Long-interval afferent inhibition measurement using two different methods: Normative values, repeatability and reliability


BORAN H. E., Alaydın H. C., KILINÇ H. E., Tankişi H., Samusyte G., Howells J., ...More

Neurophysiologie Clinique, vol.54, no.1, 2024 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 54 Issue: 1
  • Publication Date: 2024
  • Doi Number: 10.1016/j.neucli.2023.102940
  • Journal Name: Neurophysiologie Clinique
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, BIOSIS, MEDLINE
  • Gazi University Affiliated: Yes

Abstract

Background: The mechanism of Short-Latency Afferent Inhibition (SAI) is relatively well understood. In contrast, Long-Latency Afferent Inhibition (LAI) has not been as extensively studied as SAI, and its underlying mechanism remains unclear. Objective/Hypothesis: This study had two primary objectives: first, to determine the optimal ISIs for LAI measured by amplitude changes (A-LAI) using high-resolution ISI ranges; and second, to compare measurements of LAI by threshold-tracking (T-LAI). Methods: Twenty-eight healthy volunteers (12 males aged 24- 45 years) participated in the study. Paired peripheral electrical and transcranial magnetic stimulation (TMS) stimuli (TS1mv) were applied at varying (ISIs)- 100, 200, 250, 300, 350, 400, 450, 500, 550, 600, 700, 800, 900, 1000 ms. Results: Both A-LAI and T-LAI showed that LAI decreased progressively from a peak at 200 or 250 ms to 1000 ms. Using the A-LAI method, pronounced inhibition was observed at three specific ISIs: 100 ms, 250 ms and 450 ms. When A-LAI values were converted to equivalent threshold changes, they did not differ significantly from T-LAI. Reliability at distinguishing individuals, as indicated by intraclass correlation coefficient (ICC) was greater for A-LAI, with a peak value of 0.82 at 250 ms. Conclusion(s): The study demonstrates that ISIs of 100 ms and 250 ms can be reliably used in amplitude measurement LAI. The study demonstrates that both LAI measurements record a similar decline of inhibition with increasing ISI.