Diagnostic accuracy of common clinical tests for assessing abdominal muscle function after motor-complete spinal cord injury above T6

• Published in: Spinal cord 2015-02, Vol.53 (2), p.114-119
• Main Authors: Bjerkefors, A, Squair, J W, Malik, R, Lam, T, Chen, Z, Carpenter, M G
• Format: Article
• Language: English
• Subjects: 692/1807; 692/1807/2781; Abdominal Muscles - diagnostic imaging; Abdominal Muscles - physiopathology; Adult; Anatomy; Biomedical and Life Sciences; Biomedicine; Chronic Disease; Electromyography - methods; Female; Human Physiology; Humans; Isometric Contraction - physiology; Male; Medicin och hälsovetenskap; Medicin/Teknik; Medicine/Technology; Motor Activity - physiology; Neurochemistry; Neuropsychology; Neurosciences; Organ Size; original-article; Physical Examination - methods; Sensitivity and Specificity; Spinal Cord Injuries - diagnosis; Spinal Cord Injuries - diagnostic imaging; Spinal Cord Injuries - physiopathology; Ultrasonography
• ISSN: 1362-4393; 1476-5624; 1476-5624
• DOI: 10.1038/sc.2014.202

Study design: Diagnostic study. Objectives: The objective of this study was to compare patterns of electromyography (EMG) recordings of abdominal muscle function in persons with motor-complete spinal cord injury (SCI) above T6 and in able-bodied controls, and to determine whether manual examination or ultrasound measures of muscle activation can be accurate alternatives to EMG. Setting: Research center focused on SCI and University laboratory, Vancouver, Canada. Methods: Thirteen people with SCI (11 with American Spinal Injury Association Impairment Scale (AIS) A and 2 AIS B; C4-T5), and 13 matched able-bodied participants volunteered for the study. Participants completed trunk tasks during manual examination of the abdominal muscles and then performed maximal voluntary isometric contractions, while EMG activity and muscle thickness changes were recorded. The frequency of muscle responses detected by manual examination and ultrasound were compared with detection by EMG (sensitivity and specificity). Results: All individuals with SCI were able to elicit EMG activity above resting levels in at least one abdominal muscle during one task. In general, the activation pattern was task specific, confirming voluntary control of the muscles. Ultrasound, when compared with EMG, showed low sensitivity but was highly specific in its ability to detect preserved abdominal muscle function in persons with SCI. Conversely, manual examination was more sensitive than ultrasound but showed lower specificity. Conclusion: The results from this study confirm preserved voluntary abdominal muscle function in individuals classified with motor-complete SCI above T6 and highlight the need for further research in developing more accurate clinical measures to diagnose the level of trunk muscle preservation in individuals with SCI.