Electrophysiological study of neuromuscular system involvement in mitochondrial cytopathy.

Objectives: To define the neuromuscular involvement in 'mitochondrial' patients with clinical evidence of a neuromuscular disorder, and to evaluate if the proposed electrophysiological protocol was suitable to reveal a subclinical neuropathy or myopathy in 'mitochondrial' patients with no clinical sign of a neuromuscular disturbance.

Methods: Quantitative concentric needle electromyography (CNEMG), single fiber electromyography (SFEMG) and nerve conduction studies (NCS) were performed in 33 patients with mitochondrial cytopathies. Lastly, we studied 9 clinically unaffected relatives.

Extra-muscle involvement in dystrophinopathies: an electroretinography and evoked potential study.

Dystrophin is present in various tissues other than skeletal and cardiac muscles, including the central nervous system (CNS) and the outer plexiform layer of the retina. Therefore lack of dystrophin might be related to mental retardation or to changes in electrophysiological tests exploring retina and CNS. We performed electroretinography, VEPs, BAEPs, SEPs and MEPs in 18 patients with Duchenne muscular dystrophy (DMD), 18 with Becker muscular dystrophy (BMD) and 12 obligate carriers.