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According to international studies, 50% of stroke patients may experience sleep-disordered breathing (SDB), in which obstructive sleep apnea (OSA) occurs more than central sleep apnea (CSA) [1]. None of those researches were done in Kuwait. Moreover, poor rehabilitation efforts and functional outcomes may be influenced by unrecognized and untreated SDB [1]. The probability of SDB among stroke patients and its effects on the functional recovery is still not well determined and await well-designed studies [1].

Therefore, increasing the awareness for screening SDB is paramount in primary and secondary prevention of stroke, and will help in improving stroke outcomes [1].

This study was done to find out the probability of stroke patients to develop SDB its effect on the recovery process. The targeted population in this study are patients with stroke above twenty-one years old from both genders. the patients were screened to detect SDB using Berlin and STOP-Bang questionnaires in both Arabic and English languages. On the other hand, the functional recovery of the patients was assessed by Functional Outcome Measures (Fatigue Severity Scale (FSS), Function Independence Measure (FIM), Gait Speed, and STREAM).


StrokeAccording to the mortality rate in some of the developed countries, stroke is the 2nd most common cause of death [2]. It also has a major physical, psychological, and financial impact on the patients and their families, the healthcare system, and society [2]. Stroke is caused by interruption of the blood supply resulting in deprivation of the corresponding region of the brain from oxygen and nutrient [2].

There are many risk factors that lead to stroke, some of these are modifiable while the others are non-modifiable [3].

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The latter factors are age, gender, and race [3], Whereas the former factors include physical inactivity, obesity, hypertension (HTN), diabetes (DM), elevated total cholesterol, smoking, SDB, and atrial fibrillation (AF) [3]. Stroke can lead to many complications include: altered consciousness and emotions, disorders of speech, dysphagia, walking difficulties, cognitive and perceptual dysfunction, behavioral differences and SDB specifically OSA [3].

Sleep-Disordered Breathing is a serious sleep disorder in which breathing pattern is interrupted frequenting during sleep [4]. There are several types of SDB, but obstructive sleep apnea (OSA), central sleep apnea (CSA), are more common [4]. Approximately 50% of stroke patients may experience OSA more than CSA [1].

Significant of the study

SDB is common complication post-stroke leading to day time sleeping, fatigue, and missing the P.T sessions. This can interfere with the recovery process after stroke. Unfortunately, there are no researches done to study this issue among in Kuwait. By conducting this study, we will explore the probability of developing SDB among patients with stroke in Kuwait. Moreover, we will come in to conclusion how SDB can be reflected on the scores of the P.T outcome measures.

Purpose of the study

The purpose of the study is to find out the probability of stroke patients to acquire SDB and its effect on the recovery process in Kuwait.


SDB is common among patients with stroke in Kuwait and it interferes with their recovery process.


Stroke patients will be scanned whom are medically stable with Berlin and STOP-Bang Questionnaire to detect Sleep Breathing Disorder.

Stroke recovery will be assessed by Stroke Rehabilitation and Assessment of Movement (STREAM), Functional Independence Measure (FIM), Fatigue Severity Scale (FSS), and gait speed.

Data will be collected. Interrupted, and analyzed.


  • Patients exaggerated responses.
  • Limited time of data collection.
  • Inability to access all hospitals in Kuwait.
  • The psychological status of patients that may affect scoring.
  • Attrition of patients.

Literature Review


SDB is defined as “It is an umbrella term for several chronic conditions in which partial or complete cessation of breathing occurs many times throughout the night” [25]. Generally, it is divided into three types: OSA, which is a nocturnal breathing cessation as a result of obstruction of the upper airway tract without any effect on the respiratory effort [4]. In OSA, the upper respiratory muscles [Figure 1] especially the tongue, pharyngeal, and soft palate relax causing obstruction of the airflow [4].

Whereas, CSA is associated with any insult to the central respiratory centers in the brainstem with the reduction of the respiratory effort [4]. In addition, Complex sleep apnea (CompSA) also known as Mixed Apnea, is the mix of both OSA and CSA [4].

