• Nansel DD
• Haneline MT
• Wiegand A
• Hurewitz J

• Association of Chiropractic Colleges / congresses

OBJECTIVES: The objective of this study is to investigate optimal sEMG sensor placement for use during CPER evaluation of cervical lateral flexion.

METHODS: This study was reviewed and approved by the Institutional Review Board of the Palmer Center for Chiropractic Research. Bilateral dynamic sEMG readings were performed on the cervical paraspinal regions, first in the mid-cervical region with bipolar sensors affixed at the levels of C6 and T1, then in the cervico-thoracic region, with sensors at the T1 and T3 levels. Placement was bilateral over the posterolateral aspect of the cervical and upper thoracic spine straddling the spinous processes, with a 2 cm distance in between sensors. A reference electrode was placed over the electrically inactive tissue at the T8 spinous process to minimize the potential for a disturbance signal. The skin was cleaned with alcohol and shaved when necessary at the sites of electrode contact prior to placement. Silver-silver chloride self-adhesive surface electrodes were utilized which contain an embedded electro-conductive gel to ensure optimal contact. The inter-electrode distance for placement of bipolar electrodes in this study was set at 2 cm, since we were targeting relatively small muscles and since it has been reported that inter-electrode distance should not exceed one-quarter of the muscle length to obtain an optimal signal. Cervical range-of-motion was evaluated using the Cervical Range-of-Motion (CROM) Measurement System to enhance precise replication of lateral flexion movements from pass to pass. Seated subjects were passively placed in end-range lateral cervical flexion by an examiner who was blinded to any concomitant data collection. The goniometric evaluator used their fingers and palms to clasp the sides of the subject’s head while in a neutral position. In order to avoid anterior flexion and/or rotational head displacements that might influence lateral-flexion measures, the examiner positioned their feet forward or backward so that their elbows rested comfortably and symmetrically at their sides. The examiners paused at maximum end-range for a moment until signaled by the recorder that the left or right end-range measure had been read and recorded. Five left and five right alternating measures of lateral-flexion were obtained from each subject.

RESULTS: Preliminary data points to an advantage for use of the lower electrode placement. The typical sEMG pattern that was observed in this study revealed that there was increased electrical activity on the ipsilateral side of movement that switched corresponding with each pass to the right or left. Upper electrode placement did not depict this shift as accurately as did the lower placement.

DISCUSSION: Preliminary evidence suggests that the lower placement at T1 and T3 of sEMG electrodes is preferred to the mid-cervical placement. However, this premise must be established by means of a larger study. We were interested in studying EMG activity in the deeper mutifidus and rotatores muscles, although background noise associated with crosstalk from the semispinalis capitis, splenius capitis, and/or trapezius muscles was most likely present.

This abstract is reproduced with the permission of the publisher.