Differences in nerve excitability properties across upper limb sensory and motor axons.
Clin Neurophysiol
; 136: 138-149, 2022 04.
Article
em En
| MEDLINE
| ID: mdl-35217348
ABSTRACT
OBJECTIVE:
The excitability of motor and sensory axons of the main upper limb nerves were compared to characterise the differences between nerves and provide a guide for future studies in human diseases with median neuropathy at the wrist.METHODS:
Axonal excitability studies were undertaken on median and ulnar motor (APB and ADM) and sensory axons (D2 and D5) and the superficial radial axons (D1) using a threshold tracking technique.RESULTS:
Compared to the median, ulnar motor axons had reduced early depolarising threshold electrotonus (TEd40(10-20 ms) p = 0.02) and superexcitability (p = 0.03). The ulnar sensory axons required a stronger stimulus (p = 0.02) and had a larger rheobase (p = 0.02) than median axons, but were otherwise comparable. The superficial radial axons were "fanned-in" compared to median, and to a lesser degree ulnar axons, with greater resting I/V slope. Mathematical modelling of the radial and median sensory axons suggested that a 15.1% reduction in conductances between nodal and internodal compartments accounted for 82% of this discrepancy.CONCLUSIONS:
The excitability parameters of motor and sensory axons are most comparable between median and ulnar nerves.SIGNIFICANCE:
The present study demonstrates the feasibility of, and provides normative data for, axonal excitability recordings of the radial and ulnar nerves. We suggest the use of ulnar recordings as an alternative to the median nerve in the setting of compressive neuropathy at the wrist.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Axônios
/
Nervo Mediano
Limite:
Humans
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article