Journal of Neuroscience Nursing:
Quality of Life in Patients With Multiple Sclerosis in Turkey: Relationship to Depression and Fatigue
Tanrverdi, Deryaı; Okanl, Ayşeı; Sezgin, Serap; Ekinci, Mine
Ayşe Okanlı, PhD, is an assistant professor in the Nursing Department, Faculty of Health Sciences, Atatürk University, Erzurum, Turkey.
Serap Sezgin, PhD, is an assistant professor at the Department of Psychiatric Nursing, Health School, 19 Mayıs University, Samsun, Turkey.
Mine Ekinci, PhD, is an assistant professor in the Nursing Department, Faculty of Health Sciences, Atatürk University, Erzurum, Turkey.
Questions or comments about this article may be directed to Derya Tanrıverdi, PhD, at email@example.com. She is an assistant professor in the Nursing Department, Faculty of Health Sciences, Gaziantep University, Gaziantep, Turkey.
The purposes of this study were to assess the self-reported quality of life (QOL) in a group of Turkish patients with multiple sclerosis (MS) and to analyze whether the QOL was associated with fatigue and depression. The study used a descriptive design. A number of evaluation scales were administered to a study sample comprising 47 outpatients. The Short Form 36 for QOL, the Beck Depression Inventory for Depression, and the Visual Analogue Scale for Fatigue were used. The mean score for general QOL was 34.8 and indicated low QOL in MS patients. The results of our study have also shown that fatigue and depression strongly influence QOL in Turkish MS patients. Our findings may have important implications for the overall care of MS patients. The QOL of MS patients was affected negatively. Both fatigue and depression are common and treatable manifestations of MS, and these symptoms should be screened carefully in all MS patients. Care of MS patients requires the collaboration of all team members. Nurses have a key role as part of this team through the continuity of the care they provide and interaction with patients. Awareness of depression and fatigue can contribute to the nurses' ability to provide psychological support and enhance the QOL in MS patients.
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system characterized, in its classical form, by recurrent attacks followed by either partial or complete remission of symptoms (Isaksson, Gunnarsson, & Ahlström, 2006). The disease symptoms impact upon multiple aspects of life and activity (Shawaryn, Schiaffino, LaRocca, & Johnston, 2002), substantially interfere with daily activities and family, social, and working life; disturb emotional well-being; and reduce the quality of life (QOL; McAllister & Krupp, 2005). Health-related QOL (HRQoL, today predominantly known as QOL) has been increasingly used as a relevant evaluation criterion in MS. Those affected by MS exhibit significantly lower scores on QOL measurements compared with control groups (Janssens et al., 2003; Kaya, Akpınar, & Çilli, 2003; Lobentanz et al., 2004). The QOL is affected in a complex manner by the physical health, psychological status, social relationships, level of independence, and self-beliefs of an individual as well as his or her interactions with his or her environment (Fidaner et al., 1999). Previous correlative studies have demonstrated relationships between various clinical parameters and diminished QOL in MS (Lobentanz et al., 2004; Newland, 2006). Most studies in subjects with MS have shown that depression and fatigue are two of the most common symptoms and are clearly associated with reduced QOL scores (Drulovic et al., 2007; Janardhan & Bakshi, 2002; Newland, 2006; Pollmann, Busch, & Voltz, 2005; Pittion-Vouyovitch et al., 2006). Fatigue is often considered a state of exhaustion distinct from depressed mood or physical weakness (Krupp, 2003). The prevalence of fatigue in MS is high, with 53% to 80% of the subjects reporting significant problems of fatigue across different studies (Alarcia, Ara, Martin, Bertol, & Bestue, 2005; Bodini et al., 2007; Johnson, 2008; Hatzakis et al., 2005; Lobentanz et al., 2004; McAllister & Krupp, 2005; Randolph & Arnett, 2005). Fatigue has detrimental effects on activities of daily living (e.g., while doing housework, visiting friends, moving around, and doing shopping), social and occupational obligations, and overall well-being (Krupp, 2003; Lerdal, Gulowsen Celiusb, Kruppc, & Dahl, 2007; Strober & Arnett, 2005). Occasionally, patients may lose their strength to work to the extent that they become dependent on others. Those affected by MS can also suffer economic loss and loss of status. These factors can affect the QOL as much as loss of physical health. Despite its prevalence as a symptom of MS, a study by Randolph and Arnett (2005) found that 60% of the subjects were not treated with fatigue-modifying medications. Fatigue-modifying approach includes the use of pharmacologic agents as well as graded exercise training and education on the use of "energy management" strategies. Pharmacologic therapy is a common approach in the management of MS fatigue (Multiple Sclerosis Council for Clinical Practice Guidelines, 1998), although the cause of fatigue in MS is still poorly understood and therefore difficult to manage (Lerdal et al., 2007).
