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.

Sunnerhagen K. "The car is my extra legs" - Experiences of outdoor mobility amongst immigrants in Sweden with late effects of polio

BACKGROUND

The aim of the study was to describe the experience of outdoor mobility among immigrants with late effects of polio living in Sweden. There is a need to understand more about this young group of persons since they often have problems with mobility and gait, but they may also face participation restrictions due to issues associated with integration into a new community and culture.

METHOD

A total of 14 young immigrants with late effects of polio participated and were interviewed individually. The study used a qualitative method to explore personal experiences and the interviews were analyzed through an inductive approach, using qualitative content analysis.

RESULTS

The analysis led to a major theme; self-image and acceptance, that comprised a changeable process and experiences of cultural, social, and gender-specific barriers, but also of environmental and personal factors that impacted their outdoor mobility. By using a car, the participants felt they could come across as normal which also increased their self-esteem.

CONCLUSIONS

Independent mobility is a major enabler for ongoing employment and being able to use a car increases the chances for integration into society for young immigrants with late effects of polio. Public transport is not considered to be adequate or efficient enough due to the participants' mobility impairments, but driving can prevent involuntary isolation and facilitate participation. A car can increase quality of life but may also be a facilitator for work and reduce the demand for societal support.

Gait patterns in association with underlying impairments in polio survivors with calf muscle weakness

The objective was to identify gait patterns in polio survivors with calf muscle weakness and associate them to underlying lower extremity impairments, which are expected to help in the search for an optimal orthosis. Unilaterally affected patients underwent barefoot 3D-gait analyses. Gait pattern clusters were created based on the ankle and knee angle and ankle moment shown in midstance of the affected limb. Impairment clusters were created based on plantarflexor and knee-extensor strength, and ankle and knee joint range-of-motion. The association between gait patterns and underlying impairments were examined descriptively. The Random Forest Algorithm and regression analyses were used to predict gait patterns and parameters. Seven gait patterns in 73 polio survivors were identified, with two dominant patterns: one with a mildly/non-deviant ankle angle, ankle moment and knee angle (n=23), and one with a strongly deviant ankle angle and a mildly/non-deviant ankle moment and knee angle (n=18). Gait pattern prediction from underlying impairments was 49% accurate with best prediction performance for the second dominant gait pattern (sensitivity 78% and positive predictive value 74%). The underlying impairments explained between 20 and 32% of the variance in individual gait parameters. Polio survivors with calf muscle weakness who present a similar impairment profile do not necessarily walk the same. From physical examination alone, the gait pattern nor the individual gait parameters could be accurately predicted. The patient's gait should therefore be measured to help in the prescription and evaluation of orthoses for these patients.

Faster Detection of Poliomyelitis Outbreaks to Support Polio Eradication

As the global eradication of poliomyelitis approaches the final stages, prompt detection of new outbreaks is critical to enable a fast and effective outbreak response. Surveillance relies on reporting of acute flaccid paralysis (AFP) cases and laboratory confirmation through isolation of poliovirus from stool. However, delayed sample collection and testing can delay outbreak detection. We investigated whether weekly testing for clusters of AFP by location and time, using the Kulldorff scan statistic, could provide an early warning for outbreaks in 20 countries. A mixed-effects regression model was used to predict background rates of nonpolio AFP at the district level. In Tajikistan and Congo, testing for AFP clusters would have resulted in an outbreak warning 39 and 11 days, respectively, before official confirmation of large outbreaks. This method has relatively high specificity and could be integrated into the current polio information system to support rapid outbreak response activities.

Characteristics of Patients at First Visit to a Polio Clinic in Sweden

AIM

Describe polio patients visiting a polio clinic in Sweden, a country where vaccination was introduced in 1957.

DESIGN

A consecutive cohort study.

PATIENTS

Prior polio patients.

METHODS

All patients (n = 865) visiting the polio clinic at Sahlgrenska University Hospital, Gothenburg Sweden, between 1994 and 2012 were included in this study. Data at first visit regarding patient characteristics, polio classification, data of electromyography, origin, assistive devices and gait speed as well as muscle strength were collected for these patients. Twenty-three patients were excluded because no polio diagnosis could be established. A total of 842 patients with confirmed polio remained in the study.

