Macro-EMG in mitochondriopathy.

Objectives: In a previous macro-EMG study on patients with mitochondriopathy, macro-MUAP amplitude has been shown to be the electromyographic parameter most often abnormal. We wanted to investigate the role of the macro-MUAP area and if macro-EMG is more helpful than conventional needle-EMG in detecting involvement of the skeletal muscle in patients with mitochondriopathy.

Methods: From the right brachial biceps muscles of 38 healthy subjects and 20 patients with primary mitochondriopathy, aged 23-72 y, conventional needle EMGs and macro-EMGs were recorded one after the other.

Results: Macro-MUAP amplitude and macro-MUAP area were not significantly different between patients and controls. The sensitivity of the macro-EMG was 35%, that of conventional needle EMG 40%. Both methods supplemented each other.

Conclusions: The sensitivity of the macro-EMG to detect involvement of the skeletal muscle in patients with mitochondriopathy is similar to that of conventional needle EMG. Macro-MUAP area was not more helpful than macro-MUAP amplitude in this respect.