A Single Centre Cross Sectional Study Investigating the Accuracy of Transcranial Magnetic Stimulation in the Diagnosis of Degenerative Cervical Myelopathy (TMS for DCM)

I have not written an abstract yet but I have taken the following rationale from my research proposal.

Surgical decompression is recommended for moderate and severe DCM according to current clinical guidelines (Fehlings, Kwon and Tetreault, 2017) and may be able to halt the advancement of the condition and offer some degree of functional improvement (Fehlings et al., 2017a), but it is often difficult to categorise the severity as DCM lacks a singular tell-tale sign or symptom (Cook et al., 2010). To complicate matters further, a significant percentage of the population over 50 years are thought to have asymptomatic cord compression. Kovalova et al. (2016) found incidental cervical cord compression in 59% of individuals and Nouri et al. (2022) reported that cord compression may occur in up to a quarter of the healthy population and is significantly more common in people over 60 years old (35%). It has been reported that conventional MRI changes for DCM are not typically detected until it has reached an advanced stage (Martin et al., 2021) yet it remains the most important factor in decision making about treatment plans. Wilson et al. (2013) reported through survey results that imaging evidence of spinal cord structural change as demonstrated by signal abnormality on MRI was more important to some respondents than early clinical evidence of myelopathy in predicting clinical progression over time. More detailed MRI modalities looking at the micro and macro structure of MRI are emerging, for example; diffusion-weighted imaging (DTI) (Khan et al., 2023), however most hospitals won’t have access to these advanced techniques prompting the necessity for additional aids in diagnosing this condition.

Motor evoked potentials (MEPs) are a well-established inexpensive and non-invasive diagnostic tool for measuring motor function of the spinal cord, in particular the corticospinal tracts (Vázquez-Sánchez et al., 2023). However, when reviewing the available literature, studies done on the use of evoked potentials in DCM are difficult to compare; DCM is heterogenous, the methods of recording evoked potentials vary greatly and there is also huge variation in how it is diagnosed and how severity is graded. Despite this, the consensus from the studies is that MEPs, in particular CMCT abnormalities show high sensitivity for diagnosing DCM and as severity of disease increases, evoked potential abnormalities increase, leaving scope for more studies on disease monitoring and perhaps a severity scale.

There is also promising evidence about the usefulness of EPs revealing subclinical or asymptomatic abnormalities in in the presence of other overlapping conditions that commonly present with age which could help diagnose a potentially progressive spinal cord pathology early enough to monitor and treat before the symptoms are not reversible.

The literature reviewed for this study concluded that more prospective studies of the diagnostic strength of MEPs are needed with potential to incorporate a severity scale to help assess the patients who are difficult to diagnose but are at a potential risk of progressing to a point where their spinal cord is irreversibly damaged.

The aim of this research is to investigate whether transcranial magnetic stimulation (TMS) can diagnose degenerative cervical myelopathy (DCM) accurately and whether it can be used as an adjunct to support surgical decision making in patients who are difficult to diagnose. This design has the potential to refine diagnostic criteria for DCM, especially in ambiguous cases, and to expand the role of TMS as a non-invasive neurophysiological tool in spinal disorders.

Outputs

I have presented my research at the Southern Electrodiagnostic Society in Nashville in October 2024.