The following is a summary of “Reduction in short interval intracortical inhibition from the early stage reflects the pathophysiology in amyotrophic lateral sclerosis: A meta-analysis study,” published in the March 2024 issue of Neurology by Higashihara et al.
Transcranial magnetic stimulation (TMS) is being explored to identify the best biomarkers of cortical hyperexcitability in amyotrophic lateral sclerosis (ALS), a disease marked by this abnormality.
Researchers started a retrospective analysis of existing data and identified the most sensitive TMS markers of cortical hyperexcitability in ALS.
They conducted a systematic literature review, searching PubMed, MEDLINE, Embase, and Scopus (January 1, 2006, to February 28, 2023) for all relevant English-language studies. The inclusion criteria comprised studies reporting the usefulness of threshold tracking TMS (serial ascending method) in ALS and control groups.
The results showed 25 studies, more than 2500 participants, including 1530 ALS patients and 1102 controls (healthy, 907; neuromuscular, 195), underwent assessment with threshold tracking TMS. A significant reduction in mean short-interval intracortical inhibition (interstimulus interval 1–7 ms) displayed the highest standardized mean difference with moderate heterogeneity (-0.994, 95% CI -1.12 to -0.873, P<0.001; Q = 38.61, P<0.05; I 2 = 40%). A decrease in cortical silent period duration and higher motor-evoked potential amplitude and intracortical facilitation also demonstrated significant but smaller standardized mean differences.
Investigators concluded that reduced mean short-interval intracortical inhibition was ALS’s most sensitive indicator of cortical hyperexcitability.
Source: onlinelibrary.wiley.com/doi/full/10.1111/ene.16281
