The purpose of writing this report is to determine the nature, occurrence, and pathophysiology of sleep-wake disorders after sustaining Traumatic Brain Injury (TBI) and their impact on recovery and relation with other effects of TBI, along with analyzing treatment options. It also presents in the meaning of sleep-wake disturbance or disorder, a method of assessing, sample characteristics features like time and severity of TBI after the injury occurred and control of significant impacts like pain, anxiety, depression or medications. Because sleep wake disorders found in human beings who get affected by mental illness. This will lead to many problems like insomnia, narcolepsy, nightmare disorder, restless legs syndrome. People who had a history of mild to moderate TBI head injury and unresolved sleep disturbances were examined. They all had same complaints of sleep attacks and EDS. Furthermore, this paper emphasizes the classification of sleep-wake disorders to diagnose the disorder accurately and to improve communication and data for future research purposes.
A sleep-wake disturbance is a disorder that affects the proper sleep of an individual. People with a sleep-wake disorder usually have complaints with unsatisfied sleep with respect to quality, amount, and timing of sleep. All these sleep-wake disorder people share the common features resulting from stress and daytime impairment. The risk of sleeping disturbances can be increased by various factors like lifestyle, demography, environment, diseases and its treatment. Ever year in the USA, about 1.7 million people nearly 550 per 100,000 individuals undergo a traumatic brain injury (TBI) and 16.3% of those injured people are being admitted and treated in the hospitals. The physical, emotional, social and cognitive spheres of injured people, as well as their family members, are affected by the continuous effect of TBI. The sleep-wake disturbance is the common and persistent result of TBI and present as enormous daytime sleepiness, difficulties in staying or falling asleep, an excessive need for sleep and changes in rhythms of sleep-wake. For a patient after undergoing TBI, a tough interplay between Pathophysiological factors at various levels like structural, neurochemical or neuro-electrical. Psychological factors like TBI-related psychopathology or sleep related problems; Environmental factors like light, pain or noise and Social factors related to family or work. A sleep-wake disturbance is present in every level of severity with TBI and can increase during treatment given in the hospital, during rehabilitation of inpatient or after the injury and it can sustain for many years after the injury occurred. A sleep-wake disturbance can aggravate the other persistent sequelae of TBI like pain, cognitive deficits, fatigue and mood swing. About 14 of 21 studies in Meta-analysis found that 50% of people who sustain TBI had disturbances in sleep-wake. The prevalence and causes of sleep-wake disorders will be presented in this report.
Nature and Prevalence
Almost 30 to 70% of people with traumatic brain injury (TBI) will have complaints of sleep disturbances. There are many disorders encompassed with sleep-wake disturbances like insomnia disorder, circadian rhythm sleep-wake disorder, hypersomnolence disorder, breathing related disorders, a sleep arousal (NREM) non-rapid eye movement disorder, narcolepsy, nightmare disorder, restless legs syndrome, (REM) rapid eye movement disorder and medications or drugs induced sleep-wake disorders. Among these, the sleep-wake disorders that are mostly associated with people who sustain TBI are insomnia disorder, excessive sleepiness during daytime, hypersomnolence disorders like post-traumatic hypersomnia and narcolepsy, the excessive need of sleep, breathing related disorders during sleep like sleep apnoea.
Almost 30 to 60% of individuals with TBI were found to have insomnia disorder either existing as symptoms without finding all criteria for diagnosis or as a disorder. Some studies show that people with less TBI have more complaints of insomnia than people with severe TBI. It might be because of more awareness about the symptoms of the disorder in this subgroup. A study with 452 patients who had mild to severe levels of TBI after 8 years of injury found that the insomnia disorder’s diagnostic criteria were fulfilled by 29% of patients and symptoms were seen in 21% of patients without fulfilling all the diagnosis criteria for insomnia disorder. Among the patients who had insomnia disorder, it was found to be chronic in most patients and 60% of them were not able to be treated. Most studies show that people with insomnia after TBI makes use of own questionnaires about disturbances in sleep or self-sleep diaries and it is diagnosed based on the complaints. Most other sleep orders like sleep apnoea can be diagnosed with the help of a gold standard called polysomnography.
