Medical Research

Post-Polio Clinic Research

Here are summaries on the last published research studies from the Montreal Neurological Institute and Hospital Post-Polio Clinic, thanks to Dr Trojan and Dr Kaminska who wrote them for us.

Research study to improve respiratory health

Certain individuals who have suffered from polio may have a weakened respiratory function. This problem affects those who have been left with a chest wall deformity or weakness of respiratory muscles (like the diaphragm). These individuals may feel no breathing difficulty for a prolonged period. However, with increasing age, respiratory function deteriorates and difficulties may occur. Moreover, those with the post-polio syndrome may have an accelerated loss of their muscle strength, potentially including the muscles of breathing.
A team of researchers from the Montreal Neurological Institute and the Royal Victoria Hospital (McGill University Health Centre), affiliated with the post-polio clinic of the Montreal Neurological Hospital, is presently conducting a research study aimed at improving respiratory health of persons living with the post-polio syndrome who are starting to have a drop in their respiratory function. Two other illnesses are included in this study, Steinert’s myotonic dystrophy and amyotrophic lateral sclerosis. This study examines an exercise for the respiratory system – the “manual hyperinflation technique”. It involves insufflating a volume of air into the lungs using a balloon (similar to those used in emergency situations for resuscitation), as if the person was taking a big breath. The amount of air that is insufflated (pushed in) somewhat exceeds that which the person could inhale on their own, given their muscle weakness. This allows to “recruit” a maximal lung capacity. This could be considered as physiotherapy for the respiratory system. The goal of these exercises is to maintain or improve the elasticity of the lungs and the chest wall. They tend to become stiff when not fully used, as is the case when there is respiratory muscle weakness.
These exercises are entirely safe. Their main inconvenience is related to the time required to perform them. For optimal results, it is suggested to do three to four sessions daily. People with more pronounced respiratory muscle weakness from various neurological conditions already commonly perform these exercises. In addition to increasing elasticity of the respiratory system and therefore facilitating breathing, they improve the strength of cough, which allows to clear secretions more effectively and potentially to decrease the risk of pneumonia in these patients. To present, these exercises have not been formally studied to find out if they help prevent deterioration of respiration. The study currently under way is innovative as its goal is to demonstrate a beneficial effect for individuals with only mildly reduced pulmonary function. Ultimately, these exercises might be able to slow down the progressive deterioration of respiratory function. When there is a more marked deficit in breathing, respiratory assistance during sleep is required using a ventilator which is a machine that pushes air through a nasal or oro-nasal mask, somewhat similar to CPAP machines used for sleep apnea. The ventilator allows an adequate exchange of oxygen and CO2 by assisting the patient’s weakened muscles with each breath. The “manual hyperinflation technique” could delay the moment when the use of a ventilator is necessary at night, by maintaining better lung health.
Those who have participated in the study have generally appreciated the experience. It is too early to draw conclusions on the effectiveness of the exercise on physiologic measures, but preliminary results are encouraging. At least some participants have noted improvement in their breathing and endurance, and it appears that benefits are most notable in those with the post-polio syndrome compared with the other two disorders studied. No complications have been observed. Researchers are confident that these exercises can really have a positive impact on those with weakening respiratory muscles, particularly those with post-polio syndrome. They continue looking for candidate subjects for this study.
Study investigators / Research personnel Drs Daria A. Trojan, Angela Genge, Basil Petrof, and Marta Kaminska. Franceen Browman (Respiratory Therapist) and Christine Kupka (Coordonator). // This summary has been written by DrMarta Kaminska MD, FRCP(C), McGill University Health Centre, Respiratory Division, Montréal. Originally published in Folio Polio, no45, Winter 2010-2011.

