EFFICACY OF PRESSURE-BIOFEEDBACK GUIDED DEEP CERVICAL FLEXOR TRAINING ON NECK PAIN AND MUSCLE PERFORMANCE IN VISUAL DISPLAY TERMINAL OPERATORS

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1 Journal of Musculoskeletal Research, Vol. 16, No. 3 (2013) (8 pages) World Scientific Publishing Company DOI: /S EFFICACY OF PRESSURE-BIOFEEDBACK GUIDED DEEP CERVICAL FLEXOR TRAINING ON NECK PAIN AND MUSCLE PERFORMANCE IN VISUAL DISPLAY TERMINAL OPERATORS Md. Nezamuddin, Shahnawaz Anwer,, Sohrab Ahmad khan and Ameed Equebal National Institute for the Orthopedically Handicapped (NIOH) Kolkata, India Padmashree Dr. D. Y. Patil College of Physiotherapy Dr. D. Y. Patil Vidyapeeth, Pimpri, Pune, Maharashtra, India and Rehabilitation Research Chair, Department of Rehabilitation Sciences College of Applied Medical Sciences, King Saud University Riyadh, Saudi Arabia Hamdard University, New Delhi, India anwer shahnawazphysio@rediffmail.com Received 29 July 2012 Accepted 15 July 2013 Published 30 September 2013 ABSTRACT Purpose: This randomized trial study compared the efficacy of pressure-biofeedback guided deep cervical flexor training as an adjunct with conventional exercise on pain and muscle performance in visually displayed terminal operators. Methods: A total of 50 (22 men and 28 women) patients with neck pain participated in the study. Patients were randomly placed into two groups: a biofeedback group (n ¼ 25) and a control group (n ¼ 25). The biofeedback group received pressure-biofeedback guided deep cervical flexor training program for 5 days a week for 6 weeks, whereas the control group received an exercise program only. Results: On intergroup comparisons, the deep cervical flexor Correspondence to: Shahnawaz Anwer, Padmashree Dr. D. Y. Patil College of Physiotherapy, Bhosari, Pune , Maharashtra, India

2 Md. Nezamuddin et al. performance in biofeedback group, at the end of 6th week was significantly higher than those of control group ( p < 0:01). Pain intensity was also significantly reduced in biofeedback group when compared to control group at the end of trial (p < 0:004). Conclusion: The addition of pressure-biofeedback to a 6-week conventional program appeared to increase deep cervical flexor muscle performance, compared to the exercise program alone for people with reduced muscle performance. Keywords: Neck pain; Pressure-biofeedback; Deep cervical flexor; Muscle performance. INTRODUCTION Neck disorders are prevalent nowadays and are sometimes expensive to cure. Such disorders affect approximately 70% of people at some point in their life. 7,19 Improvement of cervical spine muscles performance can effectively reduce chronic neck pain. 16,28 Static posture for long duration have increased incidence of neck and shoulder pain in visual display terminal (VDT) workers. 13 The prolong period of holding a static posture of neck and shoulder region during computer work can result in increased forward neck flexion and increased static muscle tension in this region. 1 Patients with cervical headache have reported less strength and endurance in upper cervical flexors. 22 Previous research on cervical impairment suggests that the weakness of deep cervical flexor (DCF) muscle is found to be a causative or contributory factor in the pathogenesis of head and neck pain. 26 Contemporary research has suggested that the impairment in DCF muscles could result in poor support and potential overload on cervical structures insufficiency in the preprogrammed activation of cervical muscles. 9,10 Szeto et al. reported that people with neck pain would display deficits in the postural endurance of DCF muscles along with impaired activation. 23 This has been confirmed by Falla et al. who found that chronic neck pain patients during computer tasks feel difficulty in maintaining an upright neutral posture. 11 The performance of DCF muscle may influence the varied resting head posture, as this is considered to be an important stabilizer of the head-on-neck posture. 18 Watson and Trott 27 found a positive association between forward head posture (FHP) indicated by lesser isometric endurance of the DCF correlating with lesser cranio-vertebral angles. Thus, to increase the endurance of these postural muscles, DCF training is important, thereby leading to improvement in FHP. Research recommends that correct use of the DCF training before strengthening of the global cervical spine musculature is more effective in the rehabilitation of the cervical spine than just nonspecific strengthening of neck muscles. 5,15 Cranio-cervical flexor training (CCFT) program is found to be a more suitable strategy for isolation activity of DCFs. 14 There is evidence that restoration of DCF function reduces neck pain and cervicogenic headache. 11 Hence, CCF muscle training is recommended clinically for the management of neck pain. 17 But still there is lack of evidence to support the clinical use of pressurebiofeedback training in VDT operators. So the present study was intended to evaluate the effectiveness of pressure-biofeedback guided DCF training as an adjunct with conventional exercise on muscle performance and pain intensity after six weeks in VDT operators. We hypothesized that the pressure-biofeedback guided DCF training as an adjunct with conventional exercise would improve muscle performance and reduce pain intensity after six weeks in VDT operators

