Short latency afferent inhibition: comparison between threshold-tracking and conventional amplitude recording methods

CENGİZ B., BORAN H. E., ALAYDIN H. C., Tankisi H., Samusyte G., Howells J., ...More

Experimental Brain Research, vol.240, pp.1241-1247, 2022 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 240
  • Publication Date: 2022
  • Doi Number: 10.1007/s00221-022-06327-5
  • Journal Name: Experimental Brain Research
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, BIOSIS, CAB Abstracts, EMBASE, MEDLINE, Psycinfo, Veterinary Science Database
  • Page Numbers: pp.1241-1247
  • Keywords: Short latency afferent inhibition, Amplitude measurement, Threshold-tracking, Variability, TRANSCRANIAL MAGNETIC STIMULATION, INTERVAL INTRACORTICAL INHIBITION, MOTOR CORTEX, PLASTICITY
  • Gazi University Affiliated: Yes


© 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Short-latency afferent inhibition (SAI), which is conventionally measured as a reduction in motor evoked potential amplitude (A-SAI), is of clinical interest as a potential biomarker for cognitive impairment. Since threshold-tracking has some advantages for clinical studies of short-interval cortical inhibition, we have compared A-SAI with a threshold-tracking alternative method (T-SAI). In the T-SAI method, inhibition was calculated by tracking the required TMS intensity for the targeted MEP amplitude (200 uV) both for the test (TMS only) and paired (TMS and peripheral stimulation) stimuli. A-SAI and T-SAI were recorded from 31 healthy subjects using ten stimuli at each of 12 inter-stimulus intervals, once in the morning and again in the afternoon. There were no differences between morning and afternoon recordings. When A-SAI was normalized by log conversion it was closely related to T-SAI. Between subjects, variability was similar for the two techniques, but within-subject variability was significantly smaller for normalized A-SAI. Conventional amplitude measurements appear more sensitive for detecting changes within-subjects, such as in interventional studies, but threshold-tracking may be as sensitive as detecting abnormal SAI in a patient.