As the most common psychiatric disorder accompanying MS (Bodini et al., 2007; Figved et al., 2005; Hart, Fonareva, Merluzzi, & Mohr, 2005; Lobentanz et al., 2004), depression is often by far the strongest predictor for reduced QOL (Fruehwald, Loeffler-Stastka, Eher, Saletu, & Baumhacki, 2001). Many previous studies (Kaya et al., 2003; Merkelbach, Sittinger, & Koenig, 2002; Newland, 2006) have found that depression is negatively associated with decreased overall HRQoL in MS subjects. Loss of desire to live and to enjoy life, deep feelings of mourning, pessimistic thoughts for the future, and poor communication with others as well as physiological disorders such as those affecting sleep, appetite, and sexual desire are marked symptoms of depression (Mete, 2008) and a reduced QOL. The significant impact of depression on QOL suggests that detecting and treating depression can markedly improve the QOL of MS patients (Ayatollahi, Nafissi, Eshraghian, Kaviani, & Tarazi, 2007).
The nurse providing care for MS patients is an important member of the health team and plays a key role in the ongoing treatment and interactions with the patients. Nursing care is an essential component of the approach to MS, which seeks to provide the patient with awareness, development of skills, and motivation for self-care and considers the patient an active participant rather than a passive observer. The nurse who cares for MS patients with many complex care needs has responsibilities for assessing physiological, emotional, and social needs, maintaining wellness, managing symptoms, treating attacks, providing adherence to immunomodulating drugs, and psychosocial support (Tülek, 2007).
A clearer understanding of the complex relationship that exists between fatigue, depression, and QOL in patients with MS could aid healthcare providers in designing more effective self-management strategies for these patients. Managing fatigue and depression could potentially help improve the QOL of MS patients. However, few studies have been conducted on this issue in Turkey. The purposes of our investigation were to assess self-reported QOL in a group of Turkish MS patients and to analyze whether QOL was associated with fatigue and depression.
The study used a descriptive design. The study sample consisted of 47 outpatients (10 men and 37 women with a mean age of 33.19 years) in Erzurum Turkey who were consecutively admitted to the Department of Neurology of the University of Atatürk between September 2006 and June 2007 and who satisfied the criterion of a clinically or laboratory-supported definite diagnosis of MS (Poser et al., 1983). The estimated incidence rate of MS in Turkey has been reported to be 40 in 100,000. It has also been reported to be twice as common in women as in men without a clear explanation (Eraksoy, 2005). Because the disease does not have definitive specific laboratory findings and the clinical picture is varied, diagnostic criteria were used to standardize and facilitate diagnosis. The Poser et al. (1983) criteria (Table 1) have been used for diagnosis. In addition, the patients had to be clinically stable (no relapses) for at least 3 months before the assessment. The exclusion criteria were the presence of major concomitant diseases, current MS exacerbation, or an unwillingness to participate.
All the participants of this study were willing to contribute to this study, and none refused to participate. Furthermore, all had similar cultural life style and access to equal healthcare services. There was no ethnic diversity.