RESULTS

More than twenty percent of the patients were from countries outside the Nordic region and considerably younger than those from the Nordic region. The majority of the emigrants were from Asia and Africa followed by Europe (outside the Nordic region). Of all patients included ninety-seven percent (n = 817) had polio in the lower extremity and almost 53% (n = 444) had polio in the upper extremity while 28% (n = 238) had polio in the trunk, according to clinical classification of polio. Compared with a sample of the normal population, the polio patients walked 61-71% slower, and were 53-77% weaker in muscle strength of the knee and foot as well as grip strength.

CONCLUSION

The younger patients with polio emigrating from countries with different cultures may lead to a challenge for the multi professional teams working with post-polio rehabilitation and are of importance when planning for the care of polio patients the coming years.

[Hypotonic syndrome in the newborn infant]

Hypotonia is understood to refer to a pronounced decrease in muscle tone that affects normal motor development and that may affect the axial muscles as well as those of the limbs and, sometimes, the face. It is a very challenging clinical picture because it consists in a fairly wide range of conditions that affect different areas of the central and peripheral nervous system and may be the expression of pathologies that can be either benign or of an uncertain prognosis. These cover myopathies, metabolic disorders, diseases based on genetic causes, pathologies affecting the endocrine glands and progressive or chronic diseases, among other aetiologies. The important development of medicine today has made a number of tools available to the examiner with which to refine or pronounce a diagnosis. Such instruments include the developments achieved in genetic research, together with studies conducted in imaging and optical and electronic microscopy. However, in spite of having all this material available for use, it is still the clinical features that allow a rational use to be made of these advances to be able to point towards the possible causation, topographic location and developmental control. It is useful, for the diagnostic approach and the use of auxiliary methods, to know the topographic location of the disorder, whether it is situated in the brain, the cerebellum, the stem, the spinal cord, the peripheral nerves, the myoneural junction or the muscle.

Lightning can strike twice: an unlucky patient of neurological interest

Poliomyelitis, once a worldwide epidemic, is becoming increasingly rare owing to the introduction of the polio vaccine in the 1950s. It is estimated that the number of cases of polio has reduced by 99% since the Global Polio Eradication Initiative (GPEI) started in 1988. Amyotrophic lateral sclerosis (ALS) is another relatively uncommon condition which also affects anterior horn cells with debilitating neurological, and deadly, consequences. An unusual case of an aggressive form of ALS developing in a 72-year-old patient with paralytic poliomyelitis in childhood is presented. Her initial presentation was puzzling, and our approach to the diagnostic dilemma is discussed.

The meaning of gender while aging with paralytic polio

The purpose of this article is to report the influence of gender on aging with childhood onset paralytic polio. The hermeneutic phenomenological exploration of gender was done using multiple qualitative interviews with 25 women, age 55 to 75 years of age, who had polio since before 14 years of age. We noted three themes: (a) the movement of her body, (b) integrating body and gender, and (c) gender discrepancies. Findings are discussed in the context of gendered expectations and the women's bodies.

Femoral neck bone mineral density in ambulatory men with poliomyelitis

We evaluated bilateral femoral neck bone mineral densities (FNBMDs) in 32 men with poliomyelitis and their matched controls. Men with poliomyelitis had significantly lower FNBMD in both legs, and FNBMD was lowest in their shorter legs. Knee extensor strength and regular exercise were important predictive factors associated with decreased FNBMD.

INTRODUCTION

People with poliomyelitis (polio) are prone to leg fractures after mild trauma. The flaccid paralysis, asymmetric involvement, and underdeveloped growth of afflicted legs may lead to osteoporosis of either leg, characterized by different patterns. This study aimed to measure their femoral FNBMD and to explore the factors associated with changes in FNBMD in either leg.

METHODS

We did a prospective study to evaluate bilateral FNBMD with dual-energy X-ray absorptiometry in 32 men with polio (age range, 41-57 years; mean, 47 years) and 32 age- and body mass index-matched controls. Measuring the difference in leg length, we classified the legs of each polio subject as "longer" or "shorter." In addition, we chose the right leg of each control as a reference leg. We then used the Mann-Whitney U test to compare FNBMD of these three groups of legs and searched for the factors associated with FNBMD using stepwise multiple regression analyses.

RESULTS

Compared to the reference leg, men with polio had significantly lower FNBMD in both their longer and shorter legs, by 13% and 23%, respectively. The difference in FNBMD between the two legs of polio subjects was significant. Knee extensor strength and regular exercise were two important factors associated with bilateral FNBMD in men with polio.

CONCLUSIONS

Men with polio had lower bilateral FNBMD. FNBMD of the shorter leg should be the choice for predicting the risk of hip fracture in men with polio because on average, the shorter leg has lower BMD.