Once a person undergoes traumatic injury, sleepiness is a common problem especially with severe TBI injuries which leads to greater sleepiness. The hypersomnia or excessive sleepiness is the impact of TBI and polysomnography, actigraphy or multiple sleep latency testing are used to diagnose the sleep-wake disorder after TBI. To evaluate sleepiness in 514 people with TBI after 1 year of injury happened in which 132 were not- cranial trauma controls and 102 were trauma-free controls, a study uses the sickness impact profile. It is found that sleepiness gets improved in many patients especially with TBI. But, a quarter of TBI patients and non-cranial trauma control people felt sleepy for 1 year after the injury.
People who had a history of mild to moderate TBI head injury and unresolved sleep disturbances were examined. They all had same complaints of sleep attacks and EDS (excessive daytime somnolence). Along with this, they also found to have sleep paralysis, cataplexy, and hypnagogic hallucinations. The result of this study after using polysomnography shows that all of them had narcolepsy disorder. Hence, it is found that narcolepsy may be inactive but even a mild injury to the brain’s central nervous system can make the individual to be diagnosed with the symptoms (Ouellet, Beaulieu-Bonneau, & Morin, 2015).
Classification of sleep disorders
It is necessary to classify sleep-wake disorders in order to differentiate between various disorders and to clearly understand the causes, symptoms, etiology and pathophysiology before going for treatment. The effort of potential International sleep societies leads to the publication of International Classification of Sleep Disorders (ICSD). The ICSD-2 classifies the 81 major sleep disorders into 8 main groups such as insomnia, hypersomnias, parasomnias, sleep-related breathing disorders, sleep related movement disorders, circadian rhythm sleep disorders, isolated symptoms or unresolved problems and other sleep-wake disorders.
Insomnia is a sleep-wake disorder where the patient finds difficult to initiate or maintain sleep during night time. Insomnias usually have less amount of nocturnal sleep or more time of nocturnal wakefulness. The primary complaints of insomnias are the inability to sleep, waking too early, poor amount of nocturnal sleep or maintain the sleep. People with paradoxical insomnia have complaints of severe level of insomnia that happens without any evidence of disturbances in sleep and without any daytime impairment. Insomnia may be related to the ingestion or discontinuation of a drug when there is a dependency or enormous use of that drug or substance is the cause of Insomnia.
The primary complaint of hypersomnias is excessive sleepiness during daytime and inability to remain awake during the day. Other sleep-wake disorders that are associated with hypersomnias must be treated before diagnosing the hypersomnia. Idiopathic hypersomnia is referred as excessive sleepiness with long sleep duration of more than 10 hours and excessive sleepiness without long sleep time but with unexpected naps. Patients with behavioral-induced insufficient sleep syndrome usually have complaints of having short sleep time habits and tend to sleep for a longer time when that usual sleep time habit is disturbed or not maintained. A neurological or medical disorder may cause hypersomnia due to the use of drugs or certain medical conditions. If the condition is not known, a psychiatric diagnosis may be related with the hypersomnia.
The parasomnias patients have general complaints of unusual movements during sleep, abnormal behaviors or emotions, dreaming and functioning of the autonomic nervous system. The parasomnia disorder is therefore referred to unpleasant physical behavior that happens during the sleep. The common features of parasomnias are activities of skeletal muscles and changes in the autonomic nervous system. Sleep-related hallucinations, arousal, sleep walking, sleep-stage transition and sleep-related eating disorders may associate with parasomnia disorder. A parasomnia disorder may also occur due to the manifestation of a medical condition.
The dysfunction of the central nervous system may destroy the efforts of respiratory and causes the central sleep apnea syndrome. Other central sleep apnea syndromes are caused by pathologic or environmental factors. Sleep-related breathing disorders have complaints of many episodes of breathing cessation due to poor ventilation effort during sleep. These patients have complaints of EDS, difficult to breathe during sleep or insomnia. The diagnosis of this disorder needs polysomnography to observe 5 or more apneic episodes in just one hour of sleep. Disordered ventilation and need to increase breathing effort occur when there is an obstruction in the respiratory airway, which leads to obstructive sleep apnea syndromes. Disease in the intestinal lung may cause sleep related hypoventilation or hypoxemia that is associated with vascular pathology.
