Effect of aerobic exercise training and cognitive behavioural therapy on reduction of chronic fatigue in patients with facioscapulohumeral dystrophy: protocol of the FACTS-2-FSHD trial
© Voet et al; licensee BioMed Central Ltd. 2010
Received: 15 June 2010
Accepted: 30 June 2010
Published: 30 June 2010
In facioscapulohumeral dystrophy (FSHD) muscle function is impaired and declines over time. Currently there is no effective treatment available to slow down this decline. We have previously reported that loss of muscle strength contributes to chronic fatigue through a decreased level of physical activity, while fatigue and physical inactivity both determine loss of societal participation. To decrease chronic fatigue, two distinctly different therapeutic approaches can be proposed: aerobic exercise training (AET) to improve physical capacity and cognitive behavioural therapy (CBT) to stimulate an active life-style yet avoiding excessive physical strain. The primary aim of the FACTS-2-FSHD (acronym for Fitness And Cognitive behavioural TherapieS/for Fatigue and ACTivitieS in FSHD) trial is to study the effect of AET and CBT on the reduction of chronic fatigue as assessed with the Checklist Individual Strength subscale fatigue (CIS-fatigue) in patients with FSHD. Additionally, possible working mechanisms and the effects on various secondary outcome measures at all levels of the International Classification of Functioning, Disability and Health (ICF) are evaluated.
A multi-centre, assessor-blinded, randomized controlled trial is conducted. A sample of 75 FSHD patients with severe chronic fatigue (CIS-fatigue ≥ 35) will be recruited and randomized to one of three groups: (1) AET + usual care, (2) CBT + usual care or (3) usual care alone, which consists of no therapy at all or occasional (conventional) physical therapy. After an intervention period of 16 weeks and a follow-up of 3 months, the third (control) group will as yet be randomized to either AET or CBT (approximately 7 months after inclusion). Outcomes will be assessed at baseline, immediately post intervention and at 3 and 6 months follow up.
The FACTS-2-FSHD study is the first theory-based randomized clinical trial which evaluates the effect and the maintenance of effects of AET and CBT on the reduction of chronic fatigue in patients with FSHD. The interventions are based on a theoretical model of chronic fatigue in patients with FSHD. The study will provide a unique set of data with which the relationships between outcome measures at all levels of the ICF could be assessed.
Dutch Trial Register, NTR1447.
Facioscapulohumeral dystrophy (FSHD) is the third most common inherited neuromuscular disorder. It is an autosomal dominant slowly progressive myopathy with a variable age of onset, mostly in the second or third decade of life. Its yearly incidence rate is approximately 1:20.000 . The disease primarily affects the facial muscles, the muscles of the shoulder girdle (most typically the scapula stabilizers) and various leg muscles, while pelvic and trunk muscles are eventually affected as well [2–4]. The pattern of muscle weakness is often asymmetrical, and the rate and extent of progression may vary considerably with sudden periods of unexplained rapid disease progression. In a small percentage of the patients, even respiratory insufficiency may occur . Only very recently, evidence became available that there may be a selective involvement of the central nervous system as well, in terms of decreased grey matter volume  and reduced intracortical inhibition . Although FSHD is associated with a partial deletion of a critical number of repetitive elements (D4Z4) on chromosome 4q35, to date no causal gene has been identified and no curative treatment is available [3, 8]. FSHD may eventually lead to serious disabilities of speech, swallowing, reaching, standing and walking, even in early adulthood. Twenty percent of the patients become wheelchair bound. Since no cure is available, rehabilitation is the mainstay of treatment [2, 3, 9].
Improving muscle strength by strength training and/or (anabolic) medication has shown not to be successful in patients with FSHD . Until now, only one trial has investigated low-intensity aerobic exercises, indicating that aerobic training is a safe method to increase exercise performance [14, 15]. Although, in general, physical activity does not appear harmful [16, 17], more research is needed to establish whether AET is beneficial in patients with FSHD. Besides improving physical (aerobic) capacity, it seems important to optimize physical activity and change behaviour in daily life. Indeed, symptoms and signs of muscle weakness and fatigue as well as the anticipation of a (further) decline in physical capacity may elicit an inactive life-style, which may disproportionally affect physical activity, fatigue and societal participation. From this perspective, it might be beneficial to alter illness cognitions and coping styles by means of CBT. However, evidence for the effectiveness of CBT in patients FSHD is not yet available.
