decremental response
Progressive reduction in muscle response amplitude during repetitive nerve stimulation, indicating neuromuscular junction dysfunction.
Full Definition
A decremental response refers to the progressive decline in compound muscle action potential amplitude observed during repetitive nerve stimulation testing. This finding is characteristic of disorders affecting the neuromuscular junction, particularly myasthenia gravis and Lambert-Eaton myasthenic syndrome. The response typically shows a reduction of 10% or more from the first to the fourth or fifth stimulus when stimulating at low frequencies (2-3 Hz), reflecting impaired neurotransmitter release or receptor function at the neuromuscular junction.
Usage
Usage note: Typically expressed as percentage decline from initial response amplitude.
In Context
- "Repetitive stimulation of the ulnar nerve demonstrated a 15% decremental response, consistent with myasthenia gravis." — EMG report
- "The decremental response improved significantly after edrophonium administration." — Neuromuscular disorder evaluation