Muscular effects in late polio

EMG Signal Processing for the Study of Localized Muscle Fatigue-Pilot Study to Explore the Applicability of a Novel Method

This pilot study aimed to explore a method for characterization of the electromyogram frequency spectrum during a sustained exertion task, performed by the upper limb. Methods: Nine participants underwent an isometric localized muscle fatigue protocol on an isokinetic dynamometer until exhaustion, while monitored with surface electromyography (sEMG) of the shoulder's external rotators. Firstly, three methods of signal energy analysis based on primer frequency contributors were compared to the energy of the entire spectrum. Secondly, the chosen method of analysis was used to characterize the signal energy at beginning (T1), in the middle (T2) and at the end (T3) of the fatigue protocol and compared to the torque output and the shift in the median frequencies during the trial. Results: There were statistically significant differences between T1 and T3 for signal energy (p < 0.007) and for central frequency of the interval (p = 0.003). Moreover, the isometric peak torque was also different between T1 and T3 (p < 0.001). Overall, there were no differences between the signal energy enclosed in the 40 primer frequency contributors and the analysis of the full spectrum energy; consequently, it was the method of choice. The reported fatigue and the decrease in the produced muscle torque was consistent with fatigue-induced alterations in the electromyogram frequency spectrum. In conclusion, the developed protocol has potential to be considered as an easy-to-use method for EMG-based analysis of isometric muscle exertion until fatigue. Thus, the novelty of the proposed method is to explore, in muscle fatigue, the use of only the main contributors in the frequency domain of the EMG spectrum, avoiding surplus information, that may not represent muscle functioning. However, further studies are needed to investigate the stability of the present findings in a more comprehensive sample.

The relationship between quantitative magnetic resonance imaging of the ankle plantar flexors, muscle function during walking and maximal strength in people with neuromuscular diseases

BACKGROUND

Progression of plantar flexor weakness in neuromuscular diseases is usually monitored by muscle strength measurements, although they poorly relate to muscle function during walking. Pathophysiological changes such as intramuscular adipose tissue affect dynamic muscle function independent from isometric strength. Diffusion tensor imaging and T2 imaging are quantitative MRI measures reflecting muscular pathophysiological changes, and are therefore potential biomarkers to monitor plantar flexor functioning during walking in people with neuromuscular diseases.

METHODS

In fourteen individuals with plantar flexor weakness diffusion tensor imaging and T2 scans of the plantar flexors were obtained, and the diffusion indices fractional anisotropy and mean diffusivity calculated. With a dynamometer, maximal isometric plantar flexor strength was measured. 3D gait analysis was used to assess maximal ankle moment and power during walking.

FINDINGS

Fractional anisotropy, mean diffusivity and T2 relaxation time all moderately correlated with maximal plantar flexor strength (r > 0.512). Fractional anisotropy and mean diffusivity were not related with ankle moment or power (r < 0.288). T2 relaxation time was strongly related to ankle moment (r = -0.789) and ankle power (r = -0.798), and moderately related to maximal plantar flexor strength (r < 0.600).

INTERPRETATION

In conclusion, T2 relaxation time, indicative of multiple pathophysiological changes, was strongly related to plantar flexor function during walking, while fractional anisotropy and mean diffusivity, indicative of fiber size, only related to maximal plantar flexor strength. This indicates that these measures may be suitable to monitor muscle function and gain insights into the pathophysiological changes underlying a poor plantar flexor functioning during gait in people with neuromuscular diseases.

