Cortical hyperexcitability and disease spread in amyotrophic lateral sclerosis

Abstract

Cortical hyperexcitability appears to be more prominent over the dominant motor cortex, contralateral to the side of symptom onset, and contributes to a contiguous pattern of spread in sporadic ALS.

A new parameter to discriminate amyotrophic lateral sclerosis patients from healthy participants by motor cortical excitability changes

“…Short‐interval intracortical inhibition was the most effective cortical excitability parameter for the detection of the abnormality in patients with ALS. In agreement with previous studies, we detected a significantly reduced SICI in the patients with ALS compared with healthy controls . In agreement with previous studies, two peaks in SICI, at ISIs of 1 ms and 2.5 to 3 ms, were detected.…”

“…The most consistent finding with this paradigm in patients with ALS is the reduction in short‐interval intracortical inhibition (SICI) . Although intracortical facilitation (ICF) is not as persistent as the SICI abnormality, increased ICF in patients with ALS has also been reported . Employing the automatic threshold tracking method in the assessment of cortical excitability abnormalities and in distinguishing mimicking central or peripheral nervous system disorders from ALS proved to be useful more than 10 years ago .…”

“…The paired‐pulse TMS paradigm permits exploration of cortical connections in a more detailed manner . The most consistent finding with this paradigm in patients with ALS is the reduction in short‐interval intracortical inhibition (SICI) . Although intracortical facilitation (ICF) is not as persistent as the SICI abnormality, increased ICF in patients with ALS has also been reported .…”

Impaired short‐ and long‐latency afferent inhibition in amyotrophic lateral sclerosis

“…Cortical connections can be explored in the most detailed manner by paired‐pulse TMS paradigms . The most consistent finding with regard to these paradigms in ALS patients is a reduction in short‐interval intracortical inhibition . On the other hand, single pulse techniques such as the central motor conduction time (CMCT), the conduction time from the motor cortex to the spinal cord, is a measure of integrity of the corticospinal pathways.…”

Role Of spinal mechanisms in the pathophysiology of the split hand sign in amyotrophic lateral sclerosis

“…Specifically, corticomotoneuronal hyperexcitability was proposed as a mechanism underlying neuronal degeneration in ALS by means of a trans‐synaptic anterograde excitotoxic process, the dying forward hypothesis . Importantly, cortical hyperexcitability has been reported to be an early feature in sporadic ALS, linked to peripheral neurodegeneration and patterns of disease spread . Furthermore, cortical hyperexcitability was shown to precede the onset of lower motor neuron dysfunction in familial ALS secondary to mutations in the superoxide dismuate‐1 gene and in some sporadic ALS cohorts .…”