Moderne neurophysiologische Methoden in der Neuropathiediagnostik

Zusammenfassung

Elektrophysiologische Untersuchungen wie die Messung der Nervenleitgeschwindigkeit und die quantitative EMG-Analyse sind etablierte Verfahren im neurophysiologischen Labor. Sie dienen dem Erkrankungsnachweis der peripheren Nerven. Pathophysiologische Veränderungen am Nerven selbst, die zu einer Funktionsstörung führen können, werden jedoch nicht erfasst. Häufig sind auch die gemessenen neurophysiologsichen Parameter nicht sensitiv genug, eine Störung im frühen Erkrankungsstadium nachzuweisen oder beim Vorliegen von Positivsymptomen wie Parästhesien oder Faszikulationen. Die Motor Unit Number Estimation (MUNE) ist eine neurophysiologische Untersuchungstechnik, die eine Schätzung der Anzahl motorischer Einheiten und somit der funktionierenden Axone, welche einen bestimmten Muskel versorgen und der Größe individueller motorischer Einheiten ermöglicht. „Latent addition“ ist ein Parameter der veränderten Erregbarkeit an der Membran eines ruhenden Nerven. Diese modernen elektrophysiologischen Techniken weisen auch bei geringer klinischer Symptomatik Veränderungnen auf. Darüber hinaus vermitteln sie dem Untersucher Informationen über Degenerationsprozesse und Reinnervation bei peripheren Neuropathien unabhängig voneinander.

Abstract

Electrophysiological methods for the measurement of nerve conduction velocity and the quantitative analysis of the electromyogram are well established in the neurophysiological laboratory. These methods are helpful for identifying functional nerve disorders, however there are several limitations: 1) Pathophysiological changes within the nerve itself, which may lead to an abnormal function, cannot be detected. 2) The measured neurophysiological parameters are often not sensitive enough to detect disorder either in an early stage of disease or when patients suffer from positive symptoms like paresthesia or fasciculation's. Motor unit number estimation (MUNE) is a neurophysiological technique that provides information on the number and the size of individual motor units of a muscle and the number of axons innervating a muscle. Latent addition is one measure of membrane excitability changes of the resting nerve. These newer electrophysiological methods are sensitive at an early stage of disease and enable the examiner to separate axonal degeneration from collateral rerouting in peripheral nerve disorder.

Schlüsselwörter

Periphere Neuropathie - Motor Unit Number Estimation - Latent addition - Excitabilität

Key words

Peripheral neuropathies - motor unit number estimation - latent addition - excitability

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