The potential effects of a biofeedback writing exercise on radial artery blood flow and neck mobility

Abstract

Background: It has been suggested that sustained contraction of the deep neck muscles may reduce axial cervical range of motion (CROM) and radial artery blood flow velocity (vrad.art.mean). No studies have reported both phenomena in relation to acute hand, shoulder or neck trauma.

Procedures: The CROM and vrad.art.mean were measured in 20 police officers prior to and immediately after a 2-hours drive on a motorcycle and immediately after a 1-minute writing exercise using biofeedback. The CROM was measured using separate inclinometers and the vrad.art.mean was measured in both arms just proximal to the wrist using echo-Doppler.

Findings: During the study, one officer had a motorcycle accident resulting in acute symptoms of neck trauma. His vrad.art.mean was acutely reduced by 73% (right arm) and 45% (left arm). Writing with biofeedback increased his vrad.art.mean by 150% (right arm) and 80% (left arm). In the remaining 19 officers, the CROM to the right was significantly increased after the 2-hours driving task (p<0.05; paired subject t-test). Writing with biofeedback increased their CROM in both directions and vrad.art.mean in both arms (p<001).

Conclusions: A 2-hours drive showed modest physical changes in the upper extremities. Biofeedback in writing tasks might relate to the influence of relaxation and diverting attention for neck mobility and arterial blood flow improvement.

Keywords: biofeedback; blood flow; cervical range of motion; neck trauma; radial artery.

Figure 1

The biofeedback pen, consisting of a pressure sensor with a red light at the end of the shaft. When too much hand force is applied during writing, the red light signals the subject to loosen the grip.

Figure 2

The Cervical Range of Motion (CROM) measured prior to driving (initial condition), immediately after the accident and after the 1-minute writing task using a biofeedback pen. The writing task, aimed at lowering upper extremity tension was repeated after a two week recovery period. After the accident, the CROM decreased to both sides. The CROM increased after the 1-minute writing task and even further increased when this task was repeated after a two weeks recovery period.

Figure 3

The average radial artery blood flow velocity (v_rad.art.mean) measured in the left and the right arm. The initial condition showed a higher blood flow in the left arm (used for clutching) compared to the right arm (used for acceleration). After the accident, a significant decrease of blood flow was measured. The blood flow velocity returned to the normal level after the 1-minute writing exercise with a biofeedback pen on the same day. After a two weeks recovery period, baseline blood flow was returned to the normal level and even further increased after 1-minute writing exercise with the biofeedback pen.