Publications
Investigation of passive tone and viscoelasticity in neck muscles in pre-symptomatic neck flexion abnormality in Parkinson’s disease: Observational study
Authors: Theeraya Upachit 1, 2, Sitha Piyaselakul 1, Prachaya Srivanitchapoom 3, Jarugool Tretriluxana 2
Affiliations:
- Department of Anatomy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Motor and Neural plasticity Laboratory, Faculty of Physical Therapy, Mahidol University, Nakhon Pathom, Thailand
- Division of Neurology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Journal: Journal of Bodywork and Movement Therapies - January 2025, In Press, Journal Pre-proof (DOI: 10.1016/j.jbmt.2025.01.012)
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Field & Applications:
- Medical
- Neurology
- Neurodegenerative disorder
- Musculoskeletal disorder
- Balance / Postural control
Background: Forward neck flexion (FNF) is a common postural abnormality in Parkinson’s disease (PD), which disturbs the overall body alignment and can lead to more severe deformities through both central nervous system control and biomechanical compensation. The purpose of the current study was to investigate the biomechanical and viscoelastic properties of forward neck muscles related to FNF in individuals with PD, both with and without FNF, in comparison to age-matched individuals with normal posture.
Methods: Hand-held myotonometry (MyotonPRO®) was conducted to determine the biomechanical and viscoelastic properties of the sternocleidomastoid and anterior scalene muscles of all thirty participants: individuals with PD and FNF (n=10), individuals with PD without FNF (n=10), and normal controls (n=10).
Result: Individuals with PD, both with and without FNF, exhibited higher passive tone and muscle stiffness and lower elasticity, relaxation time, and creep in both muscles, particularly in the sternocleidomastoid, compared to age-matched normal controls. No significant differences in any muscle variables were found between the two PD groups.
Conclusion: These findings indicate that the biomechanical and viscoelastic properties of neck muscles are altered even in the presymptomatic stage of postural abnormalities in PD. This may provide potential evidence of underlying peripheral factors that involve postural deformities via proprioceptive disturbances and exacerbate rigidity in PD.
Keywords: biomechanical properties, viscoelasticity, Parkinson’s disease, postural abnormalities, myotonometry
This study highlights the biomechanical and viscoelastic changes in shortened neck muscles in individuals with PD. These findings suggest that myofascial alterations may contribute to axial rigidity, even during the presymptomatic stage.
Clinical Relevance:
- Biomechanical properties could serve as potential objective markers for detecting muscle rigidity in the presymptomatic stage of Parkinson’s disease, offering a means for early disease progression tracking and evaluating treatment effectiveness.
- This study revealed early peripheral structural changes associated with presymptomatic disease. Interventions targeting the underlying passive mechanisms of rigidity could potentially slow disease progression, improve outcomes, and enhance the quality of life.