A feature of sleep-wake disorders:
The continuous misalignment between the sleep pattern of a patient and the regular sleep pattern of society is the main feature of the circadian rhythm sleep disorders. The primary complaints from patients of this disorder are the inability to sleep when desired or needed. The undesired wake episodes occur as a result of inappropriate sleep times. The irregular sleep-wake disorder is associated with the unclear circadian rhythm of sleep and wakefulness. It is frequently seen in adults and related to poor synchronizing light or social activities. The delayed sleep disorder can be diagnosed only if it is not related to the psychiatric disorder. Patients who are diagnosed with insufficient sleep hygiene share the common feature of disturbance in sleep timings.
When sleep is disturbed by any simple or stereotyped movements, the disorder is referred as sleep-related movement disorders. Periodic limb movement disorder and restless legs syndrome are associated with this disorders. Patients with restless legs syndrome usually complaints about the unavoidable need to move the legs during nocturnal sleep and it may occur with painful or unpleasant symptoms. This sensation can be relieved by walking as resting the legs may worsen the sensation. Sleep-related rhythmic movement disorder refers to a recurrent rhythmic behavior that leads to movements of body, limbs or head during mild sleep and it is usually common among children but also seen in adults.
Isolated symptoms, normal variants, and unresolved problems categorize disorders due to the length of sleep, snoring and symptoms occur between the normal and abnormal border of sleep. Diagnosis of this disorder usually requires more than 10 hours of sleep length. When snoring is not related to insomnia or excessive sleeping disorder, it is diagnosed when the sound of respiratory function disturbs the patient or his bed partner. Propriospinal myoclonus disorder refers to repetitive and sudden jerk of muscles during sleep transition from wakefulness to sleep and it is associated with sleep onset insomnia. Polysomnography is used to diagnose the myoclonus that is associated with fatigue or daytime sleepiness. Abnormal sexual behaviors or sleep-related sexual disorders may associate with confusion arousal or parasomnias.
Causes of sleep-wake orders.
Other Sleep-wake disorders due to physiological (organic), not due to a substance or physiological and environmental conditions are not able to categorize into above disorder classifications. Patients with fatal familial insomnia find difficulty in initiating and maintaining sleep, which results in developing dreams. A light and unpleasant sleep lead to the fibromyalgia disorder and it causes tenderness and pain in muscles. Sleep-related headaches disorder is diagnosed when headaches occur during sleep-wake episodes. The diagnosis of a psychiatric disorder related to sleep-wake disturbances includes anxiety disorders, mood disorders, schizophrenia, somatoform and other personality disorders (Thorpy, 2013).
Sleep-wake problems are intended to use this classification for general mental health and medical clinicians who are caring for geriatric, pediatric and adult patients. They are also called by different names such as Insomnia, Narcolepsy, Hypersomnia, Daytime sleepiness, Sleep rhythm, Jet lag syndrome and Sleep-disruptive behaviors. The person or individuals with these disorders would have complications with sleep-wake complaints of dissatisfaction with respect to the timing, quality, and amount of sleep. It results in daytime distress and impairment mostly associated and considered as the core features shared by all types of sleep-wake disorders. They are mainly classified as two types 24-hour sleep-wake disorder and non-24-hour sleep disorder. The National Sleep Foundation offered to help the patients who are persistently suffered from sleep-wake disorders with a number of resources.
All organisms such as animals and plants have an endogenously generated 'circadian' clock rhythm which is also called "internal body clock" that initiates regular biological cycling process for the approximate 24-hour cycle to induce sleep or hormone production. These rhythms alternatively start and end up over the period of time but not exactly 24 hours and it is synchronized by environmental time cues daily. In human beings, circadian rhythms are regulated in a structure of the brain by the suprachiasmatic nuclei (SCN) which are known as the hypothalamus and works with the day-night cycle primarily closed to the environmental time cue which synchronizes the circadian system of a human to the 24-hour day. Most of them do not have awareness of their ability to sleep at night and awake in the day time, these motions are primarily functioned by their internal body clock where light is the primary source to help reset the circadian.
