during sleep). Primary sleep parasomnias can be classified according to the sleep state of origin: rapid eye movement sleep, non-rapid eye movement sleep, and miscellaneous (those not respecting sleep state). Secondary sleep parasomnias are classified by the organ system involved.

Investigation into sleep disturbance of patients suffering from cluster headache

The new discoveries relating to cluster headache (CH) encouraged the study of the relationship of the hypothalamus to respiratory physiology and its comorbidity with sleep apnoea. The question is whether the apnoeas are more frequent during REM sleep and the desaturations could be involved as triggers of the cluster attacks. Furthermore, could the connection with the hypothalamus, already proved, be responsible for an alteration in the structure of REM sleep and a chemoreceptor dysfunction. We set out to analyse when polysomnography investigation is necessary in patients with CH. We studied 37 patients suffering from episodic CH, 31 (83.8%) men and six (16.2%) women. For the control group, we selected 35 individuals, 31 (88.6%) men and four (11.4%) women. There was a greater percentage of obstructive sleep apnoea (OSA) in patients with CH (58.3%) compared with the control group (14.3%) and with the general population (2-4%). In cases of pain during sleep, the majority is deflagrated during the REM phase, following a desaturation episode. A stratified analysis of the apnoea/hypnoea index relating to body mass index (BMI) and age showed that patients with CH have 8.4 times more chance of exhibiting OSA than normal individuals (P < 0001). This risk increases to 24.38 in patients with a BMI > 25 kg/m(2) and increases to 13.5 in patients > 40 years old. Surprisingly, the risk decreases sharply in patients with a BMI < 25 kg/m(2) and who are < 40 years old. Due to the fact that polysomnography is a complex, costly and sometimes difficult examination, we suggest, in concordance with the results, that it should be carried out routinely in patients with CH that exhibit a BMI of > 25 kg/m(2) and/or in patients who are > 40 years of age.

Behavior during cluster headache

Cluster headache (CH), also known as "suicide headache," is characterized by a distinctive behavior during attacks. In 80% to 90% of cases, patients are restless and constantly moving in a vain attempt to relieve pain. They often perform complex, stereotyped actions. During attacks, CH sufferers do not want to be touched, stroked, or comforted and frequently moan a great deal, cry, or even scream. They sometimes indulge in violent, self-hurting behavior. Restlessness is a highly sensitive and highly specific parameter for CH and has been included among the signs and symptoms accompanying pain of the disorder in the Second Edition of the International Classification of Headache Disorders. A few hypotheses on pathophysiology of restlessness are addressed in this paper.

[Sleeping behaviour and headache attacks in cases of primary headache. Possible pathological mechanisms]

Headache is connected with sleep quality, e.g. hypnic headache and chronic paroxysmal headache attacks occur preferentially during REM sleep; this is possibly also true for cluster headache and migraine. REM sleep is typically characterized by the occurrence of ponto-geniculo-occipital spikes (PGOs). These PGOs should be able to trigger cortical spreading depression (CSD), which, although often clinically silent, is assumed to be an essential element of a migraine attack and possibly also of other forms of headache. CSDs are considered a correlate of migraine aura. They could lead to the secondary activation of trigeminovascular afferences, which would then induce a headache. Interestingly, illnesses that are comorbid with migraine cause an increase in the amount of REM sleep; conversely, various drugs administered prophylactically for these illnesses reduce the quantity of REM sleep.

Rare nocturnal headaches

PURPOSE OF REVIEW

This review describes rare headaches that can occur at night or during sleep, with a focus on cluster headaches, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing, hypnic headache and exploding head syndrome.

RECENT FINDINGS

It is known that cluster headaches and hypnic headache are associated with rapid eye movement sleep, as illustrated by recent polysomnographic studies. Functional imaging studies have documented hypothalamic activation that is likely to be of relevance to circadian rhythms. These headache syndromes have been shown to respond to melatonin and lithium therapy, both of which have an indirect impact on the sleep-wake cycle.

SUMMARY

There is growing evidence that cluster headache and hypnic headache are chronobiological disorders.

[Cluster headache: study of autonomic alterations and other associated manifestations in 28 cases]

The short lasting primary headaches are classified as those without autonomic activation and those with important activation, which includes the cluster headache. This study focuses on the pathophysiology of cluster headache mainly in its autonomic phenomenon (conjunctival injection, lacrimation, nasal congestion, rhinorrhoea, partial ptosis and eyelid oedema) showing the involvement of superior salivatory nucleus with the pain stimulus propagation, which begins in the trigeminal nerve. The autonomic alterations were studied in 28 patients being lacrimation and conjunctival injection, the main features.