Sleep disordered breathing in fatigued post-polio clinic patients

The purpose of this study was to determine the frequency, predictive factors, and symptoms predictive of sleep disordered breathing in fatigued post-polio clinic patients. The study involved a chart review of 590 post-polio clinic charts from our institution.
We concluded that sleep disordered breathing, especially obstructive sleep apnea-hypopnea, was very common in post-polio clinic patients referred for sleep evaluation. This condition occurred commonly even in those patients who did not have a history of breathing difficulties related to polio. Snoring was the only symptom that tended to predict sleep disordered breathing. This condition is best diagnosed by undergoing a complete overnight sleep study in a sleep laboratory. People with sleep disordered breathing can experience a dramatic improvement of symptoms with treatment. Even though treatment effects were not evaluated in our study, our clinical experience suggests that post-polio patients can experience an improvement in fatigue with treatment.
If an individual with previous polio has fatigue or somnolence atypical of post-polio syndrome, and other symptoms suggestive of sleep disordered breathing, we recommend that they discuss their symptoms with their physician. A consultation at a sleep clinic for evaluation may be necessary.
Reference Dahan V., Kimoff J., Petrof B., Benedetti A., Diorio D., Trojan DA. Sleep disordered breathing in fatigued post-polio clinic patients. Archives of Physical Medicine and Rehabilitation 2006;87:1352-1356.

Osteoporosis in a post-polio clinic population

The aim of this study was to determine the frequency of osteoporosis at the hip and lumbar spine (lower back) in a post-polio clinic population, and to evaluate the relationship of muscle strength and other factors with bone density at the hip. The study involved a chart review of 379 post-polio clinic charts from our institution. 164 patients met study inclusion criteria (including bone mineral densitometry measurement).
We concluded that in this preliminary study, osteoporosis and osteopenia at the hip occur commonly in post-polio clinic patients referred for bone densitometry. Osteoporosis and osteopenia at the hip occurred commonly in men, pre-menopausal women, and post-menopausal women in our patient population. Bone density at the hip was associated with muscle strength in the same leg that the bone density assessment was performed. The weaker the leg, the more likely it was for the patient to have osteoporosis at the hip in the same leg.
Based on these results, we recommend that all post-polio patients be evaluated for osteoporosis at both hips (or preferably at the hip of the weaker lower extremity) and at the lumbar spine. It is possible that with treatment, bone mineral density will improve, although this was not evaluated in our study, and has not been specifically evaluated in a post-polio population. Further work in this area is in progress.
Reference Haziza M, Kremer R, Benedetti A, Trojan DA. Osteoporosis in a post-polio clinic population. Archives of Physical Medicine and Rehabilitation. 2007;88:1030-1035.

Elevated serum inflammatory markers in post-poliomyelitis syndrome

The purpose of this study was to determine whether serum inflammatory markers are increased in post-poliomyelitis syndrome patients compared to healthy controls, and whether an association exists between elevated inflammatory markers and clinical symptoms. This study was a cross-sectional study in 51 post-polio syndrome patients and 26 normal controls.
We found that the serum (blood) inflammatory markers TNF-α, IL-6, and leptin were increased in post-polio syndrome patients compared to healthy controls. We also found a relationship between TNF-α levels and pain, specifically muscle pain, in post-polio syndrome patients. Because our study was cross-sectional (one evaluation only), we cannot conclude that inflammatory markers are a cause of pain in post-polio syndrome patients. However, our results raise the possibility that inflammatory markers can be important for clinical symptoms in post-polio syndrome.
We recommend that further studies on the role of inflammatory markers in the pathophysiology of post-polio syndrome be performed.
Reference: Fordyce CB. Gagne D, Jalili F, Alatab S, Arnold DL, Da Costa D, Sawoczczuk S, Bodner C, Shapiro S, Collet J-P, Le Cruguel J-P, Robinson A, Lapierre Y, Bar-Or A, Trojan DA. Elevated serum inflammatory markers in post-poliomyelitis syndrome. Journal of the Neurological Sciences 2008;271:80-86.

