Prevalence and Effect of Obesity on Mobility According to Different Criteria in Polio Survivors

OBJECTIVE

Obesity is a major and functionally important problem in polio survivors. The aim of this study was to investigate the prevalence of obesity using body mass index and percentage body fat in polio survivors and to analyze the relationship between obesity and mobility.

DESIGN

Eighty-four polio survivors were included. Anthropometric parameters, knee extensor strength, and the Short Physical Performance Battery were evaluated. A questionnaire was used to explore the late effects of poliomyelitis. Obesity was determined using both body mass index and percentage body fat.

RESULTS

The prevalence of obesity in polio survivors was 39.3% and 81.5% using the body mass index and percentage body fat criteria, respectively. The Short Physical Performance Battery scores were significantly different between the obese and nonobese groups as determined by percentage body fat (P < 0.05). Only percentage body fat was significantly associated with mobility after controlling for the confounding variables in obese polio survivors (P < 0.05).

CONCLUSIONS

Obesity in polio survivors was underestimated when the body mass index criteria were used. Percentage body fat was a significantly associated factor for mobility in obese polio survivors. Obesity determined by percentage body fat criteria is useful to address obesity-related problems in polio survivors.

Comparison of activity and fatigue of the respiratory muscles and pulmonary characteristics between post-polio patients and controls: A pilot study

Objectives

To compare pulmonary function measures, maximal respiratory pressure and fatigue of respiratory muscles between patients with Post-Polio Syndrome (PPS) and controls.

Design

Cross-sectional study.

Patients

Patients with PPS (N = 12; age 62.1±11.6 years) able to walk for 6 minutes without human assistance; age-matched controls with no history of polio or pulmonary dysfunction (N = 12; age 62.2±6.5 years).

Measurements

A body plethysmograph was used to quantify Residual Volume (RV), Total Lung Capacity (TLC), and Thoracic Gas Volume (TGV) etc. A manometer was used to measure Maximal Inspiratory Pressure (MIP) and Maximal Expiratory Pressure. A spirometer was used to measure Maximal Voluntary Ventilation (MVV). Surface electromyography (sEMG) recorded diaphragmatic muscle activity while performing MVV.

Results

The control group had significantly higher TGV and showed improvement in MIP following the effort (difference of 5.5±4.0cmH₂O) while the PPS group showed deterioration in MIP (difference of -2.5±5.0cmH₂O). Subjects with scoliosis had significantly higher RV/TLC values compared with subjects without scoliosis. The 25^th frequency percentile of the sEMG signal acquired during MVV was reduced in the PPS group.

Conclusions

Maximal respiratory pressure test and sEMG measurements may identify fatigue of respiratory muscles in patients with PPS. Early diagnosis of respiratory impairment may delay respiratory decline and future need of invasive respiratory aids.

Treatment with L-citrulline in patients with post-polio syndrome: study protocol for a single-center, randomised, placebo-controlled, double-blind trial

BACKGROUND

Post-polio syndrome (PPS) is a condition that affects polio survivors years after recovery from an initial acute infection by the Poliomyelitis virus. Most often, patients who suffered from polio start to experience gradual new weakening in muscles, a gradual decrease in the size of muscles (muscle atrophy) and fatigue years after the acute illness. L-citrulline is known to change muscular metabolism synthesis by raising nitric oxide (NO) levels and increasing protein synthesis. This investigator-initiated, randomised, placebo-controlled, double-blind, trial aims to demonstrate that L-citrulline positively influences muscle function and increases muscular energy production in patients with PPS.

METHODS/DESIGN

Thirty ambulant PPS patients will be recruited in Switzerland. Patients will be randomly allocated to one of the two arms of the study (placebo:verum 1:1). After a 24-week run-in phase to observe natural disease history and progression, participants will be treated either with L-citrulline or placebo for 24 weeks. The primary endpoint is change in the 6-min Walking Distance Test. Secondary endpoints will include motor function measure, quantitative muscle force, quantitative muscle magnetic resonance imaging and magnetic resonance spectroscopy and serum biomarker laboratory analysis DISCUSSION: The aim of this phase IIa trial is to determine if treatment with L-citrulline shows a positive effect on clinical function and paraclinical biomarkers in PPS. If treatment with L-citrulline shows positive effects, this might represent a cost-efficient symptomatic therapy for PPS patients.

TRIAL REGISTRATION

ClinicalTrial.gov, ID: NCT02801071 . Registered on 6 June 2016.

Aerobic Exercise Training in Post-Polio Syndrome: Process Evaluation of a Randomized Controlled Trial

Objective

To explore reasons for the lack of efficacy of a high intensity aerobic exercise program in post-polio syndrome (PPS) on cardiorespiratory fitness by evaluating adherence to the training program and effects on muscle function.

Design

A process evaluation using data from an RCT.

Patients

Forty-four severely fatigued individuals with PPS were randomized to exercise therapy (n = 22) or usual care (n = 22).

Methods

Participants in the exercise group were instructed to exercise 3 times weekly for 4 months on a bicycle ergometer (60–70% heart rate reserve).

Results

The attendance rate was high (median 89%). None of the participants trained within the target heart rate range during >75% of the designated time. Instead, participants exercised at lower intensities, though still around the anaerobic threshold (AT) most of the time. Muscle function did not improve in the exercise group.

Conclusion

Our results suggest that severely fatigued individuals with PPS cannot adhere to a high intensity aerobic exercise program on a cycle ergometer. Despite exercise intensities around the AT, lower extremity muscle function nor cardiorespiratory fitness improved. Improving the aerobic capacity in PPS is difficult through exercise primarily focusing on the lower extremities, and may require a more individualized approach, including the use of other large muscle groups instead.

Trial Registration

Netherlands National Trial Register NTR1371

Feasibility of Lung Volume Recruitment in Early Neuromuscular Weakness: A Comparison Between Amyotrophic Lateral Sclerosis, Myotonic Dystrophy, and Postpolio Syndrome

BACKGROUND

Lung volume recruitment (LVR) is a cough assistance technique used in persons with neuromuscular disorders (NMDs), most typically in those requiring noninvasive ventilation (NIV). Whether it may be useful in persons with NMDs who have milder respiratory impairment is unknown.

OBJECTIVE

To assess the feasibility, impact on quality of life (QOL), and preliminary physiological effects of daily LVR in different categories of persons with NMDs who have an early stage of respiratory impairment.

DESIGN

Feasibility study.

SETTING

Academic tertiary care center.

PARTICIPANTS

Outpatients diagnosed with amyotrophic lateral sclerosis (n = 8), postpolio syndrome (n = 10), and myotonic dystrophy (n = 6) who had restrictive respiratory defects but were not yet using NIV.

METHODS

Participants were asked to perform LVR up to 4 times daily and log their LVR use in a diary. Physiological measurements and questionnaires were completed at baseline and after 3 months.

