Poliomyelitis anterior acuta is an acute viral disease that attacks the anterior horn cells of the spinal cord and the motor neurons of the lower brain stem resulting in flaccid paresis or paralysis. Usually there is partial and sometimes complete recovery from the self-terminating disease. However, many people with a history of poliomyelitis report late onset neuromuscular symptoms and a decline in functional abilities. These late symptoms are referred to as Postpoliomyelitis Syndrome (PPS) and include new or increased muscle weakness, abnormal muscle fatigability, generalized fatigue, muscle atrophy, muscle and joint pain, muscle cramps and cold intolerance .
The prevalence of PPS has been reported from 15% to 80% of all patients with previous paralytic polio depending on the criteria applied and population studied . Nearly 60% of a sample of Dutch survivors of the 1956 polio outbreak experience late onset polio sequelae . In Western countries, where the large epidemics date back to the 1940s and 1950s, many polio survivors are now experiencing progressive complaints related to PPS. The World Health Organization (WHO) estimates that 10 to 20 million polio survivors are alive worldwide, and some estimates suggest that 4 to 8 million of them may develop PPS . Although, the efforts of the Global Polio Eradication Initiative of the WHO initiated in 1988, led to an enormous reduction in the number of acute polio cases globally ever since, polio is still a relevant problem. In Western Africa and in South Asia polio is still endemic and spread of the virus from these countries causes new outbreaks in countries that were certified as polio free. Therefore, new cases of PPS can be anticipated in the coming decades.
Fatigue is one of the most frequent complaints of PPS [5–7] and it is typically described as tiredness or lack of energy that increases with physical activity and decreases with rest . In a study on disability and health problems in 76 Dutch patients with PPS, 78% of the subjects selected fatigue as their major problem . Subjects with PPS experience higher levels of fatigue than healthy controls [10, 11]. Fatigue has a negative impact on activities of daily living and there is evidence that post-polio related fatigue is an important factor for the reduced health related quality of life (HRQoL) in polio survivors .
In current practice, rehabilitation management is the mainstay of treatment for PPS. Rehabilitation aims to improve patients' capacities to perform activities of daily living and adapt performance (i.e. actual behaviour) to the available capacities. We expect that a reduction of the imbalance between patients' capacities and performance will lead to a reduction in fatigue and improvement in activities and HRQoL. There are two possible approaches to achieve this goal; exercise therapy and cognitive behavioural therapy (CBT). However, evidence to support the effectiveness of either approach is still limited.
The insufficient evidence to support exercise consists of contradictory and incomplete information in the literature. On the one hand, PPS patients are advised to avoid muscular overuse and intensive training as this could worsen symptoms such as muscle weakness and fatigue and provoke a further loss of muscular strength . On the other hand, physically active PPS patients were found to have less symptoms of fatigue than sedentary patients . It is unclear whether symptoms of fatigue are cause or result of physical inactivity. A systematic review on exercise therapy for neuromuscular diseases included ten studies on muscle strengthening exercises and aerobic exercises in PPS of which five demonstrated significant positive effects on muscular strength and aerobic capacity without generating any adverse effects. However, all these studies had to be qualified as having insufficient or limited methodological quality . This led to the conclusion that there is insufficient evidence for the effectiveness of exercise for patients with PPS and that future, preferably multi-centre, studies are needed. A recent study on the short-term effectiveness of home- and hospital- based aerobic exercise showed improvement on fatigue and quality of life . However results were not compared with a control group and long-term effectiveness was not evaluated in this study.
There is broad evidence for the effectiveness of CBT in reducing fatigue in chronic fatigue syndrome, fatigued post cancer survivors and multiple sclerosis [16–19]. However, there are no studies of CBT for fatigue in PPS.
The evidence for a cognitive behavioural approach in PPS is currently limited to results from an uncontrolled pilot study in which cognitive behavioural strategies are incorporated in a comprehensive multidisciplinary rehabilitation program . Although significant reductions in fatigue symptoms were found, it is unclear whether these effects can be ascribed to the cognitive behavioural components of the intervention.
We anticipate that exercise therapy and CBT are both effective in reducing fatigue and improving activities and HRQoL in patients with PPS compared to the usual care. The FACTS-2-PPS study aims to give insight in the efficacy of both interventions for patients with PPS. As secondary outcomes, the working mechanisms, patients' and therapists' expectations of and experiences with both interventions and cost-effectiveness will be evaluated. These aims have led to the following research questions:
Does exercise therapy for patients with PPS reduce fatigue and improve activities and HRQoL as compared to usual care?
Does CBT for patients with PPS reduce fatigue and improve activities and HRQoL as compared to usual care?
What are the generic and disease-specific determinants for treatment success of exercise therapy and CBT?
What are patients' expectations of and experiences with exercise therapy and CBT?
What is the cost-effectiveness of exercise therapy and CBT compared to usual care?