Procedure and Data Collection
The data collection tools comprised a questionnaire on demographic characteristics and the Short Form 36 (SF-36) Health Survey, the Visual Analogue Scale for Fatigue (VAS-F), and the Beck Depression Inventory (BDI). The data were collected by means of face-to-face interviews conducted by researchers in a private room in the neurology outpatient clinic. The researchers introduced the questionnaire to the participants and explained the material covered. The average time for completing the questionnaires was 20 minutes. All of the participants completed the questionnaires.
In all the patients, HRQoL was assessed using the SF-36 questionnaire (Ware & Sherbourne 1992). The SF-36 is a validated and commonly used instrument for the self-evaluation of physical and mental health (Lerdal et al., 2007). The feasibility and validity and reliability studies of this scale were confirmed by Pınar (1994). The SF-36 is a generic HRQoL instrument that measures the eight domains of life, which are calculated as eight scales: physical functioning, role functioning physical, bodily pain, general health, vitality, social functioning, role functioning emotional, and mental health. The items are summed per scale and transformed into scores between 0 (poor health) and 100 (optimal health) (Pınar, 1994). The validity and the reliability of the SF-36 have been well established in subjects with MS (Drulovich et al., 2007; Janssens et al., 2003; Shavaryn et al., 2002; Wynia et al., 2008). In the study by Pınar, the internal consistency range was .92 for all the items. Cronbach's alpha was .87 in this study.
The presence and the severity of fatigue were assessed by means of the VAS-F (Lee, Hicks, & Nino-Murcia, 1990). The feasibility and validity and reliability studies of this scale were confirmed by Yurtsever and Bedük (2003). The scale consists of 18 items concerning fatigue, with each item rated on a 10-point scale, ranging from 0 (not at all fatigued) to 10 (extremely fatigued). The scale has two subscales: one with five items for energy (VAS-E; e.g., from have no energy to I feel extremely energetic and from I have no strength to I feel extremely strong) and one subscale with 13 items for fatigue (VAS-F; e.g., from I am not tired at all to I feel extremely tired, from I am not exhausted at all to I feel extremely exhausted, and from I can move about easily to moving about is a hard task for me). A high score in VAS-F and a low score in VAS-E reflect a higher severity of fatigue. The VAS-F has acceptable internal consistency, stability over time, and sensitivity to clinical change (Lee et al., 1990; Yurtsever & Bedük, 2003). In the study by Yurtsever and Bedük (2003), internal consistency was .90 for the items on fatigue and .74 for the items on energy. Cronbach's alpha was .88 for the fatigue items and .75 for the energy items in this study.
Depression was evaluated using the BDI (Beck, Steer, & Garbin, 1988), a 21-item scale on which a score between 0 and 3 is attributed to each item. BDI is scored by adding the ratings across the items, with higher scores indicating severity of depression; the suggested cutoff point is 17 (Savaşir & Şahin, 1997). The feasibility and validity and reliability studies of this scale were confirmed by Savaşir and Şahin (1997). The BDI includes the three basic components of depression: mood (sadness, pessimism, dissatisfaction, and tearfulness), cognitive changes (guilt, worthlessness, or feelings of failure), and vegetative signs (changes in sleep or appetite). The BDI is usually completed in 5 to 10 minutes and is the most commonly used instrument to assess depression in MS patients (Goldman Consensus Group, 2005). It has been reported to have good reliability (Cronbach's alpha = .81) and validity (Beck et al., 1988). Internal consistency was .86 in this study.
The data were analyzed using the Statistical Package for the Social Sciences (Version 11.0 for Windows; SPSS Inc., Chicago, IL). The relationship between QOL, fatigue, and depression was tested using Pearson's correlation. The strength of association was expressed as odds ratios with 95% confidence intervals. Cronbach's alpha was used to assess the internal consistency of the scales. The level of significance was set at p < .05.
