Effects of Dry Needling on Spinal Reflexes: The Hoffman-reflex

Abstract

<h3>Research Objectives</h3> Spasticity can lead to changes in spinal and supraspinal pathways which can lead to decreased function and quality of life in persons with stroke. Physical therapists worldwide have been administering trigger point deep dry needling (DDN) to treat post-stroke spasticity. Yet, currently, effects of DDN on spinal somatosensory processing are not well understood. To understand the neurophysiological mechanisms of DDN, we are currently investigating the effects of DDN on spinal somatosensory pathways in persons with and without stroke. <h3>Design</h3> Before, 0 minutes, 90 minutes, and 72 hours after DDN of the medial gastrocnemius (MG) the H-reflex and M-wave recruitment curves are measured in the soleus, MG and lateral gastrocnemius (LG). Passive ankle range of motion (ROM) before and after DDN. <h3>Setting</h3> University. <h3>Participants</h3> 11 adults 22-57 years old (median 37.5) without known neurological conditions. <h3>Interventions</h3> Trigger point dry needling to medial gastrocnemius. <h3>Main Outcome Measures</h3> H-Reflex and ROM. <h3>Results</h3> MG H-reflex latency was prolonged by 1-3 ms at 0- and 90-minutes post (in 9/11 individuals) and in 5/11 in the soleus and 3/11 in the LG. In the MG, H-reflex amplitude was significantly decreased at 72 hours post (p=0.004 by paired t-test) by 12%. Dorsiflexion ROM was increased by »4 deg at 0 minutes and 72 hours post. <h3>Conclusions</h3> DDN produces acute short-term effects (shown in the H-reflex latency shift at 0- and 90-minutes post) and significant long-term effects (shown in the reduced H-reflex at 72 hours post) in spinal pathways of the treated MG. To understand whether DDN affects the intact CNS and stroke-impaired CNS similarly or differently, studies of individuals after stroke are currently underway. <h3>Author(s) Disclosures</h3> The authors have no conflicts of interest to declare.