The risk factors of SDB include male sex due to hormonal differences between males and females [5]. Another risk factor is aging because of recurrence of apnea increases with aging [5]. In addition, obesity in which accumulation of fat around the pharyngeal airway causing collapse of the airway [5].

There are many signs and symptoms of obstructive SDB [6]. One of these symptoms is nocturnal sweating, usually around the neck and upper body areas, due to increased daytime tiredness and sleep problems [6]. Hypertension is another sign and symptom of OSA, due to decline in arterial carbon dioxide, causing elevation in sympathetic nervous system activity and resulting in peripheral vasoconstriction [6]. In addition to snoring and excessive daytime sleepiness that are also associated in OSA [6].

Many OSA patients suffer from increase in the neck circumference [6]. In fact, OSA itself serves as a risk factor for the development of other illnesses [7]. The complications of SDB include: hypertension (HTN), myocardial infraction (MI), congestive heart failure, cerebrovascular accidents, decrease quality of life, and increase the risk of motor vehicle accidents [6]

It has been shown that OSA is the most common type that is associated with stroke [8] [Figure 3]. In addition, the reason is that CSA is mainly due to a localized lesion to the brainstem where the respiratory centers are located at [8], whereas OSA is associated with the motor control of the respiration muscles so it is most common in the chronic stages of stroke [8].

In normal conditions, the ventilation control system control breathing with the two chemoreceptors [24]. The peripheral chemoreceptors, which are in the carotid bodies, sense the change of arterial blood gases (ABG) especially the decrease of PO2 and the increase of PCO2 [24]. While the central chemoreceptors, which are in the ventral surface of the medulla, sense the chance of PH, the concentration of H+, in the extracellular fluid in the brain [24]. Both chemoreceptors send afferent signals to the brainstem then to the brain cortex [24]. The brain cortex sends efferent signals to the respiratory muscles (effectors) through the corticospinal and corticobulbar tracts, and this is the normal ventilatory drive. If stroke happened in the brainstem it will result in CSA, while if it happened anywhere else in the brain cortex it results in OSA. And that is why OSA > CSA [24].

The pathophysiological effects of OSA on the body defers depending on its severity [4]. When the patient with OSA sleeps during the REM phase, their upper airways relaxes causing obstruction of the airways, which will eventually cause interruption or blockage of the air entry.

Interruption of breathing will cause decrease in oxygen (hypoxemia), increase in carbon dioxide (hypercapnia) levels in blood and intrathoracic (intrapleural and alveolar) pressure fluctuations [4, 5]. As a result of this fluctuations, the lungs and diaphragm will send signals to the brain, which will cause the patient to arouse [4, 5]. Additionally, intermittent hypoxemia and hypercapnia will cause oxidative stress that may cause systemic inflammation as normal responses from the to alert the brain of dysfunctions [4, 5]. Severe hypoxemia with impaired chemosensitivity, which is the ability of the body to detect chemical levels changes, and changes in brain circulation will increase the risk of strokes [4, 5]. Recurrent arousals will cause sympathetic hyperactivity this will cause elevation of the blood pressure and heart rate [4, 5]. Additionally, secondary to activation renin-angiotensin-aldosterone system, which is a hormone system that regulates blood pressure and fluid balance in the body, that will arterial hypertension and ventricular dysfunction [4, 5, 9]. Eventually, all the previous effects will cause cardio and cerebrovascular diseases [4, 5]

On other hand, CSA causes arterial oxygen desaturation, hypercapnia, post-apneic arousals, intrathoracic pressure fluctuations, sensation of dyspnea, fluctuating of arterial blood pressure and sympathetic excitation [10]. All these effects will increase the risk of cardiac diseases, such as heart failure, or arrhythmia, which eventually may cause death [10]. With CompSA, still the mechanism is not fully understood because mechanism of combines SDB is not fully understood, but the effect on the body depends on how the body responses [11].