to study the efficacy of AET and CBT for decreasing chronic fatigue in patients with FSHD. It is hypothesized that both AET and CBT are more effective in decreasing fatigue than usual care, which is no therapy at all or occasional (conventional) physical therapy. The improvement by AET may be obtained through enhancement of physical (aerobic) capacity, whereas beneficial effects of CBT may be achieved through changes in daily activities and behaviour. By changing illness cognitions and improving coping style, the balance between actual behaviour and physical capacity will be optimized. Since changes achieved by CBT are more 'intrinsic', possible beneficial effects of CBT may last longer than those of AET.
to evaluate the effects of AET and CBT on bodily functions and structures as defined by the International Classification of Functioning, Disability and Health (ICF): lower extremity muscle strength, pain, psychological well being, cardiovascular risk factors, aerobic exercise tolerance, sleeping pattern, as well as biomarkers in blood and urine and structural and metabolic muscle tissue characteristics.
to evaluate the effects of AET and CBT on the ICF level of activities: physical activity in daily life, self perceived functional status, and fall incidence.
to evaluate the effects of AET and CBT on the ICF level of participation: limitations in participation and autonomy and quality of life.
to evaluate the effects of AET and CBT on environmental and personal factors as defined by the ICF: coping style, illness cognitions, concentration problems, motivation, caregiver strain, experienced fatigue of the caregiver, social support and coping of the caregiver.
Inclusion and exclusion criteria
(1) age 18 years and older
(2) suffering from severe fatigue (CIS-fatigue ≥ 35) 
(3) ability to walk independently (ankle-foot orthoses and canes are accepted)
(4) being able to exercise on a bicycle ergometer
(5) being able to complete either type of intervention
(1) cognitive impairment
(2) insufficient mastery of the Dutch language
(3) neurological or orthopedic co-morbidity interfering with the interventions or possibly influencing outcomes
(5) use of psychotropic drugs (except simple sleeping medication)
(6) severe cardiopulmonary disease (chest pain, arrhythmia, pacemaker, cardiac surgery, severe exertional dyspnea, emphysema)
(7) epileptic seizures
(8) poorly regulated diabetes mellitus or hypertension
Randomization and blinding
All participants receive usual care. In the Netherlands, patients with FSHD typically receive no therapy at all, or occasional (conventional) physical therapy. Patients are not restricted in any activities, but all co-interventions are monitored throughout the study by diaries and at every measurement.
Aerobic Exercise Training (AET)
The AET consists of aerobic cycling exercise on a bicycle ergometer. The training program has a duration of 16 weeks and comprises home training twice a week and a supervised training once a week. Training sessions consist of a 30-minute aerobic exercise period with a warming-up and cooling-down period of 5 and 3 minutes, respectively. The cardiovascular load during the training period is individually adjusted and increased from a level of 60% to 75% of the heart rate reserve (HRR). HRR is the difference between the predicted maximum heart rate and the measured resting heart rate. The HRR is equivalent to the difference between the maximum and resting maximal oxygen consumption (VO2max). Each participant is learned how to adjust the physical load to the preferred individual heart rate. Participants are supplied with a Monark 827E bicycle ergometer, a Garmin forerunner 50 heart rate watch with breast belt, and a log book with training instructions at home for the duration of the intervention. During each training, the heart rate is monitored continuously by the breast belt. The number of training sessions, the total time spent on AET, possible adverse effects and the training parameters (physical load, heart rate) are recorded in the individual log book. Once a week, individually supervised training is given by trained physical therapists during one-hour sessions in small groups in a nearby rehabilitation centre. During these sessions, therapy compliance in the home situation is verified by reading out the heart rate watches and checking the log books. In addition, instructions for the next week are provided. The (unblinded) primary investigator and physician (NV) gives instructions to the physical therapists and performs integrity checks at each treatment location.