MAIN OUTCOME MEASUREMENTS

Compliance with LVR use was assessed, along with QOL and willingness to continue the treatment. Physiological measurements included forced vital capacity (FVC), lung insufflation capacity (LIC), and the LIC minus FVC difference.

RESULTS

Of the 24 recruited subjects, 7 with amyotrophic lateral sclerosis, 7 with postpolio syndrome, and 5 with myotonic dystrophy completed the study (n = 19). At baseline, mean values for FVC and spontaneous peak cough flow were 59.9% predicted and 373.1 L/min, respectively. For subjects completing the study, 74% were willing to continue long-term LVR use, and QOL scores were not adversely affected by LVR in any NMD subgroup. The LIC-FVC difference increased from baseline to follow-up by a mean of 0.243 L (P = .006) in all subjects (n = 19), suggesting a possible improvement in respiratory system mechanics.

CONCLUSIONS

In patients with NMDs who have early restrictive respiratory defects but do not yet require NIV, regular use of LVR is feasible with no negative impact on QOL over a 3-month period and may have physiological benefits. Further work is needed to determine whether early institution of LVR can improve respiratory system mechanics and help delay ventilatory failure in persons with NMDs.

Post poliomyelitis syndrome: A rare sequel of acute poliomyelitis

Post poliomyelitis syndrome (PPS) is a rare sequel of acute poliomyelitis, usually seen 30-40 years after an acute episode. It is characterized by new muscle weakness seen in survivors of acute poliomyelitis. We describe a rare case of a 50 year old man; with a previous history of poliomyelitis in right lower limb who now presented with complaints of progressive left lower limb weakness for past two years. The diagnosis was made on the basis of clinical suspicion and EMG findings. PPS is not a well recognized disease in Pakistan and due to the lack of documentation; its true prevalence is not known. Though, over the years, cases of Poliomyelitis have decreased worldwide, however, PPS still remains a constant challenge for the physicians. This report highlights the impact of the disease on the quality of life of patients suffering from PPS and emphasis on the need for new therapeutic approach.

Reliability of contractile properties of the knee extensor muscles in individuals with post-polio syndrome

Objective

To assess the reliability of contractile properties of the knee extensor muscles in 23 individuals with post-polio syndrome (PPS) and 18 age-matched healthy individuals.

Methods

Contractile properties of the knee extensors were assessed from repeated electrically evoked contractions on 2 separate days, with the use of a fixed dynamometer. Reliability was determined for fatigue resistance, rate of torque development (MRTD), and early and late relaxation time (RT50 and RT25), using the intraclass correlation coefficient (ICC) and standard error of measurement (SEM, expressed as % of the mean).

Results

In both groups, reliability for fatigue resistance was good, with high ICCs (>0.90) and small SEM values (PPS: 7.1%, healthy individuals: 7.0%). Reliability for contractile speed indices varied, with the best values found for RT50 (ICCs>0.82, SEM values <2.8%). We found no systematic differences between test and retest occasions, except for RT50 in healthy subjects (p = 0.016).

Conclusions

In PPS and healthy individuals, the reliability of fatigue resistance, as obtained from electrically evoked contractions is high. The reliability of contractile speed is only moderate, except for RT50 in PPS, demonstrating high reliability.

Significance

This was the first study to examine the reliability of electrically evoked contractile properties in individuals with PPS. Our results demonstrate its potential to study mechanisms underlying muscle fatigue in PPS and to evaluate changes in contractile properties over time in response to interventions or from natural course.

Anesthetic implications of postpolio syndrome: new concerns for an old disease

Poliomyelitis was pandemic in the United States and much of the world in the first half of the 20th century. The uses of polio vaccines have essentially eradicated the disease in the United States today. But poliovirus infection survivors who had experienced a paralytic attack can see a return of some symptoms, which is a syndrome called postpolio syndrome (PPS). The anesthetist must preoperatively assess reported amounts of patient physical activity and patient age, which can indicate the amount of muscle degeneration that may have already occurred. Patients with PPS demonstrate altered respiratory function, cold intolerance, a risk for aspiration, and experience chronic pain in muscles and joints. Patients with PPS display an increased sensitivity to some anesthetic agents such as long-acting narcotics and potent inhaled anesthetic gases with a high blood-gas partition coefficient, along with report of increased fatigue, weakness, and somnolence after anesthesia. Anesthesia care must center on the preservation of muscle function postoperatively. The anesthetist should consider the use of short-acting anesthetic agents, increased doses of analgesics, the use of warming devices, and careful attention to patient positioning. Prolonged postoperative care and hospital admission after surgery are possible.

Post-polio syndrome and rehabilitation

Post-polio syndrome (PPS) is the commonly affected term to describe the symptoms that may develop many years after acute paralytic poliomyelitis. The etiology of PPS is still unclear. An overuse of enlarged motor units is suspected causing denervation again due to distal degeneration of axons. Metabolic and functional changes has been described in muscle fibers of partially denervated muscles. Nevertheless, submaximal aerobic training and low intensity muscular strengthening have shown positive effects on muscular strength and cardiorespiratory system in patients affected by PPS. Aquatic therapy has a positive impact on pain and muscle function. In patients with severe fatigue, it is recommended to adapt the daily exercise routine to their specific case.

Fear of falling, balance confidence and health-related quality of life in individuals with postpolio syndrome

The purposes of this study were to examine prevalence of fear of falling (FOF) and decreased balance confidence in individuals with postpolio syndrome (PPS) and to determine whether balance confidence was correlated with health-related quality of life (HRQOL) in this population. A survey, which included demographic questions, the Activities-specific Balance Confidence (ABC) Scale, and the MOS SF-36v2, was made available by mail and electronically to individuals with PPS. Descriptive and correlation statistics were used to analyze the responses. Fear of falling was reported in 95% of respondents, with 80% indicating that FOF affected their quality of life. Median ABC score (42 of 100), physical component score (27 of 100), and mental component score (47 of 100) were below average compared with the general population. A moderate correlation (r = 0.4; p < 0.001) was found between balance confidence and the physical component score of HRQOL in PPS. There was an overwhelming presence of FOF and severely impaired balance confidence in the majority of those with PPS. A fair correlation between the physical functioning component of HRQOL and balance confidence was noted in this population.

Quantitative assessment of motor fatigue: Normative values and comparison with prior‐polio patients

Motor fatigue is a common complaint of polio survivors and has a negative impact on activities of daily living. The aim of this study was to establish a normative database for hand grip strength and fatigue and to investigate differences between prior-polio subjects and normal controls. Static and dynamic hand grip fatigue and maximum voluntary isometric contraction (MVIC) of hand grip were measured in subjects with a prior history of polio (n = 44) and healthy controls (n = 494). A normative database of fatigue was developed using four indices of analysis. Compared with healthy controls, subjects with prior polio had significantly reduced hand grip strength but developed greater hand grip fatigue in only one fatigue index. Quantitative measurement of fatigue in the prior-polio population may be useful in order to detect change over time and to evaluate treatment strategies.

