Respiratory Compensation in Advanced Duchenne Muscular Dystrophy

Background: “Row-a-boat” phenomenon (RBP) is a spontaneous upper-body movement in patients with advanced Duchenne muscular dystrophy (DMD), when sitting upright supported by a belt around the body in a wheelchair. However, the role of RBP has not been clarified. Objectives: To support the hypothesis that RBP is an abnormal pattern of respiration to compensate for the atrophied respiratory muscles in advanced DMD. Patients and methods: Age, degree of ventilator dependency, and blood gas and spirometry values of 12 patients with spontaneous RBP were compared to those of 8 patients without RBP. All patients were men, and all exhibited a comparable level of motor function (unable to ambulate). Spirometry was undertaken with an ambulatory pneumotachograph in six patients with RBP in two conditions: sitting with RBP and sitting without RBP. In the latter condition, because a patient’s shoulders, neck, and head were manually restricted, RBP was prevented. Results: We found that the patients with RBP were older (mean, 25.98 years vs 19.84 years), more dependent on mechanical ventilation (13.96 h/d vs 4.31 h/d), and had lower FVC and percentage of FVC (511.3 mL vs 762.5 mL and 13.37% vs 20.11%, respectively) than those without RBP. We also found that the frequency of RBP was identical with tidal breathing, and FVC was increased by 50.8% by simply allowing RBP. Conclusion: We conclude that RBP is a respiratory movement to compensate for the atrophied respiratory muscles in advanced DMD. (CHEST 2001; 119:1836 ‐1839)