Long-term high-level exercise promotes muscle reinnervation with age

The histologic features of aging muscle suggest that denervation contributes to atrophy, that immobility accelerates the process, and that routine exercise may protect against loss of motor units and muscle tissue. Here, we compared muscle biopsies from sedentary and physically active seniors and found that seniors with a long history of high-level recreational activity up to the time of muscle biopsy had 1) lower loss of muscle strength versus young men (32% loss in physically active vs 51% loss in sedentary seniors); 2) fewer small angulated (denervated) myofibers; 3) a higher percentage of fiber-type groups (reinnervated muscle fibers) that were almost exclusive of the slow type; and 4) sparse normal-size muscle fibers coexpressing fast and slow myosin heavy chains, which is not compatible with exercise-driven muscle-type transformation. The biopsies from the old physically active seniors varied from sparse fiber-type groupings to almost fully transformed muscle, suggesting that coexpressing fibers appear to fill gaps. Altogether, the data show that long-term physical activity promotes reinnervation of muscle fibers and suggest that decades of high-level exercise allow the body to adapt to age-related denervation by saving otherwise lost muscle fibers through selective recruitment to slow motor units. These effects on size and structure of myofibers may delay functional decline in late aging.

Gerenciamento da dor na Síndrome Pós-poliomielite: estudo de caso

A Síndrome Pós-Pólio (SPP) caracteriza-se por um novo episódio de fraqueza muscular e/ou fadiga muscular anormal em indivíduos que apresentaram poliomielite anterior aguda (PAA) anos antes. Ainda são poucos os relatos na literatura sobre o gerenciamento da dor na SSP. O objetivo deste trabalho é analisar o controle da dor na síndrome pós-pólio por meio de um relato de caso. Um homem de 57 anos com SPP foi submetido a 24 sessões de fisioterapia para controle do quadro álgico na síndrome, baseada em recursos eletrotermofototerápicos e cinesioterapia. Para análise da dor pré e pós-intervenção fisioterapêutica foram aplicados dois instrumentos: a Escala Analógica Visual (EVA) e a Intensidade de Dor Presente (ID). O quadro álgico no joelho direito sofreu redução de grau 8 para 4 pela EVA e grau 5 para 2 pela ID, enquanto a dor no tornozelo direito reduziu de grau 2 pela EVA e grau 1 pela ID para zero em ambas as escalas. A dor é apontada como um sintoma predominante por muitos pacientes com SPP. O sujeito deste relato, após o programa de tratamento, apresentou melhora expressiva da dor. Entretanto, devido à escassez da literatura sobre dados substanciais referentes ao seu gerenciamento, especialmente na fisioterapia, novos estudos devem ser propostos para gerar maior fundamentação teórica à abordagem fisioterapêutica na SPP.

Macro electromyography and motor unit number index in the tibialis anterior muscle: differences and similarities in characterizing motor unit properties in prior polio

Our objective was to establish the usefulness of the noninvasive method of the motor unit number index (MUNIX) in a large muscle and to study how macro electromyography (EMG) and MUNIX complement each other in describing the motor units (MUs) in prior polio. MUNIX and macro EMG were performed in 48 tibialis anterior muscles in 33 prior polio patients. In addition, the reproducibility of MUNIX was investigated. It is shown that MUNIX can be used to characterize MUs with high reproducibility, even in a large muscle. As judged by MUNIX values, the patients had a 25% reduction of motor neurons, whereas the macro EMG indicated a loss of 60% of the neurons. Macro EMG showed more pronounced changes compared with control material than the MUNIX. One of the reasons for this finding may be the difference in MU populations studied with the two methods.