3 Pressure-Biofeedback Guided DCF Training in VDT Operators METHODOLOGY Subjects The criteria for inclusion were: age group between years (both male and female), working on VDT for more than 5 h in a day for more than 2 years. Subjects were excluded if they had any history of neck surgery, spinal cord compression, spinal tumor, spinal instability, history of spinal fracture, inflammatory disease of spine, spinal infections, significant neurological deficit, Congenital or acquired postural deformity, doing prescribed exercise for cervical spine. This study has taken ethical clearance from Hamdard University, New Delhi, India. The participants were either computer science students or computer professionals. Students were recruited from Faculty of Management Studies and Information Technology, Jamia Hamdard. The computer professionals were the Employees of PRAGON IT SERVICES Pvt. Ltd., New Delhi. Study Design This was a randomized controlled trial designed to assess the effect of a 6-week pressure-biofeedback guided DCF training on pain and muscle performance in VDT operators. Randomization A total of 50 subjects were selected first according to the inclusion and exclusion criteria. The subjects were randomly allocated to either the pressurebiofeedback group or control group by computergenerated numbers. Outcome Measurement Muscle performance of DCF and pain intensity was used as the outcome measure of this study. Measurements were taken at baseline (before treatment) and at the end of 6th week. Muscle performance of DCF was measured by Cranio-cervical flexion test on pressure-biofeedback device. It is a reliable and valid tool to measure muscle performance of DCF. 12 Pain intensity was measured using VAS scale. This is a reliable and valid instrument for the measurement of both chronic and acute type of pain. 4,8 Intervention Testing procedure by CCFT 5,6,15,17,18,20,23 : The subject was made to lie in supine position. The cervical spine was kept in a neutral position as described by Chiu et al. in their study. The pressure-biofeedback unit (PBU) was inflated to a baseline of 20 mmhg after placing it between the plinth and the posterior aspect of the neck just below the occiput. Subjects were given practice sessions to learn the cranio-cervical flexion test with the PBU. One examiner observed and corrected any substitution movements to ensure performance of a correct test. The examiner corrected the test, if subjects performed an incorrect test during the practice phase. The examiner closely observed the subjects during the CCFT and any recruitment of superficial neck flexor muscle is discouraged by the examiner by verbal feedback. Each subject was reminded to relax the neck musculature and to concentrate on permitting a gentle head nodding movement. The subjects were asked to avoid head lift during CCFT, thereby reducing the recruitment of superficial flexors. Each subject had to perform the neck craniocervical flexion movement at 5 different pressure levels (22, 24, 26, 28 and 30 mmhg) with 10 s hold at each level and 30 s rest between each level. The testing procedure was terminated if subject could not hold 10 s at specific pressure level or if the maximum level of 30 mmhg was achieved. The maximum pressure level achieved (activation score) with 10 s hold was recorded for analysis purpose. However, Grant et al. in their study