Change in lower limb isokinetic muscle strength of polio survivors over 5-year follow-up

To evaluate the muscle strength of the lower limbs over time in polio survivors during 5 years of follow-up and to examine the rate of change in their muscle strength, we performed a prospective, longitudinal study of polio survivors (n = 63: 61 with postpolio syndrome) living in the community who participated voluntarily. Their isokinetic knee-extensor and knee-flexor muscle strength (peak torque) at angular velocities of 60 and 120 deg/sec, using a fixed dynamometer (Biodex) were measured over a 5-year period. At 5-year follow-up, approximately 90% of the subjects had decreased knee extensor strength at both angular velocity of 60 and 120 deg/sec: similarly, at both angular velocities, approximately 80% of the subjects had decreased knee flexor strength. The annual average rate of decrease in the peak torque of the knee extensors was significantly greater than that of the flexors at both angular velocities, and the difference in the rates between the extensors and the flexors was marked at the faster angular velocity. The polio survivors had a progressive decrease in lower limb isokinetic muscle strength over time. In addition, the annual rate of decrease of the knee-extensor, the so-called weight bearing muscle, was greater than that of the knee-flexor.

Electromyographic and neuromuscular analysis in patients with post-polio syndrome

Proceed to a comparative analysis of the electromyographic (EMG) activity of the muscles rectus femoris, vastus medialis and vastus lateralis, and to assess muscle strength and fatigue after maximal isometric contraction during knee extension. Eighteen patients with post-polio syndrome, age and weight matched, were utilized in this study. The signal acquisition system utilized consisted of three pairs of surface electrodes positioned on the motor point of the analyzed muscles. It was possible to observe with the results of this study a decreased endurance on initial muscle contraction and during contraction after 15 minutes of the initial maximal voluntary contraction, along with a muscle fatigue that was assessed through linear regression executed with Pearson's test. There were significant differences among the comparative analysis of EMG activity of the muscles rectus femoris, vastus medialis and vastus lateralis after maximal isometric contraction during knee extension. Initial muscle contraction and contraction after a 15 minute-rest from initial contraction decreased considerably, indicating a decreased endurance on muscle contraction, concluding that a lower limb muscle fatigue was present on the analyzed PPS patients.

Methodological considerations for improving the reproducibility of walking efficiency outcomes in clinical gait studies

In recent clinical gait studies, the use of net energy cost (EC) outcomes has been recommended. This study assessed the comparative reproducibility of gross and net EC of walking in adults and children with locomotion disorders, using a portable system for gas-exchange. Furthermore, methodological considerations were proposed for improving the reproducibility of these outcomes. Assessment of reproducibility was made in adults with polio residuals (n=14) versus healthy adults (n=14), and in children with cerebral palsy (n=13) versus healthy children (n=10). There were four repeated measurement sessions on different days, with inter-session periods of 1 week. All the measurements had been conducted at the outpatient clinic between 2002 and 2004. Based on the Generalizability Theory for data-analysis, it was shown that there was less intra-subject variability in gross EC of walking compared to net EC of walking among adults and children with locomotion disorders, which was apparent from the lower standard error of measurement values. Data-analysis optimisation and study design adjustments were considered and presented in a decision scheme, to demonstrate that the reproducibility of net EC can substantially be increased. The use of gross EC, rather than net EC, in patients with locomotion disorders seems a more reproducible measure of walking efficiency. However, reproducibility of net EC can substantially be improved by careful standardization and using a multiple repetition design, as a result of which this outcome measure becomes suitable for detecting clinically relevant changes at the individual level.

Effect of carbon-composite knee-ankle-foot orthoses on walking efficiency and gait in former polio patients

OBJECTIVE

To investigate the effects of total-contact fitted carbon-composite knee-ankle-foot orthoses (KAFOs) on energy cost of walking in patients with former polio who normally wear a conventional leather/metal KAFO or plastic/metal KAFO.

DESIGN

A prospective uncontrolled study with a multiple baseline and follow-up design. Follow-up measurements continued until 26 weeks after intervention.

PARTICIPANTS

Twenty adults with polio residuals (mean age 55 years).

INTERVENTION

Each participant received a new carbon-composite KAFO, fitted according to a total-contact principle, which resulted in a rigid, lightweight and well-fitting KAFO.

OUTCOME MEASURES

Energy cost of walking, walking speed, biomechanics of gait, physical functioning and patient satisfaction.

RESULTS

The energy cost decreased significantly, by 8%, compared with the original KAFO. Furthermore, the incremention energy cost during walking with the carbon-composite KAFO was reduced by 18% towards normative values. An improvement in knee flexion, forward excursion of the centre of pressure, peak ankle moment, and timing of peak ankle power were significantly associated with the decrease in energy cost. Walking speed and physical functioning remained unchanged.

CONCLUSION

In patients with former polio, carbon-composite KAFOs are superior to conventional leather/metal and plastic/metal KAFOs with respect to improving walking efficiency and gait, and are therefore important in reducing overuse and maintaining functional abilities in polio survivors.

[Fatigue syndrome in chronic neurological disorders]

Fatigue without coincident depression may accompany many neurological disorders, including multiple sclerosis, Parkinson's disease, motor neuron disease, stroke and post-polio syndrome, and is frequently reported by patients as a predominant complaint. The pathophysiology of fatigue is unknown. The role of various mechanisms has been suggested, including the effect of proinflammatory cytokines (TNF-alpha, IL-1beta and IL-6) on glutaminergic transmission, hypothalamo-pituitary-adrenal (HPA) axis dysfunction, disturbances of astroglia metabolism and decreased levels of the neurotransmitters noradrenaline and serotonin. The diagnosis of fatigue syndrome is based on exclusion of depression and additional organic conditions (anaemia, cardiovascular disorders, kidney diseases or hypothyroidism). The treatment of fatigue syndrome is complex. Physical activity, rehabilitation, psychotherapy and avoidance of factors which may increase fatigue, such as fever, anxiety, depression, pain, sleep disturbances, as well as some drugs like opioids and benzodiazepines, are important. Pharmacological treatment leads to slight improvement. Amantadine, modafinil and pemoline are administered to such patients.

Post-polio syndrome patients treated with intravenous immunoglobulin: a double-blinded randomized controlled pilot study

Post-polio syndrome (PPS) is characterized by new muscle weakness, atrophy, fatigue and pain developing several years after the acute polio. Some studies suggest an ongoing inflammation in the spinal cord in these patients. From this perspective, intravenous immunoglobulin (IvIg) could be a therapeutic option. We performed a double-blinded randomized controlled pilot study with 20 patients to investigate the possible clinical effects of IvIg in PPS. Twenty patients were randomized to either IvIg 2 g/kg body weight or placebo. Primary endpoints were changes in pain, fatigue and muscle strength 3 months after treatment. Surrogate endpoints were changes in cerebrospinal fluid (CSF) cytokine levels. Secondary endpoints were pain, fatigue and isometric muscle strength after 6 months. Patients receiving IvIg reported a significant improvement in pain during the first 3 months, but no change was noted for subjective fatigue and muscle strength. CSF levels of tumour necrosis factor-alpha (TNF-alpha) were increased compared with patients with non-inflammatory neurological disorders. In conclusion, in this small pilot study no effect was seen with IvIg treatment on muscle strength and fatigue, however IvIg treated PPS patients reported significantly less pain 3 months after treatment. TNF-alpha was increased in the CSF from PPS patients. The results are promising, but not conclusive because of the low number of patients studied.