Health status in non-dystrophic myotonias: close relation with pain and fatigue

To determine self-reported health status in non-dystrophic myotonias (NDM) and its relationship to painful myotonia and fatigue. In a cross-sectional study, 32 NDM patients with chloride and 30 with sodium channelopathies, all off treatment, completed a standardised interview, the fatigue assessment scale (FAS), and the 36-item Short-Form Health Survey (SF-36). Beside formal assessment of pain, assessment of painful or painless myotonia was determined. The domain scores of the SF-36 were compared with Dutch community scores. Apart from the relationship among SF-36 scores and (1) painful myotonia and (2) fatigue, regression analyses in both NDM groups were conducted to determine the strongest determinants of the SF-36 domains general health perception, physical component (PCS) and mental component summary (MCS). All physically oriented SF-36 domains in both NDM groups (P ≤ 0.01) and social functioning in the patients with sodium channelopathies (P = 0.048) were substantially lower relative to the Dutch community scores. The patients with painful myotonia (41.9%) scored substantially (P < 0.05) lower on most SF-36 domains than the patients without painful myotonia (58.1%). Fatigued patients (53.2%) scored substantially lower (P ≤ 0.01) on all SF-36 domains than their non-fatigued counterparts (46.8%). The regression analysis showed that fatigue was the strongest predictor for the general-health perception and painful myotonia for the physical-component summary. None of the patients showed below-norm scores on the domain mental-component summary. The impact of NDM on the physical domains of patients’ health status is substantial, and particularly painful myotonia and fatigue tend to impede their physical functioning.

Post-polio syndrome: clinical manifestations and cerebrospinal fluid markers

Post-polio syndrome (PPS) refers to a constellation of new neurological, musculoskeletal and general symptoms occurring in survivors of poliomyelitis decades after acute paralytic and nonparalytic disease. The common manifestations of PPS include generalized, central and peripheral fatigue, muscle weakness and musculoskeletal pain. The pathogenesis of PPS remains obscure. Three prevailing hypotheses have been advanced: stress-induced degeneration of surviving neurons, persistent poliovirus replication or virus reactivation and immune-mediated damage. The diagnosis of PPS is based on medical history and clinical examination, since no specific diagnostic tests are available. In the light of recent studies demonstrating a partial beneficial effect of intravenous immunoglobulin, this article will focus on cerebrospinal fluid biomarkers reflecting disease activity and pathogenic processes in PPS.

The development of a model of fatigue in neuromuscular disorders: a longitudinal study

BACKGROUND

Severe fatigue is reported by the majority of patients with three relatively common types of neuromuscular disorders.

OBJECTIVE

This study aimed to identify predictors of fatigue in a longitudinal study and to develop a model of fatigue in patients with three neuromuscular disorders.

METHODS

One hundred ninety-eight patients [60 facioscapulohumeral muscular dystrophy (FSHD), 70 adult-onset myotonic dystrophy (MD), and 68 hereditary motor and sensory neuropathy type I (HMSN-I) patients] were studied twice during an 18-month period. Fatigue severity was assessed by the Checklist Individual Strength. A multidimensional assessment method was used, including self-report questionnaires, a daily Self-Observation List, and physical activity (actometer). Muscle strength was determined using the Medical Research Council scale. Structural equation modeling was used to develop and test a model of factors contributing to the persistence of experienced fatigue.

RESULTS

Muscle strength, self-reported physical activity, sleep disturbances, and pain at baseline contributed directly or indirectly to fatigue and impairment at follow-up. Lower muscle strength contributed to lower levels of physical activity, which, in turn, contributed to fatigue severity. The model showed excellent fit for the whole group of neuromuscular disorders. In FSHD, pain also contributed to physical activity. A model with the actometer as measurement for actual physical activity instead of self-report showed an excellent model fit in FSHD and HMSN but an insufficient fit in MD.

CONCLUSION

The model of perpetuating factors for fatigue in FSHD and HMSN is different from the model in MD. The main difference is in physical (in)activity. These differences have implications for interventions based on these models.

Physical therapist management following rotator cuff repair for a patient with postpolio syndrome

BACKGROUND AND PURPOSE

Postpoliomyelitis sequelae, such as gait instability and progressive weakness, predispose people with postpolio syndrome to secondary disabilities. With aging, people who depend on their upper extremities to accommodate lower-extremity deficits may anticipate overuse injuries. The purpose of this case report is to describe the use of mobilization and exercise in postoperative rehabilitation of rotator cuff surgery on a patient with postpolio syndrome.

CASE DESCRIPTION

A 48-year-old woman with postpolio syndrome had rotator cuff surgical repair followed by physical therapy intervention. Maitland mobilization and mild functional exercises were chosen to avoid triggering fatigue.