Limited trafficking of a neurotropic virus through inefficient retrograde axonal transport and the type I interferon response

Poliovirus is an enteric virus that rarely invades the human central nervous system (CNS). To identify barriers limiting poliovirus spread from the periphery to CNS, we monitored trafficking of 10 marked viruses. After oral inoculation of susceptible mice, poliovirus was present in peripheral neurons, including vagus and sciatic nerves. To model viral trafficking in peripheral neurons, we intramuscularly injected mice with poliovirus, which follows a muscle-sciatic nerve-spinal cord-brain route. Only 20% of the poliovirus population successfully moved from muscle to brain, and three barriers limiting viral trafficking were identified. First, using light-sensitive viruses, we found limited viral replication in peripheral neurons. Second, retrograde axonal transport of poliovirus in peripheral neurons was inefficient; however, the efficiency was increased upon muscle damage, which also increased the transport efficiency of a non-viral neural tracer, wheat germ agglutinin. Third, using susceptible interferon (IFN) alpha/beta receptor knockout mice, we demonstrated that the IFN response limited viral movement from the periphery to the brain. Surprisingly, the retrograde axonal transport barrier was equivalent in strength to the IFN barrier. Illustrating the importance of barriers created by the IFN response and inefficient axonal transport, IFN alpha/beta receptor knockout mice with muscle damage permitted 80% of the viral population to access the brain, and succumbed to disease three times faster than mice with intact barriers. These results suggest that multiple separate barriers limit poliovirus trafficking from peripheral neurons to the CNS, possibly explaining the rare incidence of paralytic poliomyelitis. This study identifies inefficient axonal transport as a substantial barrier to poliovirus trafficking in peripheral neurons, which may limit CNS access for other viruses.

Premature pubarche and the growth of the trunk in paralysed children

In a hospital supervising prolonged orthopaedic treatment of children suffering from neurological affections, isolated premature pubarche appeared very frequently in children suffering from severe paralytic sequelae of acute anterior poliomyelitis. These subjects had a greater progression of scoliosis and segmental disproportion than comparable subjects of the same age. Supine length and crown-rump length were studied during growth in 16 paralysed boys and 22 paralysed girls with premature pubarche. The results were compared with those of two control populations, one normal group (274 girls, 246 boys), the other a paralysed group (49 boys and 38 girls). Paralysed children (group with premature pubarche and control group) all show considerable shortening of the legs. Up to age 11 for girls and 13 for boys, children with premature pubarche had longer trunks than normal, while supine length was normal. Premature slowing of growth then occurred, bringing the trunk to normal values and supine length to very low values for age. This is ascribed to premature pubertal growth of the trunk. The roles of hormonal changes and neurological damage are discussed.

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.

A method to measure the accuracy of loads in knee-ankle-foot orthoses using conventional gait analysis, applied to persons with poliomyelitis

OBJECTIVES

To determine (1) the forces and moments passing through knee-ankle-foot orthoses (KAFOs) during walking and (2) the accuracy with which these loads can be measured using conventional gait analysis techniques.

DESIGN

Comparative case series.

SETTING

Rehabilitation facility with human movement laboratory (gait lab).

PARTICIPANTS

Four patients with poliomyelitis wearing KAFOs.

INTERVENTIONS

KAFOs were instrumented with a load cell, and walking data were concurrently collected using conventional gait analysis.

MAIN OUTCOME MEASURES

Load measurements and gait parameters.

RESULTS

Predominant orthotic loads (knee joint forces and moments) were composed of knee flexion moments and axial compression forces. With conventional gait analysis, peak knee joint moments were substantially underestimated compared with those directly measured using the load cell. Defining the knee axis anatomically versus at the orthotic axis, tracking it dynamically, and compensating for each patient's corrected knee flexion contracture resulted in considerable improvements in the gait lab estimates of knee joint moments.

CONCLUSIONS

A practical method that directly measures moments and forces in conventional KAFOs has been applied to show that conventional gait analysis techniques substantially underestimate knee joint moments in the KAFOs of persons with poliomyelitis. Underestimation of orthotic loads could result in underdesigned orthotic components and ultimately higher incidence of component failure in clinical applications.

