The assessment and importance of disease activity versus disease damage in patients with inflammatory myopathy

[Neurophysiological substantiation and validity assessment of manual muscle testing in clinical practice. (A literature review)]

The relevance of the study of neuromuscular dysfunction's causes and mechanisms is undeniable, considering the large number of nosologies accompanied by malfunction of muscles. Adequate diagnosis and correction of these disorders is impossible without understanding of their pathogenetic mechanisms. Currently, manual muscle testing (MMT) is a widespread technique. MMT is an agile diagnostic tool used by physiatrists, doctors in sports medicine, osteopaths and rehabilitation physicians to assess the functional status of muscles. Unconditionally, this method attracts with its low cost, which will optimize the financial costs of hospital and the healthcare system as a whole. In addition, there is no clear substantiation of the objectivity and validity of the MMT to date. The article considers the issues of neurophysiological principles, classification of methods and approaches, assessment criteria of repeatability and accuracy of MMT. Understanding of the pathophysiological mechanisms of MMT effectiveness will allow to timely correct the therapy and improve the results of treatment and rehabilitation of patients with neuromuscular dysfunction.

Unlocking the secrets: the power of methylation-based cfDNA detection of tissue damage in organ systems

BACKGROUND

Detecting organ and tissue damage is essential for early diagnosis, treatment decisions, and monitoring disease progression. Methylation-based assays offer a promising approach, as DNA methylation patterns can change in response to tissue damage. These assays have potential applications in early detection, monitoring disease progression, evaluating treatment efficacy, and assessing organ viability for transplantation. cfDNA released into the bloodstream upon tissue or organ injury can serve as a biomarker for damage. The epigenetic state of cfDNA, including DNA methylation patterns, can provide insights into the extent of tissue and organ damage.

CONTENT

Firstly, this review highlights DNA methylation as an extensively studied epigenetic modification that plays a pivotal role in processes such as cell growth, differentiation, and disease development. It then presents a variety of highly precise 5-mC methylation detection techniques that serve as powerful tools for gaining profound insights into epigenetic alterations linked with tissue damage. Subsequently, the review delves into the mechanisms underlying DNA methylation changes in organ and tissue damage, encompassing inflammation, oxidative stress, and DNA damage repair mechanisms. Next, it addresses the current research status of cfDNA methylation in the detection of specific organ tissues and organ damage. Finally, it provides an overview of the multiple steps involved in identifying specific methylation markers associated with tissue and organ damage for clinical trials. This review will explore the mechanisms and current state of research on cfDNA methylation-based assay detecting organ and tissue damage, the underlying mechanisms, and potential applications in clinical practice.

Patient insights on living with idiopathic inflammatory myopathy and the limitations of disease activity measurement methods - a qualitative study

Background

The idiopathic inflammatory myopathies (IIMs) are chronic autoimmune conditions, typically resulting in proximal muscle weakness and impacting upon quality of life. Accurate measurement of IIM disease activity is imperative for appropriate medical management and carrying out valid clinical trials. The International Myositis Assessment and Clinical Studies Group (IMACS) “Disease Activity Core Set Measures” are the current gold-standard of IIM disease activity assessment. Anecdotally, patients with an IIM report that the IMACS Core Set Measures and other available methods do not necessarily capture their perceived disease activity. Investigating the patient experiences of living with an IIM and their views on the accuracy of the IMACS Core Set Measures will provide valuable insights for both clinical and research purposes.

Methods

Eighteen interviews with patients with an IIM were carried out and analysed thematically, using a grounded theory approach. Experiences on living with an IIM and perceptions on the accuracy of disease activity measurement methods were explored.

Results

Interview analysis revealed four themes: 1) fatigue, 2) pain, 3) day-to-day symptom variation, 4) limitations of creatine kinase levels and manual muscle testing.

Conclusions

This study has provided valuable insights into patient experiences of living with an IIM. Aspects of IIM disease activity perceived not to be wholly measured by the IMACS Core Set Measures have also been identified. These findings have implications for future IIM clinical care and research, in particular providing justification for research into pain, fatigue and symptom variation.