Cognitive Behavioural Therapy (CBT)
CBT will be focused on the perpetuating factors of fatigue as established in previous research [10, 12, 24] and based on experience in clinical practice. These factors encompass insufficient coping with the disease, dysfunctional illness cognitions, catastrophizing, deregulation of sleep, deregulation of activity, low social support and negative social interactions (see appendix 1 for the various modules). Because of large inter-individual differences, CBT will be adapted to the needs of each patient. For instance, barriers to become more physically active are explored and possibly alleviated in some patients, whereas overactivity is reduced in others. To determine which modules are appropriate, each perpetuating factor is assessed with specific tests, and within each module, the CBT approach is standardized (see appendix 1). The precise number of sessions is dependent on the number of modules. Each session has a duration of one hour and is given at the most nearby participating centre by a registered cognitive behavioural therapist, especially trained in CBT for FSHD. The therapists have been specifically trained to use the diagnostic tests and indicate the different modules and are regularly supervised by one of the investigators (GB).
Compliance and attrition
Therapy compliance is assessed by recording the number of treatment sessions (AET and CBT). For the participants randomized to AET, the total time spent on the bicycle ergometer at home is recorded as well. When applicable, participants are asked for their reasons for poor compliance. In the case of therapy drop out, patients are asked for the reason of non compliance and are stimulated to continue participation in the assessments until the last follow-up.
Outcome measures and tests
Primary outcome measure
Checklist Individual Strength (CIS subscale fatigue) 
Secondary outcome measures
ICF: bodily funtions
Aerobic exercise tolerance
Maximal oxygen consumption (VO2 max) using the Astrand protocol
6-minutes walking test 
Resting heart rate
Muscle strength of quadriceps,
Quantitative Muscle Assessment using fixed myometry testing
hamstrings and tibialis anterior
system (QMA) 
Cardiovascular risk factors
Weight/Body Mass Index (BMI)
Percentage body fat
Visual Analogue Scale (VAS) 
Psychological well-being and
Brief Symptom Inventory (BSI) 
Blood and urine analyses for creatine, glucose, creatine kinase,
sodium, potassium, calcium, phosphorus, ureum, ALAT, ASAT,
gamma-GT, bilirubine, AF and LDH***
Structural and metabolic muscle characteristics
T1 MRI, T2 MRI, 31P and 1H MRS analysis of muscle specific creatine, extramyocellular lipids, intramyocellular lipids, levels and phosphometabolites in thigh muscles; ultrasound of thigh muscles
Physical activity in daily life
Actometer, a motion sensing device (during a period of 2 weeks)
Checklist Individual Strength (CIS subscale physical activity) 
Self perceived functional status
Sickness Impact Profile (SIP subscales mobility control and mobility range, social behavior) 
Limitations in participation and autonomy Quality of life Fall incidence
The Impact on Participation and Autonomy Questionnaire (IPAQ)
36-Item Short-Form Health Survey (SF-36) 
Telephone computer (weekly calls)**
ICF: personal factors
Coping Inventory for Stressful Situation (CISS) 
Ziekte cognitie lijst (ZCL) 
Checklist Individual Strength (CIS subscale concentration) 
Checklist Individual Strength (CIS subscale motivation)
ICF: environmental factors
Caregiver Strain Index of partner/caregiver (CSI) 
Experienced fatigue of patient
Checklist Individual Strength (CIS subscale fatigue, filled in by
from perspective of relative.
relative about patient) 
Experienced fatigue of partner.
Checklist Individual Strength (CIS subscale fatigue, filled in by relative about him/herself) 
Sociale steunlijst-subschaal discrepantie (SSL-D verkort) 
Coping of partner
Coping Inventory for Stressful Situations (CISS) 
At the level of bodily functions and structures, patients are asked to give separate consent for several 'invasive' assessments at baseline and after the intervention period. Blood and urine samples are collected by experienced nurses and will be explored by nuclear magnetic resonance (NMR) for possible biomarkers of disease and response to the interventions. Ultrasound measurements of the thigh muscles are made by an experienced ultrasound professional, blinded for the treatment allocation, and analyzed for muscle thickness and echo intensity. In addition, Magnetic Resonance Imaging (MRI) and 31P and proton (1H) Magnetic Resonance Spectroscopy (MRS) are performed by trained professionals, blinded for the assignment to the intervention. It has been shown that in vivo MRS is able to produce spectra of multiple metabolites simultaneously and is well suited to study energy metabolism in patients with muscular dystrophies [28, 29]. The MR examinations start with T1 and T2 weighted images of the thigh for detailed structural analysis. Muscle involvement is specifically assessed by the presence of fatty infiltration on T1 weighted MR images. 1H MRS is used to assess muscle specific creatine as well as extramyocellular lipids and intramyocellular lipids levels, whereas 31P MRS is applied to get information about tissue pH and the level of high energy phosphates present in the different thigh muscles.
