Standing Balance Conditions and Digital Sway Measures for Clinical Trials of Friedreich's Ataxia

BACKGROUND

Progressive loss of standing balance is a feature of Friedreich's ataxia (FRDA).

OBJECTIVES

This study aimed to identify standing balance conditions and digital postural sway measures that best discriminate between FRDA and healthy controls (HC). We assessed test-retest reliability and correlations between sway measures and clinical scores.

METHODS

Twenty-eight subjects with FRDA and 20 HC completed six standing conditions: feet apart, feet together, and feet tandem, both with eyes opened (EO) and eyes closed. Sway was measured using a wearable sensor on the lumbar spine for 30 seconds. Test completion rate, test-retest reliability with intraclass correlation coefficients, and areas under the receiver operating characteristic curves (AUCs) for each measure were compared to identify distinguishable FRDA sway characteristics from HC. Pearson correlations were used to evaluate the relationships between discriminative measures and clinical scores.

RESULTS

Three of the six standing conditions had completion rates over 70%. Of these three conditions, natural stance and feet together with EO showed the greatest completion rates. All six of the sway measures' mean values were significantly different between FRDA and HC. Four of these six measures discriminated between groups with >0.9 AUC in all three conditions. The Friedreich Ataxia Rating Scale Upright Stability and Total scores correlated with sway measures with P-values <0.05 and r-values (0.63-0.86) and (0.65-0.81), respectively.

CONCLUSION

Digital postural sway measures using wearable sensors are discriminative and reliable for assessing standing balance in individuals with FRDA. Natural stance and feet together stance with EO conditions suggest use in clinical trials for FRDA. © 2024 International Parkinson and Movement Disorder Society.

Early-Life Social Determinants of SCA6 Age at Onset, Severity, and Progression

SCA6 patients with the same size CAG repeat allele can vary significantly in age at onset (AAO) and clinical progression. The specific external factors affecting SCA6 have yet to be investigated. We assessed the effect of early life events on AAO, severity, and progression in SCA6 patients using a social determinant of health approach. We performed a survey of biological and social factors in SCA6 patients enrolled in the SCA6 Network at the University of Chicago. AAO of ataxia symptoms and patient-reported outcome measure (PROM) of ataxia were used as primary outcome measures. Least absolute shrinkage and selection operation (LASSO) regressions were used to identify which early life factors are predictive of SCA6 AAO, severity, and progression. Multiple linear regression models were then used to assess the degree to which these determinants influence SCA6 health outcomes. A total of 105 participants with genetically confirmed SCA6 completed the assessments. SCA6 participants with maternal difficulty during pregnancy, active participation in school sports, and/or longer CAG repeats were determined to have earlier AAO. We found a 13.44-year earlier AAO for those with maternal difficulty in pregnancy than those without (p = 0.008) and a 12.31-year earlier AAO for those active in school sports than those who were not (p < 0.001). Higher education attainment was associated with decreased SCA6 severity and slower progression. Early life biological and social factors can have a strong influence on the SCA6 disease course, indicating that non-genetic factors can contribute significantly to SCA6 health outcomes.

Acute febrile juvenile rheumatoid arthritis in adults: cause of polyarthritis and fever

Acute febrile juvenile rheumatoid arthritis (JRA) of adult onset is often diagnosed by ruling out other problems. The classification of JRA is primarily based on the distinct type of onset, of which there are usually three: (1) acute febrile or Still's type, (2) polyarticular, and (3) monoarticular pauciarticular arthritis. Fever of unknown cause is frequently the initial symptom. This type of arthritis may be characterized by any or all of the following: unexplained high fever, rash, weight loss, lymphadenopathy, splenomegaly, pericarditis, pleurisy, pneumonitis, abdominal pain, myalgias, arthralgias, arthritis, sore throat, leukocytosis, anemia, circulating immune complexes, liver test abnormalities, and carpal-metacarpal and tarsal-metatarsal fusion. Patients often respond dramatically to anti-inflammatory agents. Corticosteroids, gold salts, penicillamine, and cytotoxic drugs have been effective for certain patients. The prognosis of the disease has been generally favorable. Although symptoms may recur, remission can be prolonged.

Vasculitis associated with intestinal bypass surgery

We report two cases in which necrotizing vasculitis with tenosynovitis arthralgia/arthritis syndrome developed after intestinal bypass surgery. Each of these patients had jejunoileostomies, and the excluded segment was placed in an ileal-colonic anastomosis. We speculate that since the attachment of the excluded segment to the large intestine predisposes it to increased bowel overgrowth of bacteria, these bacteria or their debris may have served as antigens for circulating immune complexes, which were detected in both patients by one or more techniques. Patients who have had an end-to-side anastomosis may be less predisposed to the more severe vasculitis syndrome because there is less likelihood of bacterial overgrowth in the bypassed intestinal segment.

Mumps class-specific immunoglobulins in radioimmunoassay and conventional serology

Antibodies against mumps virus have been studied by using immunoglobulin class-specific indicators labeled with (125)I in the radioimmunoassay (RIA) procedure. The immunoglobulins in paired acute and convalescent sera were allowed to react with mumps virus in a solid-phase RIA system. Class-specific immunoglobulin indicators (anti-immunoglobulin M [IgM] and anti-immunoglobulin G [IgG]) labeled with (125)I revealed that immunoglobulins of early antisera were preponderantly IgM, whereas immunoglobulins of late antisera were predominantly IgG. These indicators detected antibodies of the early (IgM) and late (IgG) phases of the immune response. These findings are consistent with the classical temporal order of appearance of 19s (IgM) and 7s (IgG) globulins. Specificity of these indicators for reacting with fractionated 7s and 19s globulins is also presented. Mumps virus RIA obtained with anti-IgG correlated well with conventional serological data obtained by neutralization and hemagglutination inhibition, but most strongly with complement-fixation data. In addition, antibody bound by solid phase was capable of distinguishing between related antigens of the myxovirus group.

Mumps class-specific immunoglobulins in radioimmunoassay and conventional serology

In assessing the host cell range of bovine parvoviruses, these viruses were found to replicate optimally in actively dividing bovine fetal lung and spleen cells. Other primary bovine fetal cells supported growth to a lesser extent, but bovine line cells and line cells of other animal species tested did not. Minimal infectivity remained after passage of bovine parvovirus in cells from chicken embryos and guinea pig fetuses. During bovine parvovirus replication in bovine fetal lung and spleen cells, production kinetics of infectious virus and hemagglutinins were determined. An eclipse period of 16 h occurred, and viral release from cells was not detected until 30 h after inoculation of bovine fetal lung cells and 36 h after inoculation of bovine fetal spleen cells. Cell-associated virus titers were always higher than extracellular virus titers. Hemagglutinins were detected in parallel to infectious virus.

Simultaneous administration of smallpox, measles, yellow fever, and diphtheria-pertussis-tetanus antigens to Nigerian children

Children receiving smallpox, measles, and yellow fever vaccines simultaneously at separate sites responded adequately to all three vaccines. In those children, 9 months of age and older, who received these three vaccines in addition to diphtheria-pertussis-tetanus vaccine, there was a decrease in measles seroconversion rates from 89% to 70%. Possible interactions between live and killed vaccines should be considered when the administration of multiple antigens is planned.

Evaluation of serological techniques for titration of rubella antibody

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Comparative study of fowl plague virus and a virus isolated from man

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