Polio's painful legacy

Some of the people who contracted polio in the 1950s epidemic are now experiencing new symptoms. Yet post-polio syndrome (PPS) is often not recognised.

Perceived disability, fatigue, pain and measured isometric muscle strength in patients with post-polio symptoms

BACKGROUND AND PURPOSE

Several years after the acute polio illness, patients may develop new post-polio symptoms. The purpose of the present study was to evaluate patients with post-polio symptoms with regard to perceived fatigue, functional ability, muscle strength, pain and with regard to measured physical fitness and isometric muscle strength. In addition, the relationship between the results of these subjective and objective measurements was investigated.

METHOD

This was a prospective cross-sectional study in which 32 patients with post-polio symptoms were included. Main outcome measures were the Fatigue Severity Scale (FSS), the Disability Rating Index (DRI), pain intensity, pain distribution, self-reported and measured muscle strength and oxygen uptake.

RESULTS

A marked reduction in isometric muscle strength compared to normal data, high scores in fatigue, widespread pain, low oxygen uptake and difficulties in performing some daily activities were found. Self-reported general muscle strength, pain intensity and pain distribution correlated significantly with patients' perceived fatigue and function at the activity level. There was no significant correlation between self-reported and measured results except for that found between isometric muscle strength in the legs and patients' perceived general muscle strength and oxygen uptake.

CONCLUSIONS

Evaluation of pain intensity, pain distribution, perceived muscle strength, fatigue and ability to perform daily tasks reveals important aspects of health status in patients with post-polio symptoms. Reduction in isometric muscle strength was not reflected in those tests or in reported symptoms, and should be monitored independently using a sensitive assessment tool. Accurate screening of isometric muscle strength in isolated muscle groups contributes to therapeutic management in making a functional diagnosis at the level of body function and structure when designing specific training programmes and in motivating patients. An evaluation combining self-reports with sensitive muscle strength measures provide supplementary information and is appropriate for evaluating these patients in physiotherapy practice.

Oxygen consumption, oxygen cost and physiological cost index in polio survivors: A comparison of walking without orthosis, with an ordinary or a carbon-fibre reinforced plastic knee-ankle-foot orthosis

OBJECTIVE

To examine, for polio survivors, whether walking with a carbon-fibre reinforced plastic knee-ankle-foot orthosis (carbon KAFO) is more efficient than walking with an ordinary KAFO or without an orthosis.

DESIGN

Consecutive sample.

SETTING

Post-polio clinic, University Hospital of Occupational and Environmental Health, Kitakyushu, Fukuoka, Japan.

PARTICIPANTS

Eleven polio survivors who had a carbon KAFO prescribed at the post-polio clinic.

INTERVENTIONS

A carbon KAFO was prescribed, fabricated and inspected.

MAIN OUTCOME MEASURES

Oxygen consumption, oxygen cost and physiological cost index.

RESULTS

An ordinary KAFO weighed 1403 g (standard deviation(SD) 157 g), whereas a carbon KAFO weighed 992 g (SD 168 g). Subjects walking with a carbon KAFO showed a tendency to increase step length, and to increase speed significantly compared with walking without an orthosis and with an ordinary KAFO (paired t-test, p < 0.05). Oxygen consumption per body weight, oxygen cost (O2 consumption for 1-m walk divided by body weight) and physiological cost index ((heart rate at 3-min walk - heart rate at rest) /speed) were significantly lower than those walking without an orthosis (-16%, -35%, -33%; paired t-test, p < 0.05) and were lower than those walking with an ordinary KAFO (-9%, -14%, -15%; paired t-test, p < 0.05).

CONCLUSION

The gait efficiency of polio survivors with a carbon KAFO was objectively better than those without an orthosis or with an ordinary KAFO.

Impact of age and co-morbidity on the functioning of patients with sequelae of poliomyelitis: a cross-sectional study

OBJECTIVE

To investigate the impact of age and co-morbidity on the functional independence and perceived physical functioning of patients with sequelae of poliomyelitis.

DESIGN

Cross sectional study.

SUBJECTS

A convenience sample of 168 patients with sequelae of poliomyelitis, aged 45-85 years, recruited from 2 university hospitals.

METHODS

Outcome measures were Functional Independence Measure (FIMTM) for functional independence, Short Form-36 (SF-36) for physical functioning and general mental health, Cumulative Illness Rating Scale (CIRS) for co-morbidity.

RESULTS

FIMTM scores were significantly lower for the 65-85 year age group than for the 45-54 year age group. No differences in the SF-36 were found between the age groups, except that the SF-36 general mental health sub-scale score was significantly better in the 65-85 year age group than in the 45-54 year age group. The CIRS score increased significantly with age. Linear regression showed that age, gender, polio severity, and 4 co-morbidity scores ("cardiac", "vascular", "endocrine, metabolic"and "muscle, bone, skin") were significantly and inversely associated with functional independence and physical functioning.

CONCLUSION

The level of functional independence of elderly former poliomyelitis patients is lower than that of younger patients. Specific attention should be paid to co-morbidity and ageing in this increasingly older population of polio survivors, since they negatively affect functional independence and perceived functioning.

Disability in a 4-year follow-up study of people with post-polio syndrome

OBJECTIVE

To evaluate changes over time in a clinically based cohort of individuals with post-polio syndrome.

DESIGN

A prospective longitudinal study.

SUBJECTS

A total of 106 individuals with poliomyelitis sequelae were included in the study. They were self-referred or had been referred to the post-polio clinic. After 4 years subjects were called for a follow-up and underwent the same measurements as at the initial assessment.

METHODS

The following measurements were conducted at both the initial assessment, and the follow-up: questionnaires including Nottingham Health Profile, muscle strength and walking speed.

RESULTS

Minor changes in disability during a 4-year period were shown. A significant reduction in muscle strength was only seen for 60 degrees flexion in the left leg and for right and left dorsal flexion. No change could be seen in the total Nottingham Health Profile score.

CONCLUSION

The minor changes in disability found in this study are an indication that we still do not know which subjects are at risk for deterioration. It is difficult to say whether the small changes over time shown in this study are associated with support from the polio clinic or are an expression of the natural history of the syndrome. However, it is hoped that support from the polio clinic may result in self-selected lifestyle changes, which may positively influence the development of symptoms and functional capacity.

