Reference Data of Cervical Dermatomal Somatosensory Evoked Potentials Using Low Intensity Stimulation and Report of 2 Cases.

, Seo, Min Ho; , Park, Sung Hee; , Ko, Myoung Hwan; , Eun, Jong Pil; , Seo, Jeong Hwan

Original Article

Journal of the Korean Academy of Rehabilitation Medicine 2011;35(2):236-242.

Seo, Min Ho , Park, Sung Hee , Ko, Myoung Hwan , Eun, Jong Pil , Seo, Jeong Hwan

¹Department of Physical Medicine and Rehabilitation, Chonbuk National University Medical School, Research Institute of Clinical Medicine, Chonbuk National University Hospital, Jeonju 561-712, Korea. vivaseo@shonbuk.ac.kr
²Department of Neurosurgery, Chonbuk National University Hospital, Jeonju 561-712, Korea.

Abstract

Objective
To establish reference data for dermatomal somatosensory evoked potentials (DSEP) using a stimulation intensity lower than what is conventionally utilized. Method Fifty subjects (25 older adults＞48 years old; 25 younger adults＜32 years old) without history of neck pain or cervical spine surgery were enrolled. The DSEP study was performed with stimulation intensities of 1.0, 1.5, and 2.5 times sensory threshold (ST) on right arms for C5, C6, C7, and C8 dermatomes.
Results
The mean latencies of DSEP stimulating C5, C6, C7, and C8 dermatomes with 1.5 times ST intensity were 17.6±1.7 ms, 22.2±2.1 ms, 22.8±1.4 ms, and 22.6±1.8 ms, respectively. The mean amplitude (N1P1) of DSEP stimulating C5, C6, C7, and C8 dermatomes with 1.5 times ST intensity were 0.9±0.4 ՌV, 0.9±0.5 ՌV, 1.0±0.6 ՌV, and 1.1±0.8 ՌV, respectively. The C5, C6, C7, and C8 DSEP were evoked in 84%, 98%, 100%, and 96% of cases with 2.5 times ST compared to 64%, 56%, 60%, and 62% with 1.5 times ST, respectively. When one DSEP was not evoked, the DSEP of the opposite side was evoked only in 2 subjects. Conclusion This study provides the reference data of DSEP with lower stimulation intensities than are conventionally utilized. Additionally, two cases of clinical significance were reported.

Key Words: Dermatomal somatosensory evoked potentials, Cervical radiculopathy, Stimulation intensity