Update – Neurophysiologische Methoden zur Bestimmung der Anzahl motorischer Einheiten in menschlichen Muskeln

Zusammenfassung

Die Anzahl funktionstüchtiger motorischer Einheiten stellt nach wie vor das ideale Maß zur Verlaufsbeurteilung bei Erkrankungen mit Verlust motorischer Einheiten dar. Die absolute Zahl motorischer Einheiten (ZME) sowie deren Verlauf über die Zeit erlauben neben der Beschreibung des Krankheitsverlaufes Aussagen über Regenerationsmechanismen wie Reinnervation durch kollaterale Aussprossung oder Reinnervation durch Axonwachstum. Eine exakte Bestimmung der Zahl motorischer Einheiten ist leider auch heute nicht möglich, eine Schätzung funktionstüchtiger motorischer Einheiten hingegen mit elektrophysiologischen Methoden durchführbar. Der apparative und zeitliche Aufwand älterer Methoden zur Schätzung der Anzahl motorischer Einheiten ist außerordentlich hoch und bedarf spezieller Untersucher-Erfahrung. Die 2004 erstbeschriebene Methode MUNIX hingegen ist einfach durchführbar und deutlich weniger zeitaufwendig. MUNIX eignet sich hervorragend zur Verlaufsbeurteilung der ZME bei bekanntem Verlust motorischer Einheiten. Neue Untersuchungen hingegen zeigen, dass MUNIX als diagnostische Methode per se ungeeignet ist.

Abstract

The motor unit number is still the ideal measure for describing disease progression in diseases with loss of motor units. The absolute number of motor units as well as their course over time allow not only the description of disease-progression but also give information about regeneration mechanisms – on the one hand, reinnervation by collateral sprouting, and on the other hand, reinnervation by axon growth. An exact determination of the number of motor units is unfortunately not yet possible, but an estimation of functional motor units can be carried out with electrophysiological methods. Older methods for motor unit number estimation (MUNE) are extremely time consuming and often involve high outlay costs for equipment and investigator experience. The MUNIX method, first described in 2004, is easy to implement and far less time-consuming. MUNIX is very well suited for describing motor unit number loss if motor unit loss is known. However, recent investigations show that MUNIX cannot be used as a diagnostic method per se.

Schlüsselwörter

motorische Einheit - Anzahl motorischer Einheiten - motorische Neurografie - Elektromyografie

Key words

motor unit - motor unit number - motor unit number estimation - MUNE - electroneurography - electromyography

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