Spinal cord gray matter atrophy is associated with functional decline in post-polio syndrome.

OBJECTIVE: To determine if patients with post-polio syndrome (PPS) show spinal cord gray matter (SCGM) atrophy and to assess associations between SCGM atrophy, muscle strength and patient-reported functional decline. METHODS: Twenty patients diagnosed with PPS (March of Dimes criteria) and 20 age- and sex-matched healthy controls (HC) underwent 3T axial 2D-rAMIRA magnetic resonance imaging at the intervertebral disc levels C2/C3-C6/C7, T9/T10 and the lumbar enlargement level (Tmax ) (0.5 × 0.5 mm2 in-plane resolution). SCGM areas were segmented manually by two independent raters. Muscle strength, self-reported fatigue, depression and pain measures were assessed. RESULTS: Post-polio syndrome patients showed significantly and preferentially reduced SCGM areas at C2/C3 (p = 0.048), C3/C4 (p = 0.001), C4/C5 (p < 0.001), C5/C6 (p = 0.004) and Tmax (p = 0.041) compared to HC. SCGM areas were significantly associated with muscle strength in corresponding myotomes even after adjustment for fatigue, pain and depression. SCGM areaTmax together with age and sex explained 68% of ankle dorsiflexion strength variance. No associations were found with age at or time since infection. Patients reporting PPS-related decline in arm function showed significant cervical SCGM atrophy compared to stable patients adjusted for initial disease severity. CONCLUSIONS: Patients with PPS show significant SCGM atrophy that correlates with muscle strength and is associated with PPS-related functional decline. Our findings suggest a secondary neurodegenerative process underlying SCGM atrophy in PPS that is not explained by aging or residua of the initial infection alone. Confirmation by longitudinal studies is needed. The described imaging methodology is promising for developing novel imaging surrogates for SCGM diseases.

Extra-motor manifestations in post-polio syndrome (PPS): fatigue, cognitive symptoms and radiological features.

BACKGROUND: There is a paucity of cerebral neuroimaging studies in post-polio syndrome (PPS), despite the severity of neurological and neuropsychological sequelae associated with the condition. Fatigue, poor concentration, limited exercise tolerance, paraesthesia and progressive weakness are frequently reported, but the radiological underpinnings of these symptoms are poorly characterised. OBJECTIVE: The aim of this study is to evaluate cortical and subcortical alterations in a cohort of adult polio survivors to explore the anatomical substrate of extra-motor manifestations. METHODS: Thirty-six patients with post-polio syndrome, a disease-control group with amyotrophic lateral sclerosis patients and a cohort of healthy individuals were included in a prospective neuroimaging study with a standardised clinical and radiological protocol. Validated clinical instruments were utilised to assess mood, cognitive and behavioural domains and specific aspects of fatigue. Cortical thickness analyses, subcortical volumetry, brainstem segmentation and region-of-interest (ROI) white matter analyses were undertaken to assess regional grey and white matter alterations. RESULTS: A high proportion of PPS patients exhibited apathy, verbal fluency deficits and reported self-perceived fatigue. On ROI analyses, cortical atrophy was limited to the cingulate gyrus, and the temporal pole and subcortical atrophy were only detected in the left nucleus accumbens. No FA reductions were noted to indicate white matter degeneration in any of the lobes. CONCLUSIONS: Despite the high incidence of extra-motor manifestations in PPS, only limited cortical, subcortical and white matter degeneration was identified. Our findings suggest that non-structural causes, such as polypharmacy and poor sleep, may contribute to the complex symptomatology of post-polio syndrome.

Estimation of accuracy of patient-specific musculoskeletal modelling: case study on a post polio residual paralysis subject.

For patients with patterns ranging out of anthropometric standard values, patient-specific musculoskeletal modelling becomes crucial for clinical diagnosis and follow-up. However, patient-specific modelling using imaging techniques and motion capture systems is mainly subject to experimental errors. The aim of this study was to quantify these experimental errors when performing a patient-specific musculoskeletal model. CT scan data were used to personalise the geometrical model and its inertial properties for a post polio residual paralysis subject. After having performed a gait-based experimental protocol, kinematics data were measured using a VICON motion capture system with six infrared cameras. The musculoskeletal model was computed using a direct/inverse algorithm (LifeMod software). A first source of errors was identified in the segmentation procedure in relation to the calculation of personalised inertial parameters. The second source of errors was subject related, as it depended on the reproducibility of performing the same type of gait. The impact of kinematics, kinetics and muscle forces resulting from the musculoskeletal modelling was quantified using relative errors and the absolute root mean square error. Concerning the segmentation procedure, we found that the kinematics results were not sensitive to the errors (relative error<1%). However, a strong influence was noted on the kinetics results (deviation up to 71%). Furthermore, the reproducibility error showed a significant influence (relative mean error varying from 5 to 30%). The present paper demonstrates that in patient-specific musculoskeletal modelling variations due to experimental errors derived from imaging techniques and motion capture need to be both identified and quantified. Therefore, the paper can be used as a guideline.