SDB is diagnosed in several ways based on the presence or absence of linked symptoms and recurrence of apnea during sleep [12]. A comprehensive history and physical examination will demonstrate some signs and symptoms of OSA [12]. In addition to questionnaires such as berlin and STOP-BANG questionnaires. Moreover, polysomnography, also known as sleep study, is a diagnostic test in which the patient is monitored for physiologic variables in a sleep laboratory at night [12]. Apnea-hypopnea index (AHI) is a parameter that is measured during sleep study to determine the severity of the SDB [12].

There are many literature reviews talked about the relationship between SDB and stroke and physical performance [12]. Post-stroke SDB is significantly more prevalent compared to non-stroke populations [1]. The symptoms defer between patients according to the extension of the lesion [1]. For example, When the motor cortex in the brain that control axial muscles is affected because of stroke, and the upper airways muscles gets involved, OSA will be presented with stroke patients [1]. However, when the respiratory centers in the brain is affected, CSA will be presented in stroke patients [1].

In acute stages, the severity of SDB is the same in ischemic and hemorrhagic stokes, but after three months the severity of SDB reduces in hemorrhagic and remain the same with ischemic [7]. The reason for this phenomenon is still unknown [7]. So, researchers suggested that early diagnosis and treatment of SDB would reduce the risk of stroke [7].

SDB directly affects the physical performance of stroke patients [7]. The direct reason is that SDB affects the patient sleep cycle, causing restless sleep, restless legs syndrome, fatigue, and daytime sleepiness [7]. Therefore, untreated SDB may cause lack of motivation, energy and concentration, and that is an explanation why stroke patients with SDB shows lower physical performance and slow prognosis [7]. The severity of SDB appears to be associated with a worse functional outcome following stroke, increasing the likelihood of death and dependency [23].

Researchers found that the prevalence of SDB were admitted to rehabilitation and the degree of functional impairment and the degree of functional impairment was greater in comparison to those without SDB [22].

In conclusion early detection and management of SDB disorders will increase the patient’s performance and facilitate their treatment to enhance their quality of life [13]. To investigate this problem, physical activity, fatigability, independence and endurance levels must be identified and planned to focus on finding treatments [13]. A review suggested that the use of sleeping disorders questionnaires should become standard of care in stroke clinics [7].

Validity and reliability of the outcomesBerlin Questionnaire.

There are several studies support the validity, reliability, specificity, and a sensitivity of berlin questionnaire as a screening tool of detecting the risk of SDB [14]. Berlin questionnaire accuracy increases as the AHI increases [15]. Researchers have found that the berlin questionnaire is higher with AHI >30 than AHI >5 so researchers concluded that berlin questionnaire is more accurate with severe cases [15]. However, another study showed that it is a poor predictor for OSA in the sleep clinic sittings [16]. They suggest a combination between more than one questionnaire will enhance the detection of SDB [16].

Stop-Bang Questionnaire.

There are several studies support the validity, reliability, specificity, and a sensitivity of STOP-BANG questionnaire as a screening tool of detecting the risk of SDB [17]. Not only it uses the AHI as a reference in addressing SDB, but it gives more classification by a combination with the risk factors [17]. In which detecting patients with high risk of OSA does not just dependents on how many yes answers the patient will answer [18]. The patient maybe under the high-risk classification if got yes in two or more of four questions with being male, having BMI > 35kg/m2, or neck circumference of 17 inches in males or 16 inches in females [18]. Other researchers are against it because it has a very low specifity [19].


The type of research that will be used in this study is qualitative research and quantitative research. Qualitative researches aim to gather in-depth understanding of the physical performance of the stroke patients and how SDB affects it. The discipline investigates the prevalence of SDB among stroke patients. Besides that, the researcher will also examine the physical performance of stroke patients through observations in numerical representations and statistical analysis. Along with questionnaires that will be given out to respondents for the statistical representation of the findings in the study.