Fatigue in post-poliomyelitis syndrome: association with disease-related, behavioral, and psychosocial factors

The purpose of this study was to determine which factors are associated with general, physical, and mental fatigue in post-poliomyelitis syndrome patients, and to evaluate the contribution of potentially modifiable factors to fatigue. A number of disease-related, behavioural, and psychosocial factors were considered. This study was a cross-sectional study (one evaluation only) in 52 ambulatory post-polio syndrome patients.
We found that in multivariate statistical models, important predictors for general fatigue were decreased respiratory muscle strength, presence of fibromyalgia, reduced muscle strength in the extremities, and increased stress and depression. Important predictors of physical fatigue were reduced respiratory muscle strength, decreased muscle strength in the extremities, increased age, less time since acute polio, reduced physical activity, and increased pain. An important predictor of mental fatigue was increased stress. We concluded that there are different types of fatigue in post-polio syndrome patients, and that different variables are important for different types of fatigue. Potentially modifiable factors (such as stress, depression, pain, physical activity) account for a portion of fatigue in post-polio syndrome patients. Because this study was cross-sectional, we cannot conclude that these factors were causes of fatigue. However, because many of the factors identified are amenable to treatment, our results suggest that with treatment an improvement in fatigue may be possible. Because several potentially modifiable factors were identified as important for general and physical fatigue, our results suggest that an interdisciplinary rehabilitation management program that focuses on several contributors would likely be most useful in managing these fatigue types.
Reference: Trojan DA, Arnold D, Collet J-P, Shapiro S, Bar-Or A, Robinson A, Le Cruguel J-P, Ducruet T, Narayanan S, Arcelin K, Tartaglia MC, Caramanos Z, Da Costa D. Fatigue in post-poliomyelitis syndrome: association with disease-related, behavioral, and psychosocial factors. Physical Medicine and Rehabilitation 2009;1:442-449.

Brain Volume and Fatigue in Post-Poliomyelitis Syndrome Patients

The purpose of this study was to determine if patients with post-polio syndrome (PPS) have smaller brain volumes than normal controls. We also wished to determine if there is an association between brain volume and fatigue in PPS patients.
Acute polio is associated with encephalitis (or inflammation of the brain). It is possible that early brain inflammation may produce permanent neuronal injury with brain volume loss and resultant symptoms such as fatigue. Brain volume loss in other neurological diseases has been associated with clinical symptoms such as reduced cognitive function and fatigue. The project was a cross-sectional study of 49 PPS patients, 28 normal controls, and 53 multiple sclerosis (MS) patients. The MS patients were a positive control for the research protocol because brain volume is known to be reduced with MS. All study subjects underwent magnetic resonance imaging (MRI) of the brain with calculation of brain volume using the automated program, Structured Image Evaluation, using Normalization, of Atrophy method (SIENAx). It is possible that this method of assessment may miss brain volume loss in a brain region such as the brainstem. Subjects also completed the Fatigue Severity Scale (FSS). Scans of adequate quality were available for 42 PPS patients, 27 controls, and 49 MS patients.
We found that brain volume in PPS patients was not significantly different from that in normal controls. As previously reported by others, we found significant brain volume loss in MS patients. We found no association of brain volume and fatigue in PPS patients. Our results indicate that brain atrophy is not a significant problem for PPS patients and is probably not a contributor to the symptom of fatigue in patients with this disorder.
Reference: Trojan DA, Narayanan S, Francis SJ, Caramanos Z, Robinson A, Cardoso M, Arnold DL. Brain volume and fatigue in post-poliomyelitis syndrome patients. Physical Medicine and Rehabilitation 2013 doi: 10.1016/j.pmrj.2013.09.009 (Epub ahead of print).


These studies involved a large number of co-investigators who are listed as authors. The studies were supported by the Polio Quebec Association and the Multiple Sclerosis Society of Canada (operating funds), and the Montreal Neurological Institute (salary support). We are grateful to the patients and controls who donated their time to participate in the studies.