4 Md. Nezamuddin et al. created an index to score the holding capacity out of 100. The number of completed 10 s holds (maximum 10) multiplied by the pressure increase (maximum 10 mmhg) gave the score for index. 12 Craniocervical flexion training 6,14 : Training of craniocervical flexors followed the protocol described by Jull et al. Subjects were positioned on a plinth in crook supine lying position. The starting position was standardized by placing the subjects forehead and chin horizontal in an imaginary line that was parallel to the plinth and extended from the tragus of the ear and bisected the neck longitudinally. Appropriate thicknesses of folded towels were placed under the head to maintain the neutral position, if required. The edge of towel was aligned with the base of occiput and the upper cervical region was free. PBU air bag (PBU- Stabilizer TM, Chattanooga Group, INC., Chattanooga, TN) was clipped together in three fold, fastened and placed suboccipitally. The deflated pressure sensor was kept behind the neck just next to the occiput and was inflated up to a baseline pressure of 20 mm Hg after inserting it behind the neck to just fill the space between the back of neck and supporting surface without pushing the neck into a lordosis. This provides feedback and orientation to the patient to perform the exercise. Subjects were instructed in performing craniocervical flexion and practiced head nodding action to progressively target (reach the incremental targets) and hold the 5 pressure levels for 10 s between 22 and 30 mmhg. Minimum requirement for satisfactory performance was 26 mmhg while 28 and 30 mmhg are targets for ideal performance. Duration of CCFT exercise program was 3 sets, 10 repetitions each set, 6 weeks, 5 days a week; 2 min rest was given between the sets. The control group received conventional exercise including stretching of Sternocleidomastoid, upper trapezius, levator scapulae, suboccipitalis, pectorals and strengthening of DCFs, middle & lower trapezius, serratus anterior for 10 repetitions each with 10 s hold. These muscles were chosen based on previously stated observations of weakness and tightness of muscles in the upper crossed syndrome. 14,18 Statistical Analysis Statistical analysis was done using SPSS 15.0 Software (SPSS Inc., Chicago, USA). Independent t-test was used to compare the changes in pain and DCF performance between the two groups at baseline, at the end of 6th week. Paired t-test was used to see those differences within the groups over 6 week periods. A statistical significance level was p < 0:05. RESULTS A total of 65 subjects were assessed for eligibility. Eight subjects did not satisfy the inclusion criteria and seven refused to participate. A total of 50 subjects (22 male 28 female) enrolled in the study, with 25 being randomly allocated to each group (Refer to CONSORT flowchart in Fig. 1). It was a single-blind study (i.e. participants but not the assessors were blinded to the group assignment). An informed consent was obtained from the subjects before participation in the study. The value of age showed statistically insignificant difference between two groups ( p ¼ 0:239). This showed that both groups were homogenous. The baseline reading of CCFT was found to be statistically insignificant ( p ¼ 0:085). The difference in CCFT score between the two groups was found to be statistically significant at the end of the 6th week ( p ¼ 0:010) (see Table 1). During the 6-week treatment period, the mean improvement of CCFT score in the experimental group and control group was found to be 3.36 and 1.84, respectively

5 Pressure-Biofeedback Guided DCF Training in VDT Operators Enrollment Allocation Follow up Analysis Assessed for eligibility (n =65) Randomized (n = 50) Excluded (n = 15) Not me inclusion criteria (n = 8) Refused to p pate (n = 7) Allocated to experimental group (n = 25) Allocated to control group (n = 25) Followed up (n=25) Analyzed (n =25) Followed up (n=25) Analyzed (n = 25) Fig. 1 CONSORT diagram showing the flow of participants through each stage of a randomized trial. The baseline reading of VAS score was statistically insignificant ( p ¼ 0:716). The difference in VAS score between the two groups was also found to be statistically significant at the end of 6th week ( p ¼ 0:004) (see Table 2). During the 6-week treatment period, the mean improvement of VAS score in the experimental group and control group was found to be 2.68 and 2.00, respectively. DISCUSSION The study was designed to determine the efficacy of pressure-biofeedback guided DCF training on muscle performance and pain intensity in VDT operators of age 20 to 35 years wherein the experimental group received DCF training for 6 weeks along with conventional intervention and control group was given conventional intervention only. The dependent variables were muscle performance measured by CCFT and pain intensity measured by VAS. Intergroup comparison showed statistically significant difference in muscle performance and pain intensity at the end of trial. This is concurrent with the study of Grant et al. who reported improved endurance of DCF of a screen-based keyboard operator after a four weeks period of active stabilization training of the DCF and lower scapular muscles. 12 Muscle performance showed statistically significant improvement in pressure-biofeedback Table 1 Intergroup Comparison of Muscle Performance. Experimental Group Mean (SD) n = 25 Control Group Mean (SD) n = 25 Independent t-test 95% Confidence Interval of the Difference t p Lower Upper Baseline (0.91) (1.30) Week (1.22) (1.30) Table 2 Intergroup Comparison of Pain Intensity. Experimental Group Mean (SD) n = 25 Control Group Mean (SD) n = 25 Independent t-test 95% Confidence Interval of the Difference t p Lower Upper Baseline 3.88 (1.09) 4.00 (1.22) Week (0.81) 2.00 (1.04)