An adverse event is defined as any undesirable experience or outcome. Specially assigned site investigators are instructed to report all adverse events immediately to the primary investigator (NV) and to evaluate each event for its date of onset, possible relation to the interventions (based on clinical judgment), possible treatment and course in time. In addition, adverse events can be reported by the participants directly to the primary investigator and physician (NV). All adverse events reported will be carefully monitored and registered until they have abated or a stable situation has been reached.
Generalized estimated equations analysis will be used to investigate differences in the effects on primary and secondary outcome measures between the study groups and to investigate the influence of possible effect modifiers. When necessary, analyses will be adjusted for group differences in fatigue severity and physical activity at baseline. Data will be analyzed according to the intention-to-treat principle.
In order to detect a 10% group difference (E1 and E2 versus C) in change in fatigue severity between the start and the end of the intervention period (assuming difference in standard deviation between the start and the end of the intervention (SDdif) = 10%, α = .05, β = .80), 20 participants per group are required. With an expected drop-out rate of maximally 25%, 25 participants will be recruited in each group (n = 75).
To the best of our knowledge, the FACTS-2-FSHD study is the first randomized clinical trial which evaluates the effect of AET and CBT on the reduction of chronic fatigue in patients with FSHD.
This study has several strengths. First, the selected interventions are based on a theoretical model of chronic fatigue in patients with FSHD  and are compared with usual care in a randomized design. Until now, only one randomized controlled trial has been conducted that could not establish a beneficial effect of muscle strength training compared to no training in FSHD [14, 18]. In addition, one trial has been conducted that investigated low-intensity aerobic exercises in FSHD. Although this latter study reported improved maximal oxygen uptake and workload as a result of training, this was an uncontrolled and unblinded trial of only 8 patients . The majority of the training studies in patients with muscle disorders did not include a (no-training) control group or used healthy subjects as controls. In addition, data are often presented for mixed groups of muscle disorders . Second, the proposed study uses a broad arsenal of secondary outcome measures at all levels of the ICF, including 'invasive' measurements of possible biomarkers in blood and urine as well as measurements of structural and metabolic muscle characteristics. This approach will provide a unique set of data with which it should be possible to accurately assess the relationships between disease characteristics, loss of bodily functions, activity limitations and restrictions in societal participation in patients with FSHD. Third, all patients will be followed up until 6 months after the interventions, which will not only provide information about the maintenance of effects, but also about any long-term adverse events.
A limitation of this study is that the sample size calculation was based on detection of a 10% difference between the intervention groups and the control group, presuming more or less equal effect sizes of AET and CBT. Detecting more subtle differences in the effectiveness between both interventions would require a much larger sample size. In the Netherlands alone, such a trial would not be feasible.
In conclusion, the FACTS-2-FSHD study will increase our insight into the effectiveness of aerobic exercise training and cognitive behavioural therapy to reduce chronic fatigue and to optimize physical activity and capacity in patients with FSHD. A successful outcome of this study has the potential to change existing (inter)national guidelines for physical training and to improve the quality of life in patients with FSHD.
Appendix 1 Different modules of Cognitive Behavioural Therapy
Perpetuating factors: insufficient coping with the disease
Insufficient coping with the disease is assessed with the Impact of event Scale [43, 44]. A participant can continue to be occupied with the period of being diagnosed with FSHD. By means of talking or writing about this experience (which can be referred to as 'exposure'), the participant will acquire better coping skills. Fear of progression is assessed with a questionnaire especially designed for FSHD. The therapist helps the participant to formulate explicit words to describe the thoughts of fear of progression. These thoughts are challenged against reality (reality testing). In this way, daily unhelpful thoughts about the disease progression are reduced and put into perspective.
Perpetuating factors: dysfunctional cognitions regarding fatigue, activity and other symptoms
Dysfunctional cognitions relate to a variety of ideas, including a participant's idea of lack of control over symptoms, and dysfunctional cognitions about symptoms, such as catastrophizing. The sense of control in relation to fatigue complaints will be assessed with the self-efficacy scale [34, 45].
Perpetuating factors: catastrophizing
Catastrophizing will be assessed with the Jacobsen Fatigue Catastrophizing Scale . These cognitions are disputed and more helpful ways of thinking are taught.