Respiratory failure in a patient with antecedent poliomyelitis: Amyotrophic lateral sclerosis or post-polio syndrome?

We report a 69-year-old man who developed paralytic poliomyelitis in childhood and then decades later suffered from fatal respiratory failure. Six months before this event, he had progressive weight loss and shortness of breath. He had severe muscular atrophy of the entire right leg as a sequela of the paralytic poliomyelitis. He showed mild weakness of the facial muscle and tongue, dysarthria, and severe muscle atrophy from the neck to proximal upper extremities and trunk, but no obvious pyramidal signs. Electromyogram revealed neurogenic changes in the right leg, and in the paraspinal, sternocleidomastoid, and lingual muscles. There was a slight increase in central motor conduction time from the motor cortex to the lumbar anterior horn. Pulmonary function showed restrictive ventilation dysfunction, which was the eventual cause of death. Some neuropathological features were suggestive of amyotrophic lateral sclerosis (ALS), namely Bunina bodies. In patients with a history of paralytic poliomyelitis who present after a long stable period with advanced fatal respiratory failure, one may consider not only respiratory impairment from post-polio syndrome but also the onset of ALS.

Electrophysiological findings in a cohort of old polio survivors

A population-based cohort of poliomyelitis survivors was established and followed for 15 years (mean time since polio was 40 years). Over time, the cohort demonstrated a modest decline in summated compound muscle action potential amplitudes (CMAP) and a moderate decline in the summated motor unit number estimates (MUNE). There was no association between symptoms of late deterioration and magnitude of decline. Rather, the presence of these symptoms was associated with the magnitude of the residual deficits. Two patterns of neuron loss were modeled (linear and proportional decline). The summated MUNE was a more sensitive measure of loss of motor units than was the summated CMAP and appears to be a more valid measure of attritional loss of anterior horn cells. Of these two models of neuron loss, the proportional loss of motor neurons was a better fit of the data than a linear loss.

A Comparison of Fatigue Scales in Postpoliomyelitis Syndrome

OBJECTIVE

To examine the applicability and validity of traditional fatigue questionnaires in postpoliomyelitis syndrome (PPS) patients with disabling fatigue.

DESIGN

Cross-sectional study. PPS and disabling fatigue were ascertained according to published criteria. Descriptiveness was determined using the McNemar test, and interscale z-score agreement was estimated with Pearson's coefficients.

SETTING

PPS clinic.

PARTICIPANTS

Fifty-six survivors of poliomyelitis: 39 met criteria for PPS, 25 of whom met criteria for disabling fatigue.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The Fatigue Severity Scale (FSS), visual analog scale (VAS) for fatigue, and Fatigue Impact Scale (FIS).

RESULTS

Twenty-four patients scored 50% or higher on the scale range for FSS, compared with 19 patients for VAS for fatigue (P=.042), and 7 patients for FIS (P<.001). Scores for patients with disabling fatigue averaged 81.5%, 62%, and 40.9% of the scale range for FSS, VAS for fatigue, and FIS, respectively. Agreement was moderate between the FSS and VAS for fatigue (r=.45, P=.02), but low between FSS and FIS (r=.29, P=.15), and FIS and VAS for fatigue (r=.20, P=.33). Two sample t tests showed significant differences between those with disabling fatigue and those without, based on FSS scores (t=3.8, P<.001), but not for VAS for fatigue or FIS scores.

CONCLUSIONS

FSS was the most descriptive of the instruments tested. Scores generated by the scales were not interchangeable. Of the 3 scales, FFS seemed to be the most informative for the clinical assessment of fatigue in patients with PPS.

[Post-polio syndrome: a review of its clinical characteristics and treatment]

INTRODUCTION

Post-polio syndrome (PPS) is recognised as a clinical syndrome that causes the late, progressive functional impairment suffered by survivors of an acute episode of poliomyelitis. The importance of PPS is acknowledged by increasingly wider sectors of the population and health care sectors; nevertheless, few reports have been published about its epidemiology or its clinical characteristics and treatment.

AIM

To review the current scientific evidence available on the clinical manifestations, risk factors, prevalence, diagnosis and recommendations for treatment of PPS.

DEVELOPMENT

We conducted a review of the medical literature in the MEDLINE database. The search was restricted to studies conducted in humans that had been published as complete works in English and/or Spanish up to December 2004.

CONCLUSIONS

PPS is recognised as being a specific neurological syndrome that appears several decades after the acute episode of polio; it exacerbates the motor sequelae already present in these patients and reduces their functional capacity to a point where it affects their activities of daily living. Its causation has still not been clearly identified and it constitutes a process that is difficult to diagnose and manage. In addition, no specific treatment has been developed for this condition to date. Nevertheless, the psychological and functional impact it has on its victims and the possibility of bringing about a significant improvement in the symptoms call for a greater effort by professionals to identify the clinical needs imposed by the syndrome and to break down some of the health care barriers that currently exist.

EFNS guideline on diagnosis and management of post-polio syndrome. Report of an EFNS task force

Post-polio syndrome (PPS) is characterized by new or increased muscular weakness, atrophy, muscle pain and fatigue several years after acute polio. The aim of the article is to prepare diagnostic criteria for PPS, and to evaluate the existing evidence for therapeutic interventions. The Medline, EMBASE and ISI databases were searched. Consensus in the group was reached after discussion by e-mail. We recommend Halstead's definition of PPS from 1991 as diagnostic criteria. Supervised, aerobic muscular training, both isokinetic and isometric, is a safe and effective way to prevent further decline for patients with moderate weakness (Level B). Muscular training can also improve muscular fatigue, muscle weakness and pain. Training in a warm climate and non-swimming water exercises are particularly useful (Level B). Respiratory muscle training can improve pulmonary function. Recognition of respiratory impairment and early introduction of non-invasive ventilatory aids prevent or delay further respiratory decline and the need for invasive respiratory aid (Level C). Group training, regular follow-up and patient education are useful for the patients' mental status and well-being. Weight loss, adjustment and introduction of properly fitted assistive devices should be considered (good practice points). A small number of controlled studies of potential-specific treatments for PPS have been completed, but no definitive therapeutic effect has been reported for the agents evaluated (pyridostigmine, corticosteroids, amantadine). Future randomized trials should particularly address the treatment of pain, which is commonly reported by PPS patients. There is also a need for studies evaluating the long-term effects of muscular training.

