Electrodiagnostic strategies in motor neuron diseases including ALS

Abstract

Electrophysiological evaluations, including nerve conduction studies and needle electromyography (EMG), remain the most critical tools for the diagnosis of motor neuron diseases (MND). This article provides an overview of our current diagnostic strategies focusing on ALS and related MNDs. The recently proposed Gold Coast criteria for ALS allow diagnosis even in cases lacking upper motor neuron signs. Detection and distribution assessment of denervation potentials—such as fibrillation potentials and fasciculation potentials—on EMG, alongside consistency with clinical progression, still form the core of a conclusive diagnosis. Diagnostic workflows incorporate multimodal approaches, including nerve conduction studies (preservation of sensory nerve potentials), repetitive nerve stimulation tests (decremental responses), and ultrasonography (fasciculation survey and lack of nerve enlargement). Tailored, patient-specific test protocols integrating these modalities improve diagnostic accuracy in ALS.