Evidence indicates attention can alter afferent inhibition, a Transcranial Magnetic Stimulation (TMS) evoked measure of cortical inhibition following somatosensory input. This measure is emerging as a valuable tool for clinical assessment of sensorimotor function. However, the reliability of the measure remains relatively low. Further, attention is capable of modifying the magnitude of afferent inhibition. Therefore, for afferent inhibition to become an assessment with translation within and beyond the research lab, the reliability of the measure must be improved. Controlling the focus of attention may be one method to improve the reliability of afferent inhibition. In the present study, two experiments were conducted. One to assess the biological effects of attention on SAI and LAI, and the other to address whether the reliability of SAI and LAI are altered in the presence of varying attentional demands. The magnitude of short- and long-latency afferent inhibition (SAI and LAI, respectively) was assessed under four conditions with varying attentional demands focused on the somatosensory input that mediates SAI and LAI circuits. Further, the reliability of SAI and LAI was assessed with and without directed attention to the relevant somatosensory input to explore whether attention to the tactile stimulation can improve intrasession and intersession reliability of these measures. Thirty individuals participated in four conditions; three conditions were identical in their physical parameters and varied only in the focus of directed attention (visual attend, tactile attend, non- directed attend) and one condition consisted of no external physical parameters (no stimulation). Reliability was measured by repeating conditions at three time points to assess intrasession and intersession reliability. Results indicate the magnitude of SAI and LAI were not modulated by varied attention. Reliability assessments demonstrated that the attention manipulations increased intrasession and intersession reliability of SAI and LAI compared to the no stimulation condition. This research exposes the influence of attention, and its impact on the reliability of afferent inhibition. By quantifying these influences, this research has identified new information to inform the design of TMS research in sensorimotor integration. / Thesis / Master of Science in Kinesiology / Attention can alter transcranial magnetic stimulation (TMS) evoked afferent inhibition. Measures of afferent inhibition are emerging as valuable tools for clinical assessments of sensorimotor function. However, the reliability of afferent inhibition remains relatively low, limiting its value in the clinic. Afferent inhibition is increased when the one’s attention is focused on the peripheral nerve stimulation used to elicit afferent inhibition. However, it is unknown whether afferent inhibition, with attention directed to somatosensory input, will improve the reliability of these measures. This is important as it suggests that changes to the methodology used to acquire afferent inhibition can improve the reliability of this measure, thereby increasing the opportunity for translation to the clinic. The goal of this study was to assess the influence of attention on afferent inhibition circuits, short afferent inhibition (SAI) and long afferent inhibition (LAI) and determine whether attention modulation would increase the reliability of afferent inhibition.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/27921 |
| Date | January 2022 |
| Creators | Ramdeo, Karishma |
| Contributors | Nelson, Aimee, Kinesiology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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