The spread of muscle fiber conduction velocity: increasing scope and usability

Researcher: Fiete Lange, MD, PhD

Other supervisor: Han van der Hoeven, MD, PhD

Thesis defense: 2009

The determination of muscle fiber conduction velocity (MFCV) is used in the evaluation of neuromuscular disorders. When MFCV is determined invasively (using direct fiber stimulation) the conduction velocity of muscle fibers can be measured while controlling the firing rate and stimulation intensity. The diagnostic power of invasive (needle) EMG measurements
of MFCV has already been proven in patients with traumatic nerve injury, amyotrophic lateral sclerosis and polymyositis. It is known that the conduction velocity of muscle fibers correlates linearly with the fiber diameter i.e., the conduction velocity is higher in thicker fibers. The spread of conduction velocities can therefore be used to detect changes in fiber diameter, such as in muscle hyper- or atrophy. We here investigate whether the invasive determination of MFCV and its spread can also be employed to show abnormalities in muscle function due to minor axonal damage such as in slight polyneuropathies. Additionally, the diagnostic power of
MFCV determined by noninvasive (surface) EMG measurements has already been proven for specific disorders of membranes. Furthermore, surface EMG measurements of MFCV have been shown to be very useful in fatigue studies. However, when using surf c e EMG is it difficult to extract MFCV spread from the signal. We here designed and investigated an analysis technique to estimate MFCV spread from the surface EMG signal.