How do sleep disturbance and chronic pain inter-relate? Insights from the longitudinal and cognitive-behavioral clinical trials literature

Sleep disturbance is perhaps one of the most prevalent complaints of patients with chronically painful conditions. Experimental studies of healthy subjects and cross-sectional research in clinical populations suggest the possibility that the relationship between sleep disturbance and pain might be reciprocal, such that pain disturbs sleep continuity/quality and poor sleep further exacerbates pain. This suggests that aggressive management of sleep disturbance may be an important treatment objective with possible benefits beyond the improvement in sleep. Little is known, however, about how to effectively treat sleep disturbance associated with pain or whether such treatment might have beneficial effects on reducing pain. A small, but growing literature has applied cognitive-behavioral therapies (CBT) for either pain management or insomnia to patients with chronic pain. In this article, we review the longitudinal literature on sleep disturbance associated with chronic pain and clinical trial literatures of cognitive-behavior therapy for pain management and insomnia secondary to chronic pain with the aim of evaluating whether the relationship between clinical pain and insomnia is reciprocal. While methodological problems are common, the literature suggests that the relationship is reciprocal and CBT treatments for pain or insomnia hold promise in reducing pain severity and improving sleep quality. Directions for future research include the use of validated measures of sleep, longitudinal studies, and larger randomized clinical trials incorporating appropriate attentional controls and longer periods of follow-up.

Sleep-related headache syndromes

The relationship between sleep and sleep disorders and headache remains unclear. Clinical experience and numerous studies document some sort of relationship, but the exact nature remains understudied and complex. Changes in sleep duration and sleep quality appear to be capable of affecting headaches of different types. Obstructive sleep apnea can cause or exacerbate headaches in a susceptible person. Obstructive sleep apnea also may cause a specific headache when awakening, which is different from migraine or tension headache and disappears after treatment of the sleep and breathing disturbance. Hypnic headache is another type of sleep-exclusive headache that has been proposed. Hypnic headaches are brief, moderately severe, and affect the elderly primarily.

Cluster headache associated with sleep apnoea

This study of sleep changes in patients with cluster headache (CH) was conducted in view of the nocturnal predominance of this condition, the efficacy of oxygen and the fact that the attacks follow oxygen desaturation. Proposed mechanisms include impairment of carotid body activity secondary to hypothalamic vasomotor regulatory dysfunction. Sixteen patients with episodic CH and 29 healthy volunteers underwent nocturnal polysomnography. Five (31.3%) patients with episodic CH were found to have sleep apnoea (SA). Two patients with SA experienced two attacks during the study period. The attacks followed episodes of oxygen desaturation and were associated with REM sleep. In two patients with SA and CH, treatment with continuous positive airway pressure abolished their oxygen desaturation, sleep apnoeas and headaches. Our study confirmed the high percentage of CH associated with SA. We suggest that oxygen desaturation may be a trigger factor in some patients and play a role in the pathogenesis of CH.

Cluster headaches and sleep disorders

Cluster headaches are characterized by unilateral paroxysmal attacks of severe pain with associated symptoms. The headaches occur during particular sleep stages and are associated with other chronobiologic factors. Several sleep disorders have been associated with the occurrence of cluster headache; multiple hormonal influences affect the relationship between sleep and headache. Melatonin and other treatments that affect circadian rhythm have been suggested for the treatment of cluster headache. Obstructive sleep apnea can occur in patients with cluster headache; attempts to treat one disorder may influence the other. Sleep disorders such as insomnia and narcolepsy also may be associated with and influence cluster headaches. This article examines the relationship between the various sleep disorders and cluster headache, and reviews current research. Normal and abnormal sleep and details of treatments for specific sleep disorders that may decrease the frequency and severity of cluster headaches also are discussed. The relationship between obstructive sleep apnea, which is the most common sleep disorder, and cluster headache is discussed in detail.

Sleep and headache

The relationship between sleep and headache has been known for over a century. Headache and sleeping problems are both some of the most commonly reported problems in clinical practice, and cause considerable social and family problems, as well as socio-economic impact and costs. There is a clear association between headache and sleep disturbances, especially headaches occurring during the night or early morning. The mechanism and causes are complex, multifactorial and poorly understood. Headache disorders like migraine, tension-type headache, cluster headache and hypnic headache all affect or are directly related to sleep disturbances and daytime functioning. Sleep fragmentation, insomnia and hypersomnia all show relations to headache. Primary sleep disorders like insomnia, hypersomnias including sleep disordered breathing are all associated with and may cause headache. Furthermore medical, psychiatric and rheumatic diseases are associated with sleep disturbances and headache. The current knowledge about headache and sleep is still sparse and further research is advocated.

Short-lived head pains

There are several short-lived paroxysmal head pain syndromes, many of which are responsive to indomethacin, and some of which are potentially ominous. Included in this article are icepick headache, hypnic headache syndrome, chronic paroxysmal hemicrania, cough headache syndrome, coital headache, and thunderclap headache.