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Background: Magnetic resonance imaging may suggest spinal cord compression and structural lesions in degenerative cervical myelopathy (DCM) but cannot reveal functional impairments in spinal pathways. We aimed to assess the value of contact heat evoked potentials (CHEPs) in addition to MRI and hypothesized that abnormal CHEPs may be evident in DCM independent of MR-lesions and are related to dynamic mechanical cord stress., Methods: Individuals with DCM underwent neurologic examination including segmental sensory (pinprick, light touch) and motor testing. The presence or absence of hyperintense signal on T2-weighted MRI (T2-positive/negative) was assessed. Phase-contrast MRI was used to assess spinal cord motion as an indicator of dynamic mechanical stress. Dermatomal somatosensory evoked potentials and CHEPs were recorded after stimulation of dermatomes C6, C8, and T4 (CHEPs only) to assess spinal cord integrity., Results: Of 138 individuals included in this study (age 56 ± 13 years), 35% (N = 48) presented with T2-positive and 65% (N = 90) presented with T2-negative DCM. Abnormal CHEPs were present in T2-positive DCM (C6:41%; C8:32%; T4:24%) and T2-negative DCM (C6:35%; C8:54%; T4:26%). Multisegmental CHEP abnormalities at C6 and C8 were related to increased spinal cord motion (p = 0.030; ϵ 2  = 0.072), and reduced upper extremity pinprick (p = 0.046; ϵ 2  = 0.063) and motor scores (p = 0.005; ϵ 2  = 0.108)., Conclusions: CHEPs revealed distinct patterns of spinal cord impairment independent of structural T2-positive lesions, which were associated with measures of cord motion. CHEPs thus provide valuable complementary diagnostic insights into spinal cord integrity beyond MRI. This is especially important in incipient myelopathy to inform early diagnosis and timely interventions before the development of definite cord lesions., (© 2024 The Author(s). European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Objective: Degenerative cervical myelopathy (DCM) is a centromedullary spinal cord disorder mainly affecting crossing fibers. While contact heat evoked potentials (CHEPs) are sensitive in detecting DCM by testing spinothalamic integrity, somatosensory evoked potentials (dSSEPs) show unaffected dorsal column conduction. Intra-epidermal electrically evoked potentials (IEEPs) have unknown spinal propagation after noxious stimulation. We investigated (1) the spinothalamic tract propagation and (2) the discriminative power in detecting spinal pathology of IEEPs compared to CHEPs and dSSEPs in DCM., Methods: DCM was diagnosed by neurological examination regarding stenosis (MRI). Stimulation of C6, C8, and T4 dermatomes yielded dSSEPs, CHEPs, and IEEPs. (1) Spinal propagation was assessed through concordant or discordant responses, and (2) discriminative power was determined using receiver operating characteristic curves (ROC)., Results: Twenty-seven patients (8F, 56 ± 12yrs) with DCM were analyzed and compared to age-matched healthy controls. IEEPs were abnormal in 43-54%, CHEPs in 37-69%, and dSSEPs in 4-12%. IEEPs showed high concordance with abnormalities of CHEPs (62-69%). ROC analyses showed good discriminative power of CHEPs and IEEPs contrary to dSSEPs., Conclusions: The concordance of abnormal responses of CHEPs and IEEPs contrary to dSSEPs suggests spinothalamic propagation of IEEPs., Significance: Minimal differences between CHEPs and IEEPs suggest complementary potential by the combined testing of spinothalamic tract integrity., (Copyright © 2024 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)