Surface Electromyographic Activity of Shoulder Muscles among People with Type 2 Diabetes- A Case-control Study

Abstract

Introduction: Increased prevalence of shoulder dysfunction among people with diabetes is a recognised source of disability resulting in functional impairments. Metabolic perturbations in diabetes result in glycosylation and microvascular abnormalities in shoulder muscles altering muscle mechanics and activation pattern. Aim: The present study was aimed to evaluate surface electromyographic activity of shoulder muscles among people with diabetes with and without shoulder dysfunction with an objective of suggesting clinical recommendations to maximise shoulder function. Materials and Methods: The present observational, casecontrol study was conducted over two years from March 2015 to May 2017 at Physiotherapy Department, Sancheti Hospital, Pune, Maharashtra, India. Following Institutional Ethical Committee Approval, surface-Electromyography (EMG) was recorded in 45 patients with diabetes and shoulder dysfunction, 45 patients with diabetes without shoulder dysfunction; within the age group of 40-60 years and 45 healthy aged matched controls. Muscle activity was recorded from pectoralis major, supraspinatus, infraspinatus, upper trapezius, biceps and middle deltoid muscles during Maximal Voluntary Isometric Contraction (MVIC) and various functional tasks after normalisation. Shoulder Pain and Disability Index (SPADI) was used to assess shoulder function and compared among the groups using post-hoc tests. Results: Significant linear decline in muscle activity of pectoralis major (p0.001), upper trapezius (p>0.001), biceps (p0.05). Posthoc comparison revealed higher score of SPADI in people with shoulder dysfunction compared to healthy controls (p<0.05). Conclusion: Shoulder muscles demonstrated linear decline in muscle activity from healthy people to patients with diabetes without shoulder dysfunction to people with shoulder dysfunction with maximum affection of pectoralis major muscle. Reduced shoulder muscle activity was reflected in approximately 59% higher SPADI score; suggesting moderate shoulder disability. Hence, it is recommended to commence appropriate prophylactic shoulder muscle strengthening exercise program from the onset of diabetes to maximise shoulder function among people with diabetes.

Keywords

• diabetes mellitus
• isometric contraction
• shoulder dysfunction