Perpetuating factors: deregulation of sleep
Deregulation of sleep is based on self-report in a sleep diary . An irregular sleep-wake rhythm can perpetuate fatigue. To restore the biologic rhythm, participants are encouraged to adhere to fixed bedtimes and wake-up times and discouraged from sleeping during the day, or they are helped with adapting fixed rest period(s).
Perpetuating factors: deregulation of activity
Deregulation of activity is based on activity (stepping) monitoring using an actometer and a physical activity questionnaire (Physical Activity Scale for Individuals with Physical Disabilities [44, 48]). Some patients experience fluctuating periods of activity with subsequent periods of rest during a longer period. Others avoid activity because they are concerned that activity increases fatigue; consequently, they are physically inactive. For patients with fluctuating activity levels, a base level should be established by alternating rest and activities to prevent bursts of activity. Once the participant has set a base level, the physical activity program is started, usually twice a day, starting with 5 to 10 minutes of an activity such as walking or cycling. The activity is increased by 1 minute a day each time the activity is performed (ending at a maximum of 2 times 60 minutes minutes per day). The inactive participant will start the activity program immediately. Gradually, physical activities are replaced by other activities.
Perpetuating factors: low social support and negative social interactions
Low social support and negative social interactions are based on the discrepancy subscale of the Social Support List . If a participant still has unrealistic expectations of others or perceives a discrepancy between actual support and desired support, the therapist helps to install more realistic expectations toward the participant's social support group. The partner or caregiver will be included in this treatment module.
aerobic exercise therapy
cognitive behavioural therapy
Centrale commissie mensgebonden onderzoek
Checklist individual strength
computer registry of all myopathies and polyneuropathies
experimental group 1
experimental group 2
acronym for Fitness And Cognitive behavioural TherapieS/for Fatigue and ACTivitieS in FSHD
heart rate reserve
International Classification of Functioning, Disability and Health
magnetic resonance imaging
magnetic resonance spectroscopy
nuclear magnetic resonance
maximal oxygen consumption
Vereniging spierziekten Nederland.
This study is funded by the Prinses Beatrix Fonds (PBF) (The Dutch Public Fund for Neuromuscular and Movement Disorders), the Netherlands Organization for Health Research and Development (ID: ZonMW 89000003) and by the FSHD Global Research Foundation.
- Kissel JT: Facioscapulohumeral dystrophy. Semin Neurol. 1999, 19: 35-43. 10.1055/s-2008-1040824.View ArticlePubMedGoogle Scholar
- Padberg GW, Lunt PW, Koch M, Fardeau M: Diagnostic criteria for facioscapulohumeral muscular dystrophy. Neuromuscul Disord. 1991, 1: 231-234. 10.1016/0960-8966(91)90094-9.View ArticlePubMedGoogle Scholar
- Tawil R, van der Maarel SM: Facioscapulohumeral muscular dystrophy. Muscle Nerve. 2006, 34: 1-15. 10.1002/mus.20522.View ArticlePubMedGoogle Scholar
- Padberg GW, van Engelen BG: Facioscapulohumeral muscular dystrophy. Curr Opin Neurol. 2009, 22: 539-542. 10.1097/WCO.0b013e328330a572.View ArticlePubMedGoogle Scholar
- Wohlgemuth M, van der Kooi EL, van Kesteren RG, van der Maarel SM, Padberg GW: Ventilatory support in facioscapulohumeral muscular dystrophy. Neurology. 2004, 63: 176-178.View ArticlePubMedGoogle Scholar