OUTCOMES

Measurements taken preoperatively, before and after physical therapy intervention, and 2 years after intervention showed return to independent status with excellent retention.

DISCUSSION

No fatigue or overuse weakness was encountered. This is the first case report to document physical therapy following rotator cuff repair in a patient with postpolio syndrome.

Postpolio syndrome: a challenge to the health-care system

The practical eradication of poliomyelitis in industrialized countries marks one of the most important achievements of world health policy. Yet, disability induced by polio not only continues to exist among survivors with paralytic sequelae, but may also be further accentuated in a considerable number of affected subjects by the development of postpolio syndrome (PPS). PPS aggravates the motor sequelae already present in such subjects and reduces their functional capacity to the point where it affects their activities of daily living and worsens their quality of life. Inasmuch as development of PPS questions the concept of poliomyelitis as a static disease it poses a challenge not only to health professionals but also to policy-makers tasked with providing the necessary health-care measures and appropriate resources. This study sought to review research on this syndrome and to draw up some recommendations that might prove useful to the health authorities for decision-making purposes.

[Postpolio syndrome. Neurologic and psychiatric aspects]

Postpolio syndrome is defined as a clinical syndrome of new pareses in individuals who had been affected by acute paralytic poliomyelitis years before. The objective of this study was to describe neurologic and psychiatric signs of the disease. We evaluated the clinical signs and treatment of 16 patients with postpolio syndrome. Possible symptoms of depression were evaluated by the Hamilton and Geriatric Depression Scales. Postpolio syndrome manifested at a median age of 57.5 years (range 25-73) in a median of 41 years (range 16-70 years) after acute poliomyelitis. Muscles already affected during acute poliomyelitis were affected in all patients with postpolio syndrome. Six of 16 patients (37.5%) developed paresis in muscles formerly not affected by acute poliomyelitis. In eight of 15 patients (53%), depressive episodes were recognized according to the ICD-10 criteria. Symptoms of depression should be recognized in patients with postpolio syndrome and incorporated in therapy based on physiotherapy.

Changes in macro electromyography over time in patients with a history of polio: a comparison of 2 muscles

OBJECTIVE

To investigate whether changes over time are different in a weight-bearing leg muscle than in a less heavily used arm muscle.

DESIGN

Prospective study.

SETTING

University hospital laboratory.

PARTICIPANTS

Twenty-three patients with a history of poliomyelitis.

INTERVENTION

Two investigations were performed 5 years apart, using macro electromyography and the patients' own assessments of symptoms in the tibial anterior and the biceps brachii muscles. Test-retest of macro electromyography was performed in controls and in patients with old polio.

MAIN OUTCOME MEASURES

Macro motor unit potential (MUP) and symptoms in the tibial anterior and biceps brachii over time.

RESULTS

The macro MUP amplitude increased by 24% (P<.05) in the tibial anterior but was unchanged in the biceps brachii muscle.

CONCLUSIONS

An increase in the macro MUP amplitude of the tibial anterior muscle, but not of the biceps brachii, most likely indicates a more pronounced ongoing denervation-reinnervation process over time in the tibial anterior. This difference could be activity dependent, but other factors cannot be excluded.

Le syndrome post-poliomyélitique

Postpoliomyelitis syndrome is a clinical syndrome characterized by late progression of symptoms, neuromuscular weakness, fatigue and pain, several (more than 20) Years after acute anterior poliomyelitis. In the United States, where it has been mainly described, frequency is estimated between 20 and 30p.100 in patients with sequelae of poliomyelitis. Although the cause is still unknown, postpoliomyelitis syndrome is likely due to degeneration and dysfunction of terminal axons of enlarged post-polio units, with a possible role of inflammatory reaction driven by persistence of the polio virus. Due to lack of specific therapy, rational therapeutic approaches are symptomatic, including exercise, reassurance and life-strategies for fatigue.