An Application of the Multivariate Linear Mixed Model to the Analysis of Shoulder Complexity in Breast Cancer Patients

Abstract

In this study, four major muscles acting on the scapula were investigated in patients who had been treated in the last six years for unilateral carcinoma of the breast. Muscle activity was assessed by electromyography during abduction and adduction of the affected and unaffected arms. The main principal aim of the study was to compare shoulder muscle activity in the affected and unaffected shoulder during elevation of the arm. A multivariate linear mixed model was introduced and applied to address the principal aims. The result of fitting this model to the data shows a huge improvement as compared to the alternatives.

Changes in shoulder muscle activity pattern on surface electromyography after breast cancer surgery

“…Even with normal pain‐free motion of the arm and shoulder, in the scapulothoracic, glenohumeral, acromioclavicular, and sternoclavicular joints, patients may encounter another issue, namely muscle lower muscle electrical activity. Some studies suggest that humeral elevation of the arm, upward movement on the affected side, and left shoulder movement will increase the electrical activity of all four muscles regardless of which side is affected, while treatment with wide local excision and chemotherapy is associated with generally decreased electrical activities . In our study, implant‐based and TRAM flap reconstruction did not affect shoulder muscle strength.…”

“…Forthomme et al found decreased muscle strength after an LD flap in a comparison of the isokinetic test results for different shoulder muscles. Oskrochi et al investigated shoulder muscle activities by SEMG to analyze shoulder complexity in breast cancer patients. In our study, shoulder complexity after breast cancer was assessed by both SEMG and measurement of the ROM.…”

“…The contributions made by various muscles to shoulder motion have been studied using various approaches, including assessment of muscle activation by electromyography (EMG) during arm motion . However, shoulder muscle activation in breast cancer patients depends on both clinical and patient variables, such as the use of chemotherapy, type of breast surgery, time since surgery, and current physiotherapy, exercise, and pain statuses . To date, shoulder morbidity has been described according to knowledge of how muscle activation and force production contribute to shoulder kinematics in patients with breast cancer.…”

“…In one study, fear of lymphedema and disuse of the affected arm contributed significantly to a difference in muscle strength between the affected and unaffected shoulders of patients . Pain serves to increase muscle activation and is likely to limit movement . Along with the key clinical variables of age, affected side, dominant hand, degree of arm elevation, treatment protocol, time since surgery, chemotherapy status, and degree of shoulder pain, the extent of pectoralis tightness should also be considered.…”

Blended learning with Moodle in medical statistics: an assessment of knowledge, attitudes and practices relating to e-learning

“…We fitted the mixed linear model [ 24 , 25 ] using the SAS PROC MIXED procedure to analyse the impact factors of KAP. The variables of interest included educational reform, gender, the number of communities that the student joined during the undergraduate experience (hereinafter, community number), self-perceived character, registered permanent residence, parents’ literacy, Internet age, and hours spent online per day.…”