- Quarantelli M, Lanzillo R, Del VW, Mollica C, Prinster A, Iadicicco L, Iodice V, Santoro L: Modifications of brain tissue volumes in facioscapulohumeral dystrophy. Neuroimage. 2006, 32: 1237-1242. 10.1016/j.neuroimage.2006.04.226.View ArticlePubMedGoogle Scholar
- Di Lazzaro V, Oliviero A, Tonali PA, Felicetti L, De Marco MB, Saturno E, Pilato F, Pescatori M: Dileone M, Pasqualetti P, Ricci E: Changes in motor cortex excitability in facioscapulohumeral muscular dystrophy. Neuromuscul Disord. 2004, 14: 39-45. 10.1016/j.nmd.2003.08.002.View ArticlePubMedGoogle Scholar
- van der Maarel SM, Frants RR, Padberg GW: Facioscapulohumeral muscular dystrophy. Biochim Biophys Acta. 2007, 1772: 186-194.View ArticlePubMedGoogle Scholar
- Lunt PW, Harper PS: Genetic counselling in facioscapulohumeral muscular dystrophy. J Med Genet. 1991, 28: 655-664. 10.1136/jmg.28.10.655.View ArticlePubMedPubMed CentralGoogle Scholar
- Kalkman JS, Schillings ML, van der Werf SP, Padberg GW, Zwarts MJ, van Engelen BG, Bleijenberg G: Experienced fatigue in facioscapulohumeral dystrophy, myotonic dystrophy, and HMSN-I. J Neurol Neurosurg Psychiatry. 2005, 76: 1406-1409. 10.1136/jnnp.2004.050005.View ArticlePubMedPubMed CentralGoogle Scholar
- Engel AG, Franzini-Armstrong C: Myology. 2004Google Scholar
- Kalkman JS, Schillings ML, Zwarts MJ, van Engelen BG, Bleijenberg G: The development of a model of fatigue in neuromuscular disorders: a longitudinal study. J Psychosom Res. 2007, 62: 571-579. 10.1016/j.jpsychores.2006.11.014.View ArticlePubMedGoogle Scholar
- Horlings CG, Munneke M, Bickerstaffe A, Laverman L, Allum JH, Padberg GW, Bloem BR, van Engelen BG: Epidemiology and pathophysiology of falls in facioscapulohumeral disease. J Neurol Neurosurg Psychiatry. 2009, 80: 1357-1363. 10.1136/jnnp.2009.173534.View ArticlePubMedGoogle Scholar
- van der Kooi EL, Kalkman JS, Lindeman E, Hendriks JC, van Engelen BG, Bleijenberg G, Padberg GW: Effects of training and albuterol on pain and fatigue in facioscapulohumeral muscular dystrophy. J Neurol. 2007, 254: 931-940. 10.1007/s00415-006-0432-4.View ArticlePubMedPubMed CentralGoogle Scholar
- Olsen DB, Orngreen MC, Vissing J: Aerobic training improves exercise performance in facioscapulohumeral muscular dystrophy. Neurology. 2005, 64: 1064-1066.View ArticlePubMedGoogle Scholar
- Cup EH, Pieterse AJ, Ten Broek-Pastoor JM, Munneke M, van Engelen BG, Hendricks HT, van der Wilt GJ, Oostendorp RA: Exercise therapy and other types of physical therapy for patients with neuromuscular diseases: a systematic review. Arch Phys Med Rehabil. 2007, 88: 1452-1464. 10.1016/j.apmr.2007.07.024.View ArticlePubMedGoogle Scholar
- Voet NB, van der Kooi EL, Riphagen II, Lindeman E, van Engelen BG, Geurts AC: Strength training and aerobic exercise training for muscle disease. Cochrane Database Syst Rev. 2010, CD003907-Google Scholar
- van der Kooi EL, Vogels OJ, van Asseldonk RJ, Lindeman E, Hendriks JC, Wohlgemuth M, van der Maarel SM, Padberg GW: Strength training and albuterol in facioscapulohumeral muscular dystrophy. Neurology. 2004, 63: 702-708.View ArticlePubMedGoogle Scholar
- Van Engelen BG, van VH, Van Doorn PA, Faber CG, van der Hoeven JH, Janssen NG, Notermans NC, van Schaik I, Visser LH, Verschuuren JJ: The Dutch neuromuscular database CRAMP (Computer Registry of All Myopathies and Polyneuropathies): development and preliminary data. Neuromuscul Disord. 2007, 17: 33-37. 10.1016/j.nmd.2006.09.017.View ArticlePubMedGoogle Scholar