People with Non-24 have circadian rhythms does have a failure of light to reach the SCN in total blindness who are not synchronized with the 24-hour day-night cycle. They have longer internal body clocks than normal people which help to rest his eyes for a long duration, so they are often interrupted by sleeping hours. Non-24-Hour Sleep-Wake Disorder is common in visually impaired or blind people because the lack of light information from the eyes which results in the reverting of internal body clock with non-24-hour period. It causes fluctuation in good sleep followed by periodic poor sleep and excessive daytime sleepiness. The first signs of the sleep-wake disorder could occur at any age and probably it happens after a complete loss of light perception to eyes or surgical removal of the eyes. There is a larger degree of variability is seen in sleep complaints between the individuals who suffered this disorder mainly it relates to the lack of synchronicity with internal body clock in 24 hours’ cycle. They experienced some episodes of poor sleep and then good sleep then followed by poor and so on total disruptions cause more problem in mental aspirations.
Non-24-Hour Sleep-Wake Disorder Diagnosis:
The sleep specialist will discuss the general patient history and medical documentation of sleep complaints. During the consultation, the internal body clock is checked and recorded circadian rhythm disorders. The sleep-wake patterns can be taken by using actigraphy and also a non-invasive method of monitoring human rest-activity cycles. These rest-activity patterns are recorded by a device which modeled as worn like a wristwatch to track exact movement. Overnight polysomnogram a sleep study is used for rule out other sleep deprivations.
The process of resynchronizing the individual’s internal body clock to the structured 24-hour day-night cycle has been given for this disorder. Light exposure is an only effective method to appropriately reset the phase of internal body clock in the cycling process. The usage of medications like the trial of melatonin therapy is not appropriate for clinical trial of Non-24 sleep-wake patients.
The timed light exposure altered the internal body clock to set out circadian rhythm period for reset the phase according to the environmental cue and measurement of timely performance is more important. It creates delay and less responsive to the phase to take time longer for the result. In cross-over point, the delayed responses are switch over to advance responses on Phase Response Curve (PRC) where minimized the time of the core body temperature. In practice, the individual should maintain a stable and regular schedule for continued therapeutic benefit response to reach the correct phase (Neikrug & Ancoli-Israel, 2010).
Food and Drug Administration (FDA) has approved the medication tasimelteon melatonin receptor agonist for the treatment of Non24-Hour Sleep-Wake Disorder in blind individuals. This was found to decrease the amount of time during the day for blind individuals which controls the brain function timing of the sleep (Lim, Gerstner & Holtzman, 2014).
The most common side effects of tasimelteon include a headache, drowsiness, nightmares, elevated liver enzymes, unusual dreams, upper respiratory or urinary tract infection and sleep disorder. On assessment, the patient's circadian phase is noted before and after the treatment to record the appropriate result of melatonin. Usage of dose and overdose precautions should be monitored with a physician for avoiding complicated result in melatonin supplements. Current pharmacological and nonpharmacological therapies for the patients suffering from sleep disturbances are unfortunately limited in numbers.
Generally, Sleep disorders are always associated with some problems in sleeping, too much sleep, staying asleep, falling asleep at wrong times, trouble falling and abnormal behaviors while sleep. It causes 100 more different types of sleeping and waking disorders. They are mainly characterized as insomnia relates to problems falling and staying asleep, excessive daytime sleepiness refers problems in staying awake, sleep rhythm problem causes problems sticking to a normal schedule of sleep and sleep-disruptive behaviors causes unusual behaviors during sleep. In this report, the causes and characteristics of sleep-wake disorders have been discussed in detail.
Lim, M., Gerstner, J., & Holtzman, D. (2014). The sleep–wake cycle and Alzheimer's disease: what do we know?. Neurodegenerative Disease Management, 4(5), 351-362. http://dx.doi.org/10.2217/nmt.14.33
Neikrug, A. & Ancoli-Israel, S. (2010). Sleep Disorders in the Older Adult – A Mini-Review. Gerontology, 56(2), 181-189. http://dx.doi.org/10.1159/000236900
Ouellet, M., Beaulieu-Bonneau, S., & Morin, C. (2015). Sleep-wake disturbances after traumatic brain injury. The Lancet Neurology, 14(7), 746-757. http://dx.doi.org/10.1016/s1474-4422(15)00068-x
Thorpy, M. (2012). Classification of Sleep Disorders. Neurotherapeutics, 9(4), 687-701. http://dx.doi.org/10.1007/s13311-012-0145-6