Baseline patterns of bone scintigraphy in patients with established post-poliomyelitis paralysis.

INTRODUCTION: Post-poliomyelitis syndrome causes variable musculoskeletal manifestations including pain, muscle weakness and fatigue. These manifestations are commonly secondary to overuse and misuse of muscles and joints and could follow a fall. Bone scan can be useful in determining the underlying cause and follow-up. The objective of this study was to describe the late scintigraphic patterns on bone scan following poliomyelitis. MATERIALS AND METHODS: Bone scans of 8 adult patients (7 female and 1 male), aged 35 to 53 years, who were known to have paralytic poliomyelitis, were retrospectively studied. Six patients had unilateral while 1 had bilateral disease. All patients had three-phase bone scan and 5 had SPECT study as well. Studies were reviewed by two qualified nuclear medicine physicians and findings were recorded and analyzed. RESULTS: Several patterns were consistently identified: decreased blood pool activity in the affected lower limb of all patients; deformed ipsilateral hemi-pelvis with reduced uptake on the affected side in all patients with unilateral disease; stress changes with increased uptake in the bones of the contra-lateral lower extremity; and degenerative changes in multiple joints (shoulder, knee, hip, ankle and spine). Significant scoliosis was only noted in the patient with bilateral disease. CONCLUSION: Scintigraphic patterns on bone scan associated with the post-poliomyelitis syndrome and persistent weakness following a distant episode of poliomyelitis have been described. Awareness of these characteristic scintigraphic findings may facilitate an accurate diagnosis and lead to more appropriate patient management.

Computed tomographic study of the skeletal musculature of the lower body in 45 postpolio patients.

Muscle computed tomography (CT) and muscle strength assessment of the pelvic girdle and leg muscles were performed in 32 postpolio patients experiencing new muscle weakness, and in 13 postpolio patients with stable neuromuscular condition. Muscles of the postpolio patients experiencing new muscle weakness showed significantly more CT scan abnormalities as compared with the stable postpolio patients. No other features discriminative of symptomatic postpolio patients were found. In individual patients, muscle CT scan evaluation is a useful adjunct to muscle strength assessment.

Reticuloendothelial "activation" noted after splenectomy for ITP and presence of a post-poliomyelitis asymmetry.

A radiocolloid study was carried out, after splenectomy, in a 75-year-old man who had idiopathic thrombocytopenic purpura. The patient, who did not have an increase in platelet counts after spleen removal or after platelet infusions, showed radiocolloid accumulation in the lungs and in the bone marrow. This suggested some "activation" of reticuloendothelial cells, perhaps by circulating immune complexes. The left femur (site of an episode of poliomyelitis many years previously) had less radiocolloid uptake than the right.

Dysphagia in postpolio patients: a videofluorographic follow-up study.

In patients with a history of acute paralytic poliomyelitis (APP), late progressive muscle weakness may arise, known as the progressive postpoliomyelitis muscular atrophy (PPMA). In 43 patients with PPMA, 8 were evaluated for recent or late progressive dysphagia. The mean interval between APP and onset of swallow symptoms was 27.1 years (range 23-45); the mean age of the patients was 45.4 years (range 35-52). Initial videofluorography showed signs of slight-to-moderate oropharyngeal dysfunction in 6 patients (delayed swallow reflex, diminished peristalsis of constrictor pharyngeus muscle, diminished laryngeal elevation, retention of bolus). In 2 patients, no abnormalities were found. Seven patients were reexamined after 12-36 months (mean 18). All reported subjective progression of symptoms. Videofluorography showed minor changes in 1 patient and unaltered findings in 6. No signs of aspiration were found either clinically or by video. We conclude that patients with PPMA complaining of late dysphagia do not show a significant loss in oropharyngeal function on 1-3 years follow-up.

Fibular shortening in poliomyelitis.

This study arose from observation that in children will leg shortening from paralysis, the relationship between the tibia and fibula is disturbed. This article analyses 76 patients of post polio residual paralysis involving only one lower limb. Sixteen patients had fibular shortening. Several factors that interfere with fibular growth, i.e. anatomical continuity, soleus strength, abnormal forces at distal fibular physis, result in fibular shortening. Early the age at onset of paralysis, more is the fibular shortening which is associated with lateral wedging of distal tibial epiphysis, valgus at ankle, external torsion of tibia and genu valgus.