- Ricci E, Galluzzi G, Deidda G, Cacurri S, Colantoni L, Merico B, Piazzo N, Servidei S, Vigneti E, Pasceri V, Silvestri G, Mirabella M, Mangiola F, Tonali P, Felicetti L: Progress in the molecular diagnosis of facioscapulohumeral muscular dystrophy and correlation between the number of KpnI repeats at the 4q35 locus and clinical phenotype. Ann Neurol. 1999, 45: 751-757. 10.1002/1531-8249(199906)45:6<751::AID-ANA9>3.0.CO;2-M.View ArticlePubMedGoogle Scholar
- Vercoulen JH, Swanink CM, Fennis JF, Galama JM, van der Meer JW, Bleijenberg G: Dimensional assessment of chronic fatigue syndrome. J Psychosom Res. 1994, 38: 383-392. 10.1016/0022-3999(94)90099-X.View ArticlePubMedGoogle Scholar
- Arnau RC, Meagher MW, Norris MP, Bramson R: Psychometric evaluation of the Beck Depression Inventory-II with primary care medical patients. Health Psychol. 2001, 20: 112-119. 10.1037/0278-6220.127.116.11.View ArticlePubMedGoogle Scholar
- Beck AT, Guth D, Steer RA, Ball R: Screening for major depression disorders in medical inpatients with the Beck Depression Inventory for Primary Care. Behav Res Ther. 1997, 35: 785-791. 10.1016/S0005-7967(97)00025-9.View ArticlePubMedGoogle Scholar
- Kalkman JS, Schillings ML, Zwarts MJ, van Engelen BG, Bleijenberg G: Influence of relatives on fatigue experienced by patients with facioscapulohumeral dystrophy, myotonic dystrophy and HMSN-I. Eur Neurol. 2006, 56: 24-30. 10.1159/000095137.View ArticlePubMedGoogle Scholar
- WHO: International Classification of Functioning, Disability and Health (ICF). Geneva. 2001Google Scholar
- van der Werf SP, Prins JB, Vercoulen JH, van der Meer JW, Bleijenberg G: Identifying physical activity patterns in chronic fatigue syndrome using actigraphic assessment. J Psychosom Res. 2000, 49: 373-379. 10.1016/S0022-3999(00)00197-5.View ArticlePubMedGoogle Scholar
- Vercoulen JH, Bazelmans E, Swanink CM, Fennis JF, Galama JM, Jongen PJ, Hommes O, van der Meer JW, Bleijenberg G: Physical activity in chronic fatigue syndrome: assessment and its role in fatigue. J Psychiatr Res. 1997, 31: 661-673. 10.1016/S0022-3956(97)00039-3.View ArticlePubMedGoogle Scholar
- Argov Z, Lofberg M, Arnold DL: Insights into muscle diseases gained by phosphorus magnetic resonance spectroscopy. Muscle Nerve. 2000, 23: 1316-1334. 10.1002/1097-4598(200009)23:9<1316::AID-MUS2>3.0.CO;2-I.View ArticlePubMedGoogle Scholar
- Kan HE, Scheenen TW, Wohlgemuth M, Klomp DW, van Loosbroek-Wagenmans I, Padberg GW, Heerschap A: Quantitative MR imaging of individual muscle involvement in facioscapulohumeral muscular dystrophy. Neuromuscul Disord. 2009, 19: 357-362. 10.1016/j.nmd.2009.02.009.View ArticlePubMedGoogle Scholar
- Endler NS, Parker JD: Multidimensional assessment of coping: a critical evaluation. J Pers Soc Psychol. 1990, 58: 844-854. 10.1037/0022-3518.104.22.1684.View ArticlePubMedGoogle Scholar
- Astrand PO, Ryhming I: A normogram for calculation for aerobic capacity (physical fitness) from pulse rate during sub-maximal work. J Appl Physiol. 1954, 218-222.Google Scholar
- Enright PL: The six-minute walk test. Respir Care. 2003, 48: 783-785.PubMedGoogle Scholar
- Folstein MF, Luria R: Reliability, validity, and clinical application of the Visual Analogue Mood Scale. Psychol Med. 1973, 3: 479-486. 10.1017/S0033291700054283.View ArticlePubMedGoogle Scholar
- Vercoulen JH, Hommes OR, Swanink CM, Jongen PJ, Fennis JF, Galama JM, van der Meer JW, Bleijenberg G: The measurement of fatigue in patients with multiple sclerosis. A multidimensional comparison with patients with chronic fatigue syndrome and healthy subjects. Arch Neurol. 1996, 53: 642-649.View ArticlePubMedGoogle Scholar
- Derogatis LR, Melisaratos N: The Brief Symptom Inventory: an introductory report. Psychol Med. 1983, 13: 595-605. 10.1017/S0033291700048017.View ArticlePubMedGoogle Scholar
