The effect of Lumbosacral manipulation on Gastrocnemius MEP’s using transcranial magnetic stimulation

1. The effect of Lumbosacral manipulation on GastrocnemiusMEP’s using transcranial magnetic stimulation Students: Claire Richardson (B.Sci.) Shaun Richardson (B.Sci.) Kymberley Sayers (B.Sci), Melanie Taylor (B.Sci), Nicholas Wittenberg (B.Sci)

2. Introduction • Previous studies have suggested a transient facilitation of the motor-neuron pool as a result of spinal manipulation (Dishman et al; 2002) • We will be investigating the relationship of HVLA applied to the Lumbo-Sacral joint and motor evoked potentials of the gastrocnemius muscle.

3. Previous studies have investigated the effects of HVLA using TMS in the paraspinal muscles and the gastrocnemuis muscles, finding that HVLA has a transient increase in central motor excitability. (Dishman et al, 2008) Background

4. Background • Dishman et al;2000, found through using the H-reflex as a measurement that HVLA applied to the Lumbosacral junction there appeared to be a decrease in the excitability of the motorneuron pool. • H-reflex not specific to post-synaptic pathways therefore was easily influenced by extraneous factors.

5. Background • Dishman et al;2002, completed a study investigating cortical excitability using Transcranial magnetic stimulation and measuring the resultant Motor Evoked Potentials within the gastrocnemius, both before and after HVLA. • Results showed a transient increase in motorneuronal facillitation lasting up to 120 seconds following manipulation.

6. HVLA theories • Biomechanical influence: • Biomechanical changes caused by the manipulation are thought to have physiological consequences by means of their effects on the inflow of sensory information to the central nervous system. • By releasing trapped meniscoids, discal material or segmental adhesions, the mechanical input may ultimately reduce noiciceptive input from receptive nerve endings in innervated paraspinal tissues. (Pickar et al, 2002)

7. Background • “Physiologically, spinal manipulation therapy is purported to relieve pain through modulation of noiciceptive input through a barrage of afferent input to the central nervous system resulting in pain reduction and improved perceived function.” (Learman et al., 2009).

8. Background • Gate control theory.

9. Background C + - PROJECTION NEURON - INHIBITORY INTERNEURON + + Aα/β

10. Background • In the early 1980’s, transcranial electrical stimulation was used (TES) to cause non-invasive stimulation of MEPs. This method was further refined in 1985 by Barker et al., with the introduction of transcranial magnetic stimulation (TMS). Although peripheral muscles and nerves were first investigated with TMS, studies nowadays often focus on stimulation of the cortex. TMS has been found to be a very effective method to generate MEPs. As stated by Dishman (2008) “…TMS allows for the recording of MEPs from virtually any muscle.”

11. Background • Transcranial magnetic stimulation • Electric current running through coil resulting in a magnetic field. • Placed over M1 portion supplying gastrocnemius muscle. • Causes resultant depolarisation – Motor evoked potential descends to muscle.

12. Background

13. This study aims to investigate the effect of HVLA techniques upon the motorneuronal excitability of the gastrocneumius muscle, using transcranial magnetic stimulation. Our study will build upon previous research as completed by Dishman et al. Aim

14. Methodology • Participants- • 21 Participants for this study will be drawn from the student population at Victoria University • Inclusion criteria- • Healthy participants • 18-50 years old • Either gender • Without current low back pain • Exclusion criteria- • Participants currently suffering from lower back pain. • Participants with radiculopathy or peripheral neuropathy (excluded via a neurological screening examination). • Contraindications to HVLA

15. Methodology cont. • Experimental design- • Controlled cross-over design where participants will be undergo both the control and experimental intervention, tested one week apart. The order of the treatment intervention will be randomised. • Interventions: • Control- • A right sided L5-S1 side-posture HVLA manipulation will be administered • Experimental- • The operator will assist the participant into a side posture; however no truncal torque will be applied and no manual contact will be made with the spine

16. Participants will be seated and a snugly fitting cap, with premarked sites at 1 cm spacing. Sites near the estimated motor centre of the gastrocnemius muscle (2 - 4 cm anterior to the interaural line) will be first explored to determine the site at which the largest motor-evoked potential (MEP) can be obtained. Transcranial magnetic stimulation (TMS) will be delivered The coordinates on the cap will be recorded and this site will be used for further measurements. Procedure

17. Procedure cont. 10 MEP's (spaced 4 - 5 s apart) will be recorded Participants will then relocate to a treatment table and an intervention will be randomly allocated and performed. MEP's will be measured at 20 s intervals  within the first 120 s to determine the immediate effects of the intervention on the motorneuron pool excitability. MEP's will also recorded at 5 and 10 minutes after manipulation. Participants will return for a second session one week later and will receive the same procedures with the alternative intervention.

18. Procedure

19. Procedure

20. Procedure

21. Ethics • Ethics document will be submitted to the Victorian University Human Research Ethics Committee. • All participants in our study will be voluntarily participating and are free to withdraw at any stage. All personal information gathered from the patient will remain confidential and will only be viewed by researchers conducting the study. • Possible ethical issues that could arise from our study are: • Adverse effects to HVLA (local pain and discomfort, headache, tiredness or fatigue, radiating pain or discomfort, parasthesia, dizziness, nausea, stiffness, hot skin or fainting) • Distress associated with manual therapy such as being undressed in from of researchers and having their hands placed on them whilst they perform the HVLA • Psychological impact of the TMS procedure • Side-effects from TMS • Method of recruitment- whether it is coercive, and whether the patients will benefit from being in the study

22. Ethics cont. • Ways we can minimize potential risks are: • Neurological screening of patients before participation in the study, to rule out possible contraindications to HVLA • Gowns, private dressing areas and towels to drape patients will be provided. • Patients will be given a consent form to sign • Patients will have the right to withdraw from the study at any time • A qualified and experienced practitioner will be performing the HVLA and a practitioner with a doctorate in TMS will be administering and using the equipment • A qualified first aid practitioner will be present • A qualified Osteopathic practitioner able to assess and manage adverse reactions to HVLA will be present • A qualified psychologist will be available for counselling after the study

23. Timetable

24. No budget will be needed for this project. Budget

25. Dishman JD, Bulbulian R. Transient suppression of alpha motoneuron excitability following lumbosacral spinal manipulation. Spine 2000;25:2519-25 Dishman JD, Ball KA, Burke J. Central motor excitability changes after spinal manipulation: a transcranial magnetic stimulation study. J Manipul Physiol Therap 2002;25:1–10 Dishman JD, Greco DS, Burke J. Motor evoked potentials recorded from lumbar erector spinal muscles; a study of corticospinal excitability changes associated with spinal manipulation. J Manipul Physiol Ther 2008;31:258-27 Learman KE, Myers JB, Lephart SM, Sell TC, Kerns GC, Cook CE. Effects of spinal manipulation on trunk proprioception in subjects with chronic low back pain during symptom remission J Manipulative Physiol Ther. 2009 Feb;32(2):118-26. Pickar JG, Neurophysiological effects of spinal manipulation. The Spine Journal 2002;2:357–371. Melzack R, Wall PD. Pain mechanisms: a new theory. Science 1965;150:971–9 References