Clinical application of carbon fibre reinforced plastic leg orthosis for polio survivors and its advantages and disadvantages

A prospective study was carried out on the clinical application and features of a carbon fibre reinforced plastic leg orthosis (carbon orthosis) for polio survivors. The subjects comprised 9 polio survivors, and 11 carbon knee-ankle-foot orthoses (KAFOs) were prescribed, fabricated, and checked out at the authors' post-polio clinic. Walking was classified based on the functional ambulatory category, and the features of walking with a carbon orthosis were self-evaluated by using a visual analogue scale. The period from modelling a cast to completion was 55 +/- 25 days; the weight of a carbon KAFO was 27.8% lighter than that of the ordinary KAFO; the standard carbon KAFO was 50% more expensive than the ordinary KAFO. The carbon KAFO remained undamaged for at least 2 years. It improved the scores in the functional ambulation categories, but there was no difference between walking with an ordinary and with a carbon KAFO. The self-evaluation of walking with a carbon KAFO revealed that the subjects using a carbon KAFO were satisfied with their carbon KAFO. The carbon KAFO is lightweight, durable, slim and smart, and is positively indicated for polio survivors.

Intravenous immunoglobulin for post-polio syndrome: a randomised controlled trial

BACKGROUND

Survivors of poliomyelitis often develop increased or new symptoms decades after the acute infection, known as post-polio syndrome. Production of proinflammatory cytokines within the CNS indicates an underlying inflammatory process, accessible for immunomodulatory treatment. We did a multicentre, randomised, double-blind, placebo-controlled study of intravenous immunoglobulin in post-polio syndrome.

METHODS

142 patients at four university clinics were randomly assigned infusion of either 90 g in total of intravenous immunoglobulin (n=73) or placebo (n=69) during 3 consecutive days, repeated after 3 months. Seven patients were withdrawn from the study. Thus, 135 patients were assessed per protocol. Primary endpoints were muscle strength in a selected study muscle and quality of life as measured with the SF-36 questionnaire (SF-36 PCS). Secondary endpoints were 6-minute walk test (6MWT), timed up and go (TUG), muscle strength in muscles not chosen as the study muscle, physical activity scale of the elderly (PASE), visual analogue scale (VAS) for pain, multidimensional fatigue inventory (MFI-20), balance, and sleep quality. Outcome tests were done immediately before the first infusion and 3 months after the second infusion. This study is registered with , number NCT00160082.

FINDINGS

Compared with baseline, median muscle strength differed by 8.3% between patients receiving intravenous immunoglobulin and placebo, in favour of the treatment group (p=0.029). SF-36 PCS did not differ significantly between the groups after treatment (p=0.321). Differences in the subscale vitality score (p=0.042) and PASE (p=0.018) favoured the active treatment group. MFI-20, TUG, muscle strength in the muscles not chosen as the study muscle, 6MWT, balance, and sleep quality did not differ between groups. For the whole study population there was no significant change in pain, as determined by VAS. Nevertheless, patients who reported pain at the study start improved in the intervention group but not in the placebo group (p=0.037). Intravenous immunoglobulin was well tolerated.

INTERPRETATION

Intravenous immunoglobulin could be a supportive treatment option for subgroups of patients with post-polio syndrome. Further studies on responding subgroups, long-term effects, and dosing schedules are needed.

The Relation Between Walking Capacity and Clinical Correlates in Survivors of Chronic Spinal Poliomyelitis

OBJECTIVES

To examine (1) common clinical measures that may influence walking performance in the six-minute walk test (6MWT) in people with chronic poliomyelitis and (2) the test-retest reliability of the 6MWT distance, lower-extremity muscle strength, balance, and balance confidence on separate trials.

DESIGN

A prospective quasi-experimental study.

SETTING

University-based postpolio clinic.

PARTICIPANTS

Nineteen survivors of poliomyelitis (mean age, 62.2+/-1.9y; time since polio onset, 54.4+/-8.79y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

6MWT distance, rate-pressure product (RPP), Physiological Cost Index (PCI), ratings of perceived exertion (RPE), pain, fatigue, strength, standing balance, balance confidence, limb-length discrepancy, and lung function.

RESULTS

The 6MWT distance correlated with PCI, pretest pain, lower-extremity muscle strength, balance, balance confidence, corrected leg-length discrepancy, and lung function but not with RPP, RPE, posttest pain, or pretest and posttest fatigue. The PCI correlated with balance confidence and lung function. About 68% of the variance in 6MWT distance was accounted for by balance and pretest pain. The P value was set at .05.

CONCLUSIONS

With stringent standardization of the 6MWT applied to survivors of poliomyelitis (a neuromuscular condition with a musculoskeletal component), reproducibility was high; hence, test validity and interpretation were enhanced. The 6MWT distance was useful in elucidating the relation between impairment and a functional activity-namely, walking-in survivors of poliomyelitis.

SYMPTOMS, CLINICAL AND PHYSIOLOGICAL FINDINGS MOTIVATING HOME MECHANICAL VENTILATION IN PATIENTS WITH NEUROMUSCULAR DISEASES

OBJECTIVE

To clarify the relationship between symptoms, clinical signs and physiological abnormalities that were motivating the initiation of home mechanical ventilation in patients suffering from neuromuscular diseases.

METHODS

From The Swedish Home Mechanical Ventilation Register we identified 352 patients with neuromuscular diseases and we looked at circumstances (acute vs elective) and clinical motives for starting ventilatory support.

RESULTS

Home mechanical ventilation was commenced electively in 268 patients (76%) and among these daytime sleepiness was the most common motive, being reported in 56% of the patients. In the 24 children with spinal muscular atrophy, however, 96% started ventilation electively and cough insufficiency was the most common motive. The patients were moderately hypercapnic (PaCO(2): 7.0 kPa, SD 1.3). None of the clinical motives were related to the PaCO(2) level. Average PaO(2) was above 8 kPa in all groups, but lowest in the patients with post-polio and dystrophia myotonica. Mean vital capacity was close to 40% of predicted, but significantly lower in the Duchenne patients (26% of predicted).

CONCLUSION

Daytime sleepiness was the most common clinical symptom motivating home mechanical ventilation in this group of patients with chronic hypercapnic respiratory insufficiency secondary to neuro/myopathies. Respiratory function testing is therefore suggested to be included in the diagnostic work up of daytime sleepiness in these patients.

Effect of intravenous immunoglobulin in patients with post-polio syndrome -- an uncontrolled pilot study

OBJECTIVE

To analyse changes in muscle strength, physical performance and quality of life during intravenous immunoglobulin (IVIg) treatment in patients with post-polio syndrome.

DESIGN

Open clinical trial.

PATIENTS

A total of 14 patients (6 women, 8 men; mean age 57 years, range 43-67 years) were included in the study.

INTERVENTION

Treatment with 90 g IVIg (30 g daily for 3 days).

MAIN OUTCOME

Muscle strength, measured with dynamic dynamometry, muscle function, by means of performing the 6-minute walk test, and quality of life, analysed by means of the SF-36 questionnaire, were performed before and after treatment.

RESULTS

For quality of life there was a statistically significant improvement for all but one of the 8 multi-item scales of SF-36 when comparing data before and after treatment with IVIg. The multi-item scale most improved was Vitality. There was no significant increase in muscle strength and physical performance.