Regarding ethical considerations, permission to conduct this study was obtained from the ethical committee of Atatürk University, and informed consent of each participant was also obtained. The patients were informed about the purpose of the research and assured of their right to refuse to participate or to withdraw from the study at any stage of the study. Anonymity and confidentiality of patients' data were guaranteed.
The mean age of the patients was 33.19 years (range = 18-49 years); 78.7% of the patients were women, 57.5% were secondary school graduates, and 29.8% were currently working. The mean scores for fatigue, depression, and SF-36 are summarized in Table 2.
The subjects demonstrated poor health on the SF-36, with a mean score of 34.8 for this sample. The BDI cutoff score was 17, and the proportion of the subjects with significant depression (BDI ≥ 17) was 66%. The mean VAS-F score of the patient sample was 73.1 ± 23.2. The mean VAS-E score of the patient sample was 22.0 ± 9.6. The relationship between SF-36, BDI, and VAS-F/VAS-E values was studied using Pearson's correlation (Table 3). A significant negative correlation was found between QOL and fatigue and depression, indicating lower HRQoL with higher fatigue and depression intensity (p < .01). A significant positive correlation was found between QOL and energy, indicating higher HRQoL with higher energy intensity (p < .01).
In our study, the mean time since diagnosis of the patients was 3.5 years and was not found to be significantly correlated with SF-36, VAS-F, and BDI (p > .05).
To evaluate the impact of MS on the patient, we investigated QOL, fatigue, and depression and the relationship between these parameters. This study shows that the QOL is significantly impaired in Turkish patients with MS and that fatigue and depression are independent predictors of impaired QOL in this group.
The mean score for general QOL in this sample was 34.8, indicating low HRQoL. These findings are consistent with those of other studies (Amato et al., 2001; Janardhan & Bakshi, 2000; Merkelbach et al., 2002) in which the MS subjects had low scores on all items of the SF-36. One plausible explanation for low HRQoL may be that MS affects multiple systems and leads to many problems in most components of life.
In this study, the prevalence rates of fatigue and depression were in line with the previously reported data on MS (Alarcia et al., 2005; Bodini et al., 2007; Drulovic et al., 2007; Hatzakis et al., 2005; Kaya et al., 2003; Lobentanz et al., 2004). The prevalence of fatigue in the wider MS patient population is high, with prevalence ranging from 53% to 80% (Alarcia et al., 2005; Bodini et al., 2007; Hatzakis et al., 2005; Lobentanz et al, 2004; Soyuer, Mirza, & Öztürk, 2005). Fatigue was found in 73.1% of our patients. This indicates that fatigue is a major problem for most MS patients and that screening for the presence of fatigue to apply a variety of fatigue-modifying approaches should be considered. This study has shown that fatigue in MS patients negatively affects their QOL. The patients who suffered from fatigue had lowest scores for QOL (Amato et al., 2001; Janardhan & Bakshi, 2002; Johnson, 2008; Lerdal et al., 2007; Pittion-Vouyovitch et al., 2006; Soyuer et al., 2005). One plausible explanation for the adverse impact of fatigue on HRQoL may be that it impacts upon the physical activities that patients can perform.
Depression is also a common symptom in MS, with various studies reporting prevalence ranging from 27% to 72% (Ayatollahi et al., 2007; Bodini et al., 2007; Drulovic et al., 2007; Johnson, 2008; S'a, 2008). In this study, the prevalence of depression was 66%. Our data have shown that depression heavily affects the overall QOL in MS patients. Similarly, in earlier studies, MS patients with the highest scores for depression had the lowest scores for QOL (Amato et al., 2001; Janardhan & Bakshi, 2002; Johnson, 2008; Lerdal et al., 2007; Pittion-Vouyovitch et al., 2006; Soyuer et al., 2005). Thus, depression appears to be the major factor influencing the QOL (Hart et al., 2005; Janardhan & Bakshi, 2002; Lobentanz et al., 2004). Depression might be a potential confounding factor in the self-evaluation of HRQoL, whereby depressed patients overestimate their disability. A recent study by Hart et al. (2005), which examined the impact of treating depression on QOL in MS patients, demonstrated that treatment for depression was related to better QOL. These clinically high levels of depression in MS patients require healthcare professionals to observe those who may need further psychological support (Iwasaki et al., 2005). This study suggests that all MS patients should be screened for depression because its treatment may affect not only mood but also other aspects of daily functioning.
