Somatosensory cortical plasticity in carpal tunnel syndrome—a cross-sectional fMRI evaluation
Section snippets
Methods
This cross-sectional study was completed in conjunction with a pilot clinical trial of acupuncture for the treatment of CTS, though the data used in this study were taken before any treatment had occurred. All participants in the study provided written informed consent in accordance with the Human Research Committee of the Massachusetts General Hospital.
Neurophysiological results
In our cohort of patients, paresthesias were more dominant than pain in 7/10 patients, as derived from self-report in the BCTSQ. The remaining 3/10 patients had pain/paresthesia ratios between 1.0 and 1.1 (i.e., close to an equal amount of pain and paresthesias). In sum, CTS patients reported a pain/paresthesia ratio of 0.74 ± 0.08 (μ ± SEM). In our cohort of CTS patients, the average median nerve sensory latency for D2 and D3 was 3.48 ± 0.05 ms (μ ± SEM) and 3.80 ± 0.07 ms, respectively,
Discussion
To our knowledge, this study represents the first exploration of CTS with fMRI. We have demonstrated that CTS leads to more extensive and overlapping representation in contralateral primary somatosensory cortex of median nerve affected digits. CTS provides an excellent opportunity to investigate cortical reorganization induced by clinically relevant aberrant afferentation in humans.
Acknowledgments
This research was supported by grants from the NIH: NCCAM (K01-AT002166-01, P01-AT002048-02, R21-AT001361-01), NCRR (P41RR14075), and the Mental Illness and Neuroscience Discovery (MIND) Institute, as well as the Department of Physical Medicine and Rehabilitation Mini-grant Program, Harvard Medical School (#R02034). We would also like to acknowledge Dr. Judith D. Schaechter, who contributed to data analysis and provided feedback on a draft of the manuscript.
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2020, NeuroImageCitation Excerpt :Importantly, S1 neuroplasticity following acupuncture has been documented for other chronic pain disorders using non-invasive neuroimaging techniques. For instance, carpal tunnel syndrome patients demonstrate altered S1 cortical representations and S1-adjacent white matter microstructure in the hand representation region (Napadow et al., 2006; Dhond et al., 2012; Maeda et al., 2014). Previous neuroimaging studies have shown that other chronic pain disorders also demonstrate altered brain structure in S1, as well as other pain-related brain areas (As-Sanie et al., 2012; Kong et al., 2013; Kregel et al., 2015; Ung et al., 2014).
Mapping the topological organisation of beta oscillations in motor cortex using MEG
2018, NeuroImageCitation Excerpt :Previous studies have not only shown such separation of the cortical representation of body parts in healthy individuals, but have also demonstrated altered representations following learning (Elbert et al., 1995; Godde et al., 2003; Liu and Ioannides, 2004), peripheral injury (Mogilner et al., 1993; Weiss et al., 2000), and stroke/stroke recovery (Feys et al., 2000; Forss et al., 1999; Gallien et al., 2003; Wikström et al., 2000). Alterations in digit representations have also been shown to be measurable in focal hand dystonia (Elbert et al., 1998; McKenzie et al., 2003) and carpal tunnel syndrome (Druschky et al., 2000; Napadow et al., 2006; Tecchio et al., 2002) showing the clinical potential of such measures. However, to date, most MEG studies focus on mapping the evoked response, with comparatively few studies on neural oscillations.