Loading...
Early identification, understanding, and measurement of the upper motor neuron (UMN) component of amyotrophic lateral sclerosis (ALS) are problematic. Only in the last decade have physicians attempted to use surrogate markers to detect UMN dysfunction in ALS. Techniques have included transcranial magnetic stimulation, magnetic resonance imaging in a variety of formats, and magnetic resonance spectroscopy. These researchers studied UMN function with transcranial direct-current stimulation (tDCS), which penetrates the skull and enters the brain.
The current is sufficient to modify neuronal transmembrane potentials, thereby influencing the levels of excitability and modulating the firing rates of individual neurons. When tDCS is applied for a s…