6 Md. Nezamuddin et al. 30 Inter group comparison of muscle performance 28 CCFT (mmhg) Baseline Week 6 Experimental Control Fig. 2 Comparison of muscle performance between the groups by Mean (SD). VAS Score Inter group comparison of pain intensity Baseline Week 6 Experimental Control Fig. 3 Comparison of pain Intensity between the groups by Mean (SD). Fig. 4 Pressure-biofeedback Instrument (Stabilizer TM, Chattanooga Group, INC., Chattanooga, TN). Fig. 5 Pressure sensor placement for DCF during Pressurebiofeedback training. group as compared to control group, which may be explained by following mechanism: The improvement in muscle performance leads to restoration of muscle balance, with the achievement of optimal flexibility of tight muscles and improved strength in weak/inhibited muscles. 14 Therefore, stretching of tight muscles and strengthening of weak muscles are required to achieve optimal length and strength of that muscle groups and therefore improve muscle performance. Ballantyne et al. 2 suggested that increased muscle extensibility was attributed to use of increased torque. A visco-elastic change would have been evident if increased muscle length was achieved through a constant force of stretch. The improvement in muscle performance in pressure-biofeedback group can be further explained on the basis of motor learning which requires information from external world as well as proprioception. With biofeedback training we can improve the motor behavior by reinforcing the patient to the goal oriented behavior. Pressurebiofeedback guided DCF training may provide an external feedback to the patient regarding his performance of task. 21 Basmajian has demonstrated that subjects could control the recruitment

7 Pressure-Biofeedback Guided DCF Training in VDT Operators as well as the frequency of discharge of motor units through auditory and visual feedback. 21 Similarly, in this study, we hypothesize that by analyzing the visual cues from the PBU, the experimental group consciously improved both frequency of discharge of the active motor neurons as well as the number of motor units recruited. Similarly, the finding of Waley et al. 26 suggested that the physiological basis underlying increases in muscle strength are associated with the use of feedback and found that muscle strength increases could be due to an increase in the average firing rate, motor unit recruitment and increase synchronization of the active motor unit. The result of this study indicates that the adjunctive therapy of pressure-biofeedback was an effective means for reducing pain. The analysis of difference between two groups, showed statistical significant improvement at the end of 6th week. The biofeedback group had 19% greater reduction in pain intensity than control group at the end of training periods. The findings are consistent with previous study which reported that biofeedback could be a useful alternative for musculoskeletal pain. Spence et al. 24 studied the effect of biofeedback on pain and reported that the biofeedback group significantly decreased pain. Relevance for Clinical Practice The complaints of people working with the VDT are of a wide-ranging nature and so are the treatment approaches. A possible treatment plan outlined can be extracted from this study. Most importantly, this study emphasizes on the importance of the role of pressure-biofeedback and the fact that intervention in this area can be an invaluable tool in the treatment of numerous disorders of the VDT and other musculoskeletal disorders. To our knowledge, this is the first study in which DCF training is used in VDT operators (20 35 years) age group, having reduced muscle performance and pain intensity. More studies are needed in this age group to give this protocol a more grounded base of practice. Electromyography could be used concurrently to provide additional information on muscle activation associated with any observed postural changes. Moreover, future studies could be designed by addressing potential contribution of various factors including musculoskeletal imbalances that could possibly influence muscle performance in this age group. Also, the role of confounding factors such as height, body built, neck length, recreational activities of VDT operators might have influenced the results. CONCLUSION The study concludes that pressure-biofeedback guided DCF training is more effective than conventional treatment on muscle performance in VDT operators and hence it can be included in the rehabilitation of patient suffering from reduced muscle performance of DCF. ACKNOWLEDGMENTS We acknowledge the great help received from the scholars whose articles are cited and included in references of this manuscript. We are also grateful to authors/editors/publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed. References 1. Ariens GAM, Bongers PM et al. Are neck flexion, neck rotation, and sitting at work risk factors for neck pain? Occup Environ Med 58: , Ballantyne F, Fryer G, McLaughlin P. The effect of muscle energy technique on hamstring extensibility: The mechanism of altered flexibility. J Osteopath Med 6(2): 59 63,

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