The research sampling method that will be used in this study is random sampling to obtain a more scientific result that could be used to represent the entirety of the population.

The study will be conducted with a group of stroke patients from both genders and above 21 years old, with a sample size of approximately 100 participants. The participants will be chosen from MOH general hospital as following: Ibn Sina, Adan, Jahra, PM&R, Farwaniya, Ameri, and Mubarak Al-Kabeer Hospital.

Inclusions criteria

  • Onset: 1 month – 1-year post-stroke.
  • Age: from 21 and above.
  • Both genders.
  • Able to understand and follow commands.
  • Exclusion criteria Patients with previous respiratory problems, such as: bronchial asthma.
  • Patients in the chronic stage of the stroke.
  • Patients taking medication induce sleepiness.
  • patient who have cognitive impairment.
  • Blind patients.
  • Aphasic patient.
  • Bedridden.


Physical performance of stroke patients will be assessed through observations using the PT outcome measures. Along with questionnaires that used for SDB evaluating.

Fatigue severity scale (FSS) is a short questionnaire used to measure the severity fatigue and contains nine statements [20]. Each statement has score from 1-7, 1 means disagree, and 7 means agree [20]. A total score of less than 36 suggests that the patient may not be suffering from fatigue [20]. A total score of 36 or more suggests that the patient may need further evaluation by a physician [20]. Function independence measure (FIM) is an assessment tool used to evaluate the functional status of patients during the rehabilitation process [20]. It consists of 18 items, grouped into 2 sub-scales motor and cognition [20]. A score 18-35 means total assistance, 36-53 maximal assistance, 54-71 moderate assistance, 72-89 minimal assistance, 90-107 supervision, 108-120 modified independence, and 121-126 complete independence [20].

Gait speed is used to analysis the gait speed [21]. It was recurred that the patient walks distance of 12 m (1.2m accelerating, 10m measuring the speed, and 1.2m decelerating) [21]. A speed of 0.2m/s indicates that the patient needs hospitalization, 0.6m/s indoor walker, 0.8-1.2m/s outdoor normal speed walker) [21].

Stroke Rehabilitation Assessment of Movement (STREAM) is a measurement tool used to evaluate the recovery of voluntary movement and basic mobility post stroke [20]. It assesses coordination, function mobility and range of motion [20]. Further, STREAM consists of 30 items, 20 of which assesses range of motion, and 10 assesses basic mobility [20]. In addition, the basic mobility items scoring is from 0-3, while basic mobility items scoring is from 0-4[20]. Total score is calculated using the average of the 3 subscale scores [20].

Berlin questionnaire consists of three categories to classify SDB. Patients are grouped into high, moderate, or low risk based on their responses to the items and their overall scores.

STOP-BANG questionnaire consists of eight (yes/no) questions related to the clinical features of SDB. Patients are classified into high risk, intermediate, or low risk based on their responses to the questions and their overall scores.

Low risk of OSA: yes, to 0-2 questions, intermediate risk of OSA: yes, to 3-4 questions, and high risk of OSA: yes, to 5-8 questions, yes to 2 or more of 4 stop questions + male gender, yes to 2 or more of 4 stop questions + BMI > 35 kg/m2, or yes to 2 or more of 4 stop questions + neck circumference (17/43cm in male, 16/41cm in female).


Starting from mid of January, and for four months patients who met the inclusion criteria of the study will be immediately assigned. For those selected, the purpose of the study will be explained, including the nature of the outcome measures and the questionnaires, and the need for and use of random assignment.

Participants will be assured confidentiality and given an opportunity to decline to participate in the study. In addition, all study participants with stroke who met the inclusions and exclusion criteria will be given the two SA questionnaires. After that, those who have high score in SA questionnaire. The PT outcome measures will be chosen according to patients abilities. For every patient STREAM, FIM, and FSS will be done, but for those with higher abilities and able to walk gait speed will be done. Moreover. PT outcome measures score will be correlate to SA questionnaire score. Finally, data will be collected and analyzed using SPSS.

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