Background & Aims

Lateral epicondylalgia, commonly known as tennis elbow, is a musculoskeletal condition characterised by pain, sensorimotor function and cortical reorganisation (1). In some individuals with unilateral chronic LE, sensorimotor dysfunction develops at the unaffected side despite no evidence of injury (2). Altered interhemispheric inhibition (IHI) is one mechanism that may underpin bilateral sensorimotor dysfunction in chronic LE (3, 4). Therefore, this study aimed to examine IHI between primary motor cortices (M1) in individuals with chronic LE and compare the findings with healthy controls.

Methods

Twenty individuals with chronic LE and 20 age and sex matched healthy controls participated. Transcranial magnetic stimulation was used to assess short and long-latency IHI from the affected M1 (corresponding to the injured side) to the unaffected M1 at conditioning stimulus intensities of 120%, 130%, 140% and 150% of resting motor threshold. To assess sensorimotor function, pressure pain thresholds and grip strength were examined bilaterally at the extensor carpi radialis brevis muscle.

Results

The magnitude of short- and long-latency IHI did not differ between individuals with LE and healthy controls (short IHI: p all > 0.15; long IHI: all p > 0.07). No differences in sensorimotor function were observed bilaterally for pressure pain thresholds or grip strength.

Conclusions

IHI is not altered in individuals with chronic LE and thus, IHI may not mediate the development of bilateral sensorimotor dysfunction. Future investigations are required to confirm this finding and determine the mechanism that underpins development of bilateral sensorimotor dysfunction in chronic unilateral LE.

References

1. Shiri R, Viikari-Juntura E, Varonen H, Heliovaara M. Prevalence and determinants of lateral and medial epicondylitis: a population study. Am J Epidemiol. 2006;164(11):1065-74.
2. Bisset LM, Russell T, Bradley S, Ha B, Vicenzino BT. Bilateral Sensorimotor Abnormalities in Unilateral Lateral Epicondylalgia. Archives of Physical Medicine and Rehabilitation. 2006;87(4):490-5.
3. Alhassani G, Liston MB, Schabrun SM. Interhemispheric Inhibition Is Reduced in Response to Acute
Muscle Pain: A Cross-Sectional Study Using Transcranial Magnetic Stimulation. J Pain. 2019;20(9):1091-9.
4. Schabrun SM, Christensen SW, Mrachacz-Kersting N, Graven-Nielsen T. Motor Cortex Reorganization and Impaired Function in the Transition to Sustained Muscle Pain. Cereb Cortex. 2016;26(5):1878-90.

Presenting Author

Ghufran Alhassani

Poster Authors

Ghufran Alhassani

PhD

Western Sydney University

Lead Author

Peter Clothier

PhD

Western Sydney University

Lead Author

Matthew Liston

PhD

Chartered Society of Physiotherapy, London, UK

Lead Author

Siobhan Schabrun

University of Western Ontario

Lead Author

Topics

  • Models: Musculoskeletal