Possible predictive formulas for quantitative and time-based estimation of muscle strength during motion

[Purpose] To examine the validity of the predictive formulas based on the angle information of the segment center of mass and moments of inertia, and to propose a joint moment estimation method. [Participants and Methods] Twenty nine young healthy adults were divided into two groups: the Creation group (20 adults) was needed to create the prediction formulas, and the Verification group (9 adults) was needed to verify the formulas. By monitoring the Creation group, the angular information from inertial motion sensors and moments of inertia of each limb were used to estimate actual ankle joint moment and knee joint moment. Thereafter, the actual joint moments was derived from the Verification group and compared to the predicted values via Pearson correlations. [Results] Good to excellent correlations were obtained between the actual joint moments of the two groups for most of the motions. [Conclusion] It is suggested that the predictive formulas created from the angle information of the segment center of mass and moments of inertia can be used for an approximate estimation of the lower limb joint moments in the sagittal plane and more clinically useful tools need to be considered in the future.

Manual muscle testing and hand-held dynamometry in people with inflammatory myopathy: An intra- and interrater reliability and validity study

Manual muscle testing (MMT) and hand-held dynamometry (HHD) are commonly used in people with inflammatory myopathy (IM), but their clinimetric properties have not yet been sufficiently studied. To evaluate the reliability and validity of MMT and HHD, maximum isometric strength was measured in eight muscle groups across three measurement events. To evaluate reliability of HHD, intra-class correlation coefficients (ICC), the standard error of measurements (SEM) and smallest detectable changes (SDC) were calculated. To measure reliability of MMT linear Cohen`s Kappa was computed for single muscle groups and ICC for total score. Additionally, correlations between MMT8 and HHD were evaluated with Spearman Correlation Coefficients. Fifty people with myositis (56±14 years, 76% female) were included in the study. Intra-and interrater reliability of HHD yielded excellent ICCs (0.75–0.97) for all muscle groups, except for interrater reliability of ankle extension (0.61). The corresponding SEMs% ranged from 8 to 28% and the SDCs% from 23 to 65%. MMT8 total score revealed excellent intra-and interrater reliability (ICC>0.9). Intrarater reliability of single muscle groups was substantial for shoulder and hip abduction, elbow and neck flexion, and hip extension (0.64–0.69); moderate for wrist (0.53) and knee extension (0.49) and fair for ankle extension (0.35). Interrater reliability was moderate for neck flexion (0.54) and hip abduction (0.44); fair for shoulder abduction, elbow flexion, wrist and ankle extension (0.20–0.33); and slight for knee extension (0.08). Correlations between the two tests were low for wrist, knee, ankle, and hip extension; moderate for elbow flexion, neck flexion and hip abduction; and good for shoulder abduction. In conclusion, the MMT8 total score is a reliable assessment to consider general muscle weakness in people with myositis but not for single muscle groups. In contrast, our results confirm that HHD can be recommended to evaluate strength of single muscle groups.

Functional and isokinetic assessment of muscle strength in patients with idiopathic inflammatory myopathies

OBJECTIVE

To assess muscle strength in patients with idiopathic inflammatory myopathies (IIM) using neuromuscular scales and isokinetic testing.

METHODS

Muscle function was evaluated in 27 IIM patients being followed at the Rheumatology Unit of the University of Pisa using: (i) a modified version of the grading system used to assess Duchenne dystrophy, (ii) the four-stage grading system of Henriksson and Sandstedt, (iii) an isokinetic muscle strength test (Kin Com, Chatanooga) and (iv) the Health Assessment Questionnaire (HAQ).

RESULTS

The neuromuscular scales showed normal or only mildly impaired muscle strength in 60% (Duchenne scale) and 80% (Henriksson and Sandstedt scale) of the patients, respectively, whereas isokinetic testing detected moderate to severe reductions in muscle strength in almost 70% of the patients. No correlations were observed between muscle strength and disease activity, therapy, age at evaluation and disease duration. There was a correlation between the results of the HAQ and neuromuscular testing, but not the isokinetic test.

CONCLUSIONS

Although less easy and more expensive to administer, isokinetic testing appears to be a more sensitive instrument than the standard neuromuscular tests for assessing muscle function in IIM patients. In particular, it can detect small reductions in muscle strength.