The results of this study have shown that fatigue is an important factor affecting the level of depression and that as the level of fatigue increases, so does the level of depression. This is compatible with the results of earlier studies (Lerdal et al., 2007; Pittion-Vouyovitch et al., 2006). Awareness of depression and fatigue can contribute to the nurses' ability to give psychological support and enhance the life quality of MS patients.
In our study, the mean time since diagnosis of patients was 3.5 years, but this was not significantly correlated with SF-36, VAS-F, and BDI (p > .05) and may have been due to the short time interval. Similar results have been reported in earlier studies (Fruehwald et al., 2001; Janssens et al., 2003). Nevertheless, Newland (2006) found that time since diagnosis negatively affected the QOL of MS patients. No statistically significant differences were found between fatigue, energy, and depression scores of the female and male patients (p > .05). Thus, in the light of these results, it can be said that both male and female MS patients experience similar levels of fatigue, energy, and depression.
The limitations of the study include the following: (1) small sample size; (2) only one measurement of fatigue, depression, and QOL was used; and (3) factors such as cognitive function, social status, pain, spasticity, and caregiver roles that could potentially affect QOL were not considered.
In addition, this study was conducted in only one city in Turkey, and only the individuals who lived in the city center were included in the study. The results of this study may be generalized to the sample group in this study. The sample in this study reflects only one area of Turkey. The findings therefore cannot be generalized to all patients with MS in Turkey. Thus, further studies with larger Turkish series are needed. However, we believe that because our study is the first to investigate the associations of QOL, fatigue, and depression in individuals with MS in Turkey, it will provide a foundation for future studies.
In conclusion, this study has shown that fatigue and depression negatively affect the QOL in a group of Turkish MS patients. Fatigue was also found to be an important factor affecting the level of depression; thus, fatigue and depression are associated with impaired QOL in MS patients. Our findings may have important implications toward the care of Turkish MS patients. Both fatigue and depression are common and treatable manifestations and symptoms of MS that need to be screened carefully in all MS patients. Preventive measures, early detection, and effective treatment of depression and fatigue can potentially alleviate outcomes that are even more adverse and deterioration in HRQoL. Screening for depression and fatigue in patients with MS should be implemented in the clinical setting, and interventions to treat depression and fatigue may ultimately improve HRQoL. We also believe that this study will provide a foundation for future research on this subject in Turkey.
Relevance to Clinical Practice
To minimize the severity of symptoms in patients with MS, nurses must systematically evaluate the patient's perception of symptoms. The findings of this study can provide scientific evidence for nurses to establish interventions aimed at maximizing the effectiveness of symptom management strategies in patients with MS. Exploration of the experience of fatigue and depression in patients with MS can contribute to designing more effective nursing interventions to decrease their severity and to increase HRQoL. Furthermore, a better understanding of how concurrent symptoms affect the lives of patients with MS-in terms of daily functioning, individual symptom severity, and HRQoL-can guide the direction of nursing care in the area of symptom management strategies.