CONCLUSION

Data indicate that IVIg may have a clinically relevant effect, with an improvement in quality of life. The effect may be due to a decrease in an inflammatory process in the central nervous system, which earlier has been reported in patients with past-polio syndrome after IVIg treatment. Since a possible placebo effect cannot be ruled out, a randomized controlled study is needed.

Fatigue of muscles weakened by death of motoneurons

Weakness is a characteristic of muscles influenced by the postpolio syndrome (PPS), amyotrophic lateral sclerosis (ALS), and spinal cord injury (SCI). The strength deficits relate to changes in muscle use and to the chronic denervation that can follow the spinal motoneuron death common to these disorders. PPS, ALS, and SCI also involve variable amounts of supraspinal neuron death, the effects of which on muscle weakness remains unclear. Nevertheless, weakness of muscle itself defines the functional consequences of these disorders. A weaker muscle requires an individual to work that muscle at higher than usual intensities relative to its maximal capacity, inducing progressive fatigue and an increased sense of effort. Little evidence is available to suggest that the fatigue commonly experienced by individuals with these disorders relates to an increase in the intrinsic fatigability of the muscle fibers. The only exception is when SCI induces chronic muscle paralysis. To reduce long-term functional deficits in these disorders, studies must identify the signaling pathways that influence neuron survival and determine the factors that encourage and limit sprouting of motor axons. This may ensure that a greater proportion of the fibers in each muscle remain innervated and available for use.

Strength and endurance of knee extensors in subjects after paralytic poliomyelitis

PURPOSE

To compare the strength and endurance of knee extensors in subjects after paralytic poliomyelitis as well as to extend the comparison to healthy subjects.

METHOD

Twenty subjects after poliomyelitis with new symptoms (SYM group), 10 without new symptoms (ASYM group) and 15 healthy controls were included. To determine strength, isometric maximal voluntary contraction (MVC) torque of knee extensors in both legs was determined by Biodex dynamometer at 60 degrees knee angle. To determine endurance, the subjects were asked to maintain force in the knee extensors in the same position, in the range between 40-45% of MVC torque, as long as possible. The 'tensiomyography' method was applied to measure the radial displacement of m. rectus femoris during submaximal continuous electrical stimulation until recording a flat response.

RESULTS

No significant difference in MVC torque and endurance was found between SYM and ASYM group, as well between the duration of m. rectus femoris response of both groups to submaximal electrical stimulation. MVC torque and endurance of knee extensors with 'normal' strength was significantly lower in post-polio subjects compared to healthy controls.

CONCLUSION

Endurance of knee extensor muscles in post-polio subjects is generally and significantly lower than that of knee extensors in healthy subjects, regardless of the implication of normal strength and subjective observations of post-polio subjects.

[The problem of fatigue in neurological disorders]

Fatigue or piercing feeling of weakness, lack of strength and energy or total exhaustion is a common complaint of patients with neurological disorders. From 40 to over 90 per cent of individuals with multiple sclerosis, Parkinson disease, amyotrophic lateral sclerosis, neuroboreliosis, post polio syndrome or stroke confirm its experience. It is not infrequently numbered among most disabling complaints. A separate entity, with fatigue as a cardinal sign, is a chronic fatigue syndrome, a disorder, though controversial, more and more frequently diagnosed. Fatigue ought to be discriminated from fatigability, paresis, somnolence and, first of all depression which commonly coexists in chronic disorders. The assessment is almost entirely based on self-estimate scales filled in by a patient. Attainable results of neuroimaging, electrophysiological, polisomnographic, vegetative, psychological and biochemical surveys have not allowed yet to define the pathogenesis of fatigue. The treatment basis consists of behavioral therapy, psychotherapy and a proper treatment of the basic disease.

Postural control in persons with late effects of polio

BACKGROUND

Persons who have suffered from acute poliomyelitis may decades later experience reduction of balance and gait capacity due to muscle weakness, fatigue and/or pain. This may affect the activity level in daily life of these persons.

AIMS OF THE STUDY

The aim of this study was to describe observer assessed and subjectively perceived postural control in persons with late effects of polio and to evaluate the correlation between postural control and gait velocity for this population.

METHOD

50 persons (mean age 59.8 yrs) with diagnosed polio disease and without other causes of mobility disorders were included. Balance was tested with the Timed Up and Go test (TUG), the Functional Reach test (FR) and the Falls Efficacy Scale (FES) (Swedish Version). Gait velocity over 30 m was measured for convenient and maximal velocity.

RESULTS

The subjects had reduced balance (TUG mean 9.0 sec, FR mean 23.5 cm) and perceived balance problems in ADL items (FES(S) median 119.5, normal value 130). They also showed reduced gait velocity compared to healthy persons of the same age (mean 1.01 m/s compared to 1.30 m/s, convenient speed). Correlations were demonstrated between the reduced balance and decreased convenient and maximal gait velocity (TUG/gait velocity: r = -0.7 (convenient), r = -0.8 (maximal), p <or= 0.01).

CONCLUSIONS

The knowledge of reduced balance and gait velocity in persons with late effects of polio may have an impact on how to provide service to this group to ensure safety in activities in daily life, including gait.

Insidious phrenic nerve involvement in postpolio syndrome

A 49-year-old woman with amyotrophic sequelae of poliomyelitis experienced progressive left upper limb weakness and breathing discomfort while walking that had developed over one year prior to presentation. She had flaccid quadriplegia which was more marked in the left upper limb, with the C4- and C5-innervated muscles being most severely affected. Chest radiographs double exposed at maximal inspiration and expiration revealed poor respiratory movements in the left hemidiaphragm. Phrenic nerve conduction study demonstrated conspicuous diaphragmatic paralysis on the left side. The electrophysiological study supports radiological findings and provides useful evidence for insidious phrenic nerve involvement in postpolio syndrome.

Motor unit number estimates correlate with strength in polio survivors

Motor unit number estimation (MUNE) has been proposed as an outcome measure in clinical trials for the motor neuron diseases. One major criticism of MUNE is that it may not represent a clinically meaningful endpoint. We prospectively studied a cohort of polio survivors over a period of 15 years with respect to MUNE and strength. We identified a significant association between thenar MUNE and arm strength, extensor digitorum brevis MUNE and leg strength, and the summated MUNE and global strength of the polio survivors. These findings confirm the clinical relevance of MUNE as an outcome measure in the motor neuron diseases and provide further validation for its use in clinical trial research.

Postpolio Syndrome and Anesthesia

The development of polio vaccines 50 yr ago essentially halted childhood polio epidemics in the industrialized world. During the past quarter century, a constellation of delayed neuromuscular symptoms, called postpolio syndrome, became recognized among the aging polio survivors. The prevalence of postpolio syndrome in the U.S. population is estimated to be in the hundreds of thousands. The most common symptoms are fatigue, pain, and new onset weakness thought to be related to delayed deterioration of motor neuron function. When a patient with postpolio syndrome presents for surgery, special precautions are warranted, because these patients may have respiratory impairment, sleep apnea, swallowing difficulties, and cold intolerance. This article first reviews clinical features and some pathoetiologic theories of postpolio syndrome and then focuses on anesthetic considerations including the use of common anesthetics, neuromuscular blockade, regional anesthesia, and general anesthetic management strategies.