TGF-beta1 suppresses T cell infiltration and VP2 puff B mutation enhances apoptosis in acute polioencephalitis induced by Theiler's virus

GDVII and DA strains of Theiler's murine encephalomyelitis virus (TMEV) differ in VP2 puff B. One week after GDVII virus infection, SJL/J mice had large numbers of TUNEL+ apoptotic cells with a relative lack of T cell infiltration in the brain. DA viruses with mutation in puff B induced higher levels of apoptosis than wild-type DA virus, but levels of inflammation in brains were similar between DA and DA virus mutants. The difference in inflammation among TMEVs could be due to TGF-beta1 expression that was seen only in GDVII virus infection and negatively correlated with CD3+ T cell infiltration.

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.

Characterization of early steps in the poliovirus infection process: receptor-decorated liposomes induce conversion of the virus to membrane-anchored entry-intermediate particles

The mechanism by which poliovirus infects the cell has been characterized by a combination of biochemical and structural studies, leading to a working model for cell entry. Upon receptor binding at physiological temperature, native virus (160S) undergoes a conformational change to a 135S particle from which VP4 and the N terminus of VP1 are externalized. These components interact with the membrane and are proposed to form a membrane pore. An additional conformational change in the particle is accompanied by release of the infectious viral RNA genome from the particle and its delivery, presumably through the membrane pore into the cytoplasm, leaving behind an empty 80S particle. In this report, we describe the generation of a receptor-decorated liposome system, comprising nickel-chelating nitrilotriacetic acid (NTA) liposomes and His-tagged poliovirus receptor, and its use in characterizing the early events in poliovirus infection. Receptor-decorated liposomes were able to capture virus and induce a temperature-dependent virus conversion to the 135S particle. Upon conversion, 135S particles became tethered to the liposome independently of receptor by a membrane interaction with the N terminus of VP1. Converted particles had lost VP4, which partitioned with the membrane. The development of a simple model membrane system provides a novel tool for studying poliovirus entry. The liposome system bridges the gap between previous studies using either soluble receptor or whole cells and offers a flexible template which can be extrapolated to electron microscopy experiments that analyze the structural biology of nonenveloped virus entry.

Life purpose: effect on functional decline and quality of life in polio survivors

This article explores the protective effects that finding a purpose in life has on the level of physical and mental impairment and overall quality of life. Results were gathered from a national sample of 2,153 polio survivors. Although the combined social and physical experience of living with the disabling effects of polio has been associated with accelerated aging due to an increased allostatic load, finding a purpose in life may diminish these effects. The findings of this study indicate that purpose in life is associated with less perceived decline in health. Moreover, purpose in life is predictive of better quality of life despite levels of physical and mental impairment. Rehabilitation nurses should consider ways to help persons with polio maintain activities and interests that promote their sense of purpose in life.

Clinical presentations of acute paralytic poliomyelitis

The concern about the emerging profile of poliovirus associated morbidity and mortality in the 21st century is legitimate [Paul Y. Clinical presentations of acute paralytic poliomyelitis. Vaccine 2005;23:5283]. Rather than case reports of several thousands, patients number at the most in few thousands. Furthermore, better diagnostic techniques have been offered to those handling patients with clinical syndromes resembling acute flaccid paralysis. Bizarre and unconventional clinical presentations might well be a rule than exception in near future. Furthermore, MRI can be used in the diagnosis of anterior horn infection and would play an important role in diagnosis of poliomyelitis [Kornreich L, Dagan O, Grunebaum M. MRI in acute poliomyelitis. Neuroradiology 1996;38(4):371-2]. Imaging techniques would be important in diagnosis of acute flaccid paralysis.

Age-dependent poliovirus replication in the mouse central nervous system is determined by internal ribosome entry site-mediated translation

Mouse cells are not permissive for the replication of human rhinovirus type 2 (HRV2). To determine the role of the HRV2 internal ribosome entry site (IRES) in determining species specificity, a recombinant poliovirus (P1/HRV2) was constructed by substituting the poliovirus IRES with the IRES from HRV2. This recombinant virus replicated in all human and murine cell lines examined, demonstrating that the HRV2 IRES does not limit viral replication in transformed murine cells. P1/HRV2 replicated in the brain and spinal cord in neonatal but not adult mice transgenic for the poliovirus receptor, CD155. Passage of P1/HRV2 in mice led to selection of a virus that caused paralysis in neonatal mice. To determine the relationship between HRV2 IRES-mediated translation and replication of P1/HRV2 in mice, recombinant human adenoviruses were used to express bicistronic mRNAs in murine organs. The results demonstrate that the HRV2 IRES mediates translation in organs of neonatal but not adult mice. These findings show that HRV2 IRES-mediated translation is a determinant of virus replication in the murine brain and spinal cord and suggest that the IRES determines the species specificity of HRV2 infection.