Alarcia, R., Ara, J. R., Martin, J., Bertol, V., & Bestue, M. (2005). Importance and factors related to chronic fatigue in multiple sclerosis. Neurologia
Amato, M. P., Ponziani, G., Rossi, F., Liedl, C. L., Stefanile, C., & Rossi, L. (2001). Quality of life in multiple sclerosis: The impact of depression, fatigue and disability. Multiple Sclerosis
Ayatollahi, P., Nafissi, S., Eshraghian, M. R., Kaviani, H., & Tarazi, A. (2007). Impact of depression and disability on quality of life in Iranian patients with multiple sclerosis. Multiple Sclerosis
Beck, A. T., Steer, R. A., & Garbin, M. G. (1988). Psychometric properties of the Beck Depression Inventory: Twenty-five years of evaluation. Clinical Psychology Review
Bodini, B., Mandarelli, G., Tomassini, V., Tarsitani, L., Pestalozza, I., Gasperini, C., et al. (2007). Alexithymia in multiple sclerosis: Relationship with fatigue and depression. Acta Neurologica Scandinavica
Drulovic, J., Pekmezovic, T., Matejic, B., Mesaros, S., Manigoda, M., Dujmovic, I., et al. (2007). Quality of life in patients with multiple sclerosis in Serbia. Acta Neurologica Scandinavica
Eraksoy, M. (2005). Multiple Skleroz İle Yaşamı Nasıl Kolaylaştırırız?
I, İstanbul: İstanbul Tıp Fakültesi Hasta Okulu Yayınları.
Fidaner, H., Elbi, H., Fidaner, C., Eser, S. Y., Erhan, E., & Erdem, G. (1999). Yaşam kalitesinin ölçülmesi: WHO-QOL 100 ve WHO-QOL-Brief. 3P Dergisi
Figved, N., Klevan, G., Myhr, K. M., Glad, S., Nyland, H., Larsen, J. P., et al. (2005). Neuropsychiatric symptoms in patients with multiple sclerosis. Acta Neurologica Scandinavica
Fruehwald, S., Loeffler-Stastka, H., Eher, R., Saletu, B., & Baumhacki, U. (2001). Depression and quality of life in multiple sclerosis. Acta Neurologica Scandinavica
Goldman Consensus Group. (2005). The Goldman Consensus statement on depression in multiple sclerosis. Multiple Sclerosis
Hart, S., Fonareva, I., Merluzzi, N., & Mohr, D. C. (2005). Treatment for depression and its relationship to improvement in quality of life and psychological well-being in multiple sclerosis patients. Quality of Life Research
Hatzakis, M., Turner, A. P., Williams, R. M., Bowen, J. D., Rodriquez, A. A., & Haselkorn, J. K. (2005). Predictors of prescriptions for management of fatigue among veterans with multiple sclerosis. Archives of Physical Medicine and Rehabilitation
Isaksson, A. K., Gunnarsson, L. G., & Ahlström, G. (2006). The presence and meaning of chronic sorrow in patients with multiple sclerosis. Journal of Clinical Nursing
Iwasaki, Y., Iwamoto, K., Igarashi, O., Kiyozuka, T., Aoyagi, J., Hirano, K., et al. (2005). Depression in multiple sclerosis [Letter to the editor]. Acta Neurologica Scandinavica
Janardhan, V., & Bakshi, R. (2002). Quality of life in patients with multiple sclerosis: The impact of fatigue and depression. Journal of the Neurological Sciences
Janssens, A. C. J. W., Doorn, P. A., Boer, J. B., Meché, F. G. A., Passchier, J., & Hintzen, R. Q. (2003). Impact of recently diagnosed multiple sclerosis on quality of life, anxiety, depression and distress of patients and partners. Acta Neurologica Scandinavica
Johnson, S. L. (2008). The concept of fatigue in multiple sclerosis. Journal of Neuroscience Nursing
Kaya, N., Akpınar, Z., & Çilli, A. S. (2003). Relationship between depression and anxiety and quality of life in multiple sclerosis. Anadolu Psikiyatry Dergisi
Krupp, L. B. (2003). Fatigue in multiple sclerosis: Definition, pathophysiology and treatment. CNS Drugs
Lee, K. A., Hicks, G., & Nino-Murcia, G. (1990). Validity and reliability of a scale to assess fatigue. Psychiatry Research
Lerdal, A., Gulowsen Celiusb, E., Kruppc, L., & Dahl, A. A. (2007). A prospective study of patterns of fatigue in multiple sclerosis. European Journal of Neurology
Lobentanz, I. S., Asenbaum, S., Vass, K., Sauter, C., Klösch, G., Kollegger, H., et al. (2004). Factors influencing quality of life in multiple sclerosis patients: Disability, depressive mood, fatigue and sleep quality. Acta Neurologica Scandinavica
McAllister, W. S., & Krupp, L. B. (2005). Multiple sclerosis-related fatigue. Physical Medicine and Rehabilitation Clinics of North America
Merkelbach, S., Sittinger, H., & Koenig, J. (2002). Is there a differential impact of fatigue and physical disability on quality of life in multiple sclerosis? Journal of Nervous and Mental Disease
Mete, H. E. (2008). Kronik Hastalık ve Depresyon. Klinik Psikiyatri
Multiple Sclerosis Council for Clinical Practice Guidelines. (1998). Fatigue and multiple sclerosis
. Washington, DC: Paralyzed Veterans of America.