Gait Evaluation of an Automatic Stance-Control Knee Orthosis in a Patient With Postpoliomyelitis

OBJECTIVE

To determine gait differences in a subject ambulating with a knee-ankle-foot orthosis (KAFO) with a locked knee joint versus an automatic stance-control knee joint.

DESIGN

Single-subject crossover design.

SETTING

Tertiary rehabilitation facility with a motion analysis laboratory.

PARTICIPANT

A 61-year-old ambulatory male volunteer with postpoliomyelitis walking with a stance-control KAFO.

INTERVENTIONS

Instrumented gait analysis and Physiological Cost Index in the locked knee and stance-control modes.

MAIN OUTCOME MEASURE

Differences in gait parameters.

RESULTS

On the braced limb, stance-control mode showed a near-normal knee flexion wave in swing, reduced pelvic retraction and rotational excursion, and improved hip power generation. On the nonbraced limb, the stance-control mode allowed elimination of vaulting, reduction in abnormal ankle and hip power generation, increased knee power absorption, and more typical quadriceps activation. There was a trend toward improved energy efficiency in the stance-control mode.

CONCLUSIONS

Use of a stance-control knee joint in a KAFO appears to improve gait biomechanics and improve energy efficiency compared with a locked knee.

The Course of Functional Status and Muscle Strength in Patients With Late-Onset Sequelae of Poliomyelitis: A Systematic Review

OBJECTIVES

To review systematically studies of late-onset polio sequelae on the course of functional status and muscle strength over time and to identify prognostic factors of change.

DATA SOURCES

We conducted a computerized literature search up to July 2004 in MEDLINE, EMBASE, CINAHL, Web of Science, PsychInfo, and the Cochrane controlled trial register using the key words: postpolio, postpoliomyelitis, postpoliomyelitis syndrome, post poliomyelitis muscular atrophy, and poliomyelitis.

STUDY SELECTION

Reports were selected by 1 reviewer if the study involved subjects with a history of poliomyelitis, the outcome measures described functional status or muscle strength, and follow-up was for at least 6 months.

DATA EXTRACTION

Studies were summarized with regard to population, design, sample size, outcome measures, results, and methodologic scores. Overlap in populations between studies was checked.

DATA SYNTHESIS

Of 71 potentially relevant studies, 19 were included (2 on functional status, 15 on muscle strength, 2 on both muscle strength and functional status). Two studies on the course of functional status had sufficient quality and reported inconsistent results. Four studies on the course of muscle strength had sufficient quality. Two studies reported a decline in strength and 2 reported no change. Decline in strength was only reported in studies with a follow-up period longer than 2 years. One study reported extent of paresis as a prognostic factor for change in perceived physical mobility.

CONCLUSIONS

Conclusions cannot be drawn from the literature with regard to the functional course or prognostic factors in late-onset polio sequelae. The rate of decline in muscle strength is slow, and prognostic factors have not yet been identified. Long-term follow-up studies with unselected study populations and age-matched controls are needed, with specific focus on prognostic factors.

Walking in postpoliomyelitis syndrome: the relationships between time-scored tests, walking in daily life and perceived mobility problems

OBJECTIVE

To compare walking test results with walking in daily life, and to investigate the relationships between walking tests, walking activity in daily life, and perceived mobility problems in patients with post-poliomyelitis syndrome.

SUBJECTS

Twenty-four ambulant patients with post-poliomyelitis syndrome.

METHODS

Walking tests were performed at self-preferred and maximal speed. Walking activity was measured with an ambulatory activity monitor. Heart rate, step cadence and walking speed in the test and in daily life were compared. Walking speed in daily life was represented by the intensity of walking. Perceived mobility problems were assessed with the Nottingham Health Profile.

RESULTS

Heart rate during walking was lower in the test at self-preferred speed than in daily life (mean difference: 11.3+/-10.4; p=0.001). Self-preferred walking speed in the test and in daily life correlated significantly (r=0.55; p=0.04). In a sub-group with a test performance below the median value, test performance correlated significantly with walking activity. No significant correlation was found between perceived mobility problems and walking activity.

CONCLUSION

Walking in daily life may be more demanding than walking under standardized conditions. Patients with post-poliomyelitis syndrome with the lowest test performance walked less in daily life. Patients do not necessarily match their activity pattern to their perceived mobility problems.

Non-invasive assessment of respiratory muscle strength in patients with previous poliomyelitis

In patients with poliomyelitis, respiratory failure requiring ventilatory support may occur during the acute illness. Some patients continue to require long-term nocturnal ventilatory support; others are weaned but subsequently require support because of a late deterioration in ventilatory function.

OBJECTIVES

To assess the sensitivity of sniff nasal inspiratory pressure (SNIP) to post-poliomyelitis respiratory muscle weakness and to assess the relationship between the respiratory muscle strength and the need for ventilatory support in patients with previous poliomyelitis (post-polio patients).

METHODS

Respiratory muscle strength was measured in 50 post-polio patients. Tests included forced vital capacity (FVC), maximum inspiratory and expiratory pressures (MIP and MEP), and SNIP.

RESULTS

Twenty-one patients used non-invasive nocturnal ventilatory support (NIV group) compared to 29 on no support (non-NIV group). The percentage predicted FVC was significantly lower in the NIV group compared to the non-NIV group (P=0.01). Similarly, the percentage predicted MIP was significantly lower in NIV group (P=0.007). Low SNIP values (both absolute value and percentage predicted) were associated with the need for ventilatory support (P<0.001). Of the patients requiring no support, those who had been ventilated during the acute episode of poliomyelitis had a significantly lower SNIP than those who had never been ventilated (P=0.04).

CONCLUSIONS

Post-polio patients who are currently on nocturnal ventilation have significantly lower FVC, MIP and SNIP compared to currently non-ventilated patients. Non-ventilated patients who were ventilated during the acute episode of poliomyelitis have significantly weaker respiratory muscle strength than patients who were never ventilated. This study indicates that SNIP is more sensitive to post-polio respiratory muscle weakness than other non-invasive tests. Thus measurement of SNIP is a valuable tool for monitoring the progression of respiratory muscle weakness due to previous poliomyelitis and this can be applied to other neuromuscular disorders.

A 15-year follow-up of neuromuscular function in patients with prior poliomyelitis

A population-based cohort of poliomyelitis survivors was established and followed for 15 years (mean time since poliomyelitis was 40 years). Over time, the cohort demonstrated only a modest decline in function as measured by strength measurements, electrophysiologic assessments, and timed functional tasks. There was no association between symptoms of late deterioration and magnitude of decline. Rather, the presence of these symptoms was associated with the magnitude of the residual deficits.