- Jacobs HM, Luttik A, Touw-Otten FW, de Melker RA: [The sickness impact profile; results of an evaluation study of the Dutch version]. Ned Tijdschr Geneeskd. 1990, 134: 1950-1954.PubMedGoogle Scholar
- Cardol M, de Haan RJ, van den Bos GA, de Jong BA, de G I: The development of a handicap assessment questionnaire: the Impact on Participation and Autonomy (IPA). Clin Rehabil. 1999, 13: 411-419. 10.1191/026921599668601325.View ArticlePubMedGoogle Scholar
- Aaronson NK, Muller M, Cohen PD, Essink-Bot ML, Fekkes M, Sanderman R, Sprangers MA, te Velde A, Verrips E: Translation, validation, and norming of the Dutch language version of the SF-36 Health Survey in community and chronic disease populations. J Clin Epidemiol. 1998, 51: 1055-1068. 10.1016/S0895-4356(98)00097-3.View ArticlePubMedGoogle Scholar
- Bosscher RJ, Smit JH: Confirmatory factor analysis of the General Self-Efficacy Scale. Behav Res Ther. 1998, 36: 339-343. 10.1016/S0005-7967(98)00025-4.View ArticlePubMedGoogle Scholar
- Evers AW, Kraaimaat FW, van LW, Jongen PJ, Jacobs JW, Bijlsma JW: Beyond unfavorable thinking: the illness cognition questionnaire for chronic diseases. J Consult Clin Psychol. 2001, 69: 1026-1036. 10.1037/0022-006X.69.6.1026.View ArticlePubMedGoogle Scholar
- Post MW, Festen H, van dP, Visser-Meily JM: Reproducibility of the Caregiver Strain Index and the Caregiver Reaction Assessment in partners of stroke patients living in the Dutch community. Clin Rehabil. 2007, 21: 1050-1055. 10.1177/0269215507079140.View ArticlePubMedGoogle Scholar
- Van Sonderen EL: Sociale Steun Lijst Interacties (SSL-I) en Sociale Steun Lijst Discrepanties (SSL-D). Noordelijk centrum voor gezondheidsvraagstukken. 1993Google Scholar
- Creamer M, Bell R, Failla S: Psychometric properties of the Impact of Event Scale - Revised. Behav Res Ther. 2003, 41: 1489-1496. 10.1016/j.brat.2003.07.010.View ArticlePubMedGoogle Scholar
- van der Ploeg E, Mooren TT, Kleber RJ, van d V, Brom D: Construct validation of the Dutch version of the impact of event scale. Psychol Assess. 2004, 16: 16-26. 10.1037/1040-3522.214.171.124.View ArticlePubMedGoogle Scholar
- Prins JB, Bleijenberg G, Bazelmans E, Elving LD, de Boo TM, Severens JL, van der Wilt GJ, Spinhoven P, van der Meer JW: Cognitive behaviour therapy for chronic fatigue syndrome: a multicentre randomised controlled trial. Lancet. 2001, 357: 841-847. 10.1016/S0140-6736(00)04198-2.View ArticlePubMedGoogle Scholar
- Andrykowski MA, Schmidt JE, Salsman JM, Beacham AO, Jacobsen PB: Use of a case definition approach to identify cancer-related fatigue in women undergoing adjuvant therapy for breast cancer. J Clin Oncol. 2005, 23: 6613-6622. 10.1200/JCO.2005.07.024.View ArticlePubMedPubMed CentralGoogle Scholar
- Servaes P, Verhagen C, Bleijenberg G: Fatigue in cancer patients during and after treatment: prevalence, correlates and interventions. Eur J Cancer. 2002, 38: 27-43. 10.1016/S0959-8049(01)00332-X.View ArticlePubMedGoogle Scholar
- Washburn RA, Zhu W, McAuley E, Frogley M, Figoni SF: The physical activity scale for individuals with physical disabilities: development and evaluation. Arch Phys Med Rehabil. 2002, 83: 193-200. 10.1053/apmr.2002.27467.View ArticlePubMedGoogle Scholar
- Ormel J, Kempen GI, Penninx BW, Brilman EI, Beekman AT, van SE: Chronic medical conditions and mental health in older people: disability and psychosocial resources mediate specific mental health effects. Psychol Med. 1997, 27: 1065-1077. 10.1017/S0033291797005321.View ArticlePubMedGoogle Scholar
- The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2377/10/56/prepub
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