Newland, P. K. (2006). Impact of symptoms on quality of life in women with relapsing remitting multiple sclerosis and healthy women
. Doctoral dissertation, Graduate School University of Missouri-Columbia.
Pınar, R. (1994). Evaluation of quality of life and factors affecting QoL in patients with diabetes mellitus.
Doctoral dissertation, İstanbul University Health Sciences Institute, Turkey.
Pittion-Vouyovitch, S., Debouverie, M., Guillemin, F., Vandenberghe, N., Anxionnat, R., & Vespignani, H. (2006). Fatigue in multiple sclerosis is related to disability, depression and quality of life. Journal of the Neurological Sciences
Pollmann, W., Busch, C., & Voltz, R. (2005). Quality of life in multiple sclerosis. Measures, relevance, problems, and perspectives. Nervenarzt76
Poser, C. M., Paty, D. W., Scheinberg, L., McDonald, W. I., Davis, F. A., Ebers, G. C., et al. (1983). New diagnostic criteria for multiple sclerosis: Guidelines for research protocols. Annals of Neurology
Randolph, J. J., & Arnett, P. A. (2005). Depression and fatigue in relapsing-remitting MS: The role of symptomatic variability. Multiple Sclerosis
S'a, M. J. (2008). Psychological aspects of multiple sclerosis. Clinical Neurology and Neurosurgery
Savaşir, I., & Şahin, N. H. (1997). The evaluation in the cognitive-behavioral therapy: The scales used frequently (in Turkish)
. Ankara: Turkish Psychological Association Press.
Shawaryn, M. A., Schiaffino, K. M., LaRocca, N. G., & Johnston, M. V. (2002). Determinants of health-related quality of life in multiple sclerosis: The role of illness intrusiveness. Multiple Sclerosis
Soyuer, F., Mirza, M., & O¨ztürk, A. (2005). The effects of exhaustion and inefficiency on Multiple Sclerosis. Erciyes Medical Journal
Strober, L. B., & Arnett, P. A. (2005). An examination of four models predicting fatigue in multiple sclerosis. Archives of Clinical Neuropsychology
Tülek, Z. (2007). Nursing care of the patient with multiple sclerosis. Cumhuriyet University Journal of Nursing
Ware, J. E., & Sherbourne, C. D. (1992). The MOS 36-item Short-Form Health Survey (SF-36): I. Conceptual framework and item selection. Medical Care
Wynia, K., Middel, B., van Dijk, J. P., De Keyser, J. H. A., & Reijneveld, S. A. (2008). The impact of disabilities on quality of life in people with multiple sclerosis. Multiple Sclerosis
Yurtsever, S., & Bedük, T. (2003). Hemodiyaliz Hastalarında Yorgunluğun Değerlendirilmesi. Hemşirelikte Araştırma Geliştirme Dergisi
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